From patchwork Thu Jan 14 13:40:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 12019565 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44A1FC433E0 for ; Thu, 14 Jan 2021 13:42:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 177E323A60 for ; Thu, 14 Jan 2021 13:42:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726570AbhANNly convert rfc822-to-8bit (ORCPT ); Thu, 14 Jan 2021 08:41:54 -0500 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:29954 "EHLO us-smtp-delivery-44.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726730AbhANNlx (ORCPT ); Thu, 14 Jan 2021 08:41:53 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-274-1oUAL2fBOOi3yU-f8rLKqQ-1; Thu, 14 Jan 2021 08:40:57 -0500 X-MC-Unique: 1oUAL2fBOOi3yU-f8rLKqQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 61E05100C60C; Thu, 14 Jan 2021 13:40:55 +0000 (UTC) Received: from krava.redhat.com (unknown [10.40.195.188]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6973360C6B; Thu, 14 Jan 2021 13:40:51 +0000 (UTC) From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov , Song Liu , lkml , bpf@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Mark Rutland , Namhyung Kim , Alexander Shishkin , Michael Petlan , Ian Rogers , Stephane Eranian , Alexei Budankov , Andi Kleen , Adrian Hunter Subject: [PATCH bpf-next 1/3] bpf: Move stack_map_get_build_id into lib Date: Thu, 14 Jan 2021 14:40:42 +0100 Message-Id: <20210114134044.1418404-2-jolsa@kernel.org> In-Reply-To: <20210114134044.1418404-1-jolsa@kernel.org> References: <20210114134044.1418404-1-jolsa@kernel.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jolsa@kernel.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Moving stack_map_get_build_id into lib with declaration in linux/buildid.h header: int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id); This function returns build id for given struct vm_area_struct. There is no functional change to stack_map_get_build_id function. Cc: Alexei Starovoitov Acked-by: Song Liu Signed-off-by: Jiri Olsa --- include/linux/buildid.h | 11 ++++ kernel/bpf/stackmap.c | 143 ++-------------------------------------- lib/Makefile | 3 +- lib/buildid.c | 136 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 153 insertions(+), 140 deletions(-) create mode 100644 include/linux/buildid.h create mode 100644 lib/buildid.c diff --git a/include/linux/buildid.h b/include/linux/buildid.h new file mode 100644 index 000000000000..08028a212589 --- /dev/null +++ b/include/linux/buildid.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_BUILDID_H +#define _LINUX_BUILDID_H + +#include + +#define BUILD_ID_SIZE_MAX 20 + +int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id); + +#endif diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index aea96b638473..55d254a59f07 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -7,10 +7,9 @@ #include #include #include -#include -#include #include #include +#include #include "percpu_freelist.h" #define STACK_CREATE_FLAG_MASK \ @@ -143,140 +142,6 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) return ERR_PTR(err); } -#define BPF_BUILD_ID 3 -/* - * Parse build id from the note segment. This logic can be shared between - * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are - * identical. - */ -static inline int stack_map_parse_build_id(void *page_addr, - unsigned char *build_id, - void *note_start, - Elf32_Word note_size) -{ - Elf32_Word note_offs = 0, new_offs; - - /* check for overflow */ - if (note_start < page_addr || note_start + note_size < note_start) - return -EINVAL; - - /* only supports note that fits in the first page */ - if (note_start + note_size > page_addr + PAGE_SIZE) - return -EINVAL; - - while (note_offs + sizeof(Elf32_Nhdr) < note_size) { - Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs); - - if (nhdr->n_type == BPF_BUILD_ID && - nhdr->n_namesz == sizeof("GNU") && - nhdr->n_descsz > 0 && - nhdr->n_descsz <= BPF_BUILD_ID_SIZE) { - memcpy(build_id, - note_start + note_offs + - ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr), - nhdr->n_descsz); - memset(build_id + nhdr->n_descsz, 0, - BPF_BUILD_ID_SIZE - nhdr->n_descsz); - return 0; - } - new_offs = note_offs + sizeof(Elf32_Nhdr) + - ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4); - if (new_offs <= note_offs) /* overflow */ - break; - note_offs = new_offs; - } - return -EINVAL; -} - -/* Parse build ID from 32-bit ELF */ -static int stack_map_get_build_id_32(void *page_addr, - unsigned char *build_id) -{ - Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr; - Elf32_Phdr *phdr; - int i; - - /* only supports phdr that fits in one page */ - if (ehdr->e_phnum > - (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr)) - return -EINVAL; - - phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr)); - - for (i = 0; i < ehdr->e_phnum; ++i) { - if (phdr[i].p_type == PT_NOTE && - !stack_map_parse_build_id(page_addr, build_id, - page_addr + phdr[i].p_offset, - phdr[i].p_filesz)) - return 0; - } - return -EINVAL; -} - -/* Parse build ID from 64-bit ELF */ -static int stack_map_get_build_id_64(void *page_addr, - unsigned char *build_id) -{ - Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr; - Elf64_Phdr *phdr; - int i; - - /* only supports phdr that fits in one page */ - if (ehdr->e_phnum > - (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr)) - return -EINVAL; - - phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr)); - - for (i = 0; i < ehdr->e_phnum; ++i) { - if (phdr[i].p_type == PT_NOTE && - !stack_map_parse_build_id(page_addr, build_id, - page_addr + phdr[i].p_offset, - phdr[i].p_filesz)) - return 0; - } - return -EINVAL; -} - -/* Parse build ID of ELF file mapped to vma */ -static int stack_map_get_build_id(struct vm_area_struct *vma, - unsigned char *build_id) -{ - Elf32_Ehdr *ehdr; - struct page *page; - void *page_addr; - int ret; - - /* only works for page backed storage */ - if (!vma->vm_file) - return -EINVAL; - - page = find_get_page(vma->vm_file->f_mapping, 0); - if (!page) - return -EFAULT; /* page not mapped */ - - ret = -EINVAL; - page_addr = kmap_atomic(page); - ehdr = (Elf32_Ehdr *)page_addr; - - /* compare magic x7f "ELF" */ - if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0) - goto out; - - /* only support executable file and shared object file */ - if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) - goto out; - - if (ehdr->e_ident[EI_CLASS] == ELFCLASS32) - ret = stack_map_get_build_id_32(page_addr, build_id); - else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) - ret = stack_map_get_build_id_64(page_addr, build_id); -out: - kunmap_atomic(page_addr); - put_page(page); - return ret; -} - static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, u64 *ips, u32 trace_nr, bool user) { @@ -317,18 +182,18 @@ static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, for (i = 0; i < trace_nr; i++) { id_offs[i].status = BPF_STACK_BUILD_ID_IP; id_offs[i].ip = ips[i]; - memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE); + memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX); } return; } for (i = 0; i < trace_nr; i++) { vma = find_vma(current->mm, ips[i]); - if (!vma || stack_map_get_build_id(vma, id_offs[i].build_id)) { + if (!vma || build_id_parse(vma, id_offs[i].build_id)) { /* per entry fall back to ips */ id_offs[i].status = BPF_STACK_BUILD_ID_IP; id_offs[i].ip = ips[i]; - memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE); + memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX); continue; } id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i] diff --git a/lib/Makefile b/lib/Makefile index afeff05fa8c5..a6b160c3a4fa 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -36,7 +36,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ flex_proportions.o ratelimit.o show_mem.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ earlycpio.o seq_buf.o siphash.o dec_and_lock.o \ - nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o + nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o \ + buildid.o lib-$(CONFIG_PRINTK) += dump_stack.o lib-$(CONFIG_SMP) += cpumask.o diff --git a/lib/buildid.c b/lib/buildid.c new file mode 100644 index 000000000000..4a4f520c0e29 --- /dev/null +++ b/lib/buildid.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include + +#define BUILD_ID 3 +/* + * Parse build id from the note segment. This logic can be shared between + * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are + * identical. + */ +static inline int parse_build_id(void *page_addr, + unsigned char *build_id, + void *note_start, + Elf32_Word note_size) +{ + Elf32_Word note_offs = 0, new_offs; + + /* check for overflow */ + if (note_start < page_addr || note_start + note_size < note_start) + return -EINVAL; + + /* only supports note that fits in the first page */ + if (note_start + note_size > page_addr + PAGE_SIZE) + return -EINVAL; + + while (note_offs + sizeof(Elf32_Nhdr) < note_size) { + Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs); + + if (nhdr->n_type == BUILD_ID && + nhdr->n_namesz == sizeof("GNU") && + nhdr->n_descsz > 0 && + nhdr->n_descsz <= BUILD_ID_SIZE_MAX) { + memcpy(build_id, + note_start + note_offs + + ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr), + nhdr->n_descsz); + memset(build_id + nhdr->n_descsz, 0, + BUILD_ID_SIZE_MAX - nhdr->n_descsz); + return 0; + } + new_offs = note_offs + sizeof(Elf32_Nhdr) + + ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4); + if (new_offs <= note_offs) /* overflow */ + break; + note_offs = new_offs; + } + return -EINVAL; +} + +/* Parse build ID from 32-bit ELF */ +static int get_build_id_32(void *page_addr, unsigned char *build_id) +{ + Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr; + Elf32_Phdr *phdr; + int i; + + /* only supports phdr that fits in one page */ + if (ehdr->e_phnum > + (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr)) + return -EINVAL; + + phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr)); + + for (i = 0; i < ehdr->e_phnum; ++i) { + if (phdr[i].p_type == PT_NOTE && + !parse_build_id(page_addr, build_id, + page_addr + phdr[i].p_offset, + phdr[i].p_filesz)) + return 0; + } + return -EINVAL; +} + +/* Parse build ID from 64-bit ELF */ +static int get_build_id_64(void *page_addr, unsigned char *build_id) +{ + Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr; + Elf64_Phdr *phdr; + int i; + + /* only supports phdr that fits in one page */ + if (ehdr->e_phnum > + (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr)) + return -EINVAL; + + phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr)); + + for (i = 0; i < ehdr->e_phnum; ++i) { + if (phdr[i].p_type == PT_NOTE && + !parse_build_id(page_addr, build_id, + page_addr + phdr[i].p_offset, + phdr[i].p_filesz)) + return 0; + } + return -EINVAL; +} + +/* Parse build ID of ELF file mapped to vma */ +int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id) +{ + Elf32_Ehdr *ehdr; + struct page *page; + void *page_addr; + int ret; + + /* only works for page backed storage */ + if (!vma->vm_file) + return -EINVAL; + + page = find_get_page(vma->vm_file->f_mapping, 0); + if (!page) + return -EFAULT; /* page not mapped */ + + ret = -EINVAL; + page_addr = kmap_atomic(page); + ehdr = (Elf32_Ehdr *)page_addr; + + /* compare magic x7f "ELF" */ + if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0) + goto out; + + /* only support executable file and shared object file */ + if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) + goto out; + + if (ehdr->e_ident[EI_CLASS] == ELFCLASS32) + ret = get_build_id_32(page_addr, build_id); + else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) + ret = get_build_id_64(page_addr, build_id); +out: + kunmap_atomic(page_addr); + put_page(page); + return ret; +}