From patchwork Mon Mar 6 14:08:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161187 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F10EC61DA4 for ; Mon, 6 Mar 2023 14:13:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229794AbjCFONC (ORCPT ); Mon, 6 Mar 2023 09:13:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230315AbjCFOMg (ORCPT ); Mon, 6 Mar 2023 09:12:36 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE7213347F for ; Mon, 6 Mar 2023 06:09:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678111721; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+xIRykpdRJE+DsCK9N+IP6zxk5kG+sp7fs6Ep7aFl78=; b=VmtHhBI1uwG2zny82HscafySQFY0uOgB1EVe0JKXR2Naobt/jkrer1IcvTRlUFw4qaj8Qm NCjQL252kogerjSN+7Y4WfIuwXLKAOXI4gf1vlIRCXbtyy8bXL6EWYu7EAeJ/g5lUKrZOv Sw+grbgqgz4pT0Drm5vjI1N6OL0t5lk= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-388-rIh6hJ_zPrWPtqFeHy2cTQ-1; Mon, 06 Mar 2023 09:08:27 -0500 X-MC-Unique: rIh6hJ_zPrWPtqFeHy2cTQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0F6603810B07; Mon, 6 Mar 2023 14:08:27 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id B5B3140ED76C; Mon, 6 Mar 2023 14:08:26 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 01/10] livepatch: Create and include UAPI headers Date: Mon, 6 Mar 2023 09:08:15 -0500 Message-Id: <20230306140824.3858543-2-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Define klp prefixes in include/uapi/linux/livepatch.h, and use them for replacing hard-coded values in kernel/livepatch/core.c. Update MAINTAINERS. Note: Add defines to uapi as these are also to be used by a newly introduced klp-convert script. Signed-off-by: Josh Poimboeuf Signed-off-by: Joao Moreira Signed-off-by: Joe Lawrence Reviewed-by: Marcos Paulo de Souza --- MAINTAINERS | 1 + include/linux/livepatch.h | 1 + include/uapi/linux/livepatch.h | 15 +++++++++++++++ kernel/livepatch/core.c | 4 ++-- 4 files changed, 19 insertions(+), 2 deletions(-) create mode 100644 include/uapi/linux/livepatch.h diff --git a/MAINTAINERS b/MAINTAINERS index 135d93368d36..5bdf333fb1f3 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12069,6 +12069,7 @@ F: Documentation/ABI/testing/sysfs-kernel-livepatch F: Documentation/livepatch/ F: arch/powerpc/include/asm/livepatch.h F: include/linux/livepatch.h +F: include/uapi/linux/livepatch.h F: kernel/livepatch/ F: kernel/module/livepatch.c F: lib/livepatch/ diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h index 293e29960c6e..46da4c0df6c1 100644 --- a/include/linux/livepatch.h +++ b/include/linux/livepatch.h @@ -13,6 +13,7 @@ #include #include #include +#include #if IS_ENABLED(CONFIG_LIVEPATCH) diff --git a/include/uapi/linux/livepatch.h b/include/uapi/linux/livepatch.h new file mode 100644 index 000000000000..e19430918a07 --- /dev/null +++ b/include/uapi/linux/livepatch.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ + +/* + * livepatch.h - Kernel Live Patching Core + * + * Copyright (C) 2016 Josh Poimboeuf + */ + +#ifndef _UAPI_LIVEPATCH_H +#define _UAPI_LIVEPATCH_H + +#define KLP_RELA_PREFIX ".klp.rela." +#define KLP_SYM_PREFIX ".klp.sym." + +#endif /* _UAPI_LIVEPATCH_H */ diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 201f0c0482fb..c565d33db582 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -234,7 +234,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab, /* Format: .klp.sym.sym_objname.sym_name,sympos */ cnt = sscanf(strtab + sym->st_name, - ".klp.sym.%55[^.].%511[^,],%lu", + KLP_SYM_PREFIX "%55[^.].%511[^,],%lu", sym_objname, sym_name, &sympos); if (cnt != 3) { pr_err("symbol %s has an incorrectly formatted name\n", @@ -305,7 +305,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs, * See comment in klp_resolve_symbols() for an explanation * of the selected field width value. */ - cnt = sscanf(shstrtab + sec->sh_name, ".klp.rela.%55[^.]", + cnt = sscanf(shstrtab + sec->sh_name, KLP_RELA_PREFIX "%55[^.]", sec_objname); if (cnt != 1) { pr_err("section %s has an incorrectly formatted name\n", From patchwork Mon Mar 6 14:08:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161248 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8ABCFC6FD1D for ; Mon, 6 Mar 2023 14:16:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229539AbjCFOQG (ORCPT ); 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Mon, 06 Mar 2023 09:08:28 -0500 X-MC-Unique: oGB7oEgdMLyrk5Qx8Dq7_g-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 86B5D800B23; Mon, 6 Mar 2023 14:08:27 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1F6C2408573E; Mon, 6 Mar 2023 14:08:27 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 02/10] livepatch: Add klp-convert tool Date: Mon, 6 Mar 2023 09:08:16 -0500 Message-Id: <20230306140824.3858543-3-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Livepatches may use symbols which are not contained in its own scope, and, because of that, may end up compiled with relocations that will only be resolved during module load. Yet, when the referenced symbols are not exported, solving this relocation requires information on the object that holds the symbol (either vmlinux or modules) and its position inside the object, as an object may contain multiple symbols with the same name. Providing such information must be done accordingly to what is specified in Documentation/livepatch/module-elf-format.txt. Currently, there is no trivial way to embed the required information as requested in the final livepatch elf object. klp-convert solves this problem in two different forms: (i) by relying on symbols.klp, which is built during kernel compilation, to automatically infer the relocation targeted symbol, and, when such inference is not possible (ii) by using annotations in the elf object to convert the relocation accordingly to the specification, enabling it to be handled by the livepatch loader. Given the above, create scripts/livepatch to hold tools developed for livepatches and add source files for klp-convert there. The core file of klp-convert is scripts/livepatch/klp-convert.c, which implements the heuristics used to solve the relocations and the conversion of unresolved symbols into the expected format, as defined in [1]. klp-convert receives as arguments the symbols.klp file, an input livepatch module to be converted and the output name for the converted livepatch. When it starts running, klp-convert parses symbols.klp and builds two internal lists of symbols, one containing the exported and another containing the non-exported symbols. Then, by parsing the rela sections in the elf object, klp-convert identifies which symbols must be converted, which are those unresolved and that do not have a corresponding exported symbol, and attempts to convert them accordingly to the specification. By using symbols.klp, klp-convert identifies which symbols have names that only appear in a single kernel object, thus being capable of resolving these cases without the intervention of the developer. When various homonymous symbols exist through kernel objects, it is not possible to infer the right one, thus klp-convert falls back into using developer annotations. If these were not provided, then the tool will print a list with all acceptable targets for the symbol being processed. Annotations in the context of klp-convert are accessible as struct klp_module_reloc entries in sections named .klp.module_relocs.. These entries are pairs of symbol references and positions which are to be resolved against definitions in . Define the structure klp_module_reloc in include/linux/uapi/livepatch.h allowing developers to annotate the livepatch source code with it. klp-convert relies on libelf and on a list implementation. Add files scripts/livepatch/elf.c and scripts/livepatch/elf.h, which are a libelf interfacing layer and scripts/livepatch/list.h, which is a list implementation. Update Makefiles to correctly support the compilation of the new tool, update MAINTAINERS file and add a .gitignore file. [1] - Documentation/livepatch/module-elf-format.txt Signed-off-by: Josh Poimboeuf Signed-off-by: Konstantin Khlebnikov Signed-off-by: Joao Moreira Signed-off-by: Joe Lawrence Reviewed-by: Marcos Paulo de Souza --- MAINTAINERS | 1 + include/linux/livepatch.h | 12 + include/uapi/linux/livepatch.h | 10 + scripts/Makefile | 1 + scripts/livepatch/.gitignore | 1 + scripts/livepatch/Makefile | 5 + scripts/livepatch/elf.c | 817 +++++++++++++++++++++++++++++ scripts/livepatch/elf.h | 74 +++ scripts/livepatch/klp-convert.c | 893 ++++++++++++++++++++++++++++++++ scripts/livepatch/klp-convert.h | 47 ++ scripts/livepatch/list.h | 391 ++++++++++++++ 11 files changed, 2252 insertions(+) create mode 100644 scripts/livepatch/.gitignore create mode 100644 scripts/livepatch/Makefile create mode 100644 scripts/livepatch/elf.c create mode 100644 scripts/livepatch/elf.h create mode 100644 scripts/livepatch/klp-convert.c create mode 100644 scripts/livepatch/klp-convert.h create mode 100644 scripts/livepatch/list.h diff --git a/MAINTAINERS b/MAINTAINERS index 5bdf333fb1f3..c68f4c1ac1ef 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12074,6 +12074,7 @@ F: kernel/livepatch/ F: kernel/module/livepatch.c F: lib/livepatch/ F: samples/livepatch/ +F: scripts/livepatch/ F: tools/testing/selftests/livepatch/ LLC (802.2) diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h index 46da4c0df6c1..cd5809010bca 100644 --- a/include/linux/livepatch.h +++ b/include/linux/livepatch.h @@ -235,6 +235,18 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs, unsigned int symindex, unsigned int secindex, const char *objname); +/* Used to annotate symbol relocations in livepatches */ +#define KLP_MODULE_RELOC(obj) \ + struct klp_module_reloc \ + __section(".klp.module_relocs." #obj) \ + __aligned(4) + +#define KLP_SYMPOS(symbol, pos) \ + { \ + .sym = &symbol, \ + .sympos = pos, \ + } + #else /* !CONFIG_LIVEPATCH */ static inline int klp_module_coming(struct module *mod) { return 0; } diff --git a/include/uapi/linux/livepatch.h b/include/uapi/linux/livepatch.h index e19430918a07..2ee98e985c2a 100644 --- a/include/uapi/linux/livepatch.h +++ b/include/uapi/linux/livepatch.h @@ -9,7 +9,17 @@ #ifndef _UAPI_LIVEPATCH_H #define _UAPI_LIVEPATCH_H +#include + #define KLP_RELA_PREFIX ".klp.rela." #define KLP_SYM_PREFIX ".klp.sym." +struct klp_module_reloc { + union { + void *sym; + __u64 sym64; /* Force 64-bit width */ + }; + __u32 sympos; +} __packed; + #endif /* _UAPI_LIVEPATCH_H */ diff --git a/scripts/Makefile b/scripts/Makefile index 1575af84d557..46a249ff6815 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -41,6 +41,7 @@ targets += module.lds subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins subdir-$(CONFIG_MODVERSIONS) += genksyms subdir-$(CONFIG_SECURITY_SELINUX) += selinux +subdir-$(CONFIG_LIVEPATCH) += livepatch # Let clean descend into subdirs subdir- += basic dtc gdb kconfig mod diff --git a/scripts/livepatch/.gitignore b/scripts/livepatch/.gitignore new file mode 100644 index 000000000000..dc22fe4b6a5b --- /dev/null +++ b/scripts/livepatch/.gitignore @@ -0,0 +1 @@ +klp-convert diff --git a/scripts/livepatch/Makefile b/scripts/livepatch/Makefile new file mode 100644 index 000000000000..71dce0f3e893 --- /dev/null +++ b/scripts/livepatch/Makefile @@ -0,0 +1,5 @@ +hostprogs-always-y := klp-convert + +klp-convert-objs := klp-convert.o elf.o + +HOSTLDLIBS_klp-convert := -lelf diff --git a/scripts/livepatch/elf.c b/scripts/livepatch/elf.c new file mode 100644 index 000000000000..c649268a4a55 --- /dev/null +++ b/scripts/livepatch/elf.c @@ -0,0 +1,817 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * elf.c - ELF access library + * + * Adapted from kpatch (https://github.com/dynup/kpatch): + * Copyright (C) 2013-2016 Josh Poimboeuf + * Copyright (C) 2014 Seth Jennings + */ + +#include +#include +#include +#include +#include +#include +#include + +#include "elf.h" + +#define WARN(format, ...) \ + fprintf(stderr, "%s: " format "\n", elf->name, ##__VA_ARGS__) + +/* + * Fallback for systems without this "read, mmaping if possible" cmd. + */ +#ifndef ELF_C_READ_MMAP +#define ELF_C_READ_MMAP ELF_C_READ +#endif + +bool is_rela_section(struct section *sec) +{ + return (sec->sh.sh_type == SHT_RELA); +} + +struct section *find_section_by_name(struct elf *elf, const char *name) +{ + struct section *sec; + + list_for_each_entry(sec, &elf->sections, list) + if (!strcmp(sec->name, name)) + return sec; + + return NULL; +} + +static struct section *find_section_by_index(struct elf *elf, + int idx) +{ + struct section *sec; + + list_for_each_entry(sec, &elf->sections, list) + if (sec->idx == idx) + return sec; + + return NULL; +} + +static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx) +{ + struct symbol *sym; + + list_for_each_entry(sym, &elf->symbols, list) + if (sym->idx == idx) + return sym; + + return NULL; +} + +static int read_sections(struct elf *elf) +{ + Elf_Scn *s = NULL; + struct section *sec; + size_t shstrndx, sections_nr; + size_t i; + + if (elf_getshdrnum(elf->elf, §ions_nr)) { + perror("elf_getshdrnum"); + return -1; + } + + if (elf_getshdrstrndx(elf->elf, &shstrndx)) { + perror("elf_getshdrstrndx"); + return -1; + } + + for (i = 0; i < sections_nr; i++) { + sec = calloc(1, sizeof(*sec)); + if (!sec) { + perror("calloc"); + return -1; + } + + INIT_LIST_HEAD(&sec->relas); + + list_add_tail(&sec->list, &elf->sections); + + s = elf_getscn(elf->elf, i); + if (!s) { + perror("elf_getscn"); + return -1; + } + + sec->idx = elf_ndxscn(s); + + if (!gelf_getshdr(s, &sec->sh)) { + perror("gelf_getshdr"); + return -1; + } + + sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name); + if (!sec->name) { + perror("elf_strptr"); + return -1; + } + + sec->elf_data = elf_getdata(s, NULL); + if (!sec->elf_data) { + perror("elf_getdata"); + return -1; + } + + if (sec->elf_data->d_off != 0 || + sec->elf_data->d_size != sec->sh.sh_size) { + WARN("unexpected data attributes for %s", sec->name); + return -1; + } + + sec->data = sec->elf_data->d_buf; + sec->size = sec->elf_data->d_size; + } + + /* sanity check, one more call to elf_nextscn() should return NULL */ + if (elf_nextscn(elf->elf, s)) { + WARN("section entry mismatch"); + return -1; + } + + return 0; +} + +static int read_symbols(struct elf *elf) +{ + struct section *symtab; + struct symbol *sym; + int symbols_nr, i; + + symtab = find_section_by_name(elf, ".symtab"); + if (!symtab) { + WARN("missing symbol table"); + return -1; + } + + symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize; + + for (i = 0; i < symbols_nr; i++) { + sym = calloc(1, sizeof(*sym)); + if (!sym) { + perror("calloc"); + return -1; + } + + sym->idx = i; + + if (!gelf_getsym(symtab->elf_data, i, &sym->sym)) { + perror("gelf_getsym"); + goto err; + } + + sym->name = elf_strptr(elf->elf, symtab->sh.sh_link, + sym->sym.st_name); + if (!sym->name) { + perror("elf_strptr"); + goto err; + } + + sym->type = GELF_ST_TYPE(sym->sym.st_info); + sym->bind = GELF_ST_BIND(sym->sym.st_info); + + if (sym->sym.st_shndx > SHN_UNDEF && + sym->sym.st_shndx < SHN_LORESERVE) { + sym->sec = find_section_by_index(elf, + sym->sym.st_shndx); + if (!sym->sec) { + WARN("couldn't find section for symbol %s", + sym->name); + goto err; + } + if (sym->type == STT_SECTION) { + sym->name = sym->sec->name; + sym->sec->sym = sym; + } + } + + sym->offset = sym->sym.st_value; + sym->size = sym->sym.st_size; + + list_add_tail(&sym->list, &elf->symbols); + } + + return 0; + +err: + free(sym); + return -1; +} + +static int read_relas(struct elf *elf) +{ + struct section *sec; + struct rela *rela; + int relas_nr, i; + unsigned int symndx; + + list_for_each_entry(sec, &elf->sections, list) { + if (sec->sh.sh_type != SHT_RELA) + continue; + + sec->base = find_section_by_name(elf, sec->name + 5); + if (!sec->base) { + WARN("can't find base section for rela section %s", + sec->name); + return -1; + } + + sec->base->rela = sec; + + relas_nr = sec->sh.sh_size / sec->sh.sh_entsize; + for (i = 0; i < relas_nr; i++) { + rela = calloc(1, sizeof(*rela)); + if (!rela) { + perror("calloc"); + return -1; + } + + if (!gelf_getrela(sec->elf_data, i, &rela->rela)) { + perror("gelf_getrela"); + return -1; + } + + rela->type = GELF_R_TYPE(rela->rela.r_info); + rela->addend = rela->rela.r_addend; + rela->offset = rela->rela.r_offset; + symndx = GELF_R_SYM(rela->rela.r_info); + rela->sym = find_symbol_by_index(elf, symndx); + if (!rela->sym) { + WARN("can't find rela entry symbol %u for %s", + symndx, sec->name); + return -1; + } + + list_add_tail(&rela->list, &sec->relas); + } + } + + return 0; +} + +struct section *create_rela_section(struct elf *elf, const char *name, + struct section *base) +{ + struct section *sec; + + sec = calloc(1, sizeof(*sec)); + if (!sec) { + WARN("calloc failed"); + return NULL; + } + INIT_LIST_HEAD(&sec->relas); + + sec->base = base; + sec->name = strdup(name); + if (!sec->name) { + WARN("strdup failed"); + return NULL; + } + sec->sh.sh_name = ~0; + sec->sh.sh_type = SHT_RELA; + + if (elf->elf_class == ELFCLASS32) { + sec->sh.sh_entsize = sizeof(Elf32_Rela); + sec->sh.sh_addralign = 4; + } else { + sec->sh.sh_entsize = sizeof(Elf64_Rela); + sec->sh.sh_addralign = 8; + } + sec->sh.sh_flags = SHF_ALLOC; + + sec->elf_data = calloc(1, sizeof(*sec->elf_data)); + if (!sec->elf_data) { + WARN("calloc failed"); + return NULL; + } + sec->elf_data->d_type = ELF_T_RELA; + + list_add_tail(&sec->list, &elf->sections); + + return sec; +} + +static int update_shstrtab(struct elf *elf) +{ + struct section *shstrtab, *sec; + size_t orig_size, new_size = 0, offset, len; + char *buf; + + shstrtab = find_section_by_name(elf, ".shstrtab"); + if (!shstrtab) { + WARN("can't find .shstrtab"); + return -1; + } + + orig_size = new_size = shstrtab->size; + + list_for_each_entry(sec, &elf->sections, list) { + if (sec->sh.sh_name != ~0U) + continue; + new_size += strlen(sec->name) + 1; + } + + if (new_size == orig_size) + return 0; + + buf = malloc(new_size); + if (!buf) { + WARN("malloc failed"); + return -1; + } + memcpy(buf, (void *)shstrtab->data, orig_size); + + offset = orig_size; + list_for_each_entry(sec, &elf->sections, list) { + if (sec->sh.sh_name != ~0U) + continue; + sec->sh.sh_name = offset; + len = strlen(sec->name) + 1; + memcpy(buf + offset, sec->name, len); + offset += len; + } + + shstrtab->elf_data->d_buf = shstrtab->data = buf; + shstrtab->elf_data->d_size = shstrtab->size = new_size; + shstrtab->sh.sh_size = new_size; + + return 1; +} + +static void free_shstrtab(struct elf *elf) +{ + struct section *shstrtab; + + shstrtab = find_section_by_name(elf, ".shstrtab"); + if (!shstrtab) + return; + + free(shstrtab->elf_data->d_buf); +} + +static int update_strtab(struct elf *elf) +{ + struct section *strtab; + struct symbol *sym; + size_t orig_size, new_size = 0, offset, len; + char *buf; + + strtab = find_section_by_name(elf, ".strtab"); + if (!strtab) { + WARN("can't find .strtab"); + return -1; + } + + orig_size = new_size = strtab->size; + + list_for_each_entry(sym, &elf->symbols, list) { + if (sym->sym.st_name != ~0U) + continue; + new_size += strlen(sym->name) + 1; + } + + if (new_size == orig_size) + return 0; + + buf = malloc(new_size); + if (!buf) { + WARN("malloc failed"); + return -1; + } + memcpy(buf, (void *)strtab->data, orig_size); + + offset = orig_size; + list_for_each_entry(sym, &elf->symbols, list) { + if (sym->sym.st_name != ~0U) + continue; + sym->sym.st_name = offset; + len = strlen(sym->name) + 1; + memcpy(buf + offset, sym->name, len); + offset += len; + } + + strtab->elf_data->d_buf = strtab->data = buf; + strtab->elf_data->d_size = strtab->size = new_size; + strtab->sh.sh_size = new_size; + + return 1; +} + +static void free_strtab(struct elf *elf) +{ + struct section *strtab; + + strtab = find_section_by_name(elf, ".strtab"); + if (!strtab) + return; + + if (strtab->elf_data) + free(strtab->elf_data->d_buf); +} + +static int update_symtab(struct elf *elf) +{ + struct section *symtab, *sec; + struct symbol *sym; + char *buf; + size_t size; + int offset = 0, nr_locals = 0, idx, nr_syms; + + idx = 0; + list_for_each_entry(sec, &elf->sections, list) + sec->idx = idx++; + + idx = 0; + list_for_each_entry(sym, &elf->symbols, list) { + sym->idx = idx++; + if (sym->sec) + sym->sym.st_shndx = sym->sec->idx; + } + nr_syms = idx; + + symtab = find_section_by_name(elf, ".symtab"); + if (!symtab) { + WARN("can't find symtab"); + return -1; + } + + symtab->sh.sh_link = find_section_by_name(elf, ".strtab")->idx; + + /* create new symtab buffer */ + if (elf->elf_class == ELFCLASS32) + size = nr_syms * sizeof(Elf32_Sym); + else + size = nr_syms * sizeof(Elf64_Sym); + buf = calloc(1, size); + if (!buf) { + WARN("calloc failed"); + return -1; + } + + offset = 0; + list_for_each_entry(sym, &elf->symbols, list) { + + if (elf->elf_class == ELFCLASS32) { + /* Manually convert to 32-bit Elf32_Sym */ + Elf32_Sym sym32; + + sym32.st_name = sym->sym.st_name; + sym32.st_info = sym->sym.st_info; + sym32.st_other = sym->sym.st_other; + sym32.st_shndx = sym->sym.st_shndx; + sym32.st_value = sym->sym.st_value; + sym32.st_size = sym->sym.st_size; + memcpy(buf + offset, &sym32, sizeof(Elf32_Sym)); + } else { + /* Existing 64-bit GElf_Syms are fine */ + memcpy(buf + offset, &sym->sym, sizeof(Elf64_Sym)); + } + + offset += symtab->sh.sh_entsize; + + if (sym->bind == STB_LOCAL) + nr_locals++; + } + + symtab->elf_data->d_buf = symtab->data = buf; + symtab->elf_data->d_size = symtab->size = size; + symtab->sh.sh_size = size; + + /* update symtab section header */ + symtab->sh.sh_info = nr_locals; + + return 1; +} + +static void free_symtab(struct elf *elf) +{ + struct section *symtab; + + symtab = find_section_by_name(elf, ".symtab"); + if (!symtab) + return; + + free(symtab->elf_data->d_buf); +} + +static int update_relas(struct elf *elf) +{ + struct section *sec, *symtab; + struct rela *rela; + int nr_relas, idx, size; + void *relas; + + symtab = find_section_by_name(elf, ".symtab"); + + list_for_each_entry(sec, &elf->sections, list) { + if (!is_rela_section(sec)) + continue; + + sec->sh.sh_link = symtab->idx; + if (sec->base) + sec->sh.sh_info = sec->base->idx; + + nr_relas = 0; + list_for_each_entry(rela, &sec->relas, list) + nr_relas++; + + if (elf->elf_class == ELFCLASS32) + size = nr_relas * sizeof(Elf32_Rela); + else + size = nr_relas * sizeof(Elf64_Rela); + + relas = malloc(size); + if (!relas) { + WARN("malloc failed"); + return -1; + } + + sec->elf_data->d_buf = sec->data = relas; + sec->elf_data->d_size = sec->size = size; + sec->sh.sh_size = size; + + idx = 0; + list_for_each_entry(rela, &sec->relas, list) { + if (elf->elf_class == ELFCLASS32) { + Elf32_Rela *relas32 = relas; + + relas32[idx].r_offset = rela->offset; + relas32[idx].r_addend = rela->addend; + relas32[idx].r_info = ELF32_R_INFO(rela->sym->idx, + rela->type); + } else { + Elf64_Rela *relas64 = relas; + + relas64[idx].r_offset = rela->offset; + relas64[idx].r_addend = rela->addend; + relas64[idx].r_info = ELF64_R_INFO(rela->sym->idx, + rela->type); + } + idx++; + } + } + + return 1; +} + +static void update_groups(struct elf *elf) +{ + struct section *sec, *symtab; + + symtab = find_section_by_name(elf, ".symtab"); + + list_for_each_entry(sec, &elf->sections, list) { + if (sec->sh.sh_type == SHT_GROUP) + sec->sh.sh_link = symtab->idx; + } +} + +static void free_relas(struct elf *elf) +{ + struct section *sec, *symtab; + + symtab = find_section_by_name(elf, ".symtab"); + if (!symtab) + return; + + list_for_each_entry(sec, &elf->sections, list) { + if (!is_rela_section(sec)) + continue; + + free(sec->elf_data->d_buf); + } +} + +static int write_file(struct elf *elf, const char *file) +{ + int fd; + Elf *e; + GElf_Ehdr eh, ehout; + Elf_Scn *scn; + Elf_Data *data; + GElf_Shdr sh; + struct section *sec; + + fd = creat(file, 0664); + if (fd == -1) { + WARN("couldn't create %s", file); + return -1; + } + + e = elf_begin(fd, ELF_C_WRITE, NULL); + if (!e) { + WARN("elf_begin failed"); + return -1; + } + + if (!gelf_newehdr(e, gelf_getclass(elf->elf))) { + WARN("gelf_newehdr failed"); + return -1; + } + + if (!gelf_getehdr(e, &ehout)) { + WARN("gelf_getehdr failed"); + return -1; + } + + if (!gelf_getehdr(elf->elf, &eh)) { + WARN("gelf_getehdr failed"); + return -1; + } + + memset(&ehout, 0, sizeof(ehout)); + ehout.e_ident[EI_DATA] = eh.e_ident[EI_DATA]; + ehout.e_machine = eh.e_machine; + ehout.e_flags = eh.e_flags; + ehout.e_type = eh.e_type; + ehout.e_version = EV_CURRENT; + ehout.e_shstrndx = find_section_by_name(elf, ".shstrtab")->idx; + + list_for_each_entry(sec, &elf->sections, list) { + if (!sec->idx) + continue; + scn = elf_newscn(e); + if (!scn) { + WARN("elf_newscn failed"); + return -1; + } + + data = elf_newdata(scn); + if (!data) { + WARN("elf_newdata failed"); + return -1; + } + + if (!elf_flagdata(data, ELF_C_SET, ELF_F_DIRTY)) { + WARN("elf_flagdata failed"); + return -1; + } + + data->d_type = sec->elf_data->d_type; + data->d_buf = sec->elf_data->d_buf; + data->d_size = sec->elf_data->d_size; + + if (!gelf_getshdr(scn, &sh)) { + WARN("gelf_getshdr failed"); + return -1; + } + + sh = sec->sh; + + if (!gelf_update_shdr(scn, &sh)) { + WARN("gelf_update_shdr failed"); + return -1; + } + } + + if (!gelf_update_ehdr(e, &ehout)) { + WARN("gelf_update_ehdr failed"); + return -1; + } + + if (elf_update(e, ELF_C_WRITE) < 0) { + fprintf(stderr, "%s\n", elf_errmsg(-1)); + WARN("elf_update failed"); + return -1; + } + + elf_end(e); + + return 0; +} + +int elf_write_file(struct elf *elf, const char *file) +{ + int ret_shstrtab = 0; + int ret_strtab = 0; + int ret_symtab = 0; + int ret_relas = 0; + int ret; + + ret_shstrtab = update_shstrtab(elf); + if (ret_shstrtab < 0) { + ret = ret_shstrtab; + goto out; + } + + ret_strtab = update_strtab(elf); + if (ret_strtab < 0) { + ret = ret_strtab; + goto out; + } + + ret_symtab = update_symtab(elf); + if (ret_symtab < 0) { + ret = ret_symtab; + goto out; + } + + ret_relas = update_relas(elf); + if (ret_relas < 0) { + ret = ret_relas; + goto out; + } + + update_groups(elf); + + ret = write_file(elf, file); + if (ret) + return ret; + +out: + if (ret_relas > 0) + free_relas(elf); + if (ret_symtab > 0) + free_symtab(elf); + if (ret_strtab > 0) + free_strtab(elf); + if (ret_shstrtab > 0) + free_shstrtab(elf); + + return ret; +} + +struct elf *elf_open(const char *name) +{ + struct elf *elf; + + elf_version(EV_CURRENT); + + elf = calloc(1, sizeof(*elf)); + if (!elf) { + perror("calloc"); + return NULL; + } + + INIT_LIST_HEAD(&elf->sections); + INIT_LIST_HEAD(&elf->symbols); + + elf->fd = open(name, O_RDONLY); + if (elf->fd == -1) { + perror("open"); + goto err; + } + + elf->elf = elf_begin(elf->fd, ELF_C_READ_MMAP, NULL); + if (!elf->elf) { + perror("elf_begin"); + goto err; + } + + if (!gelf_getehdr(elf->elf, &elf->ehdr)) { + perror("gelf_getehdr"); + goto err; + } + + elf->elf_class = gelf_getclass(elf->elf); + if ((elf->elf_class != ELFCLASS32) && (elf->elf_class != ELFCLASS64)) { + WARN("invalid elf class"); + goto err; + } + + if (read_sections(elf)) + goto err; + + if (read_symbols(elf)) + goto err; + + if (read_relas(elf)) + goto err; + + return elf; + +err: + elf_close(elf); + return NULL; +} + +void elf_close(struct elf *elf) +{ + struct section *sec, *tmpsec; + struct symbol *sym, *tmpsym; + struct rela *rela, *tmprela; + + list_for_each_entry_safe(sym, tmpsym, &elf->symbols, list) { + list_del(&sym->list); + free(sym); + } + list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) { + list_for_each_entry_safe(rela, tmprela, &sec->relas, list) { + list_del(&rela->list); + free(rela); + } + list_del(&sec->list); + free(sec); + } + if (elf->fd > 0) + close(elf->fd); + if (elf->elf) + elf_end(elf->elf); + free(elf); +} diff --git a/scripts/livepatch/elf.h b/scripts/livepatch/elf.h new file mode 100644 index 000000000000..a5969ae6a0be --- /dev/null +++ b/scripts/livepatch/elf.h @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2016 Josh Poimboeuf + */ + +#ifndef _KLP_POST_ELF_H +#define _KLP_POST_ELF_H + +#include +#include +#include +#include "list.h" + +#ifdef LIBELF_USE_DEPRECATED +# define elf_getshdrnum elf_getshnum +# define elf_getshdrstrndx elf_getshstrndx +#endif + +struct section { + struct list_head list; + GElf_Shdr sh; + struct section *base, *rela; + struct list_head relas; + struct symbol *sym; + Elf_Data *elf_data; + char *name; + int idx; + void *data; + unsigned int size; +}; + +struct symbol { + struct list_head list; + GElf_Sym sym; + struct section *sec; + char *name; + unsigned int idx; + unsigned char bind, type; + unsigned long offset; + unsigned int size; +}; + +struct rela { + struct list_head list; + GElf_Rela rela; + struct symbol *sym; + struct section *klp_rela_sec; + unsigned int type; + unsigned long offset; + int addend; +}; + +struct elf { + Elf *elf; + GElf_Ehdr ehdr; + int fd; + char *name; + int elf_class; + struct list_head sections; + struct list_head symbols; +}; + + +struct elf *elf_open(const char *name); +bool is_rela_section(struct section *sec); +struct section *find_section_by_name(struct elf *elf, const char *name); +struct section *create_rela_section(struct elf *elf, const char *name, + struct section *base); + +void elf_close(struct elf *elf); +int elf_write_file(struct elf *elf, const char *file); + + +#endif /* _KLP_POST_ELF_H */ diff --git a/scripts/livepatch/klp-convert.c b/scripts/livepatch/klp-convert.c new file mode 100644 index 000000000000..f5d126b96922 --- /dev/null +++ b/scripts/livepatch/klp-convert.c @@ -0,0 +1,893 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2016 Josh Poimboeuf + * Copyright (C) 2017 Joao Moreira + */ + +#include +#include +#include +#include "elf.h" +#include "list.h" +#include "klp-convert.h" + +/* + * Symbols parsed from symbols.klp are kept in two lists: + * - symbols: keeps non-exported symbols + * - exp_symbols: keeps exported symbols (__ksymtab_prefixed) + */ +static LIST_HEAD(symbols); +static LIST_HEAD(exp_symbols); + +/* In-livepatch user-provided symbol positions are kept in list usr_symbols */ +static LIST_HEAD(usr_symbols); + +/* Converted symbols and their struct symbol -> struct sympos association */ +static LIST_HEAD(converted_symbols); + +struct converted_sym { + struct list_head list; + struct symbol *symbol; + struct sympos sympos; +}; + +#define safe_snprintf(var, size, format, args...) \ + ({ \ + size_t __size = size; \ + int __ret; \ + \ + __ret = snprintf(var, size, format, ##args); \ + __ret < 0 || (size_t)__ret >= __size; \ + }) + +static void free_syms_lists(void) +{ + struct symbol_entry *entry, *aux; + struct sympos *sp, *sp_aux; + + list_for_each_entry_safe(entry, aux, &symbols, list) { + free(entry->object_name); + free(entry->symbol_name); + list_del(&entry->list); + free(entry); + } + + list_for_each_entry_safe(entry, aux, &exp_symbols, list) { + free(entry->object_name); + free(entry->symbol_name); + list_del(&entry->list); + free(entry); + } + + list_for_each_entry_safe(sp, sp_aux, &usr_symbols, list) { + free(sp->object_name); + free(sp->symbol_name); + list_del(&sp->list); + free(sp); + } +} + +/* Parses file and fill symbols and exp_symbols list */ +static bool load_syms_lists(const char *symbols_list) +{ + FILE *fsyms; + size_t len = 0; + ssize_t n; + char *obj = NULL, *sym = NULL; + bool ret = false; + + fsyms = fopen(symbols_list, "r"); + if (!fsyms) { + WARN("Unable to open Symbol list: %s", symbols_list); + return false; + } + + /* read file format version */ + n = getline(&sym, &len, fsyms); + if (n <= 0) { + WARN("Unable to read Symbol list: %s", symbols_list); + goto done; + } + + if (strncmp(sym, "klp-convert-symbol-data.0.1", 27) != 0) { + WARN("Symbol list is in unknown format."); + goto done; + } + + len = 0; + free(sym); + sym = NULL; + + /* read file */ + n = getline(&sym, &len, fsyms); + while (n > 0) { + if (sym[n-1] == '\n') + sym[n-1] = '\0'; + + /* Objects in symbols.klp are flagged with '*' */ + if (sym[0] == '*') { + free(obj); + obj = strdup(sym+1); + if (!obj) { + WARN("Unable to allocate object name\n"); + goto done; + } + free(sym); + } else { + struct symbol_entry *entry; + + if (!obj) { + WARN("File format error\n"); + goto done; + } + + entry = calloc(1, sizeof(struct symbol_entry)); + if (!entry) { + WARN("Unable to allocate Symbol entry\n"); + goto done; + } + + entry->object_name = strdup(obj); + if (!entry->object_name) { + WARN("Unable to allocate entry object name\n"); + free(entry); + goto done; + } + + entry->symbol_name = sym; + if (strncmp(entry->symbol_name, "__ksymtab_", 10) == 0) + list_add(&entry->list, &exp_symbols); + else + list_add(&entry->list, &symbols); + } + len = 0; + sym = NULL; + n = getline(&sym, &len, fsyms); + } + ret = true; + +done: + free(sym); + free(obj); + fclose(fsyms); + return ret; +} + +/* Searches for sympos of specific symbol in usr_symbols list */ +static bool get_usr_sympos(struct symbol *s, struct sympos *sp) +{ + struct sympos *aux; + + list_for_each_entry(aux, &usr_symbols, list) { + if (strcmp(aux->symbol_name, s->name) == 0) { + sp->symbol_name = aux->symbol_name; + sp->object_name = aux->object_name; + sp->pos = aux->pos; + return true; + } + } + return false; +} + +/* Removes symbols used for sympos annotation from livepatch elf object */ +static void clear_sympos_symbols(struct section *annotation_sec, + struct elf *klp_elf) +{ + struct symbol *sym, *aux; + + list_for_each_entry_safe(sym, aux, &klp_elf->symbols, list) { + if (sym->sec == annotation_sec) { + + struct section *sec; + struct rela *rela, *tmprela; + + list_for_each_entry(sec, &klp_elf->sections, list) { + list_for_each_entry_safe(rela, tmprela, &sec->relas, list) { + if (rela->sym == sym) { + list_del(&rela->list); + free(rela); + } + } + } + + list_del(&sym->list); + free(sym); + } + } +} + +/* Removes annotation from livepatch elf object */ +static void clear_sympos_annontations(struct elf *klp_elf) +{ + struct section *sec, *aux; + + list_for_each_entry_safe(sec, aux, &klp_elf->sections, list) { + if (strncmp(sec->name, ".klp.module_relocs.", 19) == 0) { + clear_sympos_symbols(sec, klp_elf); + list_del(&sec->list); + free(sec); + continue; + } + if (strncmp(sec->name, ".rela.klp.module_relocs.", 24) == 0) { + + struct rela *rela, *tmprela; + + list_for_each_entry_safe(rela, tmprela, &sec->relas, list) { + list_del(&rela->list); + free(rela); + } + list_del(&sec->list); + free(sec); + continue; + } + } +} + +/* + * User provided sympos annotation checks: + * - do two or more elements in usr_symbols have the same object and + * name, but different symbol position + * - are there any usr_symbols without a rela? + */ +static bool sympos_sanity_check(struct elf *klp_elf) +{ + bool sane = true; + struct sympos *sp, *aux; + struct section *sec; + struct rela *rela; + + list_for_each_entry(sp, &usr_symbols, list) { + bool found_rela = false; + + aux = list_next_entry(sp, list); + list_for_each_entry_from(aux, &usr_symbols, list) { + if (sp->pos != aux->pos && + strcmp(sp->object_name, aux->object_name) == 0 && + strcmp(sp->symbol_name, aux->symbol_name) == 0) { + WARN("Conflicting KLP_SYMPOS definition: %s.%s %d vs. %d.", + sp->object_name, sp->symbol_name, sp->pos, aux->pos); + sane = false; + } + } + + list_for_each_entry(sec, &klp_elf->sections, list) { + list_for_each_entry(rela, &sec->relas, list) { + if (!strcmp(sp->symbol_name, rela->sym->name)) { + found_rela = true; + break; + } + } + } + if (!found_rela) { + sane = false; + WARN("Couldn't find rela for annotated symbol: %s", + sp->symbol_name); + } + } + + return sane; +} + +/* Parses the livepatch elf object and fills usr_symbols */ +static bool load_usr_symbols(struct elf *klp_elf) +{ + char objname[MODULE_NAME_LEN]; + struct sympos *sp; + struct section *sec, *relasec; + struct rela *rela; + Elf_Data converted_data; + struct klp_module_reloc *reloc; + int i, nr_entries; + + list_for_each_entry(sec, &klp_elf->sections, list) { + if (sscanf(sec->name, ".klp.module_relocs.%55s", objname) != 1) + continue; + + /* + * SYMPOS annotations are saved into arrays in + * .klp.module_relocs.* sections of type PROGBITS, so we + * need to manually translate the .sympos endianness in + * case we may be cross-compiling. + */ + sec->elf_data->d_type = ELF_T_WORD; + converted_data.d_buf = sec->elf_data->d_buf; + converted_data.d_size = sec->elf_data->d_size; + converted_data.d_version = sec->elf_data->d_version; + gelf_xlatetom(klp_elf->elf, &converted_data, sec->elf_data, + elf_getident(klp_elf->elf, NULL)[EI_DATA]); + + reloc = converted_data.d_buf; + relasec = sec->rela; + + i = 0; + nr_entries = sec->size / sizeof(*reloc); + list_for_each_entry(rela, &relasec->relas, list) { + if (i >= nr_entries) { + WARN("section %s length beyond nr_entries\n", + relasec->name); + return false; + } + sp = calloc(1, sizeof(struct sympos)); + if (!sp) { + WARN("Unable to allocate sympos memory\n"); + return false; + } + sp->object_name = strdup(objname); + if (!sp->object_name) { + WARN("Unable to allocate object name\n"); + free(sp); + return false; + } + sp->symbol_name = strdup(rela->sym->name); + if (!sp->symbol_name) { + WARN("Unable to allocate symbol name\n"); + free(sp); + return false; + } + sp->pos = reloc[i].sympos; + list_add(&sp->list, &usr_symbols); + i++; + } + if (i != nr_entries) { + WARN("nr_entries mismatch (%d != %d) for %s\n", + i, nr_entries, relasec->name); + return false; + } + } + clear_sympos_annontations(klp_elf); + return sympos_sanity_check(klp_elf); +} + +/* prints list of valid sympos for symbol with provided name */ +static void print_valid_module_relocs(char *name) +{ + struct symbol_entry *e; + char *cur_obj = ""; + int counter = 0; + bool first = true; + + /* Symbols from the same object are locally gathered in the list */ + list_for_each_entry(e, &symbols, list) { + if (strcmp(e->object_name, cur_obj) != 0) { + cur_obj = e->object_name; + counter = 0; + } + if (strcmp(e->symbol_name, name) == 0) { + if (counter == 0) { + if (first) { + fprintf(stderr, "Valid KLP_SYMPOS for symbol %s:\n", name); + fprintf(stderr, "-------------------------------------------------\n"); + } else { + fprintf(stderr, "}\n"); + } + + fprintf(stderr, "KLP_MODULE_RELOC(%s){\n", + cur_obj); + first = false; + } + fprintf(stderr, "\tKLP_SYMPOS(%s,%d)\n", name, counter); + counter++; + } + } + if (!first) { + fprintf(stderr, "}\n"); + fprintf(stderr, "-------------------------------------------------\n"); + } +} + +/* + * Searches for symbol in symbols list and returns its sympos if it is unique, + * otherwise prints a list with all considered valid sympos + */ +static struct symbol_entry *find_sym_entry_by_name(char *name) +{ + struct symbol_entry *found = NULL; + struct symbol_entry *e; + + list_for_each_entry(e, &symbols, list) { + if (strcmp(e->symbol_name, name) == 0) { + + /* + * If there exist multiple symbols with the same + * name then user-provided sympos is required + */ + if (found) { + WARN("Define KLP_SYMPOS for the symbol: %s", + e->symbol_name); + + print_valid_module_relocs(name); + return NULL; + } + found = e; + } + } + + return found; +} + +/* Checks if sympos is valid, otherwise prints valid sympos list */ +static bool valid_sympos(struct sympos *sp) +{ + struct symbol_entry *e; + + if (sp->pos == 0) { + + /* + * sympos of 0 is reserved for uniquely named obj:sym, + * verify that this is the case + */ + int counter = 0; + + list_for_each_entry(e, &symbols, list) { + if ((strcmp(e->symbol_name, sp->symbol_name) == 0) && + (strcmp(e->object_name, sp->object_name) == 0)) { + counter++; + } + } + if (counter == 1) + return true; + + WARN("Provided KLP_SYMPOS of 0, but found %d symbols matching: %s.%s,%d", + counter, sp->object_name, sp->symbol_name, + sp->pos); + + } else { + + /* + * sympos > 0 indicates a specific commonly-named obj:sym, + * indexing starts with 1 + */ + int index = 1; + + list_for_each_entry(e, &symbols, list) { + if ((strcmp(e->symbol_name, sp->symbol_name) == 0) && + (strcmp(e->object_name, sp->object_name) == 0)) { + if (index == sp->pos) + return true; + index++; + } + } + + WARN("Provided KLP_SYMPOS does not match a symbol: %s.%s,%d", + sp->object_name, sp->symbol_name, sp->pos); + } + + print_valid_module_relocs(sp->symbol_name); + + return false; +} + +/* + * Add this symbol to the converted_symbols list to cache its sympos and + * for later renaming. + */ +static bool remember_sympos(struct symbol *s, struct sympos *sp) +{ + struct converted_sym *cs; + + cs = calloc(1, sizeof(*cs)); + if (!cs) { + WARN("Unable to allocate converted_symbol entry"); + return false; + } + + cs->symbol = s; + cs->sympos = *sp; + list_add(&cs->list, &converted_symbols); + + return true; +} + +/* Returns the right sympos respective to a symbol to be relocated */ +static bool find_sympos(struct symbol *s, struct sympos *sp) +{ + struct symbol_entry *entry; + struct converted_sym *cs; + + /* did we already convert this symbol? */ + list_for_each_entry(cs, &converted_symbols, list) { + if (cs->symbol == s) { + *sp = cs->sympos; + return true; + } + } + + /* did the user specified via annotation? */ + if (get_usr_sympos(s, sp)) { + if (valid_sympos(sp)) { + remember_sympos(s, sp); + return true; + } + return false; + } + + /* + * user didn't specify, so search the symbols list. A pos of 0 + * indicates this should be a unique symbol. + */ + entry = find_sym_entry_by_name(s->name); + if (entry) { + sp->symbol_name = entry->symbol_name; + sp->object_name = entry->object_name; + sp->pos = 0; + remember_sympos(s, sp); + return true; + } + return false; +} + +/* + * Finds or creates a klp rela section based on another given section (@oldsec) + * and sympos (@*sp), then returns it + */ +static struct section *get_or_create_klp_rela_section(struct section *oldsec, + struct sympos *sp, struct elf *klp_elf) +{ + char *name; + struct section *sec; + unsigned int length; + + length = strlen(KLP_RELA_PREFIX) + strlen(sp->object_name) + + strlen(oldsec->base->name) + 2; + + name = calloc(1, length); + if (!name) { + WARN("Memory allocation failed (%s%s.%s)\n", KLP_RELA_PREFIX, + sp->object_name, oldsec->base->name); + return NULL; + } + + if (safe_snprintf(name, length, KLP_RELA_PREFIX "%s.%s", + sp->object_name, oldsec->base->name)) { + WARN("Length error (%s)", name); + free(name); + return NULL; + } + + sec = find_section_by_name(klp_elf, name); + if (!sec) + sec = create_rela_section(klp_elf, name, oldsec->base); + + if (sec) + sec->sh.sh_flags |= SHF_RELA_LIVEPATCH; + + free(name); + return sec; +} + +/* Converts rela symbol names */ +static bool convert_symbol(struct symbol *s, struct sympos *sp) +{ + char *name; + char pos[4]; /* assume that pos will never be > 999 */ + unsigned int length; + + if (safe_snprintf(pos, sizeof(pos), "%d", sp->pos)) { + WARN("Insufficient buffer for expanding sympos (%s.%s,%d)\n", + sp->object_name, sp->symbol_name, sp->pos); + return false; + } + + length = strlen(KLP_SYM_PREFIX) + strlen(sp->object_name) + + strlen(sp->symbol_name) + sizeof(pos) + 3; + + name = calloc(1, length); + if (!name) { + WARN("Memory allocation failed (%s%s.%s,%s)\n", KLP_SYM_PREFIX, + sp->object_name, sp->symbol_name, pos); + return false; + } + + if (safe_snprintf(name, length, KLP_SYM_PREFIX "%s.%s,%s", + sp->object_name, sp->symbol_name, pos)) { + + WARN("Length error (%s%s.%s,%s)", KLP_SYM_PREFIX, + sp->object_name, sp->symbol_name, pos); + free(name); + return false; + } + + /* + * Despite the memory waste, we don't mind freeing the original symbol + * name memory chunk. Keeping it there is harmless and, since removing + * bytes from the string section is non-trivial, it is unworthy. + */ + s->name = name; + s->sec = NULL; + s->sym.st_name = -1; + s->sym.st_shndx = SHN_LIVEPATCH; + + return true; +} + +/* Checks if a rela was converted */ +static bool is_converted_rela(struct rela *rela) +{ + return !!rela->klp_rela_sec; +} + +/* + * Convert rela that cannot be resolved by the classic module loader + * to the special klp rela one. + */ +static bool convert_rela(struct section *oldsec, struct rela *rela, + struct sympos *sp, struct elf *klp_elf) +{ + struct section *sec; + + sec = get_or_create_klp_rela_section(oldsec, sp, klp_elf); + if (!sec) { + WARN("Can't create or access klp.rela section (%s.%s)\n", + sp->object_name, sp->symbol_name); + return false; + } + + rela->klp_rela_sec = sec; + + return true; +} + +static void move_rela(struct rela *r) +{ + /* Move the converted rela to klp rela section */ + list_del(&r->list); + list_add_tail(&r->list, &r->klp_rela_sec->relas); +} + +/* Checks if given symbol name matches a symbol in exp_symbols */ +static bool is_exported(char *sname) +{ + struct symbol_entry *e; + + /* + * exp_symbols itens are prefixed with __ksymtab_ - comparisons must + * skip prefix and check if both are properly null-terminated + */ + list_for_each_entry(e, &exp_symbols, list) { + if (strcmp(e->symbol_name + 10, sname) == 0) + return true; + } + return false; +} + +/* Checks if symbol should be skipped */ +static bool skip_symbol(struct symbol *sym) +{ + /* already resolved? */ + if (sym->sec) + return true; + + /* skip symbol with index 0 */ + if (!sym->idx) + return true; + + /* we should not touch .TOC. on ppc64le */ + if (strcmp(sym->name, ".TOC.") == 0) + return true; + + if (is_exported(sym->name)) + return true; + + return false; +} + +/* Checks if a section is a klp rela section */ +static bool is_klp_rela_section(char *sname) +{ + int len = strlen(KLP_RELA_PREFIX); + + if (strncmp(sname, KLP_RELA_PREFIX, len) == 0) + return true; + return false; +} + +/* + * Frees the list, new names and rela sections as created by + * remember_sympos(), convert_rela(), and convert_symbol() + */ +static void free_converted_resources(struct elf *klp_elf) +{ + struct converted_sym *cs, *cs_aux; + struct section *sec; + + list_for_each_entry_safe(cs, cs_aux, &converted_symbols, list) { + free(cs->symbol->name); + free(cs); + } + + list_for_each_entry(sec, &klp_elf->sections, list) { + if (is_klp_rela_section(sec->name)) { + free(sec->elf_data); + free(sec->name); + } + } +} + +/* + * Checks if section may be skipped (conditions) + */ +static bool skip_section(struct section *sec) +{ + if (!is_rela_section(sec)) + return true; + + if (is_klp_rela_section(sec->name)) + return true; + + return false; +} + +/* + * Checks if rela conversion is supported in given section + */ +static bool supported_section(struct section *sec, char *object_name) +{ +#if 0 + /* + * klp-relocations forbidden in sections that otherwise would + * match in allowed_prefixes[] + */ + static const char * const not_allowed[] = { + ".rela.data.rel.ro", + ".rela.data.rel.ro.local", + ".rela.data..ro_after_init", + NULL + }; +#endif + + /* klp-relocations allowed in sections only for vmlinux */ + static const char * const allowed_vmlinux[] = { + ".rela__jump_table", + NULL + }; + + /* klp-relocations allowed in sections with prefixes */ + static const char * const allowed_prefixes[] = { + ".rela.data", + ".rela.rodata", // supported ??? + ".rela.sdata", + ".rela.text", + ".rela.toc", + NULL + }; + + const char * const *name; + +#if 0 + for (name = not_allowed; *name; name++) + if (strcmp(sec->name, *name) == 0) + return false; +#endif + + if (strcmp(object_name, "vmlinux") == 0) { + for (name = allowed_vmlinux; *name; name++) + if (strcmp(sec->name, *name) == 0) + return true; + } + + for (name = allowed_prefixes; *name; name++) + if (strncmp(sec->name, *name, strlen(*name)) == 0) + return true; + + return false; +} + +int main(int argc, const char **argv) +{ + const char *klp_in_module, *klp_out_module, *symbols_list; + struct rela *rela, *tmprela; + struct section *sec; + struct sympos sp; + struct elf *klp_elf; + struct converted_sym *cs; + int errors = 0; + + if (argc != 4) { + WARN("Usage: %s ", argv[0]); + return -1; + } + + symbols_list = argv[1]; + klp_in_module = argv[2]; + klp_out_module = argv[3]; + + klp_elf = elf_open(klp_in_module); + if (!klp_elf) { + WARN("Unable to read elf file %s\n", klp_in_module); + return -1; + } + + if (!load_syms_lists(symbols_list)) + return -1; + + if (!load_usr_symbols(klp_elf)) { + WARN("Unable to load user-provided sympos"); + return -1; + } + + list_for_each_entry(sec, &klp_elf->sections, list) { + if (skip_section(sec)) + continue; + + list_for_each_entry(rela, &sec->relas, list) { + if (skip_symbol(rela->sym)) + continue; + + /* rela needs to be converted */ + + if (!find_sympos(rela->sym, &sp)) { + WARN("Unable to find missing symbol: %s", + rela->sym->name); + errors++; + continue; + } + if (!supported_section(sec, sp.object_name)) { + WARN("Conversion not supported for symbol: %s section: %s object: %s", + rela->sym->name, sec->name, + sp.object_name); + errors++; + continue; + } + if (!convert_rela(sec, rela, &sp, klp_elf)) { + WARN("Unable to convert relocation: %s", + rela->sym->name); + return -1; + } + } + + if (errors) + return -1; + + /* Now move all converted relas in list-safe manner */ + list_for_each_entry_safe(rela, tmprela, &sec->relas, list) { + if (is_converted_rela(rela)) + move_rela(rela); + } + } + + /* Rename the converted symbols */ + list_for_each_entry(cs, &converted_symbols, list) { + if (!convert_symbol(cs->symbol, &cs->sympos)) { + WARN("Unable to convert symbol name (%s)\n", + cs->symbol->name); + return -1; + } + } + + free_syms_lists(); + if (elf_write_file(klp_elf, klp_out_module)) + return -1; + + free_converted_resources(klp_elf); + elf_close(klp_elf); + + return 0; +} + +/* Functions kept commented since they might be useful for future debugging */ + +/* Dumps sympos list (useful for debugging purposes) + * static void dump_sympos(void) + * { + * struct sympos *sp; + * + * fprintf(stderr, "BEGIN OF SYMPOS DUMP\n"); + * list_for_each_entry(sp, &usr_symbols, list) { + * fprintf(stderr, "%s %s %d\n", sp->symbol_name, sp->object_name, + * sp->pos); + * } + * fprintf(stderr, "END OF SYMPOS DUMP\n"); + * } + * + * + * / Dump symbols list for debugging purposes / + * static void dump_symbols(void) + * { + * struct symbol_entry *entry; + * + * fprintf(stderr, "BEGIN OF SYMBOLS DUMP\n"); + * list_for_each_entry(entry, &symbols, list) + * printf("%s %s\n", entry->object_name, entry->symbol_name); + * fprintf(stderr, "END OF SYMBOLS DUMP\n"); + * } + */ diff --git a/scripts/livepatch/klp-convert.h b/scripts/livepatch/klp-convert.h new file mode 100644 index 000000000000..35b9dc4e32c4 --- /dev/null +++ b/scripts/livepatch/klp-convert.h @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2016 Josh Poimboeuf + * Copyright (C) 2017 Joao Moreira + * + */ + +#define SHN_LIVEPATCH 0xff20 +#define SHF_RELA_LIVEPATCH 0x00100000 +#define MODULE_NAME_LEN (64 - sizeof(GElf_Addr)) +#define WARN(format, ...) \ + fprintf(stderr, "klp-convert: " format "\n", ##__VA_ARGS__) + +struct symbol_entry { + struct list_head list; + char *symbol_name; + char *object_name; +}; + +struct sympos { + struct list_head list; + char *symbol_name; + char *object_name; + int pos; +}; + +/* + * klp-convert uses macros and structures defined in the linux sources + * package (see include/uapi/linux/livepatch.h). To prevent the + * dependency when building locally, they are defined below. Also notice + * that these should match the definitions from the targeted kernel. + */ + +#define KLP_RELA_PREFIX ".klp.rela." +#define KLP_SYM_PREFIX ".klp.sym." + +#ifndef __packed +#define __packed __attribute__((packed)) +#endif + +struct klp_module_reloc { + union { + void *sym; + uint64_t sym64; /* Force 64-bit width */ + }; + uint32_t sympos; +} __packed; diff --git a/scripts/livepatch/list.h b/scripts/livepatch/list.h new file mode 100644 index 000000000000..4d429120fabf --- /dev/null +++ b/scripts/livepatch/list.h @@ -0,0 +1,391 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_LIST_H +#define _LINUX_LIST_H + +/* + * Simple doubly linked list implementation. + * + * Some of the internal functions ("__xxx") are useful when + * manipulating whole lists rather than single entries, as + * sometimes we already know the next/prev entries and we can + * generate better code by using them directly rather than + * using the generic single-entry routines. + */ + +#define WRITE_ONCE(a, b) (a = b) +#define READ_ONCE(a) a + +#undef offsetof +#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) + +/** + * container_of - cast a member of a structure out to the containing structure + * @ptr: the pointer to the member. + * @type: the type of the container struct this is embedded in. + * @member: the name of the member within the struct. + * + */ +#define container_of(ptr, type, member) ({ \ + const typeof(((type *)0)->member) * __mptr = (ptr); \ + (type *)((char *)__mptr - offsetof(type, member)); }) + +struct list_head { + struct list_head *next, *prev; +}; + +#define LIST_HEAD_INIT(name) { &(name), &(name) } + +#define LIST_HEAD(name) \ + struct list_head name = LIST_HEAD_INIT(name) + +static inline void INIT_LIST_HEAD(struct list_head *list) +{ + WRITE_ONCE(list->next, list); + list->prev = list; +} + +/* + * Insert a new entry between two known consecutive entries. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_add(struct list_head *new, + struct list_head *prev, + struct list_head *next) +{ + next->prev = new; + new->next = next; + new->prev = prev; + WRITE_ONCE(prev->next, new); +} + +/** + * list_add - add a new entry + * @new: new entry to be added + * @head: list head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ +static inline void list_add(struct list_head *new, struct list_head *head) +{ + __list_add(new, head, head->next); +} + + +/** + * list_add_tail - add a new entry + * @new: new entry to be added + * @head: list head to add it before + * + * Insert a new entry before the specified head. + * This is useful for implementing queues. + */ +static inline void list_add_tail(struct list_head *new, struct list_head *head) +{ + __list_add(new, head->prev, head); +} + +/* + * Delete a list entry by making the prev/next entries + * point to each other. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_del(struct list_head *prev, struct list_head *next) +{ + next->prev = prev; + WRITE_ONCE(prev->next, next); +} + +/** + * list_del - deletes entry from list. + * @entry: the element to delete from the list. + * Note: list_empty() on entry does not return true after this, the entry is + * in an undefined state. + */ +static inline void __list_del_entry(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); +} + +static inline void list_del(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); +} + +/** + * list_is_last - tests whether @list is the last entry in list @head + * @list: the entry to test + * @head: the head of the list + */ +static inline int list_is_last(const struct list_head *list, + const struct list_head *head) +{ + return list->next == head; +} + +/** + * list_empty - tests whether a list is empty + * @head: the list to test. + */ +static inline int list_empty(const struct list_head *head) +{ + return READ_ONCE(head->next) == head; +} + +/** + * list_entry - get the struct for this entry + * @ptr: the &struct list_head pointer. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_head within the struct. + */ +#define list_entry(ptr, type, member) \ + container_of(ptr, type, member) + +/** + * list_first_entry - get the first element from a list + * @ptr: the list head to take the element from. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_head within the struct. + * + * Note, that list is expected to be not empty. + */ +#define list_first_entry(ptr, type, member) \ + list_entry((ptr)->next, type, member) + +/** + * list_last_entry - get the last element from a list + * @ptr: the list head to take the element from. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_head within the struct. + * + * Note, that list is expected to be not empty. + */ +#define list_last_entry(ptr, type, member) \ + list_entry((ptr)->prev, type, member) + +/** + * list_first_entry_or_null - get the first element from a list + * @ptr: the list head to take the element from. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_head within the struct. + * + * Note that if the list is empty, it returns NULL. + */ +#define list_first_entry_or_null(ptr, type, member) \ + (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL) + +/** + * list_next_entry - get the next element in list + * @pos: the type * to cursor + * @member: the name of the list_head within the struct. + */ +#define list_next_entry(pos, member) \ + list_entry((pos)->member.next, typeof(*(pos)), member) + +/** + * list_prev_entry - get the prev element in list + * @pos: the type * to cursor + * @member: the name of the list_head within the struct. + */ +#define list_prev_entry(pos, member) \ + list_entry((pos)->member.prev, typeof(*(pos)), member) + +/** + * list_for_each - iterate over a list + * @pos: the &struct list_head to use as a loop cursor. + * @head: the head for your list. + */ +#define list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/** + * list_for_each_prev - iterate over a list backwards + * @pos: the &struct list_head to use as a loop cursor. + * @head: the head for your list. + */ +#define list_for_each_prev(pos, head) \ + for (pos = (head)->prev; pos != (head); pos = pos->prev) + +/** + * list_for_each_safe - iterate over a list safe against removal of list entry + * @pos: the &struct list_head to use as a loop cursor. + * @n: another &struct list_head to use as temporary storage + * @head: the head for your list. + */ +#define list_for_each_safe(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, n = pos->next) + +/** + * list_for_each_prev_safe - iterate over a list backwards safe against removal + of list entry + * @pos: the &struct list_head to use as a loop cursor. + * @n: another &struct list_head to use as temporary storage + * @head: the head for your list. + */ +#define list_for_each_prev_safe(pos, n, head) \ + for (pos = (head)->prev, n = pos->prev; \ + pos != (head); \ + pos = n, n = pos->prev) + +/** + * list_for_each_entry - iterate over list of given type + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_head within the struct. + */ +#define list_for_each_entry(pos, head, member) \ + for (pos = list_first_entry(head, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_next_entry(pos, member)) + +/** + * list_for_each_entry_reverse - iterate backwards over list of given type. + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_head within the struct. + */ +#define list_for_each_entry_reverse(pos, head, member) \ + for (pos = list_last_entry(head, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_prev_entry(pos, member)) + +/** + * list_prepare_entry - prepare a pos entry for use in + list_for_each_entry_continue() + * @pos: the type * to use as a start point + * @head: the head of the list + * @member: the name of the list_head within the struct. + * + * Prepares a pos entry for use as a start point in + list_for_each_entry_continue(). + */ +#define list_prepare_entry(pos, head, member) \ + ((pos) ? : list_entry(head, typeof(*pos), member)) + +/** + * list_for_each_entry_continue - continue iteration over list of given type + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_head within the struct. + * + * Continue to iterate over list of given type, continuing after + * the current position. + */ +#define list_for_each_entry_continue(pos, head, member) \ + for (pos = list_next_entry(pos, member); \ + &pos->member != (head); \ + pos = list_next_entry(pos, member)) + +/** + * list_for_each_entry_continue_reverse - iterate backwards from the given point + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_head within the struct. + * + * Start to iterate over list of given type backwards, continuing after + * the current position. + */ +#define list_for_each_entry_continue_reverse(pos, head, member) \ + for (pos = list_prev_entry(pos, member); \ + &pos->member != (head); \ + pos = list_prev_entry(pos, member)) + +/** + * list_for_each_entry_from - iterate over list of given type from the current + point + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_head within the struct. + * + * Iterate over list of given type, continuing from current position. + */ +#define list_for_each_entry_from(pos, head, member) \ + for (; &pos->member != (head); \ + pos = list_next_entry(pos, member)) + +/** + * list_for_each_entry_safe - iterate over list of given type safe against + removal of list entry + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_head within the struct. + */ +#define list_for_each_entry_safe(pos, n, head, member) \ + for (pos = list_first_entry(head, typeof(*pos), member), \ + n = list_next_entry(pos, member); \ + &pos->member != (head); \ + pos = n, n = list_next_entry(n, member)) + +/** + * list_for_each_entry_safe_continue - continue list iteration safe against + * removal + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_head within the struct. + * + * Iterate over list of given type, continuing after current point, + * safe against removal of list entry. + */ +#define list_for_each_entry_safe_continue(pos, n, head, member) \ + for (pos = list_next_entry(pos, member), \ + n = list_next_entry(pos, member); \ + &pos->member != (head); \ + pos = n, n = list_next_entry(n, member)) + +/** + * list_for_each_entry_safe_from - iterate over list from current point safe + * against removal + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_head within the struct. + * + * Iterate over list of given type from current point, safe against + * removal of list entry. + */ +#define list_for_each_entry_safe_from(pos, n, head, member) \ + for (n = list_next_entry(pos, member); \ + &pos->member != (head); \ + pos = n, n = list_next_entry(n, member)) + +/** + * list_for_each_entry_safe_reverse - iterate backwards over list safe against + * removal + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_head within the struct. + * + * Iterate backwards over list of given type, safe against removal + * of list entry. + */ +#define list_for_each_entry_safe_reverse(pos, n, head, member) \ + for (pos = list_last_entry(head, typeof(*pos), member), \ + n = list_prev_entry(pos, member); \ + &pos->member != (head); \ + pos = n, n = list_prev_entry(n, member)) + +/** + * list_safe_reset_next - reset a stale list_for_each_entry_safe loop + * @pos: the loop cursor used in the list_for_each_entry_safe loop + * @n: temporary storage used in list_for_each_entry_safe + * @member: the name of the list_head within the struct. + * + * list_safe_reset_next is not safe to use in general if the list may be + * modified concurrently (eg. the lock is dropped in the loop body). An + * exception to this is if the cursor element (pos) is pinned in the list, + * and list_safe_reset_next is called after re-taking the lock and before + * completing the current iteration of the loop body. + */ +#define list_safe_reset_next(pos, n, member) \ + (n = list_next_entry(pos, member)) + +#endif From patchwork Mon Mar 6 14:08:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161185 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C05E3C61DA4 for ; Mon, 6 Mar 2023 14:12:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230219AbjCFOMo (ORCPT ); Mon, 6 Mar 2023 09:12:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231502AbjCFOMV (ORCPT ); Mon, 6 Mar 2023 09:12:21 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9B2033440 for ; Mon, 6 Mar 2023 06:09:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678111709; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aTfeyHCszsMv9gyl7yv5PA648Uf9sQDoAl7w9f2+5CI=; b=ipdctqJ28Cd9mOQmImc/0bHffON9HU1I86WB1/zkSgxJyqvGD11Wiirk6Ho+qbqPkiFWYH o3F14AficlZbmyLU2MJMMbqnOEH9dNqR1wXkJ+KtfmxBAbL1pAQCAcZSwC9TJiDC2TyYER YF4tAPmY8jiW+sevnMkcQAfArrHPc8I= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-584-oAIwZ54WPPO-lO6noN_p_Q-1; Mon, 06 Mar 2023 09:08:28 -0500 X-MC-Unique: oAIwZ54WPPO-lO6noN_p_Q-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E81DB3810B0C; Mon, 6 Mar 2023 14:08:27 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id 97A0E40C10FA; Mon, 6 Mar 2023 14:08:27 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 03/10] kbuild/modpost: create symbols.klp and integrate klp-convert Date: Mon, 6 Mar 2023 09:08:17 -0500 Message-Id: <20230306140824.3858543-4-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org For automatic resolution of livepatch relocations, a file called symbols.klp is used. This file maps symbols within every compiled kernel object allowing the identification of symbols whose name is unique, thus relocation can be automatically inferred, or providing information that helps developers when code annotation is required for solving the matter. Add support for creating symbols.klp in the main Makefile. First, ensure that built-in is compiled when CONFIG_LIVEPATCH is enabled (as required to achieve a complete symbols.klp file). Define the command to build symbols.klp (filechk_klp_map) and hook it in the modules rule. Save the list of livepatch modules in $(MODULES_LIVEPATCH). As it is undesirable to have symbols from livepatch objects inside symbols.klp, filechk_klp_map filters out modules.livepatch from modules.order: `sort $(MODORDER) $(MODULES_LIVEPATCH) | uniq -u`. The "clean" Makefile target may remove the modules.livepatch file, however, symbols.klp may be needed for building external modules, so defer its cleanup to the "mrproper" target. Finally, update the modpost program so that it does not warn about unresolved symbols resolved by klp-convert. Signed-off-by: Josh Poimboeuf Signed-off-by: Konstantin Khlebnikov Signed-off-by: Miroslav Benes Signed-off-by: Joao Moreira Signed-off-by: Joe Lawrence Acked-by: Marcos Paulo de Souza --- .gitignore | 2 ++ Documentation/dontdiff | 1 + Makefile | 16 +++++++++++----- scripts/Makefile.modfinal | 33 +++++++++++++++++++++++++++++++++ scripts/Makefile.modpost | 5 +++++ scripts/mod/modpost.c | 28 ++++++++++++++++++++++++++-- scripts/mod/modpost.h | 1 + 7 files changed, 79 insertions(+), 7 deletions(-) diff --git a/.gitignore b/.gitignore index 20dce5c3b9e0..fc9b2f13b049 100644 --- a/.gitignore +++ b/.gitignore @@ -53,6 +53,7 @@ *.xz *.zst Module.symvers +modules.livepatch modules.order # @@ -66,6 +67,7 @@ modules.order /vmlinux.symvers /vmlinux-gdb.py /vmlinuz +/symbols.klp /System.map /Module.markers /modules.builtin diff --git a/Documentation/dontdiff b/Documentation/dontdiff index 352ff53a2306..23c2a89fb791 100644 --- a/Documentation/dontdiff +++ b/Documentation/dontdiff @@ -76,6 +76,7 @@ Module.markers Module.symvers PENDING SCCS +symbols.klp System.map* TAGS aconf diff --git a/Makefile b/Makefile index 3f6628780eb2..dd5d6c258906 100644 --- a/Makefile +++ b/Makefile @@ -730,8 +730,13 @@ KBUILD_MODULES := KBUILD_BUILTIN := 1 # If we have only "make modules", don't compile built-in objects. +# When we're building livepatch modules, we need to consider the +# built-in objects during the descend as well, as built-in objects may +# hold symbols which are referenced from livepatches and are required by +# klp-convert post-processing tool for resolving these cases. + ifeq ($(MAKECMDGOALS),modules) - KBUILD_BUILTIN := + KBUILD_BUILTIN := $(if $(CONFIG_LIVEPATCH),1) endif # If we have "make modules", compile modules @@ -1183,6 +1188,7 @@ PHONY += prepare0 export extmod_prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/) export MODORDER := $(extmod_prefix)modules.order export MODULES_NSDEPS := $(extmod_prefix)modules.nsdeps +export MODULES_LIVEPATCH := $(extmod-prefix)modules.livepatch ifeq ($(KBUILD_EXTMOD),) @@ -1543,8 +1549,8 @@ endif # # *.ko are usually independent of vmlinux, but CONFIG_DEBUG_INFOBTF_MODULES -# is an exception. -ifdef CONFIG_DEBUG_INFO_BTF_MODULES +# and CONFIG_LIVEPATCH are exceptions. +ifneq ($(or $(CONFIG_DEBUG_INFO_BTF_MODULES),$(CONFIG_LIVEPATCH)),) KBUILD_BUILTIN := 1 modules: vmlinux endif @@ -1602,14 +1608,14 @@ endif # CONFIG_MODULES CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \ modules.builtin modules.builtin.modinfo modules.nsdeps \ compile_commands.json .thinlto-cache rust/test rust/doc \ - .vmlinux.objs .vmlinux.export.c + modules.livepatch .vmlinux.objs .vmlinux.export.c # Directories & files removed with 'make mrproper' MRPROPER_FILES += include/config include/generated \ arch/$(SRCARCH)/include/generated .objdiff \ debian snap tar-install \ .config .config.old .version \ - Module.symvers \ + Module.symvers symbols.klp \ certs/signing_key.pem \ certs/x509.genkey \ vmlinux-gdb.py \ diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index a30d5b08eee9..a8901e4e98c5 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -14,6 +14,7 @@ include $(srctree)/scripts/Makefile.lib # find all modules listed in modules.order modules := $(call read-file, $(MODORDER)) +modules-klp := $(call read-file, $(MODULES_LIVEPATCH)) __modfinal: $(modules:%.o=%.ko) @: @@ -65,6 +66,38 @@ endif targets += $(modules:%.o=%.ko) $(modules:%.o=%.mod.o) +# Livepatch +# --------------------------------------------------------------------------- + +%.tmp.ko: %.o %.mod.o symbols.klp FORCE + +$(call if_changed,ld_ko_o) + +quiet_cmd_klp_convert = KLP $@ + cmd_klp_convert = scripts/livepatch/klp-convert symbols.klp $< $@ + +$(modules-klp:%.o=%.ko): %.ko: %.tmp.ko FORCE + $(call if_changed,klp_convert) + +targets += $(modules-klp:.ko=.tmp.ko) + +ifeq ($(KBUILD_EXTMOD),) +filechk_klp_map = \ + echo "klp-convert-symbol-data.0.1"; \ + echo "*vmlinux"; \ + $(NM) -f posix vmlinux | cut -d\ -f1; \ + sort $(MODORDER) $(MODULES_LIVEPATCH) | \ + uniq -u | \ + sed 's/\.o$$//' | \ + while read o; \ + do \ + echo "*$$(basename $$o)"; \ + $(NM) -f posix $$o.o | cut -d\ -f1; \ + done + +symbols.klp: FORCE + $(call filechk,klp_map) +endif + # Add FORCE to the prequisites of a target to force it to be always rebuilt. # --------------------------------------------------------------------------- diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 43343e13c542..02f1354d4cff 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -47,6 +47,7 @@ modpost-args = \ $(if $(KBUILD_MODPOST_WARN),-w) \ $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \ $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \ + $(if $(CONFIG_LIVEPATCH),-l $(MODULES_LIVEPATCH)) \ -o $@ modpost-deps := $(MODPOST) @@ -138,6 +139,10 @@ $(output-symdump): $(modpost-deps) FORCE $(call if_changed,modpost) __modpost: $(output-symdump) +ifndef CONFIG_LIVEPATCH + $(Q)rm -f $(MODULES_LIVEPATCH) + $(Q)touch $(MODULES_LIVEPATCH) +endif PHONY += FORCE FORCE: diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index efff8078e395..0a8f0ce75761 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1831,6 +1831,10 @@ static void read_symbols(const char *modname) handle_moddevtable(mod, &info, sym, symname); } + /* Livepatch modules have unresolved symbols resolved by klp-convert */ + if (get_modinfo(&info, "livepatch")) + mod->is_livepatch = true; + for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { symname = remove_dot(info.strtab + sym->st_name); @@ -1919,7 +1923,7 @@ static void check_exports(struct module *mod) const char *basename; exp = find_symbol(s->name); if (!exp) { - if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS) + if (!s->weak && !mod->is_livepatch && nr_unresolved++ < MAX_UNRESOLVED_REPORTS) modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR, "\"%s\" [%s.ko] undefined!\n", s->name, mod->name); @@ -2320,6 +2324,20 @@ static void write_namespace_deps_files(const char *fname) free(ns_deps_buf.p); } +static void write_livepatch_modules(const char *fname) +{ + struct buffer buf = { }; + struct module *mod; + + list_for_each_entry(mod, &modules, list) { + if (mod->is_livepatch) + buf_printf(&buf, "%s.o\n", mod->name); + } + + write_if_changed(&buf, fname); + free(buf.p); +} + struct dump_list { struct list_head list; const char *file; @@ -2330,11 +2348,12 @@ int main(int argc, char **argv) struct module *mod; char *missing_namespace_deps = NULL; char *dump_write = NULL, *files_source = NULL; + char *livepatch_modules = NULL; int opt; LIST_HEAD(dump_lists); struct dump_list *dl, *dl2; - while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) { + while ((opt = getopt(argc, argv, "ei:l:mnT:o:awENd:")) != -1) { switch (opt) { case 'e': external_module = true; @@ -2344,6 +2363,9 @@ int main(int argc, char **argv) dl->file = optarg; list_add_tail(&dl->list, &dump_lists); break; + case 'l': + livepatch_modules = optarg; + break; case 'm': modversions = true; break; @@ -2403,6 +2425,8 @@ int main(int argc, char **argv) if (dump_write) write_dump(dump_write); + if (livepatch_modules) + write_livepatch_modules(livepatch_modules); if (sec_mismatch_count && !sec_mismatch_warn_only) error("Section mismatches detected.\n" "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 1178f40a73f3..9be9bf6fb7da 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -119,6 +119,7 @@ struct module { bool is_gpl_compatible; bool from_dump; /* true if module was loaded from *.symvers */ bool is_vmlinux; + bool is_livepatch; bool seen; bool has_init; bool has_cleanup; From patchwork Mon Mar 6 14:08:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161352 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B171C678D4 for ; Mon, 6 Mar 2023 14:56:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229805AbjCFO4M (ORCPT ); Mon, 6 Mar 2023 09:56:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229732AbjCFO4K (ORCPT ); Mon, 6 Mar 2023 09:56:10 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A41842FCD9 for ; Mon, 6 Mar 2023 06:55:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678114512; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qrV6uJIm/Y4g08NszDYAhcJIJkYS8EE2yW4AwS7aHm8=; b=grgpPr3sY06o/VdxMEkpl7C1HPT+ZJFA5bKzUfgnAnywtPQc3bMc4hDwAe0orFRxoN1Lei 6vtbF3+TcFFc/YZHjrv6Z8upRvaW50KS6VuIREelZhitkoaFJNiQxkbuv2Hg94S4JXQ4f4 D2W9sxlAUskZeZDlv0ttDi+dzckQZ0s= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-315-I2Hxq88LP7WCK-SdI9Epqg-1; Mon, 06 Mar 2023 09:08:28 -0500 X-MC-Unique: I2Hxq88LP7WCK-SdI9Epqg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 54EF785CBE2; Mon, 6 Mar 2023 14:08:28 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id 039C040ED76C; Mon, 6 Mar 2023 14:08:27 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 04/10] livepatch: Add sample livepatch module Date: Mon, 6 Mar 2023 09:08:18 -0500 Message-Id: <20230306140824.3858543-5-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Add a new livepatch sample in samples/livepatch/ to make use of symbols that must be post-processed to enable load-time relocation resolution. As the new sample is to be used as an example, it is annotated with KLP_MODULE_RELOC and with KLP_SYMPOS macros. The livepatch sample updates the function cmdline_proc_show to print the string referenced by the symbol saved_command_line appended by the string "livepatch=1". Update livepatch-sample.c to remove livepatch MODULE_INFO statement. Signed-off-by: Josh Poimboeuf Signed-off-by: Joao Moreira Signed-off-by: Joe Lawrence Reviewed-by: Marcos Paulo de Souza --- samples/livepatch/Makefile | 1 + .../livepatch/livepatch-annotated-sample.c | 93 +++++++++++++++++++ 2 files changed, 94 insertions(+) create mode 100644 samples/livepatch/livepatch-annotated-sample.c diff --git a/samples/livepatch/Makefile b/samples/livepatch/Makefile index 9f853eeb6140..f2b41f4d6c16 100644 --- a/samples/livepatch/Makefile +++ b/samples/livepatch/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch-shadow-fix2.o obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch-callbacks-demo.o obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch-callbacks-mod.o obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch-callbacks-busymod.o +obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch-annotated-sample.o diff --git a/samples/livepatch/livepatch-annotated-sample.c b/samples/livepatch/livepatch-annotated-sample.c new file mode 100644 index 000000000000..4fe0e16423c7 --- /dev/null +++ b/samples/livepatch/livepatch-annotated-sample.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2014 Seth Jennings + */ + +/* + * livepatch-annotated-sample.c - Kernel Live Patching Sample Module + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include + +/* + * This (dumb) live patch overrides the function that prints the + * kernel boot cmdline when /proc/cmdline is read. + * + * This livepatch uses the symbol saved_command_line whose relocation + * must be resolved during load time. To enable that, this module + * must be post-processed by a tool called klp-convert, which embeds + * information to be used by the loader to solve the relocation. + * + * The module is annotated with KLP_MODULE_RELOC/KLP_SYMPOS macros. + * These annotations are used by klp-convert to infer that the symbol + * saved_command_line is in the object vmlinux. + * + * As saved_command_line has no other homonimous symbol across + * kernel objects, this annotation is not a requirement, and can be + * suppressed with no harm to klp-convert. Yet, it is kept here as an + * example on how to annotate livepatch modules that contain symbols + * whose names are used in more than one kernel object. + * + * Example: + * + * $ cat /proc/cmdline + * + * + * $ insmod livepatch-sample.ko + * $ cat /proc/cmdline + * livepatch=1 + * + * $ echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled + * $ cat /proc/cmdline + * + */ + +extern char *saved_command_line; + +#include +static int livepatch_cmdline_proc_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%s livepatch=1\n", saved_command_line); + return 0; +} + +KLP_MODULE_RELOC(vmlinux) vmlinux_relocs[] = { + KLP_SYMPOS(saved_command_line, 0) +}; + +static struct klp_func funcs[] = { + { + .old_name = "cmdline_proc_show", + .new_func = livepatch_cmdline_proc_show, + }, { } +}; + +static struct klp_object objs[] = { + { + /* name being NULL means vmlinux */ + .funcs = funcs, + }, { } +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int livepatch_init(void) +{ + return klp_enable_patch(&patch); +} + +static void livepatch_exit(void) +{ +} + +module_init(livepatch_init); +module_exit(livepatch_exit); +MODULE_LICENSE("GPL"); +MODULE_INFO(livepatch, "Y"); From patchwork Mon Mar 6 14:08:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161188 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75510C678D4 for ; Mon, 6 Mar 2023 14:13:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229988AbjCFONI (ORCPT ); Mon, 6 Mar 2023 09:13:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230156AbjCFOMo (ORCPT ); Mon, 6 Mar 2023 09:12:44 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85EC332E7E for ; Mon, 6 Mar 2023 06:09:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678111712; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Z74+MVPVrIYUn/gpDGp216mCCa9lSsexpc614qbTsSg=; b=H6h+zBSnTbgweP2FK1UBW+jvyvlI4jf1sDb/3/PZOE4SNRaR3PSKC5HioU1ukU9XU4ye50 dIA8a1bhP7uGDreyLWa0a4fiKXtvA0YCgZjww9Ji4fXdFBfCN44+iOK59Tz6PYdpoGz9GM sH8my+0GRhJpuq1G5eBLDgaMsUl9EMI= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-408-veemvvR3Mwaabnm8_S_q8g-1; Mon, 06 Mar 2023 09:08:29 -0500 X-MC-Unique: veemvvR3Mwaabnm8_S_q8g-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B15323810B0E; Mon, 6 Mar 2023 14:08:28 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id 63B0840C945A; Mon, 6 Mar 2023 14:08:28 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 05/10] documentation: Update on livepatch elf format Date: Mon, 6 Mar 2023 09:08:19 -0500 Message-Id: <20230306140824.3858543-6-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Add a section to Documentation/livepatch/module-elf-format.rst describing how klp-convert works for fixing relocations. Signed-off-by: Joao Moreira Signed-off-by: Joe Lawrence Reviewed-by: Marcos Paulo de Souza --- Documentation/livepatch/livepatch.rst | 3 ++ Documentation/livepatch/module-elf-format.rst | 42 +++++++++++++++++-- 2 files changed, 42 insertions(+), 3 deletions(-) diff --git a/Documentation/livepatch/livepatch.rst b/Documentation/livepatch/livepatch.rst index 68e3651e8af9..6b317a57c276 100644 --- a/Documentation/livepatch/livepatch.rst +++ b/Documentation/livepatch/livepatch.rst @@ -261,6 +261,9 @@ into three levels: absolute position in the database, but rather the order it has been found only for a particular object ( vmlinux or a kernel module ). Note that kallsyms allows for searching symbols according to the object name. + Uniquely named symbols may use a symbol position of 0. Non-unique + symbols need to specify their object / kallsyms position, starting + at position 1. - struct klp_object defines an array of patched functions (struct klp_func) in the same object. Where the object is either vmlinux diff --git a/Documentation/livepatch/module-elf-format.rst b/Documentation/livepatch/module-elf-format.rst index 7347638895a0..72a072514581 100644 --- a/Documentation/livepatch/module-elf-format.rst +++ b/Documentation/livepatch/module-elf-format.rst @@ -2,7 +2,8 @@ Livepatch module Elf format =========================== -This document outlines the Elf format requirements that livepatch modules must follow. +This document outlines the Elf format requirements that livepatch modules must +follow. .. Table of Contents @@ -259,7 +260,8 @@ Livepatch symbol names must conform to the following format:: The position of the symbol in the object (as according to kallsyms) This is used to differentiate duplicate symbols within the same object. The symbol position is expressed numerically (0, 1, 2...). - The symbol position of a unique symbol is 0. + The symbol position of a unique symbol is 0. The symbol position of + the first non-unique symbol is 1, the second is 2, etc. Examples: --------- @@ -291,7 +293,41 @@ Examples: Note that the 'Ndx' (Section index) for these symbols is SHN_LIVEPATCH (0xff20). "OS" means OS-specific. -5. Symbol table and Elf section access +5. Automatic conversion of unresolved relocations +================================================= +Sometimes livepatches may operate on symbols which are not self-contained nor +exported. When this happens, these symbols remain unresolved in the elf object +and will trigger an error during the livepatch instantiation. + +Whenever possible, the kernel building infrastructure solves this problem +automatically. First, a symbol database containing information on all compiled +objects is built. Second, this database - a file named symbols.klp, placed in +the kernel source root directory - is used to identify targets for unresolved +relocations, converting them in the livepatch elf accordingly to the +specifications above-described. While the first stage is fully handled by the +building system, the second is done by a tool called klp-convert, which can be +found in "scripts/livepatch". + +When an unresolved relocation has as target a symbol whose name is also used by +different symbols throughout the kernel, the relocation cannot be resolved +automatically. In these cases, the livepatch developer must add annotations to +the livepatch, making it possible for the system to identify which is the +correct target amongst multiple homonymous symbols. Such annotations must be +done through a data structure as follows::: + + struct KLP_MODULE_RELOC(object) data_structure_name[] = { + KLP_SYMPOS(symbol, pos) + }; + +In the above example, object refers to the object file which contains the +symbol, being vmlinux or a module; symbol refers to the symbol name that will +be relocated and pos is its position in the object. + +When a data structure like this is added to the livepatch, the resulting elf +will hold symbols that will be identified by klp-convert and used to solve name +ambiguities. + +6. Symbol table and Elf section access ====================================== A livepatch module's symbol table is accessible through module->symtab. From patchwork Mon Mar 6 14:08:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161328 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40284C6FA99 for ; Mon, 6 Mar 2023 14:37:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230420AbjCFOhy (ORCPT ); Mon, 6 Mar 2023 09:37:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230491AbjCFOhv (ORCPT ); Mon, 6 Mar 2023 09:37:51 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 856801FFA for ; Mon, 6 Mar 2023 06:36:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678113354; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wJ+e8RQw0LRjpZu8Y7BGJtcItMGFr3Edq82YojT+bYo=; b=JcRk8q3D/pHlwbi+QZ7/Z8KUA1yVNSWj2kIcKDX9vmq8lR2dklQXlGuv7UJeAXq/yJAphO PN25CKrgeyYIAwodJHaHsVQJKiMR6Ls786XWxMDtQCKa/r2FFVJoobQXzPAzMvBbBFsQ5e Ts8pnr01+yFoY1ums2L59/9aqgHyXXo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-440-sBpGNHCVMHK3OOb0tiRtig-1; Mon, 06 Mar 2023 09:08:29 -0500 X-MC-Unique: sBpGNHCVMHK3OOb0tiRtig-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 22E22802D2F; Mon, 6 Mar 2023 14:08:29 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id C172B40C10FA; Mon, 6 Mar 2023 14:08:28 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 06/10] livepatch/selftests: add klp-convert Date: Mon, 6 Mar 2023 09:08:20 -0500 Message-Id: <20230306140824.3858543-7-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Add a simple klp-convert livepatch selftest that exercises various symbol homonym sympos scenarios. Signed-off-by: Joe Lawrence Reviewed-by: Marcos Paulo de Souza --- lib/livepatch/Makefile | 7 + lib/livepatch/test_klp_convert.h | 14 ++ lib/livepatch/test_klp_convert1.c | 113 +++++++++++++++ lib/livepatch/test_klp_convert2.c | 110 ++++++++++++++ lib/livepatch/test_klp_convert_mod_a.c | 25 ++++ lib/livepatch/test_klp_convert_mod_b.c | 13 ++ .../selftests/livepatch/test-livepatch.sh | 134 ++++++++++++++++++ 7 files changed, 416 insertions(+) create mode 100644 lib/livepatch/test_klp_convert.h create mode 100644 lib/livepatch/test_klp_convert1.c create mode 100644 lib/livepatch/test_klp_convert2.c create mode 100644 lib/livepatch/test_klp_convert_mod_a.c create mode 100644 lib/livepatch/test_klp_convert_mod_b.c diff --git a/lib/livepatch/Makefile b/lib/livepatch/Makefile index dcc912b3478f..ced00515ff84 100644 --- a/lib/livepatch/Makefile +++ b/lib/livepatch/Makefile @@ -7,8 +7,15 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \ test_klp_callbacks_demo2.o \ test_klp_callbacks_busy.o \ test_klp_callbacks_mod.o \ + test_klp_convert1.o \ + test_klp_convert2.o \ + test_klp_convert_mod.o \ test_klp_livepatch.o \ test_klp_shadow_vars.o \ test_klp_state.o \ test_klp_state2.o \ test_klp_state3.o + +test_klp_convert_mod-y := \ + test_klp_convert_mod_a.o \ + test_klp_convert_mod_b.o diff --git a/lib/livepatch/test_klp_convert.h b/lib/livepatch/test_klp_convert.h new file mode 100644 index 000000000000..5d97bc546d6e --- /dev/null +++ b/lib/livepatch/test_klp_convert.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _TEST_KLP_CONVERT_ +#define _TEST_KLP_CONVERT_ + +/* klp-convert symbols - vmlinux */ +extern char *saved_command_line; +/* klp-convert symbols - test_klp_convert_mod.ko */ +extern char driver_name[]; +extern char homonym_string[]; +extern const char *get_homonym_string(void); +extern const char *test_klp_get_driver_name(void); + +#endif diff --git a/lib/livepatch/test_klp_convert1.c b/lib/livepatch/test_klp_convert1.c new file mode 100644 index 000000000000..d4e1163c01cc --- /dev/null +++ b/lib/livepatch/test_klp_convert1.c @@ -0,0 +1,113 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2019 Joe Lawrence + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include "test_klp_convert.h" + +static noinline void print_saved_command_line(void) +{ + pr_info("saved_command_line, 0: %s\n", saved_command_line); +} + +static noinline void print_driver_name(void) +{ + pr_info("driver_name, 0: %s\n", driver_name); + pr_info("test_klp_get_driver_name(), 0: %s\n", test_klp_get_driver_name()); +} + +static noinline void print_homonym_string(void) +{ + pr_info("homonym_string, 1: %s\n", homonym_string); + pr_info("get_homonym_string(), 1: %s\n", get_homonym_string()); +} + +/* provide a sysfs handle to invoke debug functions */ +static int print_debug; +static int print_debug_set(const char *val, const struct kernel_param *kp) +{ + print_saved_command_line(); + print_driver_name(); + print_homonym_string(); + + return 0; +} +static const struct kernel_param_ops print_debug_ops = { + .set = print_debug_set, + .get = param_get_int, +}; +module_param_cb(print_debug, &print_debug_ops, &print_debug, 0200); +MODULE_PARM_DESC(print_debug, "print klp-convert debugging info"); + +/* + * saved_command_line is a unique symbol, so the sympos annotation is + * optional. Provide to test that sympos=0 works correctly. + */ +KLP_MODULE_RELOC(vmlinux) vmlinux_relocs[] = { + KLP_SYMPOS(saved_command_line, 0) +}; + +/* + * driver_name symbols can be found in vmlinux (multiple) and also + * test_klp_convert_mod, therefore the annotation is required to + * clarify that we want the one from test_klp_convert_mod. + * + * test_klp_convert_mod contains multiple homonym_string and + * get_homonym_string symbols, test resolving the first set here and + * the others in test_klp_convert2.c + * + * test_klp_get_driver_name is a uniquely named symbol, test that sympos=0 + * work correctly. + */ +KLP_MODULE_RELOC(test_klp_convert_mod) test_klp_convert_mod_relocs_a[] = { + KLP_SYMPOS(driver_name, 0), + KLP_SYMPOS(homonym_string, 1), + KLP_SYMPOS(get_homonym_string, 1), + KLP_SYMPOS(test_klp_get_driver_name, 0), +}; + +static struct klp_func funcs[] = { + { + }, { } +}; + +static struct klp_object objs[] = { + { + /* name being NULL means vmlinux */ + .funcs = funcs, + }, + { + .name = "test_klp_convert_mod", + .funcs = funcs, + }, { } +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int test_klp_convert_init(void) +{ + int ret; + + ret = klp_enable_patch(&patch); + if (ret) + return ret; + + return 0; +} + +static void test_klp_convert_exit(void) +{ +} + +module_init(test_klp_convert_init); +module_exit(test_klp_convert_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Lawrence "); +MODULE_DESCRIPTION("Livepatch test: klp-convert1"); +MODULE_INFO(livepatch, "Y"); diff --git a/lib/livepatch/test_klp_convert2.c b/lib/livepatch/test_klp_convert2.c new file mode 100644 index 000000000000..2a2a153aa0b9 --- /dev/null +++ b/lib/livepatch/test_klp_convert2.c @@ -0,0 +1,110 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2019 Joe Lawrence + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include "test_klp_convert.h" + +static noinline void print_saved_command_line(void) +{ + pr_info("saved_command_line (auto): %s\n", saved_command_line); +} + +static noinline void print_driver_name(void) +{ + pr_info("driver_name, 0: %s\n", driver_name); + pr_info("test_klp_get_driver_name(), (auto): %s\n", test_klp_get_driver_name()); +} + +static noinline void print_homonym_string(void) +{ + pr_info("homonym_string, 2: %s\n", homonym_string); + pr_info("get_homonym_string(), 2: %s\n", get_homonym_string()); +} + +/* provide a sysfs handle to invoke debug functions */ +static int print_debug; +static int print_debug_set(const char *val, const struct kernel_param *kp) +{ + print_saved_command_line(); + print_driver_name(); + print_homonym_string(); + + return 0; +} +static const struct kernel_param_ops print_debug_ops = { + .set = print_debug_set, + .get = param_get_int, +}; +module_param_cb(print_debug, &print_debug_ops, &print_debug, 0200); +MODULE_PARM_DESC(print_debug, "print klp-convert debugging info"); + +/* + * saved_command_line is a uniquely named symbol, so the sympos + * annotation is optional. Skip it and test that klp-convert can + * resolve the symbol on its own. + */ + +/* + * driver_name symbols can be found in vmlinux (multiple) and also + * test_klp_convert_mod, therefore the annotation is required to + * clarify that we want the one from test_klp_convert_mod. + * + * test_klp_convert_mod contains multiple homonym_string symbols, + * test_klp_convert1.c resolved to the first one, resolve to the + * second one here. + * + * test_klp_get_driver_name is a uniquely named symbol, test klp-convert can + * resolve it automatically. + */ +KLP_MODULE_RELOC(test_klp_convert_mod) test_klp_convert_mod_relocs_a[] = { + KLP_SYMPOS(driver_name, 0), + KLP_SYMPOS(homonym_string, 2), + KLP_SYMPOS(get_homonym_string, 2), +}; + +static struct klp_func funcs[] = { + { + }, { } +}; + +static struct klp_object objs[] = { + { + /* name being NULL means vmlinux */ + .funcs = funcs, + }, + { + .name = "test_klp_convert_mod", + .funcs = funcs, + }, { } +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int test_klp_convert_init(void) +{ + int ret; + + ret = klp_enable_patch(&patch); + if (ret) + return ret; + + return 0; +} + +static void test_klp_convert_exit(void) +{ +} + +module_init(test_klp_convert_init); +module_exit(test_klp_convert_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Lawrence "); +MODULE_DESCRIPTION("Livepatch test: klp-convert2"); +MODULE_INFO(livepatch, "Y"); diff --git a/lib/livepatch/test_klp_convert_mod_a.c b/lib/livepatch/test_klp_convert_mod_a.c new file mode 100644 index 000000000000..ae5e911fbb9b --- /dev/null +++ b/lib/livepatch/test_klp_convert_mod_a.c @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2019 Joe Lawrence + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include + +/* Unique symbols that don't need sympos annotation */ +static const char driver_name[] = KBUILD_MODNAME; +__used static const char *test_klp_get_driver_name(void) +{ + return driver_name; +} + +/* Common symbol names that need sympos */ +static const char homonym_string[] = "homonym string A"; +__used static const char *get_homonym_string(void) +{ + return homonym_string; +} + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Lawrence "); +MODULE_DESCRIPTION("Livepatch test: klp-convert module"); diff --git a/lib/livepatch/test_klp_convert_mod_b.c b/lib/livepatch/test_klp_convert_mod_b.c new file mode 100644 index 000000000000..5eca8a4cae38 --- /dev/null +++ b/lib/livepatch/test_klp_convert_mod_b.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2019 Joe Lawrence + +/* + * A second compilation unit to provide another set of similarly named + * symbols, forcing a livepatch to use sympos annotations. + */ + +static const char homonym_string[] = "homonym string B"; +__used static const char *get_homonym_string(void) +{ + return homonym_string; +} diff --git a/tools/testing/selftests/livepatch/test-livepatch.sh b/tools/testing/selftests/livepatch/test-livepatch.sh index 5fe79ac34be1..25c21ddf30f0 100755 --- a/tools/testing/selftests/livepatch/test-livepatch.sh +++ b/tools/testing/selftests/livepatch/test-livepatch.sh @@ -6,6 +6,10 @@ MOD_LIVEPATCH=test_klp_livepatch MOD_REPLACE=test_klp_atomic_replace +MOD_KLP_CONVERT_MOD=test_klp_convert_mod +MOD_KLP_CONVERT1=test_klp_convert1 +MOD_KLP_CONVERT2=test_klp_convert2 +MOD_KLP_CONVERT_SECTIONS=test_klp_convert_sections setup_config @@ -159,4 +163,134 @@ livepatch: '$MOD_REPLACE': unpatching complete % rmmod $MOD_REPLACE" +# TEST: klp-convert symbols +# - load a livepatch that modifies the output from /proc/cmdline +# including a reference to vmlinux-local symbol that klp-convert +# will process +# - verify correct behavior +# - unload the livepatch and make sure the patch was removed + +start_test "klp-convert symbols" + +saved_cmdline=$(cat /proc/cmdline) + +load_mod $MOD_KLP_CONVERT_MOD + +load_lp $MOD_KLP_CONVERT1 +echo 1 > /sys/module/$MOD_KLP_CONVERT1/parameters/print_debug +disable_lp $MOD_KLP_CONVERT1 +unload_lp $MOD_KLP_CONVERT1 + +load_lp $MOD_KLP_CONVERT2 +echo 1 > /sys/module/$MOD_KLP_CONVERT2/parameters/print_debug +disable_lp $MOD_KLP_CONVERT2 +unload_lp $MOD_KLP_CONVERT2 + +unload_mod $MOD_KLP_CONVERT_MOD + +check_result "% modprobe $MOD_KLP_CONVERT_MOD +% modprobe $MOD_KLP_CONVERT1 +livepatch: enabling patch '$MOD_KLP_CONVERT1' +livepatch: '$MOD_KLP_CONVERT1': initializing patching transition +livepatch: '$MOD_KLP_CONVERT1': starting patching transition +livepatch: '$MOD_KLP_CONVERT1': completing patching transition +livepatch: '$MOD_KLP_CONVERT1': patching complete +$MOD_KLP_CONVERT1: saved_command_line, 0: $saved_cmdline +$MOD_KLP_CONVERT1: driver_name, 0: $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT1: test_klp_get_driver_name(), 0: $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT1: homonym_string, 1: homonym string A +$MOD_KLP_CONVERT1: get_homonym_string(), 1: homonym string A +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT1/enabled +livepatch: '$MOD_KLP_CONVERT1': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT1': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT1': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT1': unpatching complete +% rmmod $MOD_KLP_CONVERT1 +% modprobe $MOD_KLP_CONVERT2 +livepatch: enabling patch '$MOD_KLP_CONVERT2' +livepatch: '$MOD_KLP_CONVERT2': initializing patching transition +livepatch: '$MOD_KLP_CONVERT2': starting patching transition +livepatch: '$MOD_KLP_CONVERT2': completing patching transition +livepatch: '$MOD_KLP_CONVERT2': patching complete +$MOD_KLP_CONVERT2: saved_command_line (auto): $saved_cmdline +$MOD_KLP_CONVERT2: driver_name, 0: $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT2: test_klp_get_driver_name(), (auto): $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT2: homonym_string, 2: homonym string B +$MOD_KLP_CONVERT2: get_homonym_string(), 2: homonym string B +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT2/enabled +livepatch: '$MOD_KLP_CONVERT2': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT2': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT2': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT2': unpatching complete +% rmmod $MOD_KLP_CONVERT2 +% rmmod $MOD_KLP_CONVERT_MOD" + + +# TEST: klp-convert symbols (late module patching) +# - load a livepatch that modifies the output from /proc/cmdline +# including a reference to vmlinux-local symbol that klp-convert +# will process +# - load target module +# - verify correct behavior +# - unload the livepatch + +start_test "klp-convert symbols (late module patching)" + +saved_cmdline=$(cat /proc/cmdline) + +load_lp $MOD_KLP_CONVERT1 +load_mod $MOD_KLP_CONVERT_MOD +echo 1 > /sys/module/$MOD_KLP_CONVERT1/parameters/print_debug +disable_lp $MOD_KLP_CONVERT1 +unload_lp $MOD_KLP_CONVERT1 +unload_mod $MOD_KLP_CONVERT_MOD + +load_lp $MOD_KLP_CONVERT2 +load_mod $MOD_KLP_CONVERT_MOD +echo 1 > /sys/module/$MOD_KLP_CONVERT2/parameters/print_debug +disable_lp $MOD_KLP_CONVERT2 +unload_lp $MOD_KLP_CONVERT2 +unload_mod $MOD_KLP_CONVERT_MOD + +check_result "% modprobe $MOD_KLP_CONVERT1 +livepatch: enabling patch '$MOD_KLP_CONVERT1' +livepatch: '$MOD_KLP_CONVERT1': initializing patching transition +livepatch: '$MOD_KLP_CONVERT1': starting patching transition +livepatch: '$MOD_KLP_CONVERT1': completing patching transition +livepatch: '$MOD_KLP_CONVERT1': patching complete +% modprobe $MOD_KLP_CONVERT_MOD +livepatch: applying patch '$MOD_KLP_CONVERT1' to loading module '$MOD_KLP_CONVERT_MOD' +$MOD_KLP_CONVERT1: saved_command_line, 0: $saved_cmdline +$MOD_KLP_CONVERT1: driver_name, 0: $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT1: test_klp_get_driver_name(), 0: $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT1: homonym_string, 1: homonym string A +$MOD_KLP_CONVERT1: get_homonym_string(), 1: homonym string A +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT1/enabled +livepatch: '$MOD_KLP_CONVERT1': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT1': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT1': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT1': unpatching complete +% rmmod $MOD_KLP_CONVERT1 +% rmmod $MOD_KLP_CONVERT_MOD +% modprobe $MOD_KLP_CONVERT2 +livepatch: enabling patch '$MOD_KLP_CONVERT2' +livepatch: '$MOD_KLP_CONVERT2': initializing patching transition +livepatch: '$MOD_KLP_CONVERT2': starting patching transition +livepatch: '$MOD_KLP_CONVERT2': completing patching transition +livepatch: '$MOD_KLP_CONVERT2': patching complete +% modprobe $MOD_KLP_CONVERT_MOD +livepatch: applying patch '$MOD_KLP_CONVERT2' to loading module '$MOD_KLP_CONVERT_MOD' +$MOD_KLP_CONVERT2: saved_command_line (auto): $saved_cmdline +$MOD_KLP_CONVERT2: driver_name, 0: $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT2: test_klp_get_driver_name(), (auto): $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT2: homonym_string, 2: homonym string B +$MOD_KLP_CONVERT2: get_homonym_string(), 2: homonym string B +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT2/enabled +livepatch: '$MOD_KLP_CONVERT2': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT2': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT2': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT2': unpatching complete +% rmmod $MOD_KLP_CONVERT2 +% rmmod $MOD_KLP_CONVERT_MOD" + exit 0 From patchwork Mon Mar 6 14:08:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161293 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56753C6FA99 for ; Mon, 6 Mar 2023 14:25:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id 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Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 07/10] livepatch/selftests: test multiple sections Date: Mon, 6 Mar 2023 09:08:21 -0500 Message-Id: <20230306140824.3858543-8-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Add a test case in which klp-convert needs to convert a symbol that is shared across ELF sections. Special sections like .altinstructions do this. It is possible that symbols may be shared across various .text sections as well. Signed-off-by: Joe Lawrence --- lib/livepatch/Makefile | 1 + lib/livepatch/test_klp_convert_sections.c | 120 ++++++++++++++++++ .../selftests/livepatch/test-livepatch.sh | 43 +++++++ 3 files changed, 164 insertions(+) create mode 100644 lib/livepatch/test_klp_convert_sections.c diff --git a/lib/livepatch/Makefile b/lib/livepatch/Makefile index ced00515ff84..77e21317d4da 100644 --- a/lib/livepatch/Makefile +++ b/lib/livepatch/Makefile @@ -9,6 +9,7 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \ test_klp_callbacks_mod.o \ test_klp_convert1.o \ test_klp_convert2.o \ + test_klp_convert_sections.o \ test_klp_convert_mod.o \ test_klp_livepatch.o \ test_klp_shadow_vars.o \ diff --git a/lib/livepatch/test_klp_convert_sections.c b/lib/livepatch/test_klp_convert_sections.c new file mode 100644 index 000000000000..fb6cdb9aaa90 --- /dev/null +++ b/lib/livepatch/test_klp_convert_sections.c @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2020 Joe Lawrence + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include "test_klp_convert.h" + +/* klp-convert symbols - vmlinux */ +extern char *saved_command_line; + +/* + * Scatter references to the same symbol (saved_command_line) across a + * few different ELF sections. At the same time, include multiple + * references within the same function. + */ +__section(".text.print_saved_command_line") +static noinline void print_saved_command_line(void) +{ + pr_info("saved_command_line (1): %s\n", saved_command_line); +} + +__section(".text.print_saved_command_line2") +static noinline void print_saved_command_line2(void) +{ + pr_info("saved_command_line (1): %s\n", saved_command_line); + pr_info("saved_command_line (2): %s\n", saved_command_line); +} + +__section(".text.print_saved_command_line3") +static noinline void print_saved_command_line3(void) +{ + pr_info("saved_command_line (1): %s\n", saved_command_line); + pr_info("saved_command_line (2): %s\n", saved_command_line); + pr_info("saved_command_line (3): %s\n", saved_command_line); +} + +/* + * Create relocations in .rela.data that need conversion, sharing + * symbols with ordinary .text relas. + */ +const char *(*p_test_klp_get_driver_name)(void) = test_klp_get_driver_name; +const char *(*p_get_homonym_string)(void) = get_homonym_string; + +static noinline void print_via_function_pointers(void) +{ + pr_info("test_klp_get_driver_name(): %s\n", test_klp_get_driver_name()); + pr_info("p_test_klp_get_driver_name(): %s\n", p_test_klp_get_driver_name()); + pr_info("get_homonym_string(): %s\n", get_homonym_string()); + pr_info("p_get_homonym_string(): %s\n", p_get_homonym_string()); +} + +/* provide a sysfs handle to invoke debug functions */ +static int print_debug; +static int print_debug_set(const char *val, const struct kernel_param *kp) +{ + print_saved_command_line(); + print_saved_command_line2(); + print_saved_command_line3(); + print_via_function_pointers(); + + return 0; +} +static const struct kernel_param_ops print_debug_ops = { + .set = print_debug_set, + .get = param_get_int, +}; + +module_param_cb(print_debug, &print_debug_ops, &print_debug, 0200); +MODULE_PARM_DESC(print_debug, "print klp-convert debugging info"); + + +KLP_MODULE_RELOC(test_klp_convert_mod) test_klp_convert_mod_relocs_a[] = { + KLP_SYMPOS(get_homonym_string, 1), +}; + +static struct klp_func funcs[] = { + { + }, { } +}; + +static struct klp_object objs[] = { + { + /* name being NULL means vmlinux */ + .funcs = funcs, + }, + { + .name = "test_klp_convert_mod", + .funcs = funcs, + }, { } +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int test_klp_convert_sections_init(void) +{ + int ret; + + ret = klp_enable_patch(&patch); + if (ret) + return ret; + + return 0; +} + +static void test_klp_convert_sections_exit(void) +{ +} + +module_init(test_klp_convert_sections_init); +module_exit(test_klp_convert_sections_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Lawrence "); +MODULE_DESCRIPTION("Livepatch test: klp-convert-sections"); +MODULE_INFO(livepatch, "Y"); diff --git a/tools/testing/selftests/livepatch/test-livepatch.sh b/tools/testing/selftests/livepatch/test-livepatch.sh index 25c21ddf30f0..bcb8b468b80a 100755 --- a/tools/testing/selftests/livepatch/test-livepatch.sh +++ b/tools/testing/selftests/livepatch/test-livepatch.sh @@ -293,4 +293,47 @@ livepatch: '$MOD_KLP_CONVERT2': unpatching complete % rmmod $MOD_KLP_CONVERT2 % rmmod $MOD_KLP_CONVERT_MOD" + +# TEST: klp-convert symbols across ELF sections +# - load a livepatch that references symbols that require klp-convert +# and reference the same symbol from multiple ELF sections +# - verify correct behavior +# - unload the livepatch + +start_test "klp-convert symbols across ELF sections" + +saved_cmdline=$(cat /proc/cmdline) + +load_mod $MOD_KLP_CONVERT_MOD +load_lp $MOD_KLP_CONVERT_SECTIONS +echo 1 > /sys/module/$MOD_KLP_CONVERT_SECTIONS/parameters/print_debug +disable_lp $MOD_KLP_CONVERT_SECTIONS +unload_lp $MOD_KLP_CONVERT_SECTIONS +unload_mod $MOD_KLP_CONVERT_MOD + +check_result "% modprobe $MOD_KLP_CONVERT_MOD +% modprobe $MOD_KLP_CONVERT_SECTIONS +livepatch: enabling patch '$MOD_KLP_CONVERT_SECTIONS' +livepatch: '$MOD_KLP_CONVERT_SECTIONS': initializing patching transition +livepatch: '$MOD_KLP_CONVERT_SECTIONS': starting patching transition +livepatch: '$MOD_KLP_CONVERT_SECTIONS': completing patching transition +livepatch: '$MOD_KLP_CONVERT_SECTIONS': patching complete +$MOD_KLP_CONVERT_SECTIONS: saved_command_line (1): $saved_cmdline +$MOD_KLP_CONVERT_SECTIONS: saved_command_line (1): $saved_cmdline +$MOD_KLP_CONVERT_SECTIONS: saved_command_line (2): $saved_cmdline +$MOD_KLP_CONVERT_SECTIONS: saved_command_line (1): $saved_cmdline +$MOD_KLP_CONVERT_SECTIONS: saved_command_line (2): $saved_cmdline +$MOD_KLP_CONVERT_SECTIONS: saved_command_line (3): $saved_cmdline +$MOD_KLP_CONVERT_SECTIONS: test_klp_get_driver_name(): $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT_SECTIONS: p_test_klp_get_driver_name(): $MOD_KLP_CONVERT_MOD +$MOD_KLP_CONVERT_SECTIONS: get_homonym_string(): homonym string A +$MOD_KLP_CONVERT_SECTIONS: p_get_homonym_string(): homonym string A +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT_SECTIONS/enabled +livepatch: '$MOD_KLP_CONVERT_SECTIONS': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT_SECTIONS': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT_SECTIONS': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT_SECTIONS': unpatching complete +% rmmod $MOD_KLP_CONVERT_SECTIONS +% rmmod $MOD_KLP_CONVERT_MOD" + exit 0 From patchwork Mon Mar 6 14:08:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161250 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 882BEC6FA99 for ; Mon, 6 Mar 2023 14:18:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229520AbjCFOSL (ORCPT ); Mon, 6 Mar 2023 09:18:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229935AbjCFORr (ORCPT ); Mon, 6 Mar 2023 09:17:47 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 91AB430EBF for ; Mon, 6 Mar 2023 06:16:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; 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Mon, 6 Mar 2023 14:08:29 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id 95B7C40C10FA; Mon, 6 Mar 2023 14:08:29 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 08/10] livepatch/selftests: add __asm__ symbol renaming examples Date: Mon, 6 Mar 2023 09:08:22 -0500 Message-Id: <20230306140824.3858543-9-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org GCC can rename symbols like static data and optimized functions, adding a suffix that includes illegal C characters. Extend the klp-convert examples to demonstrate how to use __asm__ renaming from C code to create klp-relocations to such renamed symbols. Signed-off-by: Joe Lawrence --- lib/livepatch/test_klp_convert.h | 2 ++ lib/livepatch/test_klp_convert1.c | 8 ++++++++ lib/livepatch/test_klp_convert_mod_a.c | 6 ++++++ lib/livepatch/test_klp_convert_mod_b.c | 6 ++++++ tools/testing/selftests/livepatch/test-livepatch.sh | 4 ++++ 5 files changed, 26 insertions(+) diff --git a/lib/livepatch/test_klp_convert.h b/lib/livepatch/test_klp_convert.h index 5d97bc546d6e..42befbfd63cb 100644 --- a/lib/livepatch/test_klp_convert.h +++ b/lib/livepatch/test_klp_convert.h @@ -10,5 +10,7 @@ extern char driver_name[]; extern char homonym_string[]; extern const char *get_homonym_string(void); extern const char *test_klp_get_driver_name(void); +extern char klp_string_a[] __asm__("klp_string.12345"); +extern char klp_string_b[] __asm__("klp_string.67890"); #endif diff --git a/lib/livepatch/test_klp_convert1.c b/lib/livepatch/test_klp_convert1.c index d4e1163c01cc..9541f40d70a8 100644 --- a/lib/livepatch/test_klp_convert1.c +++ b/lib/livepatch/test_klp_convert1.c @@ -25,6 +25,12 @@ static noinline void print_homonym_string(void) pr_info("get_homonym_string(), 1: %s\n", get_homonym_string()); } +static noinline void print_static_strings(void) +{ + pr_info("klp_string.12345 = %s\n", klp_string_a); + pr_info("klp_string.67890 = %s\n", klp_string_b); +} + /* provide a sysfs handle to invoke debug functions */ static int print_debug; static int print_debug_set(const char *val, const struct kernel_param *kp) @@ -32,6 +38,7 @@ static int print_debug_set(const char *val, const struct kernel_param *kp) print_saved_command_line(); print_driver_name(); print_homonym_string(); + print_static_strings(); return 0; } @@ -67,6 +74,7 @@ KLP_MODULE_RELOC(test_klp_convert_mod) test_klp_convert_mod_relocs_a[] = { KLP_SYMPOS(homonym_string, 1), KLP_SYMPOS(get_homonym_string, 1), KLP_SYMPOS(test_klp_get_driver_name, 0), + KLP_SYMPOS(klp_string_b, 1), }; static struct klp_func funcs[] = { diff --git a/lib/livepatch/test_klp_convert_mod_a.c b/lib/livepatch/test_klp_convert_mod_a.c index ae5e911fbb9b..9af0fcab0c8d 100644 --- a/lib/livepatch/test_klp_convert_mod_a.c +++ b/lib/livepatch/test_klp_convert_mod_a.c @@ -20,6 +20,12 @@ __used static const char *get_homonym_string(void) return homonym_string; } +__used static void static_string_function(void) +{ + __used static char klp_string[] __asm__("klp_string.12345") = + __FILE__ " static string"; +} + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Joe Lawrence "); MODULE_DESCRIPTION("Livepatch test: klp-convert module"); diff --git a/lib/livepatch/test_klp_convert_mod_b.c b/lib/livepatch/test_klp_convert_mod_b.c index 5eca8a4cae38..0a68e898fe03 100644 --- a/lib/livepatch/test_klp_convert_mod_b.c +++ b/lib/livepatch/test_klp_convert_mod_b.c @@ -11,3 +11,9 @@ __used static const char *get_homonym_string(void) { return homonym_string; } + +__used static void static_string_function(void) +{ + __used static char klp_string[] __asm__("klp_string.67890") = + __FILE__ " static string"; +} diff --git a/tools/testing/selftests/livepatch/test-livepatch.sh b/tools/testing/selftests/livepatch/test-livepatch.sh index bcb8b468b80a..ec3b6c919b01 100755 --- a/tools/testing/selftests/livepatch/test-livepatch.sh +++ b/tools/testing/selftests/livepatch/test-livepatch.sh @@ -200,6 +200,8 @@ $MOD_KLP_CONVERT1: driver_name, 0: $MOD_KLP_CONVERT_MOD $MOD_KLP_CONVERT1: test_klp_get_driver_name(), 0: $MOD_KLP_CONVERT_MOD $MOD_KLP_CONVERT1: homonym_string, 1: homonym string A $MOD_KLP_CONVERT1: get_homonym_string(), 1: homonym string A +test_klp_convert1: klp_string.12345 = lib/livepatch/test_klp_convert_mod_a.c static string +test_klp_convert1: klp_string.67890 = lib/livepatch/test_klp_convert_mod_b.c static string % echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT1/enabled livepatch: '$MOD_KLP_CONVERT1': initializing unpatching transition livepatch: '$MOD_KLP_CONVERT1': starting unpatching transition @@ -265,6 +267,8 @@ $MOD_KLP_CONVERT1: driver_name, 0: $MOD_KLP_CONVERT_MOD $MOD_KLP_CONVERT1: test_klp_get_driver_name(), 0: $MOD_KLP_CONVERT_MOD $MOD_KLP_CONVERT1: homonym_string, 1: homonym string A $MOD_KLP_CONVERT1: get_homonym_string(), 1: homonym string A +test_klp_convert1: klp_string.12345 = lib/livepatch/test_klp_convert_mod_a.c static string +test_klp_convert1: klp_string.67890 = lib/livepatch/test_klp_convert_mod_b.c static string % echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT1/enabled livepatch: '$MOD_KLP_CONVERT1': initializing unpatching transition livepatch: '$MOD_KLP_CONVERT1': starting unpatching transition From patchwork Mon Mar 6 14:08:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161186 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 100A9C6FD1C for ; Mon, 6 Mar 2023 14:12:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231374AbjCFOMu (ORCPT ); Mon, 6 Mar 2023 09:12:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231484AbjCFOM3 (ORCPT ); Mon, 6 Mar 2023 09:12:29 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47A5434022 for ; Mon, 6 Mar 2023 06:09:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; 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Mon, 6 Mar 2023 14:08:30 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1457E40C945A; Mon, 6 Mar 2023 14:08:30 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 09/10] livepatch/selftests: add data relocations test Date: Mon, 6 Mar 2023 09:08:23 -0500 Message-Id: <20230306140824.3858543-10-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Add a test which creates a variety of klp-data-relocations. Note that this test case exercises late-klp-relocations for references to data. For this, we only need to adjust pointer storage classes (and not the target data) to affect where the relocation ends up. Signed-off-by: Joe Lawrence --- lib/livepatch/Makefile | 4 +- lib/livepatch/test_klp_convert.h | 21 ++ lib/livepatch/test_klp_convert_data.c | 190 ++++++++++++++++++ lib/livepatch/test_klp_convert_mod_c.c | 36 ++++ .../selftests/livepatch/test-livepatch.sh | 95 +++++++++ 5 files changed, 345 insertions(+), 1 deletion(-) create mode 100644 lib/livepatch/test_klp_convert_data.c create mode 100644 lib/livepatch/test_klp_convert_mod_c.c diff --git a/lib/livepatch/Makefile b/lib/livepatch/Makefile index 77e21317d4da..da39aaa5c8fc 100644 --- a/lib/livepatch/Makefile +++ b/lib/livepatch/Makefile @@ -9,6 +9,7 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \ test_klp_callbacks_mod.o \ test_klp_convert1.o \ test_klp_convert2.o \ + test_klp_convert_data.o \ test_klp_convert_sections.o \ test_klp_convert_mod.o \ test_klp_livepatch.o \ @@ -19,4 +20,5 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \ test_klp_convert_mod-y := \ test_klp_convert_mod_a.o \ - test_klp_convert_mod_b.o + test_klp_convert_mod_b.o \ + test_klp_convert_mod_c.o diff --git a/lib/livepatch/test_klp_convert.h b/lib/livepatch/test_klp_convert.h index 42befbfd63cb..08c0f4b1dc6b 100644 --- a/lib/livepatch/test_klp_convert.h +++ b/lib/livepatch/test_klp_convert.h @@ -12,5 +12,26 @@ extern const char *get_homonym_string(void); extern const char *test_klp_get_driver_name(void); extern char klp_string_a[] __asm__("klp_string.12345"); extern char klp_string_b[] __asm__("klp_string.67890"); +extern int global_small; +// .rela.data.rel.ro, .rela.rodata supported ???: +extern int const_global_small; +extern int static_small; +extern int static_const_small; +extern int global_large[]; +// .rela.data.rel.ro, .rela.rodata supported ???: +extern int const_global_large[]; +extern int static_large[]; +extern int static_const_large[]; +extern int local_small; +extern int const_local_small; +extern int static_local_small; +extern int static_const_local_small; +extern int local_large[4]; +extern int const_local_large[4]; +extern int static_local_large[4]; +extern int static_const_local_large[4]; +// .rela.data..ro_after_init supported ???: +extern int static_ro_after_init; +extern int static_read_mostly; #endif diff --git a/lib/livepatch/test_klp_convert_data.c b/lib/livepatch/test_klp_convert_data.c new file mode 100644 index 000000000000..da94f7af272f --- /dev/null +++ b/lib/livepatch/test_klp_convert_data.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2021 Joe Lawrence + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include "test_klp_convert.h" + +/* Small global */ +int *p_global_small = &global_small; + +/* Small global (const) */ +// .rela.data.rel.ro, .rela.rodata supported ???: +int * const p_const_global_small = &const_global_small; + +/* Small file-static */ +static int *p_static_small = &static_small; + +/* Small file-static (constant) */ +static int * const p_static_const_small = &static_const_small; + +/* Large global */ +int *p_global_large[4] = { + &global_large[0], &global_large[1], + &global_large[2], &global_large[3], +}; + +/* Large global (const) */ +// .rela.data.rel.ro, .rela.rodata supported ???: +int * const p_const_global_large[4] = { + &const_global_large[0], &const_global_large[1], + &const_global_large[2], &const_global_large[3], +}; + +/* Large file-static global */ +static int *p_static_large[4] = { + &static_large[0], &static_large[1], + &static_large[2], &static_large[3], +}; + +/* Large file-static (const) */ +static int * const p_static_const_large[4] = { + &static_const_large[0], &static_const_large[1], + &static_const_large[2], &static_const_large[3], +}; + +// .rela.data.rel.ro, .rela.rodata supported ???: +// static int * __ro_after_init p_static_ro_after_init = &static_ro_after_init; +static int * __read_mostly p_static_read_mostly = &static_read_mostly; + +static void print_variables(void) +{ + /* Small local */ + int *p_local_small = &local_small; + + /* Small local (const) */ + int * const p_const_local_small = &const_local_small; + + /* Small static-local */ + static int *p_static_local_small = &static_local_small; + + /* Small static-local (const) */ + static int * const p_static_const_local_small = &static_const_local_small; + + /* Large local */ + int *p_local_large[4] = { + &local_large[0], &local_large[1], + &local_large[2], &local_large[3], + }; + + /* Large local (const) */ + int * const p_const_local_large[4] = { + &const_local_large[0], &const_local_large[1], + &const_local_large[2], &const_local_large[3], + }; + + /* Large static-local local */ + static int *p_static_local_large[4] = { + &static_local_large[0], &static_local_large[1], + &static_local_large[2], &static_local_large[3], + }; + + /* Large static-local (const) */ + static int * const p_static_const_local_large[4] = { + &static_const_local_large[0], &static_const_local_large[1], + &static_const_local_large[2], &static_const_local_large[3], + }; + + pr_info("local_small: %x\n", *p_local_small); + pr_info("const_local_small: %x\n", *p_const_local_small); + pr_info("static_local_small: %x\n", *p_static_local_small); + pr_info("static_const_local_small: %x\n", *p_static_const_local_small); + pr_info("local_large[0..3]: %x %x %x %x\n", + *p_local_large[0], *p_local_large[1], + *p_local_large[2], *p_local_large[3]); + pr_info("const_local_large[0..3]: %x %x %x %x\n", + *p_const_local_large[0], *p_const_local_large[1], + *p_const_local_large[2], *p_const_local_large[3]); + pr_info("static_local_large[0..3]: %x %x %x %x\n", + *p_static_local_large[0], *p_static_local_large[1], + *p_static_local_large[2], *p_static_local_large[3]); + pr_info("static_const_local_large[0..3]: %x %x %x %x\n", + *p_static_const_local_large[0], *p_static_const_local_large[1], + *p_static_const_local_large[2], *p_static_const_local_large[3]); + + pr_info("global_small: %x\n", *p_global_small); + // .rela.data.rel.ro, .rela.rodata supported ???: + pr_info("const_global_small: %x\n", *p_const_global_small); + pr_info("static_small: %x\n", *p_static_small); + pr_info("static_const_small: %x\n", *p_static_const_small); + pr_info("global_large[0..3]: %x %x %x %x\n", + *p_global_large[0], *p_global_large[1], + *p_global_large[2], *p_global_large[3]); + // .rela.data.rel.ro, .rela.rodata supported ???: + pr_info("const_global_large[0..3]: %x %x %x %x\n", + *p_const_global_large[0], *p_const_global_large[1], + *p_const_global_large[2], *p_const_global_large[3]); + pr_info("static_large[0..3]: %x %x %x %x\n", + *p_static_large[0], *p_static_large[1], + *p_static_large[2], *p_static_large[3]); + pr_info("static_const_large[0..3]: %x %x %x %x\n", + *p_static_const_large[0], *p_static_const_large[1], + *p_static_const_large[2], *p_static_const_large[3]); + + // .rela.data..ro_after_init supported ???: + // pr_info("static_ro_after_init: %x\n", *p_static_ro_after_init); + pr_info("static_read_mostly: %x\n", *p_static_read_mostly); +} + +/* provide a sysfs handle to invoke debug functions */ +static int print_debug; +static int print_debug_set(const char *val, const struct kernel_param *kp) +{ + print_variables(); + + return 0; +} +static const struct kernel_param_ops print_debug_ops = { + .set = print_debug_set, + .get = param_get_int, +}; +module_param_cb(print_debug, &print_debug_ops, &print_debug, 0200); +MODULE_PARM_DESC(print_debug, "print klp-convert debugging info"); + + +static struct klp_func funcs[] = { + { + }, { } +}; + +static struct klp_object objs[] = { + { + /* name being NULL means vmlinux */ + .funcs = funcs, + }, + { + .name = "test_klp_convert_mod", + .funcs = funcs, + }, { } +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int test_klp_convert_init(void) +{ + int ret; + + ret = klp_enable_patch(&patch); + if (ret) + return ret; + + return 0; +} + +static void test_klp_convert_exit(void) +{ +} + +module_init(test_klp_convert_init); +module_exit(test_klp_convert_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Lawrence "); +MODULE_DESCRIPTION("Livepatch test: klp-convert-data"); +MODULE_INFO(livepatch, "Y"); diff --git a/lib/livepatch/test_klp_convert_mod_c.c b/lib/livepatch/test_klp_convert_mod_c.c new file mode 100644 index 000000000000..8f94a313e651 --- /dev/null +++ b/lib/livepatch/test_klp_convert_mod_c.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2021 Joe Lawrence + +#include + +/* + * test_klp_convert_data will create klp-relocations to these variables. + * They are named for the storage class of the variable that refers to + * the. This makes it easier to correlate those symbols to the + * relocations that refer to them in readelf output. + */ +__used static int global_small = 0x1111; +// .rela.data.rel.ro, .rela.rodata supported ???: +__used static int const_global_small = 0x2222; +__used static int static_small = 0x3333; +__used static int static_const_small = 0x4444; + +__used static int global_large[4] = { 0x1111, 0x2222, 0x3333, 0x4444 }; +// .rela.data.rel.ro, .rela.rodata supported ???: +__used static int const_global_large[4] = { 0x5555, 0x6666, 0x7777, 0x8888 }; +__used static int static_large[4] = { 0x9999, 0xaaaa, 0xbbbb, 0xcccc }; +__used static int static_const_large[4] = { 0xdddd, 0xeeee, 0xffff, 0x0000 }; + +__used static int local_small = 0x1111; +__used static int const_local_small = 0x2222; +__used static int static_local_small = 0x3333; +__used static int static_const_local_small = 0x4444; + +__used static int local_large[4] = { 0x1111, 0x2222, 0x3333, 0x4444 }; +__used static int const_local_large[4] = { 0x5555, 0x6666, 0x7777, 0x8888 }; +__used static int static_local_large[4] = { 0x9999, 0xaaaa, 0xbbbb, 0xcccc }; +__used static int static_const_local_large[4] = { 0xdddd, 0xeeee, 0xffff, 0x0000 }; + +// .rela.data..ro_after_init supported ???: +// __used static int static_ro_after_init = 0x1111; +__used static int static_read_mostly = 0x2222; diff --git a/tools/testing/selftests/livepatch/test-livepatch.sh b/tools/testing/selftests/livepatch/test-livepatch.sh index ec3b6c919b01..5bda36b65bb5 100755 --- a/tools/testing/selftests/livepatch/test-livepatch.sh +++ b/tools/testing/selftests/livepatch/test-livepatch.sh @@ -9,6 +9,7 @@ MOD_REPLACE=test_klp_atomic_replace MOD_KLP_CONVERT_MOD=test_klp_convert_mod MOD_KLP_CONVERT1=test_klp_convert1 MOD_KLP_CONVERT2=test_klp_convert2 +MOD_KLP_CONVERT_DATA=test_klp_convert_data MOD_KLP_CONVERT_SECTIONS=test_klp_convert_sections setup_config @@ -340,4 +341,98 @@ livepatch: '$MOD_KLP_CONVERT_SECTIONS': unpatching complete % rmmod $MOD_KLP_CONVERT_SECTIONS % rmmod $MOD_KLP_CONVERT_MOD" + +# TEST: klp-convert data relocations + +start_test "klp-convert data relocations" + +load_mod $MOD_KLP_CONVERT_MOD +load_lp $MOD_KLP_CONVERT_DATA + +echo 1 > /sys/module/$MOD_KLP_CONVERT_DATA/parameters/print_debug + +disable_lp $MOD_KLP_CONVERT_DATA +unload_lp $MOD_KLP_CONVERT_DATA +unload_mod $MOD_KLP_CONVERT_MOD + +check_result "% modprobe $MOD_KLP_CONVERT_MOD +% modprobe $MOD_KLP_CONVERT_DATA +livepatch: enabling patch '$MOD_KLP_CONVERT_DATA' +livepatch: '$MOD_KLP_CONVERT_DATA': initializing patching transition +livepatch: '$MOD_KLP_CONVERT_DATA': starting patching transition +livepatch: '$MOD_KLP_CONVERT_DATA': completing patching transition +livepatch: '$MOD_KLP_CONVERT_DATA': patching complete +$MOD_KLP_CONVERT_DATA: local_small: 1111 +$MOD_KLP_CONVERT_DATA: const_local_small: 2222 +$MOD_KLP_CONVERT_DATA: static_local_small: 3333 +$MOD_KLP_CONVERT_DATA: static_const_local_small: 4444 +$MOD_KLP_CONVERT_DATA: local_large[0..3]: 1111 2222 3333 4444 +$MOD_KLP_CONVERT_DATA: const_local_large[0..3]: 5555 6666 7777 8888 +$MOD_KLP_CONVERT_DATA: static_local_large[0..3]: 9999 aaaa bbbb cccc +$MOD_KLP_CONVERT_DATA: static_const_local_large[0..3]: dddd eeee ffff 0 +$MOD_KLP_CONVERT_DATA: global_small: 1111 +$MOD_KLP_CONVERT_DATA: const_global_small: 2222 +$MOD_KLP_CONVERT_DATA: static_small: 3333 +$MOD_KLP_CONVERT_DATA: static_const_small: 4444 +$MOD_KLP_CONVERT_DATA: global_large[0..3]: 1111 2222 3333 4444 +$MOD_KLP_CONVERT_DATA: const_global_large[0..3]: 5555 6666 7777 8888 +$MOD_KLP_CONVERT_DATA: static_large[0..3]: 9999 aaaa bbbb cccc +$MOD_KLP_CONVERT_DATA: static_const_large[0..3]: dddd eeee ffff 0 +$MOD_KLP_CONVERT_DATA: static_read_mostly: 2222 +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT_DATA/enabled +livepatch: '$MOD_KLP_CONVERT_DATA': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT_DATA': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT_DATA': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT_DATA': unpatching complete +% rmmod $MOD_KLP_CONVERT_DATA +% rmmod $MOD_KLP_CONVERT_MOD" + + +# TEST: klp-convert data relocations (late module patching) + +start_test "klp-convert data relocations (late module patching)" + +load_lp $MOD_KLP_CONVERT_DATA +load_mod $MOD_KLP_CONVERT_MOD + +echo 1 > /sys/module/$MOD_KLP_CONVERT_DATA/parameters/print_debug + +disable_lp $MOD_KLP_CONVERT_DATA +unload_lp $MOD_KLP_CONVERT_DATA +unload_mod $MOD_KLP_CONVERT_MOD + +check_result "% modprobe $MOD_KLP_CONVERT_DATA +livepatch: enabling patch '$MOD_KLP_CONVERT_DATA' +livepatch: '$MOD_KLP_CONVERT_DATA': initializing patching transition +livepatch: '$MOD_KLP_CONVERT_DATA': starting patching transition +livepatch: '$MOD_KLP_CONVERT_DATA': completing patching transition +livepatch: '$MOD_KLP_CONVERT_DATA': patching complete +% modprobe $MOD_KLP_CONVERT_MOD +livepatch: applying patch '$MOD_KLP_CONVERT_DATA' to loading module '$MOD_KLP_CONVERT_MOD' +$MOD_KLP_CONVERT_DATA: local_small: 1111 +$MOD_KLP_CONVERT_DATA: const_local_small: 2222 +$MOD_KLP_CONVERT_DATA: static_local_small: 3333 +$MOD_KLP_CONVERT_DATA: static_const_local_small: 4444 +$MOD_KLP_CONVERT_DATA: local_large[0..3]: 1111 2222 3333 4444 +$MOD_KLP_CONVERT_DATA: const_local_large[0..3]: 5555 6666 7777 8888 +$MOD_KLP_CONVERT_DATA: static_local_large[0..3]: 9999 aaaa bbbb cccc +$MOD_KLP_CONVERT_DATA: static_const_local_large[0..3]: dddd eeee ffff 0 +$MOD_KLP_CONVERT_DATA: global_small: 1111 +$MOD_KLP_CONVERT_DATA: const_global_small: 2222 +$MOD_KLP_CONVERT_DATA: static_small: 3333 +$MOD_KLP_CONVERT_DATA: static_const_small: 4444 +$MOD_KLP_CONVERT_DATA: global_large[0..3]: 1111 2222 3333 4444 +$MOD_KLP_CONVERT_DATA: const_global_large[0..3]: 5555 6666 7777 8888 +$MOD_KLP_CONVERT_DATA: static_large[0..3]: 9999 aaaa bbbb cccc +$MOD_KLP_CONVERT_DATA: static_const_large[0..3]: dddd eeee ffff 0 +$MOD_KLP_CONVERT_DATA: static_read_mostly: 2222 +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT_DATA/enabled +livepatch: '$MOD_KLP_CONVERT_DATA': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT_DATA': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT_DATA': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT_DATA': unpatching complete +% rmmod $MOD_KLP_CONVERT_DATA +% rmmod $MOD_KLP_CONVERT_MOD" + + exit 0 From patchwork Mon Mar 6 14:08:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Lawrence X-Patchwork-Id: 13161249 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDD12C678D4 for ; Mon, 6 Mar 2023 14:17:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229613AbjCFORz (ORCPT ); Mon, 6 Mar 2023 09:17:55 -0500 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mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-616-FAoZp5ncNvWMUae1Mdcpqg-1; Mon, 06 Mar 2023 09:08:31 -0500 X-MC-Unique: FAoZp5ncNvWMUae1Mdcpqg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CE9A7802D2A; Mon, 6 Mar 2023 14:08:30 +0000 (UTC) Received: from jlaw-desktop.redhat.com (unknown [10.22.17.104]) by smtp.corp.redhat.com (Postfix) with ESMTP id 791B640C10FA; Mon, 6 Mar 2023 14:08:30 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Josh Poimboeuf , Miroslav Benes , Petr Mladek , Marcos Paulo de Souza Subject: [PATCH v7 10/10] livepatch/selftests: add static keys test Date: Mon, 6 Mar 2023 09:08:24 -0500 Message-Id: <20230306140824.3858543-11-joe.lawrence@redhat.com> In-Reply-To: <20230306140824.3858543-1-joe.lawrence@redhat.com> References: <20230306140824.3858543-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Add a livepatch kselftest that exercises klp-convert support for static keys: - Use static_branch_(un)likely() on vmlinux-defined keys, forcing .rela__jump_table klp-relocations for them. - Use only static_key_enable() on module-defined keys, creating .text klp-relocations for them. Signed-off-by: Joe Lawrence --- lib/livepatch/Makefile | 2 + lib/livepatch/test_klp_convert.h | 8 ++ lib/livepatch/test_klp_convert_keys.c | 91 +++++++++++++ lib/livepatch/test_klp_convert_keys_mod.c | 52 +++++++ .../selftests/livepatch/test-livepatch.sh | 127 ++++++++++++++++++ 5 files changed, 280 insertions(+) create mode 100644 lib/livepatch/test_klp_convert_keys.c create mode 100644 lib/livepatch/test_klp_convert_keys_mod.c diff --git a/lib/livepatch/Makefile b/lib/livepatch/Makefile index da39aaa5c8fc..a3c2ac61387f 100644 --- a/lib/livepatch/Makefile +++ b/lib/livepatch/Makefile @@ -11,6 +11,8 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \ test_klp_convert2.o \ test_klp_convert_data.o \ test_klp_convert_sections.o \ + test_klp_convert_keys.o \ + test_klp_convert_keys_mod.o \ test_klp_convert_mod.o \ test_klp_livepatch.o \ test_klp_shadow_vars.o \ diff --git a/lib/livepatch/test_klp_convert.h b/lib/livepatch/test_klp_convert.h index 08c0f4b1dc6b..97d4c26e4c39 100644 --- a/lib/livepatch/test_klp_convert.h +++ b/lib/livepatch/test_klp_convert.h @@ -34,4 +34,12 @@ extern int static_const_local_large[4]; extern int static_ro_after_init; extern int static_read_mostly; +/* klp-convert symbols - vmlinux */ +extern struct static_key_false tracepoint_printk_key; + +/* klp-convert symbols - test_klp_keys_mod.ko */ +extern struct static_key_true test_klp_true_key; +extern struct static_key_false test_klp_false_key; + + #endif diff --git a/lib/livepatch/test_klp_convert_keys.c b/lib/livepatch/test_klp_convert_keys.c new file mode 100644 index 000000000000..90c20e84a146 --- /dev/null +++ b/lib/livepatch/test_klp_convert_keys.c @@ -0,0 +1,91 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2020 Joe Lawrence + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include "test_klp_convert.h" + +/* + * Carry our own copy of print_key_status() as we want static key code + * patching updates to occur in the livepatch module as well as the + * target module that defines the static keys. + */ +static void print_key_status(char *msg) +{ + pr_info("%s: %s\n", __func__, msg); + + /* static_key_enable() only tests the key value */ + pr_info("static_key_enabled(&tracepoint_printk_key) is %s\n", + static_key_enabled(&tracepoint_printk_key) ? "true" : "false"); + pr_info("static_key_enabled(&test_klp_true_key) is %s\n", + static_key_enabled(&test_klp_true_key) ? "true" : "false"); + pr_info("static_key_enabled(&test_klp_false_key) is %s\n", + static_key_enabled(&test_klp_false_key) ? "true" : "false"); + + /* + * static_branch_(un)likely() requires code patching when the + * key value changes + */ + pr_info("static_branch_unlikely(&tracepoint_printk_key) is %s\n", + static_branch_unlikely(&tracepoint_printk_key) ? "true" : "false"); +} + +/* + * sysfs interface to poke the key + */ +static bool enable_false_key; +static int set_enable_false_key(const char *val, const struct kernel_param *kp) +{ + print_key_status("set_enable_false_key start"); + static_branch_enable(&test_klp_false_key); + print_key_status("set_enable_false_key enabling test_klp_false_key"); + + return 0; +} +module_param_call(enable_false_key, set_enable_false_key, NULL, + &enable_false_key, 0644); +MODULE_PARM_DESC(enable_false_key, "Static branch enable"); + + +static struct klp_func funcs[] = { + { } +}; + +static struct klp_object objs[] = { + { + .name = "test_klp_convert_keys_mod", + .funcs = funcs, + }, {} +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int test_klp_convert_keys_init(void) +{ + int ret; + + ret = klp_enable_patch(&patch); + if (ret) + return ret; + + return 0; +} + +static void test_klp_convert_keys_exit(void) +{ +} + +module_init(test_klp_convert_keys_init); +module_exit(test_klp_convert_keys_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Lawrence "); +MODULE_DESCRIPTION("Livepatch test: static keys"); +MODULE_INFO(livepatch, "Y"); diff --git a/lib/livepatch/test_klp_convert_keys_mod.c b/lib/livepatch/test_klp_convert_keys_mod.c new file mode 100644 index 000000000000..7b11c2da09c9 --- /dev/null +++ b/lib/livepatch/test_klp_convert_keys_mod.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2020 Joe Lawrence + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include + +static DEFINE_STATIC_KEY_TRUE(test_klp_true_key); +static DEFINE_STATIC_KEY_FALSE(test_klp_false_key); + +static void print_key_status(char *msg) +{ + pr_info("%s: %s\n", __func__, msg); + + /* static_key_enable() only tests the key value */ + pr_info("static_key_enabled(&test_klp_true_key) is %s\n", + static_key_enabled(&test_klp_true_key) ? "true" : "false"); + pr_info("static_key_enabled(&test_klp_false_key) is %s\n", + static_key_enabled(&test_klp_false_key) ? "true" : "false"); + + /* + * static_branch_(un)likely() requires code patching when the + * key value changes + */ + pr_info("static_branch_likely(&test_klp_true_key) is %s\n", + static_branch_likely(&test_klp_true_key) ? "true" : "false"); + pr_info("static_branch_unlikely(&test_klp_false_key) is %s\n", + static_branch_unlikely(&test_klp_false_key) ? "true" : "false"); +} + +static int test_klp_keys_mod_init(void) +{ + print_key_status("initial conditions"); + static_branch_disable(&test_klp_true_key); + print_key_status("disabled test_klp_true_key"); + + return 0; +} + +static void test_klp_keys_mod_exit(void) +{ + print_key_status("unloading conditions"); +} + +module_init(test_klp_keys_mod_init); +module_exit(test_klp_keys_mod_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Lawrence "); +MODULE_DESCRIPTION("Livepatch test: static keys target module"); diff --git a/tools/testing/selftests/livepatch/test-livepatch.sh b/tools/testing/selftests/livepatch/test-livepatch.sh index 5bda36b65bb5..8ad284a57770 100755 --- a/tools/testing/selftests/livepatch/test-livepatch.sh +++ b/tools/testing/selftests/livepatch/test-livepatch.sh @@ -11,6 +11,8 @@ MOD_KLP_CONVERT1=test_klp_convert1 MOD_KLP_CONVERT2=test_klp_convert2 MOD_KLP_CONVERT_DATA=test_klp_convert_data MOD_KLP_CONVERT_SECTIONS=test_klp_convert_sections +MOD_KLP_CONVERT_KEYS_MOD=test_klp_convert_keys_mod +MOD_KLP_CONVERT_KEYS=test_klp_convert_keys setup_config @@ -435,4 +437,129 @@ livepatch: '$MOD_KLP_CONVERT_DATA': unpatching complete % rmmod $MOD_KLP_CONVERT_MOD" +# TEST: klp-convert static keys +# - load a module which defines static keys, updates one of the keys on +# load (forcing jump table patching) +# - load a livepatch that references the same keys, resolved by +# klp-convert tool +# - poke the livepatch sysfs interface to update one of the key (forcing +# jump table patching again) +# - disable and unload the livepatch +# - remove the module + +start_test "klp-convert static keys" + +load_mod $MOD_KLP_CONVERT_KEYS_MOD +load_lp $MOD_KLP_CONVERT_KEYS + +echo 1 > /sys/module/$MOD_KLP_CONVERT_KEYS/parameters/enable_false_key + +disable_lp $MOD_KLP_CONVERT_KEYS +unload_lp $MOD_KLP_CONVERT_KEYS +unload_mod $MOD_KLP_CONVERT_KEYS_MOD + +check_result "% modprobe $MOD_KLP_CONVERT_KEYS_MOD +$MOD_KLP_CONVERT_KEYS_MOD: print_key_status: initial conditions +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_true_key) is true +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_likely(&test_klp_true_key) is true +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_unlikely(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: print_key_status: disabled test_klp_true_key +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_likely(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_unlikely(&test_klp_false_key) is false +% modprobe $MOD_KLP_CONVERT_KEYS +livepatch: enabling patch '$MOD_KLP_CONVERT_KEYS' +livepatch: '$MOD_KLP_CONVERT_KEYS': initializing patching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': starting patching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': completing patching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': patching complete +$MOD_KLP_CONVERT_KEYS: print_key_status: set_enable_false_key start +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&tracepoint_printk_key) is false +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS: static_branch_unlikely(&tracepoint_printk_key) is false +$MOD_KLP_CONVERT_KEYS: print_key_status: set_enable_false_key enabling test_klp_false_key +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&tracepoint_printk_key) is false +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&test_klp_false_key) is true +$MOD_KLP_CONVERT_KEYS: static_branch_unlikely(&tracepoint_printk_key) is false +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT_KEYS/enabled +livepatch: '$MOD_KLP_CONVERT_KEYS': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': unpatching complete +% rmmod $MOD_KLP_CONVERT_KEYS +% rmmod $MOD_KLP_CONVERT_KEYS_MOD +$MOD_KLP_CONVERT_KEYS_MOD: print_key_status: unloading conditions +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_false_key) is true +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_likely(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_unlikely(&test_klp_false_key) is true" + + +# TEST: klp-convert static keys (late module patching) +# - load a module which defines static keys, updates one of the keys on +# load (forcing jump table patching) +# - load a livepatch that references the same keys, resolved by +# klp-convert tool +# - poke the livepatch sysfs interface to update one of the key (forcing +# jump table patching again) +# - disable and unload the livepatch +# - remove the module + +start_test "klp-convert static keys (late module patching)" + +load_lp $MOD_KLP_CONVERT_KEYS +load_mod $MOD_KLP_CONVERT_KEYS_MOD + +echo 1 > /sys/module/$MOD_KLP_CONVERT_KEYS/parameters/enable_false_key + +disable_lp $MOD_KLP_CONVERT_KEYS +unload_lp $MOD_KLP_CONVERT_KEYS +unload_mod $MOD_KLP_CONVERT_KEYS_MOD + +check_result "% modprobe $MOD_KLP_CONVERT_KEYS +livepatch: enabling patch '$MOD_KLP_CONVERT_KEYS' +livepatch: '$MOD_KLP_CONVERT_KEYS': initializing patching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': starting patching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': completing patching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': patching complete +% modprobe $MOD_KLP_CONVERT_KEYS_MOD +livepatch: applying patch '$MOD_KLP_CONVERT_KEYS' to loading module '$MOD_KLP_CONVERT_KEYS_MOD' +$MOD_KLP_CONVERT_KEYS_MOD: print_key_status: initial conditions +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_true_key) is true +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_likely(&test_klp_true_key) is true +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_unlikely(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: print_key_status: disabled test_klp_true_key +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_likely(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_unlikely(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS: print_key_status: set_enable_false_key start +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&tracepoint_printk_key) is false +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&test_klp_false_key) is false +$MOD_KLP_CONVERT_KEYS: static_branch_unlikely(&tracepoint_printk_key) is false +$MOD_KLP_CONVERT_KEYS: print_key_status: set_enable_false_key enabling test_klp_false_key +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&tracepoint_printk_key) is false +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS: static_key_enabled(&test_klp_false_key) is true +$MOD_KLP_CONVERT_KEYS: static_branch_unlikely(&tracepoint_printk_key) is false +% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT_KEYS/enabled +livepatch: '$MOD_KLP_CONVERT_KEYS': initializing unpatching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': starting unpatching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': completing unpatching transition +livepatch: '$MOD_KLP_CONVERT_KEYS': unpatching complete +% rmmod $MOD_KLP_CONVERT_KEYS +% rmmod $MOD_KLP_CONVERT_KEYS_MOD +$MOD_KLP_CONVERT_KEYS_MOD: print_key_status: unloading conditions +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_key_enabled(&test_klp_false_key) is true +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_likely(&test_klp_true_key) is false +$MOD_KLP_CONVERT_KEYS_MOD: static_branch_unlikely(&test_klp_false_key) is true" + + exit 0