From patchwork Fri Apr 26 23:22:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10919941 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6929314B6 for ; Sat, 27 Apr 2019 06:43:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 59E3128E6B for ; Sat, 27 Apr 2019 06:43:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4D97C28E78; Sat, 27 Apr 2019 06:43:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 1586528E7B for ; Sat, 27 Apr 2019 06:43:29 +0000 (UTC) Received: (qmail 1626 invoked by uid 550); 27 Apr 2019 06:43:17 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 1394 invoked from network); 27 Apr 2019 06:43:16 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=2uQh+p4niM1XazCyX0W8SClLNopGSLFeOTKZKD97XRE=; b=jRSkWPKFy+aX307nFA9nwPtBSyUtI3Rx2wzXkDoawmNR9EBxnEgbgOuHqpJlUzURZT sV7k69m+oa16kaqF4hrYU8VlNGgLedRPtIQMrWtFfI1lYATZNKlBhFfYsdwu71vQpo8l 4hsC4E1OYjLOCvcQc0ZNw7818nwUnGdICNM7KZF/Pj8oVL04L5HnrLC4hGuv9gcmfZac QEF3y8KkPlAdKQa7pk8VGNHlHNoii/EZVaGEr6IiXqB8Q9AYGmnR5/+s61lipbxEVDy4 WVZil8tiOMGEBeIN6IOofRQtzUr/x76R5xEihGyGfY+KVuW7UGM6aZN17saLTTNxIC81 Y9Xg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=2uQh+p4niM1XazCyX0W8SClLNopGSLFeOTKZKD97XRE=; b=qhWojdXuAJK/qQKTTWVvgqdHfu04ngQqdne9qcNt2bTs1SziMIUHLFI6Vypd+d3YND A9GFQOpi40gA/FOaH/4eUGwQC3zOSWSzXKJYcyXcgn1vcN1vWANX2xc/FqzG7WtoXwyt GrO2jlVYQs36TPvP4yMXTc828nTtRyKmpNlIJ5wp1/D5/VYKeQwQuYxnmNfxFjQbxJ/n 3ycDk2CFIQOJrc4HPGvw3bHee5bfvt8MUDKLGE57KT2GjTTDU9J3UEeCcN1bhhS2xdF3 yJX1SkmG6wf1+/xdKFYhR3OlZ6W+Oq5jd1/uADqQX0PtrinjV5RkfTYCyF7sOL8sBUur c//Q== X-Gm-Message-State: APjAAAXWDM12qYB4gDtE4U2JjHefllwD5pzoDZJPNZkm2jBz9vc+AwBI 97h+fA6TOzxXrswRmtZWT4k= X-Google-Smtp-Source: APXvYqxfDuRpBbYxO71iQgRCpp9YwcxdysZGYp8xW7ZBvNhCbiRnBK6qmFG1IHuGhuou8D2zduF20Q== X-Received: by 2002:a62:26c1:: with SMTP id m184mr12194274pfm.102.1556347384381; Fri, 26 Apr 2019 23:43:04 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Kees Cook , Dave Hansen , Masami Hiramatsu Subject: [PATCH v6 01/24] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Date: Fri, 26 Apr 2019 16:22:40 -0700 Message-Id: <20190426232303.28381-2-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit text_mutex is currently expected to be held before text_poke() is called, but kgdb does not take the mutex, and instead *supposedly* ensures the lock is not taken and will not be acquired by any other core while text_poke() is running. The reason for the "supposedly" comment is that it is not entirely clear that this would be the case if gdb_do_roundup is zero. Create two wrapper functions, text_poke() and text_poke_kgdb(), which do or do not run the lockdep assertion respectively. While we are at it, change the return code of text_poke() to something meaningful. One day, callers might actually respect it and the existing BUG_ON() when patching fails could be removed. For kgdb, the return value can actually be used. Cc: Andy Lutomirski Cc: Kees Cook Cc: Dave Hansen Cc: Masami Hiramatsu Fixes: 9222f606506c ("x86/alternatives: Lockdep-enforce text_mutex in text_poke*()") Suggested-by: Peter Zijlstra Acked-by: Jiri Kosina Acked-by: Peter Zijlstra (Intel) Reviewed-by: Masami Hiramatsu Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/include/asm/text-patching.h | 1 + arch/x86/kernel/alternative.c | 52 ++++++++++++++++++++-------- arch/x86/kernel/kgdb.c | 11 +++--- 3 files changed, 45 insertions(+), 19 deletions(-) diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index e85ff65c43c3..f8fc8e86cf01 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -35,6 +35,7 @@ extern void *text_poke_early(void *addr, const void *opcode, size_t len); * inconsistent instruction while you patch. */ extern void *text_poke(void *addr, const void *opcode, size_t len); +extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len); extern int poke_int3_handler(struct pt_regs *regs); extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); extern int after_bootmem; diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 9a79c7808f9c..0a814d73547a 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -679,18 +679,7 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode, return addr; } -/** - * text_poke - Update instructions on a live kernel - * @addr: address to modify - * @opcode: source of the copy - * @len: length to copy - * - * Only atomic text poke/set should be allowed when not doing early patching. - * It means the size must be writable atomically and the address must be aligned - * in a way that permits an atomic write. It also makes sure we fit on a single - * page. - */ -void *text_poke(void *addr, const void *opcode, size_t len) +static void *__text_poke(void *addr, const void *opcode, size_t len) { unsigned long flags; char *vaddr; @@ -703,8 +692,6 @@ void *text_poke(void *addr, const void *opcode, size_t len) */ BUG_ON(!after_bootmem); - lockdep_assert_held(&text_mutex); - if (!core_kernel_text((unsigned long)addr)) { pages[0] = vmalloc_to_page(addr); pages[1] = vmalloc_to_page(addr + PAGE_SIZE); @@ -733,6 +720,43 @@ void *text_poke(void *addr, const void *opcode, size_t len) return addr; } +/** + * text_poke - Update instructions on a live kernel + * @addr: address to modify + * @opcode: source of the copy + * @len: length to copy + * + * Only atomic text poke/set should be allowed when not doing early patching. + * It means the size must be writable atomically and the address must be aligned + * in a way that permits an atomic write. It also makes sure we fit on a single + * page. + */ +void *text_poke(void *addr, const void *opcode, size_t len) +{ + lockdep_assert_held(&text_mutex); + + return __text_poke(addr, opcode, len); +} + +/** + * text_poke_kgdb - Update instructions on a live kernel by kgdb + * @addr: address to modify + * @opcode: source of the copy + * @len: length to copy + * + * Only atomic text poke/set should be allowed when not doing early patching. + * It means the size must be writable atomically and the address must be aligned + * in a way that permits an atomic write. It also makes sure we fit on a single + * page. + * + * Context: should only be used by kgdb, which ensures no other core is running, + * despite the fact it does not hold the text_mutex. + */ +void *text_poke_kgdb(void *addr, const void *opcode, size_t len) +{ + return __text_poke(addr, opcode, len); +} + static void do_sync_core(void *info) { sync_core(); diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 4ff6b4cdb941..2b203ee5b879 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -759,13 +759,13 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) if (!err) return err; /* - * It is safe to call text_poke() because normal kernel execution + * It is safe to call text_poke_kgdb() because normal kernel execution * is stopped on all cores, so long as the text_mutex is not locked. */ if (mutex_is_locked(&text_mutex)) return -EBUSY; - text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr, - BREAK_INSTR_SIZE); + text_poke_kgdb((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr, + BREAK_INSTR_SIZE); err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); if (err) return err; @@ -784,12 +784,13 @@ int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) if (bpt->type != BP_POKE_BREAKPOINT) goto knl_write; /* - * It is safe to call text_poke() because normal kernel execution + * It is safe to call text_poke_kgdb() because normal kernel execution * is stopped on all cores, so long as the text_mutex is not locked. */ if (mutex_is_locked(&text_mutex)) goto knl_write; - text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE); + text_poke_kgdb((void *)bpt->bpt_addr, bpt->saved_instr, + BREAK_INSTR_SIZE); err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE)) goto knl_write; From patchwork Fri Apr 26 23:22:41 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10919969 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1B7B0912 for ; 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Fri, 26 Apr 2019 23:43:05 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Kees Cook , Dave Hansen , Masami Hiramatsu Subject: [PATCH v6 02/24] x86/jump_label: Use text_poke_early() during early init Date: Fri, 26 Apr 2019 16:22:41 -0700 Message-Id: <20190426232303.28381-3-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit There is no apparent reason not to use text_poke_early() during early-init, since no patching of code that might be on the stack is done and only a single core is running. This is required for the next patches that would set a temporary mm for text poking, and this mm is only initialized after some static-keys are enabled/disabled. Cc: Andy Lutomirski Cc: Kees Cook Cc: Dave Hansen Cc: Masami Hiramatsu Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/kernel/jump_label.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index f99bd26bd3f1..e7d8c636b228 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -50,7 +50,12 @@ static void __ref __jump_label_transform(struct jump_entry *entry, jmp.offset = jump_entry_target(entry) - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); - if (early_boot_irqs_disabled) + /* + * As long as only a single processor is running and the code is still + * not marked as RO, text_poke_early() can be used; Checking that + * system_state is SYSTEM_BOOTING guarantees it. + */ + if (system_state == SYSTEM_BOOTING) poker = text_poke_early; if (type == JUMP_LABEL_JMP) { From patchwork Fri Apr 26 23:22:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10919987 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 97F42912 for ; 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Fri, 26 Apr 2019 23:43:07 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Kees Cook , Dave Hansen , Nadav Amit Subject: [PATCH v6 03/24] x86/mm: Introduce temporary mm structs Date: Fri, 26 Apr 2019 16:22:42 -0700 Message-Id: <20190426232303.28381-4-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Andy Lutomirski Using a dedicated page-table for temporary PTEs prevents other cores from using - even speculatively - these PTEs, thereby providing two benefits: (1) Security hardening: an attacker that gains kernel memory writing abilities cannot easily overwrite sensitive data. (2) Avoiding TLB shootdowns: the PTEs do not need to be flushed in remote page-tables. To do so a temporary mm_struct can be used. Mappings which are private for this mm can be set in the userspace part of the address-space. During the whole time in which the temporary mm is loaded, interrupts must be disabled. The first use-case for temporary mm struct, which will follow, is for poking the kernel text. [ Commit message was written by Nadav Amit ] Cc: Kees Cook Cc: Dave Hansen Acked-by: Peter Zijlstra (Intel) Reviewed-by: Masami Hiramatsu Tested-by: Masami Hiramatsu Signed-off-by: Andy Lutomirski Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/include/asm/mmu_context.h | 33 ++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 19d18fae6ec6..24dc3b810970 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -356,4 +356,37 @@ static inline unsigned long __get_current_cr3_fast(void) return cr3; } +typedef struct { + struct mm_struct *mm; +} temp_mm_state_t; + +/* + * Using a temporary mm allows to set temporary mappings that are not accessible + * by other CPUs. Such mappings are needed to perform sensitive memory writes + * that override the kernel memory protections (e.g., W^X), without exposing the + * temporary page-table mappings that are required for these write operations to + * other CPUs. Using a temporary mm also allows to avoid TLB shootdowns when the + * mapping is torn down. + * + * Context: The temporary mm needs to be used exclusively by a single core. To + * harden security IRQs must be disabled while the temporary mm is + * loaded, thereby preventing interrupt handler bugs from overriding + * the kernel memory protection. + */ +static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm) +{ + temp_mm_state_t temp_state; + + lockdep_assert_irqs_disabled(); + temp_state.mm = this_cpu_read(cpu_tlbstate.loaded_mm); + switch_mm_irqs_off(NULL, mm, current); + return temp_state; +} + +static inline void unuse_temporary_mm(temp_mm_state_t prev_state) +{ + lockdep_assert_irqs_disabled(); + switch_mm_irqs_off(NULL, prev_state.mm, current); +} + #endif /* _ASM_X86_MMU_CONTEXT_H */ From patchwork Fri Apr 26 23:22:43 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920005 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C516714B6 for ; Sat, 27 Apr 2019 06:44:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B3BB228E6B for ; Sat, 27 Apr 2019 06:44:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A597D28E7C; Sat, 27 Apr 2019 06:44:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id C29FA28E6B for ; Sat, 27 Apr 2019 06:44:18 +0000 (UTC) Received: (qmail 1888 invoked by uid 550); 27 Apr 2019 06:43:21 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 1817 invoked from network); 27 Apr 2019 06:43:20 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=wqvLZPneRcLgxY6Wjfk6EEQBPauaGcOxn9fq0yjJ9xE=; b=vdYahecrwl2Sp5UawSR3og0bnv/oKfDwV/Dqodp6SG75rtt3oI1BxkHqScjMRc/B0U ndpm0CSM99X5DI5nXyZ0qilWlZ5y+YmffvE0rzTsPOh9Lg0wVC5gzIbXO3T2rI/43jKw dSv/fQEMrgklgF9DfRp0UTkxOOmbTA2q76DVrniyNWh8V594RE3EBRYYfPR9C72DIbVe QvUfF6WjCix52aEKKarcvG6J8JGMJ6kiAHPNxAecwgyTiM6P6ST8UlxjffLYXWC/UN5g Hhv9thRtl94b6Emad3qIhmqwC571N8N4kkx/zbp3oEc24WAmffQk4ZXiiSSJrBGsI7VY gu0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=wqvLZPneRcLgxY6Wjfk6EEQBPauaGcOxn9fq0yjJ9xE=; b=r4MB4mvf5KgyrIxkfgkdwMlwVF1bLj89PBDeQPeocEjBz3cPqMpIPsrmoGQ3sb2HI5 0/aIv5tjHQ+WBSsHafF9vxT+kdrS4GfhyE79xiV+P1lCwFiCdv79m6EzgdyEmTjoPjKz R/nXtNdwY7yV8U+UjmYShQ0hcivpTxJ8Q9hrpNfA6no2IPfzCJe4OB8gY1IltdNRqXkd WKgz2VHWjrJ/QcibC9Cb8le0picr0Sqew4zW8eRJ46mzL7NkDRfX4mMRabl0txHMkPgb N4dOSc+MgIGzmcdgba1foyuX9rnE9yArxq3VDawXuQJWVPWgA7E+wiZRavpYf4U84KPs i8Qg== X-Gm-Message-State: APjAAAWSugiKXWHtAQ2qyRLWcMyoJ3nkcFBMFbTOQoazVEuUkXleYhbf i/HX8JMDAOQXuIhau3NzWJU= X-Google-Smtp-Source: APXvYqyiprnnWU4rXtsHhhC4I5UqVMx78ccNfm1X35wazpAaZSJma1EHcKW1CFUxAhCYo5lEBNcLEA== X-Received: by 2002:a17:902:aa83:: with SMTP id d3mr8074837plr.108.1556347388411; Fri, 26 Apr 2019 23:43:08 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit Subject: [PATCH v6 04/24] x86/mm: Save debug registers when loading a temporary mm Date: Fri, 26 Apr 2019 16:22:43 -0700 Message-Id: <20190426232303.28381-5-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit Prevent user watchpoints from mistakenly firing while the temporary mm is being used. As the addresses of the temporary mm might overlap those of the user-process, this is necessary to prevent wrong signals or worse things from happening. Cc: Andy Lutomirski Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/include/asm/mmu_context.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 24dc3b810970..93dff1963337 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -13,6 +13,7 @@ #include #include #include +#include extern atomic64_t last_mm_ctx_id; @@ -380,6 +381,21 @@ static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm) lockdep_assert_irqs_disabled(); temp_state.mm = this_cpu_read(cpu_tlbstate.loaded_mm); switch_mm_irqs_off(NULL, mm, current); + + /* + * If breakpoints are enabled, disable them while the temporary mm is + * used. Userspace might set up watchpoints on addresses that are used + * in the temporary mm, which would lead to wrong signals being sent or + * crashes. + * + * Note that breakpoints are not disabled selectively, which also causes + * kernel breakpoints (e.g., perf's) to be disabled. This might be + * undesirable, but still seems reasonable as the code that runs in the + * temporary mm should be short. + */ + if (hw_breakpoint_active()) + hw_breakpoint_disable(); + return temp_state; } @@ -387,6 +403,13 @@ static inline void unuse_temporary_mm(temp_mm_state_t prev_state) { lockdep_assert_irqs_disabled(); switch_mm_irqs_off(NULL, prev_state.mm, current); + + /* + * Restore the breakpoints if they were disabled before the temporary mm + * was loaded. + */ + if (hw_breakpoint_active()) + hw_breakpoint_restore(); } #endif /* _ASM_X86_MMU_CONTEXT_H */ From patchwork Fri Apr 26 23:22:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920019 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4FD0414B6 for ; Sat, 27 Apr 2019 06:44:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 400B928E6B for ; Sat, 27 Apr 2019 06:44:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3388828E7B; Sat, 27 Apr 2019 06:44:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 54ECA28E6B for ; Sat, 27 Apr 2019 06:44:26 +0000 (UTC) Received: (qmail 3075 invoked by uid 550); 27 Apr 2019 06:43:23 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 1902 invoked from network); 27 Apr 2019 06:43:22 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=gMfxobg7i1AP5PQ14JM+oGjrmklNXXx9IUFM/PW54zo=; b=XKJ4fAeBY8aGdbJDn84dW83HzgSvQACPuhXWJHvF1CWt6rAKSo0+tUCXqeDEYn8KGx u3zXII+RSuYhdLmlbo5/0feDTgEEs6/tOmzti0w5Pevv/8Nua7dmelg2Hg1YTOM0HPNp IuB1XxBtPV5C1LDrt4HWOamCYTjBpu9Uc9bqXu6wh2x58Sr/Usj1f74P/vpY9jMFSCFS THBbi+fo5P15SNYnnZLc+khNDUp7StdyPifYfNcqKpXcU/HGBdU106YbtBqZ2gBNSvKt YTZSQ/QqPm8CwczIhg2BokKOhThemqJ36d1wwJl1ZB93G6rLPD545DygLOMnvs67gNXF w1Rg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=gMfxobg7i1AP5PQ14JM+oGjrmklNXXx9IUFM/PW54zo=; b=oATs5081V8e8esjCNNQnXC7dxGY4KWZKEbYLMrHtcTj6UDE9L27HfBMS1mY7wMW2GV sXPuj9WWiRla3+Bn6tB/x4Ohgtr60WcRc5AIgmcrTppQW1hwaxbNErvI/2aifp+eywfD JPkdKwSGiET1YoJZ/VQq36QhpigN9IOoTi+78/juumgi4HqalzmYiWad5YfJwgPwRS5d a/wlPTtSbZEM2riPIhjlhT4Tlt7tlbnhJbeFSctI0njbNf6sFz6OlnLQT1b2igquS5js q/WXwXg6ADWxrCMYuW7T2mxYZ+AvUpCXXy6VEDWXRltjDZdFzABiGjXEq+qHKNsNwJQi 6DQg== X-Gm-Message-State: APjAAAXA5V6N8CiBP1ueuHlHKb3PNqd049GMzgeQ6kXuLwMW4SFrVwPI 97SZmfZVhtzAhiHPKPG7EHw= X-Google-Smtp-Source: APXvYqwk9lLXQyc9bNgKLLm6YtZMcI1PVJ4KR2rM1C+cN3nT9zotDQcbIXGbwEvAmUupbSpfYScE8w== X-Received: by 2002:a17:902:a7:: with SMTP id a36mr50206141pla.111.1556347390037; Fri, 26 Apr 2019 23:43:10 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Arnaldo Carvalho de Melo Subject: [PATCH v6 05/24] uprobes: Initialize uprobes earlier Date: Fri, 26 Apr 2019 16:22:44 -0700 Message-Id: <20190426232303.28381-6-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit In order to have a separate address space for text poking, we need to duplicate init_mm early during start_kernel(). This, however, introduces a problem since uprobes functions are called from dup_mmap(), but uprobes is still not initialized in this early stage. Since uprobes initialization is necassary for fork, and since all the dependant initialization has been done when fork is initialized (percpu and vmalloc), move uprobes initialization to fork_init(). It does not seem uprobes introduces any security problem for the poking_mm. Crash and burn if uprobes initialization fails, similarly to other early initializations. Change the init_probes() name to probes_init() to match other early initialization functions name convention. Cc: Arnaldo Carvalho de Melo Reported-by: kernel test robot Signed-off-by: Nadav Amit --- include/linux/uprobes.h | 5 +++++ kernel/events/uprobes.c | 8 +++----- kernel/fork.c | 1 + 3 files changed, 9 insertions(+), 5 deletions(-) diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 103a48a48872..12bf0b68ed92 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -115,6 +115,7 @@ struct uprobes_state { struct xol_area *xol_area; }; +extern void __init uprobes_init(void); extern int set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); extern int set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); extern bool is_swbp_insn(uprobe_opcode_t *insn); @@ -154,6 +155,10 @@ extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, struct uprobes_state { }; +static inline void uprobes_init(void) +{ +} + #define uprobe_get_trap_addr(regs) instruction_pointer(regs) static inline int diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index c5cde87329c7..e6a0d6be87e3 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -2294,16 +2294,14 @@ static struct notifier_block uprobe_exception_nb = { .priority = INT_MAX-1, /* notified after kprobes, kgdb */ }; -static int __init init_uprobes(void) +void __init uprobes_init(void) { int i; for (i = 0; i < UPROBES_HASH_SZ; i++) mutex_init(&uprobes_mmap_mutex[i]); - if (percpu_init_rwsem(&dup_mmap_sem)) - return -ENOMEM; + BUG_ON(percpu_init_rwsem(&dup_mmap_sem)); - return register_die_notifier(&uprobe_exception_nb); + BUG_ON(register_die_notifier(&uprobe_exception_nb)); } -__initcall(init_uprobes); diff --git a/kernel/fork.c b/kernel/fork.c index 9dcd18aa210b..44fba5e5e916 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -815,6 +815,7 @@ void __init fork_init(void) #endif lockdep_init_task(&init_task); + uprobes_init(); } int __weak arch_dup_task_struct(struct task_struct *dst, From patchwork Fri Apr 26 23:22:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920037 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 673DB912 for ; 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Fri, 26 Apr 2019 23:43:12 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Kees Cook , Dave Hansen Subject: [PATCH v6 06/24] fork: Provide a function for copying init_mm Date: Fri, 26 Apr 2019 16:22:45 -0700 Message-Id: <20190426232303.28381-7-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit Provide a function for copying init_mm. This function will be later used for setting a temporary mm. Cc: Andy Lutomirski Cc: Kees Cook Cc: Dave Hansen Acked-by: Peter Zijlstra (Intel) Reviewed-by: Masami Hiramatsu Tested-by: Masami Hiramatsu Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- include/linux/sched/task.h | 1 + kernel/fork.c | 24 ++++++++++++++++++------ 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index 2e97a2227045..f1227f2c38a4 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -76,6 +76,7 @@ extern void exit_itimers(struct signal_struct *); extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long); extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *); struct task_struct *fork_idle(int); +struct mm_struct *copy_init_mm(void); extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); diff --git a/kernel/fork.c b/kernel/fork.c index 44fba5e5e916..fbe9dfcd8680 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1299,13 +1299,20 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm) complete_vfork_done(tsk); } -/* - * Allocate a new mm structure and copy contents from the - * mm structure of the passed in task structure. +/** + * dup_mm() - duplicates an existing mm structure + * @tsk: the task_struct with which the new mm will be associated. + * @oldmm: the mm to duplicate. + * + * Allocates a new mm structure and duplicates the provided @oldmm structure + * content into it. + * + * Return: the duplicated mm or NULL on failure. */ -static struct mm_struct *dup_mm(struct task_struct *tsk) +static struct mm_struct *dup_mm(struct task_struct *tsk, + struct mm_struct *oldmm) { - struct mm_struct *mm, *oldmm = current->mm; + struct mm_struct *mm; int err; mm = allocate_mm(); @@ -1372,7 +1379,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) } retval = -ENOMEM; - mm = dup_mm(tsk); + mm = dup_mm(tsk, current->mm); if (!mm) goto fail_nomem; @@ -2187,6 +2194,11 @@ struct task_struct *fork_idle(int cpu) return task; } +struct mm_struct *copy_init_mm(void) +{ + return dup_mm(NULL, &init_mm); +} + /* * Ok, this is the main fork-routine. * From patchwork Fri Apr 26 23:22:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920049 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8942414B6 for ; Sat, 27 Apr 2019 06:44:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7A23E287C0 for ; Sat, 27 Apr 2019 06:44:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6E19A28843; Sat, 27 Apr 2019 06:44:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 44AF6287C0 for ; 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d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=ZPFv6m+iH8EeSMp9wFrys9PGKYZJjpGjv1/CHTAfS5M=; b=apWAtdTALB+WaNoWYicdaCfyyZG+WIBcj2Xn6x8tYoqCO3MZ6ZvzjpCCWskOY+6d7I O1TPGtfMWiu4u1zKPPouhe/Vz139K2/UEyYnFAzzaMsfeamRJKNG/Wc/x+5Ljot057B/ KAbZ8HAZRzwVzYsXT+VxAbyVOELVq0f22nl082ZuHL/wNW2V5dz33CTpxKfjS6jjyjXn mceSMZYCi8mzBW+nc9ZFL3xJXOtiJM1V0Hm93zRo6SPkIFHeRqF3Ium97hOHYUdQJeq5 CA+2qLZHA/tAOw140uUZ1hHTggzQRzQlb4XQxh3j1uJYhBFqQoXlFzW2+eNyZuQ3+aLz 6oMA== X-Gm-Message-State: APjAAAVcmfwPrhpONkQ70UkXXFZ5agtUkMi1PG3JGMOyOeUteT2pLGlZ v5uyXlAzRrqKIZYA/LL1PoQ= X-Google-Smtp-Source: APXvYqyVtXk5iHrU+w85KghleSi1h9IdIHLthG9HVX8BbnAS3s4DC3QPi8s9GkBRV20LWDs74Eyk7w== X-Received: by 2002:a63:1359:: with SMTP id 25mr46901248pgt.92.1556347393845; Fri, 26 Apr 2019 23:43:13 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Kees Cook , Dave Hansen Subject: [PATCH v6 07/24] x86/alternative: Initialize temporary mm for patching Date: Fri, 26 Apr 2019 16:22:46 -0700 Message-Id: <20190426232303.28381-8-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit To prevent improper use of the PTEs that are used for text patching, the next patches will use a temporary mm struct. Initailize it by copying the init mm. The address that will be used for patching is taken from the lower area that is usually used for the task memory. Doing so prevents the need to frequently synchronize the temporary-mm (e.g., when BPF programs are installed), since different PGDs are used for the task memory. Finally, randomize the address of the PTEs to harden against exploits that use these PTEs. Cc: Kees Cook Cc: Dave Hansen Acked-by: Peter Zijlstra (Intel) Reviewed-by: Masami Hiramatsu Tested-by: Masami Hiramatsu Suggested-by: Andy Lutomirski Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/include/asm/pgtable.h | 3 +++ arch/x86/include/asm/text-patching.h | 2 ++ arch/x86/kernel/alternative.c | 3 +++ arch/x86/mm/init.c | 37 ++++++++++++++++++++++++++++ init/main.c | 3 +++ 5 files changed, 48 insertions(+) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 5cfbbb6d458d..6b6bfdfe83aa 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1038,6 +1038,9 @@ static inline void __meminit init_trampoline_default(void) /* Default trampoline pgd value */ trampoline_pgd_entry = init_top_pgt[pgd_index(__PAGE_OFFSET)]; } + +void __init poking_init(void); + # ifdef CONFIG_RANDOMIZE_MEMORY void __meminit init_trampoline(void); # else diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index f8fc8e86cf01..a75eed841eed 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -39,5 +39,7 @@ extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len); extern int poke_int3_handler(struct pt_regs *regs); extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); extern int after_bootmem; +extern __ro_after_init struct mm_struct *poking_mm; +extern __ro_after_init unsigned long poking_addr; #endif /* _ASM_X86_TEXT_PATCHING_H */ diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 0a814d73547a..11d5c710a94f 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -679,6 +679,9 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode, return addr; } +__ro_after_init struct mm_struct *poking_mm; +__ro_after_init unsigned long poking_addr; + static void *__text_poke(void *addr, const void *opcode, size_t len) { unsigned long flags; diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index f905a2371080..c25bb00955db 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -22,6 +22,7 @@ #include #include #include +#include /* * We need to define the tracepoints somewhere, and tlb.c @@ -700,6 +701,42 @@ void __init init_mem_mapping(void) early_memtest(0, max_pfn_mapped << PAGE_SHIFT); } +/* + * Initialize an mm_struct to be used during poking and a pointer to be used + * during patching. + */ +void __init poking_init(void) +{ + spinlock_t *ptl; + pte_t *ptep; + + pr_err("%s\n", __func__); + poking_mm = copy_init_mm(); + BUG_ON(!poking_mm); + + /* + * Randomize the poking address, but make sure that the following page + * will be mapped at the same PMD. We need 2 pages, so find space for 3, + * and adjust the address if the PMD ends after the first one. + */ + poking_addr = TASK_UNMAPPED_BASE; + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) + poking_addr += (kaslr_get_random_long("Poking") & PAGE_MASK) % + (TASK_SIZE - TASK_UNMAPPED_BASE - 3 * PAGE_SIZE); + + if (((poking_addr + PAGE_SIZE) & ~PMD_MASK) == 0) + poking_addr += PAGE_SIZE; + + /* + * We need to trigger the allocation of the page-tables that will be + * needed for poking now. Later, poking may be performed in an atomic + * section, which might cause allocation to fail. + */ + ptep = get_locked_pte(poking_mm, poking_addr, &ptl); + BUG_ON(!ptep); + pte_unmap_unlock(ptep, ptl); +} + /* * devmem_is_allowed() checks to see if /dev/mem access to a certain address * is valid. The argument is a physical page number. diff --git a/init/main.c b/init/main.c index 598e278b46f7..949eed8015ec 100644 --- a/init/main.c +++ b/init/main.c @@ -504,6 +504,8 @@ void __init __weak thread_stack_cache_init(void) void __init __weak mem_encrypt_init(void) { } +void __init __weak poking_init(void) { } + bool initcall_debug; core_param(initcall_debug, initcall_debug, bool, 0644); @@ -737,6 +739,7 @@ asmlinkage __visible void __init start_kernel(void) taskstats_init_early(); delayacct_init(); + poking_init(); check_bugs(); acpi_subsystem_init(); From patchwork Fri Apr 26 23:22:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920065 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5A0B4912 for ; Sat, 27 Apr 2019 06:45:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4A5A3287C0 for ; Sat, 27 Apr 2019 06:45:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3E7DE28843; Sat, 27 Apr 2019 06:45:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id F3DB3287C0 for ; Sat, 27 Apr 2019 06:45:05 +0000 (UTC) Received: (qmail 3463 invoked by uid 550); 27 Apr 2019 06:43:28 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 3401 invoked from network); 27 Apr 2019 06:43:27 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=uR9dojmxOmmxTLzrNkqbIEwKeNq3pUquy4Aauxui5YA=; b=oILNkBTMPI8hbOfV9CTJU+m4eHw0hAUfxbTTNr2/RxOTWPpKbRKo8diZaBeA/Rmbm3 h5rZrB3HG0y3SmWymgT3Ka+NNLrVVEWGy5GTcbQKRQEA3wiSNrIdF0YIzNUEW260wZEH KE+3wzmKUfVn5aWbi1XY/cRblwX7PCPz65YSoU43s/26wSMoHptHFPQTS+iXil5iGEw+ MKuU4t2I8rSFdXKCm6I3uOxZEQ1YYZq5IGQ+JuIwxQpw5oc2ihHafO/Cd4i7/tLG7zpn Edmk3MnDF5/iWexA4JDZ+DyyFjQlaqdQ8ZangVzJbGAkvZg6LY9bd008qQlPu4OkFzMW +mVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=uR9dojmxOmmxTLzrNkqbIEwKeNq3pUquy4Aauxui5YA=; b=HBunCo9MGGL/oNXmrf6LtDtKyWBVReNhF1IfhWJEUprMKWX9pq6Gu+Yy17tGnR7eEQ aRwvSD1JcfZxeUM6CH9JkhWJo58nEHFhqJKoviCCo1x6Xz7z/zQ2qt1tO99HHWB6hWZc QTMTEpTiUs9k/odotqH89/JqhXe0MU8LNfFigsq5fDO07Fq/7aQ+6uL0NyOrRi5s41sp bL7XV4X4k9XXyRfIGd9NYG+UHIAK6PEWudGj4HW9PfqYAo9yaMaIxKPHD+RVgI2TgwZ3 4rneg82v6CKeN0sX8YXw1KFD2FShHdHGVlNgNheJacUZn7+3NUvFbYgqe2B+OPgzsGTk URRQ== X-Gm-Message-State: APjAAAUJx/8DMxRDLYiuk+o0OAvys/zntlAwTPC1hkXyG78QTFsuq79E Q/XLed5sB5PA9zhDqNBr9E0= X-Google-Smtp-Source: APXvYqxGAw4qwJwGwZPBWfL5T3kXq42Nxulr2Eo5xhNgNYA2PVHpEfWTNqR9D9nfEhSjkOIDkP0Vjg== X-Received: by 2002:a17:902:e683:: with SMTP id cn3mr6142181plb.115.1556347395492; Fri, 26 Apr 2019 23:43:15 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Kees Cook , Dave Hansen , Masami Hiramatsu Subject: [PATCH v6 08/24] x86/alternative: Use temporary mm for text poking Date: Fri, 26 Apr 2019 16:22:47 -0700 Message-Id: <20190426232303.28381-9-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit text_poke() can potentially compromise security as it sets temporary PTEs in the fixmap. These PTEs might be used to rewrite the kernel code from other cores accidentally or maliciously, if an attacker gains the ability to write onto kernel memory. Moreover, since remote TLBs are not flushed after the temporary PTEs are removed, the time-window in which the code is writable is not limited if the fixmap PTEs - maliciously or accidentally - are cached in the TLB. To address these potential security hazards, use a temporary mm for patching the code. Finally, text_poke() is also not conservative enough when mapping pages, as it always tries to map 2 pages, even when a single one is sufficient. So try to be more conservative, and do not map more than needed. Cc: Andy Lutomirski Cc: Kees Cook Cc: Dave Hansen Cc: Masami Hiramatsu Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/include/asm/fixmap.h | 2 - arch/x86/kernel/alternative.c | 108 +++++++++++++++++++++++++++------- arch/x86/xen/mmu_pv.c | 2 - 3 files changed, 86 insertions(+), 26 deletions(-) diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index 50ba74a34a37..9da8cccdf3fb 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -103,8 +103,6 @@ enum fixed_addresses { #ifdef CONFIG_PARAVIRT FIX_PARAVIRT_BOOTMAP, #endif - FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */ - FIX_TEXT_POKE0, /* first page is last, because allocation is backward */ #ifdef CONFIG_X86_INTEL_MID FIX_LNW_VRTC, #endif diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 11d5c710a94f..599203876c32 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -684,41 +685,104 @@ __ro_after_init unsigned long poking_addr; static void *__text_poke(void *addr, const void *opcode, size_t len) { + bool cross_page_boundary = offset_in_page(addr) + len > PAGE_SIZE; + struct page *pages[2] = {NULL}; + temp_mm_state_t prev; unsigned long flags; - char *vaddr; - struct page *pages[2]; - int i; + pte_t pte, *ptep; + spinlock_t *ptl; + pgprot_t pgprot; /* - * While boot memory allocator is runnig we cannot use struct - * pages as they are not yet initialized. + * While boot memory allocator is running we cannot use struct pages as + * they are not yet initialized. There is no way to recover. */ BUG_ON(!after_bootmem); if (!core_kernel_text((unsigned long)addr)) { pages[0] = vmalloc_to_page(addr); - pages[1] = vmalloc_to_page(addr + PAGE_SIZE); + if (cross_page_boundary) + pages[1] = vmalloc_to_page(addr + PAGE_SIZE); } else { pages[0] = virt_to_page(addr); WARN_ON(!PageReserved(pages[0])); - pages[1] = virt_to_page(addr + PAGE_SIZE); + if (cross_page_boundary) + pages[1] = virt_to_page(addr + PAGE_SIZE); } - BUG_ON(!pages[0]); + /* + * If something went wrong, crash and burn since recovery paths are not + * implemented. + */ + BUG_ON(!pages[0] || (cross_page_boundary && !pages[1])); + local_irq_save(flags); - set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0])); - if (pages[1]) - set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1])); - vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0); - memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len); - clear_fixmap(FIX_TEXT_POKE0); - if (pages[1]) - clear_fixmap(FIX_TEXT_POKE1); - local_flush_tlb(); - sync_core(); - /* Could also do a CLFLUSH here to speed up CPU recovery; but - that causes hangs on some VIA CPUs. */ - for (i = 0; i < len; i++) - BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]); + + /* + * Map the page without the global bit, as TLB flushing is done with + * flush_tlb_mm_range(), which is intended for non-global PTEs. + */ + pgprot = __pgprot(pgprot_val(PAGE_KERNEL) & ~_PAGE_GLOBAL); + + /* + * The lock is not really needed, but this allows to avoid open-coding. + */ + ptep = get_locked_pte(poking_mm, poking_addr, &ptl); + + /* + * This must not fail; preallocated in poking_init(). + */ + VM_BUG_ON(!ptep); + + pte = mk_pte(pages[0], pgprot); + set_pte_at(poking_mm, poking_addr, ptep, pte); + + if (cross_page_boundary) { + pte = mk_pte(pages[1], pgprot); + set_pte_at(poking_mm, poking_addr + PAGE_SIZE, ptep + 1, pte); + } + + /* + * Loading the temporary mm behaves as a compiler barrier, which + * guarantees that the PTE will be set at the time memcpy() is done. + */ + prev = use_temporary_mm(poking_mm); + + kasan_disable_current(); + memcpy((u8 *)poking_addr + offset_in_page(addr), opcode, len); + kasan_enable_current(); + + /* + * Ensure that the PTE is only cleared after the instructions of memcpy + * were issued by using a compiler barrier. + */ + barrier(); + + pte_clear(poking_mm, poking_addr, ptep); + if (cross_page_boundary) + pte_clear(poking_mm, poking_addr + PAGE_SIZE, ptep + 1); + + /* + * Loading the previous page-table hierarchy requires a serializing + * instruction that already allows the core to see the updated version. + * Xen-PV is assumed to serialize execution in a similar manner. + */ + unuse_temporary_mm(prev); + + /* + * Flushing the TLB might involve IPIs, which would require enabled + * IRQs, but not if the mm is not used, as it is in this point. + */ + flush_tlb_mm_range(poking_mm, poking_addr, poking_addr + + (cross_page_boundary ? 2 : 1) * PAGE_SIZE, + PAGE_SHIFT, false); + + /* + * If the text does not match what we just wrote then something is + * fundamentally screwy; there's nothing we can really do about that. + */ + BUG_ON(memcmp(addr, opcode, len)); + + pte_unmap_unlock(ptep, ptl); local_irq_restore(flags); return addr; } diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index a21e1734fc1f..beb44e22afdf 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -2318,8 +2318,6 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot) #elif defined(CONFIG_X86_VSYSCALL_EMULATION) case VSYSCALL_PAGE: #endif - case FIX_TEXT_POKE0: - case FIX_TEXT_POKE1: /* All local page mappings */ pte = pfn_pte(phys, prot); break; From patchwork Fri Apr 26 23:22:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920081 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2ACA314DB for ; Sat, 27 Apr 2019 06:45:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1C39C287C0 for ; Sat, 27 Apr 2019 06:45:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0F6ED28843; Sat, 27 Apr 2019 06:45:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 3CB69287C0 for ; Sat, 27 Apr 2019 06:45:19 +0000 (UTC) Received: (qmail 3639 invoked by uid 550); 27 Apr 2019 06:43:30 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 3471 invoked from network); 27 Apr 2019 06:43:28 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=3mFI7V2IpbwOhuCcp+g9CO2dE2meFXsvyyAeb18NWyo=; b=JlRIHgbr6HB0GM/dfrBCsDnNLxTkOKzTB7qYCbAx4tDSjiPWdWErWZcgNMKz3646h4 C8cKj9bZkmi6cPWikKj5uJAC7SrSg/qfrmI03cXhBRcOJHEMan3BYUSQ1ScXOsNa4u3Z IDQ4DfzWzmEsKN3rKTGM5uTvN695pUVNWWV4a8LMMvLzAhr7fWiHf2k7ZmkakgE11lMg wbrOSfmIb0CTjB/azGiS0/j+OjbriGytqXhtU6Bd27x2yAPLaWXYIt792EgmySvUAGOQ 9VF/satnq8MCbRYyAQp+FRH27QsFCLaAp8PdnQobxJM8asT3n363jT4JX9FD5F/9ebkE 0Uqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=3mFI7V2IpbwOhuCcp+g9CO2dE2meFXsvyyAeb18NWyo=; b=rMNEqX/JppVddZAr0sjRTuGuRiwPntdRmCu5UJkz4/UYz7Tv6QYUNPsRXp0aISG9xY NOVHmwxBwDsU9PYH1uYe1zmqNBxA7nmzYYRDX5MYT/ghqvF+YCPjP4H4TNmwqOjuo1X+ B4mUUnfJx7yOVDsX5YXJEjOl97ocgO3LMDWxZbOhOI2xmTq3+foqXHu9YnoH6csRzM3T PUIrjdUvGW4zhpOIBNOeX7sRalCfkt0L0ohUEnP0KqfjA5WAkOI9lt74xIl9P6Yf4ugX ixae2tS/cwWAOqBPnXuCLRdeV4uPS2OWklvids6QTAUhhG4dqjlTIzOt6KtJAuolb+I9 j66g== X-Gm-Message-State: APjAAAUvlqf6IfLPvqfsS061ULytmAL3O424pdmT9kFUZT4qdWY0uRfP zntMURb4cG8QaUIgkRM8eW8= X-Google-Smtp-Source: APXvYqx2WhBZnJIn8mqH1b7ixt4GF/6k4yp110M4lMdf7eXq6Mz7eqmVNfTsfdPSyk5JMfubTGyIEQ== X-Received: by 2002:a17:902:2927:: with SMTP id g36mr48053244plb.6.1556347396829; Fri, 26 Apr 2019 23:43:16 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit Subject: [PATCH v6 09/24] x86/kgdb: Avoid redundant comparison of patched code Date: Fri, 26 Apr 2019 16:22:48 -0700 Message-Id: <20190426232303.28381-10-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit text_poke() already ensures that the written value is the correct one and fails if that is not the case. There is no need for an additional comparison. Remove it. Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/kernel/kgdb.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 2b203ee5b879..13b13311b792 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -747,7 +747,6 @@ void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) { int err; - char opc[BREAK_INSTR_SIZE]; bpt->type = BP_BREAKPOINT; err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, @@ -766,11 +765,6 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) return -EBUSY; text_poke_kgdb((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); - err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); - if (err) - return err; - if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE)) - return -EINVAL; bpt->type = BP_POKE_BREAKPOINT; return err; @@ -778,9 +772,6 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) { - int err; - char opc[BREAK_INSTR_SIZE]; - if (bpt->type != BP_POKE_BREAKPOINT) goto knl_write; /* @@ -791,10 +782,7 @@ int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) goto knl_write; text_poke_kgdb((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE); - err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); - if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE)) - goto knl_write; - return err; + return 0; knl_write: return probe_kernel_write((char *)bpt->bpt_addr, From patchwork Fri Apr 26 23:22:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920083 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8D701912 for ; 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Fri, 26 Apr 2019 23:43:19 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit Subject: [PATCH v6 10/24] x86/ftrace: Set trampoline pages as executable Date: Fri, 26 Apr 2019 16:22:49 -0700 Message-Id: <20190426232303.28381-11-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit Since alloc_module() will not set the pages as executable soon, set ftrace trampoline pages as executable after they are allocated. For the time being, do not change ftrace to use the text_poke() interface. As a result, ftrace still breaks W^X. Reviewed-by: Steven Rostedt (VMware) Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/kernel/ftrace.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index ef49517f6bb2..53ba1aa3a01f 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -730,6 +730,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) unsigned long end_offset; unsigned long op_offset; unsigned long offset; + unsigned long npages; unsigned long size; unsigned long retq; unsigned long *ptr; @@ -762,6 +763,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) return 0; *tramp_size = size + RET_SIZE + sizeof(void *); + npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE); /* Copy ftrace_caller onto the trampoline memory */ ret = probe_kernel_read(trampoline, (void *)start_offset, size); @@ -806,6 +808,12 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) /* ALLOC_TRAMP flags lets us know we created it */ ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP; + /* + * Module allocation needs to be completed by making the page + * executable. The page is still writable, which is a security hazard, + * but anyhow ftrace breaks W^X completely. + */ + set_memory_x((unsigned long)trampoline, npages); return (unsigned long)trampoline; fail: tramp_free(trampoline, *tramp_size); From patchwork Fri Apr 26 23:22:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920085 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 078A5912 for ; Sat, 27 Apr 2019 06:45:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EBD1428BC3 for ; Sat, 27 Apr 2019 06:45:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DF7AA28E78; Sat, 27 Apr 2019 06:45:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 1A21928BC3 for ; Sat, 27 Apr 2019 06:45:44 +0000 (UTC) Received: (qmail 3909 invoked by uid 550); 27 Apr 2019 06:43:33 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 3812 invoked from network); 27 Apr 2019 06:43:32 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=yNv4uuWY37+QDIo+8eJ5Cs1RQKFygWuhu/mUpTFc+50=; b=qfcv0jVylRwgUSdFp0yVo6y3SoCAOjol9XbR7W5+lwraaEg2QoXyt+VrAjGp9wzdAn BOm9G9cC4mrsWbrKkWfeWua0CLcUhNFX2UYmr160CAGJNRPhpKunjycWCJnpjaUptQXK FymoezD52jYoCa9vw1d8DrTtNcDpUD3gesH2ZoYEwsgq0bZE6tTukM9zPOscjJPRRiHd 0d0EQKT1ASnMLtYxkgiq4MVCWAUZf/kjKC/u6ibFbPlbEhDhs/jBfSTvPAadE2T4MBPs yoHMRLVUDfJJ0O31Q2uS3OPiszz2lAVHUHfzcDpTk8KxpsBn4aqr0vTCALbdk7a/EPYd 2uWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=yNv4uuWY37+QDIo+8eJ5Cs1RQKFygWuhu/mUpTFc+50=; b=D5xaIKYht8SzqD+gXl6Tt0SXQyoSGSdMHoW8A+pWsZzdcGrrYYSNPFUTJ1LPhBreQn dLI7SDZ4PaxCE0UPfIdN60xpZte6xyJPQ4QWCR62AZt7fH1mYkS29JeVkmIK5KQBS8l7 R4aQrgLW49UK2MIFvrM/mvymbtAYYSVjUySQQmLkSDTNlR7DTAToRGLu1yhRiVqBZQz9 VtfKK3rnfpFTOHzFWoEVjhMsH/djtmlYIHxDvjR6ZEXEjLmM6ekYYagP4t1VA2yU5gHE N8GlUAL5JWjC8jqT+OsxR1DAj8UJtn2uJuqVbTHdUKHYrcIl28PAPBslj6kO81ui5MGV IBAA== X-Gm-Message-State: APjAAAUwBkxX7YE3xVppNud8Lkcfyfr1kF88yrlGRp318jSe1vczpvmo FwK3yNAM2HJhQzG/iGpAAqI= X-Google-Smtp-Source: APXvYqxCgMCnuubydaHXfJIDthz2u46RkKoNrhpM9xg9spe5Zm1Eq7YBRg8tloTlDMLwvkBDrQMPvQ== X-Received: by 2002:a63:7f0b:: with SMTP id a11mr44847434pgd.234.1556347400564; Fri, 26 Apr 2019 23:43:20 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit Subject: [PATCH v6 11/24] x86/kprobes: Set instruction page as executable Date: Fri, 26 Apr 2019 16:22:50 -0700 Message-Id: <20190426232303.28381-12-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit Set the page as executable after allocation. This patch is a preparatory patch for a following patch that makes module allocated pages non-executable. While at it, do some small cleanup of what appears to be unnecessary masking. Acked-by: Masami Hiramatsu Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/kernel/kprobes/core.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index a034cb808e7e..1591852d3ac4 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -431,8 +431,20 @@ void *alloc_insn_page(void) void *page; page = module_alloc(PAGE_SIZE); - if (page) - set_memory_ro((unsigned long)page & PAGE_MASK, 1); + if (!page) + return NULL; + + /* + * First make the page read-only, and only then make it executable to + * prevent it from being W+X in between. + */ + set_memory_ro((unsigned long)page, 1); + + /* + * TODO: Once additional kernel code protection mechanisms are set, ensure + * that the page was not maliciously altered and it is still zeroed. + */ + set_memory_x((unsigned long)page, 1); return page; } @@ -440,8 +452,12 @@ void *alloc_insn_page(void) /* Recover page to RW mode before releasing it */ void free_insn_page(void *page) { - set_memory_nx((unsigned long)page & PAGE_MASK, 1); - set_memory_rw((unsigned long)page & PAGE_MASK, 1); + /* + * First make the page non-executable, and only then make it writable to + * prevent it from being W+X in between. + */ + set_memory_nx((unsigned long)page, 1); + set_memory_rw((unsigned long)page, 1); module_memfree(page); } From patchwork Fri Apr 26 23:22:51 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920087 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4D41C912 for ; Sat, 27 Apr 2019 06:46:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3E20F28BC3 for ; Sat, 27 Apr 2019 06:46:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3223B28E78; Sat, 27 Apr 2019 06:46:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 023A228BC3 for ; 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d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=0/++kCIdz9NinK/+MFp07AkuSYwP6lr30tD8Xi+P1Ns=; b=acxe2OE4qruZCNB/DY14PTFmh2qDyHnB7g3ynwtj8uNyihnSi7KPDQnPA5CeK2Rs+V r6LoRTaLlLKp0RDnK2nesOM6+GBHsn6+Ml3V6EhuGw+gN5H8MJnGuygkyHdRq+MIre67 yByu7WyS3p90EolakNGile86fDm1ufMpnG43593Q6eZQ+vuBDopAo8mWnL8/+Hc/qYRv XIZZoePm7yqGysq32kZJ+8o9y42gjW2PdKXV/Gpm0Qg+UsH0vcTSlYRvGTWiASc8g3vU 6p5neFF3Ocfr4UA7Bv7LzWT4PV1BMsc/qCzIosLbo3RgodKjrc6btEZilMxIzHzlSCoo K7hA== X-Gm-Message-State: APjAAAXT2DT2U3bo2HgBk6lNmNNYWpkVvR6qB8B6saZMaaqmG4cSDjr9 4mowe7e74V4nUA0rImF65Fs= X-Google-Smtp-Source: APXvYqwD3aMW9+fxSDptS7zjHtrUL6axD8ahdhvdTbAECEHQ3uOfUvnD7wIP6ssynsnm5EaQ/VhgYw== X-Received: by 2002:a17:902:20c6:: with SMTP id v6mr48012719plg.276.1556347402023; Fri, 26 Apr 2019 23:43:22 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Kees Cook , Dave Hansen , Masami Hiramatsu , Jessica Yu Subject: [PATCH v6 12/24] x86/module: Avoid breaking W^X while loading modules Date: Fri, 26 Apr 2019 16:22:51 -0700 Message-Id: <20190426232303.28381-13-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit When modules and BPF filters are loaded, there is a time window in which some memory is both writable and executable. An attacker that has already found another vulnerability (e.g., a dangling pointer) might be able to exploit this behavior to overwrite kernel code. Prevent having writable executable PTEs in this stage. In addition, avoiding having W+X mappings can also slightly simplify the patching of modules code on initialization (e.g., by alternatives and static-key), as would be done in the next patch. This was actually the main motivation for this patch. To avoid having W+X mappings, set them initially as RW (NX) and after they are set as RO set them as X as well. Setting them as executable is done as a separate step to avoid one core in which the old PTE is cached (hence writable), and another which sees the updated PTE (executable), which would break the W^X protection. Cc: Kees Cook Cc: Peter Zijlstra Cc: Dave Hansen Cc: Masami Hiramatsu Cc: Jessica Yu Suggested-by: Thomas Gleixner Suggested-by: Andy Lutomirski Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/kernel/alternative.c | 28 +++++++++++++++++++++------- arch/x86/kernel/module.c | 2 +- include/linux/filter.h | 1 + kernel/module.c | 5 +++++ 4 files changed, 28 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 599203876c32..3d2b6b6fb20c 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -668,15 +668,29 @@ void __init alternative_instructions(void) * handlers seeing an inconsistent instruction while you patch. */ void *__init_or_module text_poke_early(void *addr, const void *opcode, - size_t len) + size_t len) { unsigned long flags; - local_irq_save(flags); - memcpy(addr, opcode, len); - local_irq_restore(flags); - sync_core(); - /* Could also do a CLFLUSH here to speed up CPU recovery; but - that causes hangs on some VIA CPUs. */ + + if (boot_cpu_has(X86_FEATURE_NX) && + is_module_text_address((unsigned long)addr)) { + /* + * Modules text is marked initially as non-executable, so the + * code cannot be running and speculative code-fetches are + * prevented. Just change the code. + */ + memcpy(addr, opcode, len); + } else { + local_irq_save(flags); + memcpy(addr, opcode, len); + local_irq_restore(flags); + sync_core(); + + /* + * Could also do a CLFLUSH here to speed up CPU recovery; but + * that causes hangs on some VIA CPUs. + */ + } return addr; } diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c index b052e883dd8c..cfa3106faee4 100644 --- a/arch/x86/kernel/module.c +++ b/arch/x86/kernel/module.c @@ -87,7 +87,7 @@ void *module_alloc(unsigned long size) p = __vmalloc_node_range(size, MODULE_ALIGN, MODULES_VADDR + get_module_load_offset(), MODULES_END, GFP_KERNEL, - PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, + PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0)); if (p && (kasan_module_alloc(p, size) < 0)) { vfree(p); diff --git a/include/linux/filter.h b/include/linux/filter.h index 6074aa064b54..14ec3bdad9a9 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -746,6 +746,7 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) { set_memory_ro((unsigned long)hdr, hdr->pages); + set_memory_x((unsigned long)hdr, hdr->pages); } static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) diff --git a/kernel/module.c b/kernel/module.c index 0b9aa8ab89f0..2b2845ae983e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1950,8 +1950,13 @@ void module_enable_ro(const struct module *mod, bool after_init) return; frob_text(&mod->core_layout, set_memory_ro); + frob_text(&mod->core_layout, set_memory_x); + frob_rodata(&mod->core_layout, set_memory_ro); + frob_text(&mod->init_layout, set_memory_ro); + frob_text(&mod->init_layout, set_memory_x); + frob_rodata(&mod->init_layout, set_memory_ro); if (after_init) From patchwork Fri Apr 26 23:22:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920089 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9F15C912 for ; 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Fri, 26 Apr 2019 23:43:23 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Kees Cook , Dave Hansen , Masami Hiramatsu Subject: [PATCH v6 13/24] x86/jump-label: Remove support for custom poker Date: Fri, 26 Apr 2019 16:22:52 -0700 Message-Id: <20190426232303.28381-14-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit There are only two types of poking: early and breakpoint based. The use of a function pointer to perform poking complicates the code and is probably inefficient due to the use of indirect branches. Cc: Andy Lutomirski Cc: Kees Cook Cc: Dave Hansen Cc: Masami Hiramatsu Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/kernel/jump_label.c | 26 ++++++++++---------------- 1 file changed, 10 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index e7d8c636b228..e631c358f7f4 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -37,7 +37,6 @@ static void bug_at(unsigned char *ip, int line) static void __ref __jump_label_transform(struct jump_entry *entry, enum jump_label_type type, - void *(*poker)(void *, const void *, size_t), int init) { union jump_code_union jmp; @@ -50,14 +49,6 @@ static void __ref __jump_label_transform(struct jump_entry *entry, jmp.offset = jump_entry_target(entry) - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); - /* - * As long as only a single processor is running and the code is still - * not marked as RO, text_poke_early() can be used; Checking that - * system_state is SYSTEM_BOOTING guarantees it. - */ - if (system_state == SYSTEM_BOOTING) - poker = text_poke_early; - if (type == JUMP_LABEL_JMP) { if (init) { expect = default_nop; line = __LINE__; @@ -80,16 +71,19 @@ static void __ref __jump_label_transform(struct jump_entry *entry, bug_at((void *)jump_entry_code(entry), line); /* - * Make text_poke_bp() a default fallback poker. + * As long as only a single processor is running and the code is still + * not marked as RO, text_poke_early() can be used; Checking that + * system_state is SYSTEM_BOOTING guarantees it. It will be set to + * SYSTEM_SCHEDULING before other cores are awaken and before the + * code is write-protected. * * At the time the change is being done, just ignore whether we * are doing nop -> jump or jump -> nop transition, and assume * always nop being the 'currently valid' instruction - * */ - if (poker) { - (*poker)((void *)jump_entry_code(entry), code, - JUMP_LABEL_NOP_SIZE); + if (init || system_state == SYSTEM_BOOTING) { + text_poke_early((void *)jump_entry_code(entry), code, + JUMP_LABEL_NOP_SIZE); return; } @@ -101,7 +95,7 @@ void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type) { mutex_lock(&text_mutex); - __jump_label_transform(entry, type, NULL, 0); + __jump_label_transform(entry, type, 0); mutex_unlock(&text_mutex); } @@ -131,5 +125,5 @@ __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, jlstate = JL_STATE_NO_UPDATE; } if (jlstate == JL_STATE_UPDATE) - __jump_label_transform(entry, type, text_poke_early, 1); + __jump_label_transform(entry, type, 1); } From patchwork Fri Apr 26 23:22:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920091 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 50F4414D5 for ; Sat, 27 Apr 2019 06:46:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 41D3728BC3 for ; Sat, 27 Apr 2019 06:46:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 350D528E78; Sat, 27 Apr 2019 06:46:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 4099228BC3 for ; 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Remove it. Cc: Andy Lutomirski Cc: Kees Cook Cc: Dave Hansen Cc: Masami Hiramatsu Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/include/asm/text-patching.h | 4 ++-- arch/x86/kernel/alternative.c | 11 ++++------- 2 files changed, 6 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index a75eed841eed..c90678fd391a 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -18,7 +18,7 @@ static inline void apply_paravirt(struct paravirt_patch_site *start, #define __parainstructions_end NULL #endif -extern void *text_poke_early(void *addr, const void *opcode, size_t len); +extern void text_poke_early(void *addr, const void *opcode, size_t len); /* * Clear and restore the kernel write-protection flag on the local CPU. @@ -37,7 +37,7 @@ extern void *text_poke_early(void *addr, const void *opcode, size_t len); extern void *text_poke(void *addr, const void *opcode, size_t len); extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len); extern int poke_int3_handler(struct pt_regs *regs); -extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); +extern void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); extern int after_bootmem; extern __ro_after_init struct mm_struct *poking_mm; extern __ro_after_init unsigned long poking_addr; diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 3d2b6b6fb20c..18f959975ea0 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -265,7 +265,7 @@ static void __init_or_module add_nops(void *insns, unsigned int len) extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; extern s32 __smp_locks[], __smp_locks_end[]; -void *text_poke_early(void *addr, const void *opcode, size_t len); +void text_poke_early(void *addr, const void *opcode, size_t len); /* * Are we looking at a near JMP with a 1 or 4-byte displacement. @@ -667,8 +667,8 @@ void __init alternative_instructions(void) * instructions. And on the local CPU you need to be protected again NMI or MCE * handlers seeing an inconsistent instruction while you patch. */ -void *__init_or_module text_poke_early(void *addr, const void *opcode, - size_t len) +void __init_or_module text_poke_early(void *addr, const void *opcode, + size_t len) { unsigned long flags; @@ -691,7 +691,6 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode, * that causes hangs on some VIA CPUs. */ } - return addr; } __ro_after_init struct mm_struct *poking_mm; @@ -893,7 +892,7 @@ NOKPROBE_SYMBOL(poke_int3_handler); * replacing opcode * - sync cores */ -void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) +void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) { unsigned char int3 = 0xcc; @@ -935,7 +934,5 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) * the writing of the new instruction. */ bp_patching_in_progress = false; - - return addr; } From patchwork Fri Apr 26 23:22:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920093 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 40FCC14D5 for ; Sat, 27 Apr 2019 06:46:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 30CA228BC3 for ; Sat, 27 Apr 2019 06:46:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 237B428E78; Sat, 27 Apr 2019 06:46:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 093EC28BC3 for ; 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d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=KTT3A6U4NQUMX3UyJFnXteqziiXHIb6+tR0GZna3rFw=; b=q2zmbeG+YjVxuPc3aWU3z8lWjXjCfjoxfGjnqOTQidTX2s7y4ujnyROu0DD973Zvmh Q/WMVqtIQxr9DEwAzQDMVQMLTxozDNFdLN0UNqfUK5tjfqtpJORnD67rCjIPbV4eH42E Ls88ft1NL00mhxUAiI1YsgYWBGfIePP2yc3z2SM5Tufq3NGwuHNQxZLCYeCN6RErQUpB GGm+vLsDWBWlxrUsN9DL42vPkmZbs1YpCPJ0xu9BHxPHZeGnPZh17pTiAORZVgDaTdNE 4OWpQjmKqp1BIQVJNupiYxYPWvCB6nXDwOH+FUyKeRcZ+mbLoyNhndQtWIV/1Jv/WTnq +lCw== X-Gm-Message-State: APjAAAWyvY0SDD3kfTRPPltS0yyz+pOuQ4G6/q+ObX0ZSJqGDIQB3wCt ZZeRogAlmnMyg2PGsu1Oirs= X-Google-Smtp-Source: APXvYqyp4gEOWvDPMwsB34y/cGZ+L+Sv84P2bxDYEtUS3BvBcKjFjt/Gwr89xaPGQr7jlRcueADDmQ== X-Received: by 2002:a17:902:2827:: with SMTP id e36mr49087254plb.45.1556347406278; Fri, 26 Apr 2019 23:43:26 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe Subject: [PATCH v6 15/24] x86/mm/cpa: Add set_direct_map_ functions Date: Fri, 26 Apr 2019 16:22:54 -0700 Message-Id: <20190426232303.28381-16-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Rick Edgecombe Add two new functions set_direct_map_default_noflush() and set_direct_map_invalid_noflush() for setting the direct map alias for the page to its default valid permissions and to an invalid state that cannot be cached in a TLB, respectively. These functions do not flush the TLB. Note, __kernel_map_pages() does something similar but flushes the TLB and doesn't reset the permission bits to default on all architectures. Also add an ARCH config ARCH_HAS_SET_DIRECT_MAP for specifying whether these have an actual implementation or a default empty one. Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Signed-off-by: Rick Edgecombe --- arch/Kconfig | 4 ++++ arch/x86/Kconfig | 1 + arch/x86/include/asm/set_memory.h | 3 +++ arch/x86/mm/pageattr.c | 14 +++++++++++--- include/linux/set_memory.h | 11 +++++++++++ 5 files changed, 30 insertions(+), 3 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 3ab446bd12ef..5e43fcbad4ca 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -249,6 +249,10 @@ config ARCH_HAS_FORTIFY_SOURCE config ARCH_HAS_SET_MEMORY bool +# Select if arch has all set_direct_map_invalid/default() functions +config ARCH_HAS_SET_DIRECT_MAP + bool + # Select if arch init_task must go in the __init_task_data section config ARCH_TASK_STRUCT_ON_STACK bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2ec5e850b807..45d788354376 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -66,6 +66,7 @@ config X86 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE select ARCH_HAS_SET_MEMORY + select ARCH_HAS_SET_DIRECT_MAP select ARCH_HAS_STRICT_KERNEL_RWX select ARCH_HAS_STRICT_MODULE_RWX select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h index 07a25753e85c..ae7b909dc242 100644 --- a/arch/x86/include/asm/set_memory.h +++ b/arch/x86/include/asm/set_memory.h @@ -85,6 +85,9 @@ int set_pages_nx(struct page *page, int numpages); int set_pages_ro(struct page *page, int numpages); int set_pages_rw(struct page *page, int numpages); +int set_direct_map_invalid_noflush(struct page *page); +int set_direct_map_default_noflush(struct page *page); + extern int kernel_set_to_readonly; void set_kernel_text_rw(void); void set_kernel_text_ro(void); diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 4c570612e24e..3574550192c6 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -2209,8 +2209,6 @@ int set_pages_rw(struct page *page, int numpages) return set_memory_rw(addr, numpages); } -#ifdef CONFIG_DEBUG_PAGEALLOC - static int __set_pages_p(struct page *page, int numpages) { unsigned long tempaddr = (unsigned long) page_address(page); @@ -2249,6 +2247,17 @@ static int __set_pages_np(struct page *page, int numpages) return __change_page_attr_set_clr(&cpa, 0); } +int set_direct_map_invalid_noflush(struct page *page) +{ + return __set_pages_np(page, 1); +} + +int set_direct_map_default_noflush(struct page *page) +{ + return __set_pages_p(page, 1); +} + +#ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { if (PageHighMem(page)) @@ -2282,7 +2291,6 @@ void __kernel_map_pages(struct page *page, int numpages, int enable) } #ifdef CONFIG_HIBERNATION - bool kernel_page_present(struct page *page) { unsigned int level; diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h index 2a986d282a97..b5071497b8cb 100644 --- a/include/linux/set_memory.h +++ b/include/linux/set_memory.h @@ -17,6 +17,17 @@ static inline int set_memory_x(unsigned long addr, int numpages) { return 0; } static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; } #endif +#ifndef CONFIG_ARCH_HAS_SET_DIRECT_MAP +static inline int set_direct_map_invalid_noflush(struct page *page) +{ + return 0; +} +static inline int set_direct_map_default_noflush(struct page *page) +{ + return 0; +} +#endif + #ifndef set_mce_nospec static inline int set_mce_nospec(unsigned long pfn) { From patchwork Fri Apr 26 23:22:55 2019 Content-Type: text/plain; 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Wysocki" , Pavel Machek Subject: [PATCH v6 16/24] mm: Make hibernate handle unmapped pages Date: Fri, 26 Apr 2019 16:22:55 -0700 Message-Id: <20190426232303.28381-17-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Rick Edgecombe Make hibernate handle unmapped pages on the direct map when CONFIG_ARCH_HAS_SET_ALIAS is set. These functions allow for setting pages to invalid configurations, so now hibernate should check if the pages have valid mappings and handle if they are unmapped when doing a hibernate save operation. Previously this checking was already done when CONFIG_DEBUG_PAGEALLOC was configured. It does not appear to have a big hibernating performance impact. The speed of the saving operation before this change was measured as 819.02 MB/s, and after was measured at 813.32 MB/s. Before: [ 4.670938] PM: Wrote 171996 kbytes in 0.21 seconds (819.02 MB/s) After: [ 4.504714] PM: Wrote 178932 kbytes in 0.22 seconds (813.32 MB/s) Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: "Rafael J. Wysocki" Cc: Pavel Machek Cc: Borislav Petkov Acked-by: Pavel Machek Signed-off-by: Rick Edgecombe --- arch/x86/mm/pageattr.c | 4 ---- include/linux/mm.h | 18 ++++++------------ kernel/power/snapshot.c | 5 +++-- mm/page_alloc.c | 7 +++++-- 4 files changed, 14 insertions(+), 20 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 3574550192c6..daf4d645e537 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -2257,7 +2257,6 @@ int set_direct_map_default_noflush(struct page *page) return __set_pages_p(page, 1); } -#ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { if (PageHighMem(page)) @@ -2302,11 +2301,8 @@ bool kernel_page_present(struct page *page) pte = lookup_address((unsigned long)page_address(page), &level); return (pte_val(*pte) & _PAGE_PRESENT); } - #endif /* CONFIG_HIBERNATION */ -#endif /* CONFIG_DEBUG_PAGEALLOC */ - int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, unsigned numpages, unsigned long page_flags) { diff --git a/include/linux/mm.h b/include/linux/mm.h index 6b10c21630f5..083d7b4863ed 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2610,37 +2610,31 @@ static inline void kernel_poison_pages(struct page *page, int numpages, int enable) { } #endif -#ifdef CONFIG_DEBUG_PAGEALLOC extern bool _debug_pagealloc_enabled; -extern void __kernel_map_pages(struct page *page, int numpages, int enable); static inline bool debug_pagealloc_enabled(void) { - return _debug_pagealloc_enabled; + return IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) && _debug_pagealloc_enabled; } +#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP) +extern void __kernel_map_pages(struct page *page, int numpages, int enable); + static inline void kernel_map_pages(struct page *page, int numpages, int enable) { - if (!debug_pagealloc_enabled()) - return; - __kernel_map_pages(page, numpages, enable); } #ifdef CONFIG_HIBERNATION extern bool kernel_page_present(struct page *page); #endif /* CONFIG_HIBERNATION */ -#else /* CONFIG_DEBUG_PAGEALLOC */ +#else /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */ static inline void kernel_map_pages(struct page *page, int numpages, int enable) {} #ifdef CONFIG_HIBERNATION static inline bool kernel_page_present(struct page *page) { return true; } #endif /* CONFIG_HIBERNATION */ -static inline bool debug_pagealloc_enabled(void) -{ - return false; -} -#endif /* CONFIG_DEBUG_PAGEALLOC */ +#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */ #ifdef __HAVE_ARCH_GATE_AREA extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm); diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index f08a1e4ee1d4..bc9558ab1e5b 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1342,8 +1342,9 @@ static inline void do_copy_page(long *dst, long *src) * safe_copy_page - Copy a page in a safe way. * * Check if the page we are going to copy is marked as present in the kernel - * page tables (this always is the case if CONFIG_DEBUG_PAGEALLOC is not set - * and in that case kernel_page_present() always returns 'true'). + * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or + * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present() + * always returns 'true'. */ static void safe_copy_page(void *dst, struct page *s_page) { diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d96ca5bc555b..34a70681a4af 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1131,7 +1131,9 @@ static __always_inline bool free_pages_prepare(struct page *page, } arch_free_page(page, order); kernel_poison_pages(page, 1 << order, 0); - kernel_map_pages(page, 1 << order, 0); + if (debug_pagealloc_enabled()) + kernel_map_pages(page, 1 << order, 0); + kasan_free_nondeferred_pages(page, order); return true; @@ -2001,7 +2003,8 @@ inline void post_alloc_hook(struct page *page, unsigned int order, set_page_refcounted(page); arch_alloc_page(page, order); - kernel_map_pages(page, 1 << order, 1); + if (debug_pagealloc_enabled()) + kernel_map_pages(page, 1 << order, 1); kasan_alloc_pages(page, order); kernel_poison_pages(page, 1 << order, 1); set_page_owner(page, order, gfp_flags); From patchwork Fri Apr 26 23:22:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920097 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 246E8912 for ; Sat, 27 Apr 2019 06:47:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 110BC28BC3 for ; Sat, 27 Apr 2019 06:47:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F20FC28E78; Sat, 27 Apr 2019 06:47:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 717D928BC3 for ; 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d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=71dbHy9m/CIhCtlniLjnIfT11ydtbrFJWfPgh/aDBts=; b=NJ+832X/7Rf6oI3yQWwUjfvNDqZF2jsDAsX89LKWKLUO9BS5vsXHhRNFopzNDvF6zL d0KGUjvc9XVZ4cbFm6wyjhfgCBp7O4JlzYD2GIqQyRGAasPT9QKaiSj1Yb/oKOfG8ey/ Kgae+NICG186hSEYNUl15G4o7phSKOOdtdHAy9W3b7CuXrjWK9z0TJpFT7Pt8aOsctrz iMT3XZQbbn1gB9vE/5ncx4iXwZb0UTjssnVTBTk2vI8snKgd8+2ZC5lTX/Hvz681hr+W W25rD8mvSASLwDPeOW90GX4EAoLkpLA3+sFkd+fYVS7+WMHJp3ocKGbYYovC+lhXiTQH Yd0A== X-Gm-Message-State: APjAAAXPKJvKqd6GafsKtjUmDHwJjiFdAmqdX1ygiZHTqzLWFPbtBxKk ye5WPqHq0CIcrQiTbx07IA8= X-Google-Smtp-Source: APXvYqyURRPLLrg0ynk67t/jHVJBTNh21u6U/GXsGcvBn1nAU+eeDbHBRYN9HLkqe6vwNFju/6m6NQ== X-Received: by 2002:a65:500d:: with SMTP id f13mr8345688pgo.250.1556347409072; Fri, 26 Apr 2019 23:43:29 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe Subject: [PATCH v6 17/24] vmalloc: Add flag for free of special permsissions Date: Fri, 26 Apr 2019 16:22:56 -0700 Message-Id: <20190426232303.28381-18-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Rick Edgecombe Add a new flag VM_FLUSH_RESET_PERMS, for enabling vfree operations to immediately clear executable TLB entries before freeing pages, and handle resetting permissions on the directmap. This flag is useful for any kind of memory with elevated permissions, or where there can be related permissions changes on the directmap. Today this is RO+X and RO memory. Although this enables directly vfreeing non-writeable memory now, non-writable memory cannot be freed in an interrupt because the allocation itself is used as a node on deferred free list. So when RO memory needs to be freed in an interrupt the code doing the vfree needs to have its own work queue, as was the case before the deferred vfree list was added to vmalloc. For architectures with set_direct_map_ implementations this whole operation can be done with one TLB flush when centralized like this. For others with directmap permissions, currently only arm64, a backup method using set_memory functions is used to reset the directmap. When arm64 adds set_direct_map_ functions, this backup can be removed. When the TLB is flushed to both remove TLB entries for the vmalloc range mapping and the direct map permissions, the lazy purge operation could be done to try to save a TLB flush later. However today vm_unmap_aliases could flush a TLB range that does not include the directmap. So a helper is added with extra parameters that can allow both the vmalloc address and the direct mapping to be flushed during this operation. The behavior of the normal vm_unmap_aliases function is unchanged. Cc: Borislav Petkov Suggested-by: Dave Hansen Suggested-by: Andy Lutomirski Suggested-by: Will Deacon Signed-off-by: Rick Edgecombe --- include/linux/vmalloc.h | 15 ++++++ mm/vmalloc.c | 113 +++++++++++++++++++++++++++++++++------- 2 files changed, 109 insertions(+), 19 deletions(-) diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 398e9c95cd61..c6eebb839552 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -21,6 +21,11 @@ struct notifier_block; /* in notifier.h */ #define VM_UNINITIALIZED 0x00000020 /* vm_struct is not fully initialized */ #define VM_NO_GUARD 0x00000040 /* don't add guard page */ #define VM_KASAN 0x00000080 /* has allocated kasan shadow memory */ +/* + * Memory with VM_FLUSH_RESET_PERMS cannot be freed in an interrupt or with + * vfree_atomic(). + */ +#define VM_FLUSH_RESET_PERMS 0x00000100 /* Reset direct map and flush TLB on unmap */ /* bits [20..32] reserved for arch specific ioremap internals */ /* @@ -142,6 +147,13 @@ extern int map_kernel_range_noflush(unsigned long start, unsigned long size, pgprot_t prot, struct page **pages); extern void unmap_kernel_range_noflush(unsigned long addr, unsigned long size); extern void unmap_kernel_range(unsigned long addr, unsigned long size); +static inline void set_vm_flush_reset_perms(void *addr) +{ + struct vm_struct *vm = find_vm_area(addr); + + if (vm) + vm->flags |= VM_FLUSH_RESET_PERMS; +} #else static inline int map_kernel_range_noflush(unsigned long start, unsigned long size, @@ -157,6 +169,9 @@ static inline void unmap_kernel_range(unsigned long addr, unsigned long size) { } +static inline void set_vm_flush_reset_perms(void *addr) +{ +} #endif /* Allocate/destroy a 'vmalloc' VM area. */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index e86ba6e74b50..e5e9e1fcac01 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -1059,24 +1060,9 @@ static void vb_free(const void *addr, unsigned long size) spin_unlock(&vb->lock); } -/** - * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer - * - * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily - * to amortize TLB flushing overheads. What this means is that any page you - * have now, may, in a former life, have been mapped into kernel virtual - * address by the vmap layer and so there might be some CPUs with TLB entries - * still referencing that page (additional to the regular 1:1 kernel mapping). - * - * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can - * be sure that none of the pages we have control over will have any aliases - * from the vmap layer. - */ -void vm_unmap_aliases(void) +static void _vm_unmap_aliases(unsigned long start, unsigned long end, int flush) { - unsigned long start = ULONG_MAX, end = 0; int cpu; - int flush = 0; if (unlikely(!vmap_initialized)) return; @@ -1113,6 +1099,27 @@ void vm_unmap_aliases(void) flush_tlb_kernel_range(start, end); mutex_unlock(&vmap_purge_lock); } + +/** + * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer + * + * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily + * to amortize TLB flushing overheads. What this means is that any page you + * have now, may, in a former life, have been mapped into kernel virtual + * address by the vmap layer and so there might be some CPUs with TLB entries + * still referencing that page (additional to the regular 1:1 kernel mapping). + * + * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can + * be sure that none of the pages we have control over will have any aliases + * from the vmap layer. + */ +void vm_unmap_aliases(void) +{ + unsigned long start = ULONG_MAX, end = 0; + int flush = 0; + + _vm_unmap_aliases(start, end, flush); +} EXPORT_SYMBOL_GPL(vm_unmap_aliases); /** @@ -1505,6 +1512,72 @@ struct vm_struct *remove_vm_area(const void *addr) return NULL; } +static inline void set_area_direct_map(const struct vm_struct *area, + int (*set_direct_map)(struct page *page)) +{ + int i; + + for (i = 0; i < area->nr_pages; i++) + if (page_address(area->pages[i])) + set_direct_map(area->pages[i]); +} + +/* Handle removing and resetting vm mappings related to the vm_struct. */ +static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) +{ + unsigned long addr = (unsigned long)area->addr; + unsigned long start = ULONG_MAX, end = 0; + int flush_reset = area->flags & VM_FLUSH_RESET_PERMS; + int i; + + /* + * The below block can be removed when all architectures that have + * direct map permissions also have set_direct_map_() implementations. + * This is concerned with resetting the direct map any an vm alias with + * execute permissions, without leaving a RW+X window. + */ + if (flush_reset && !IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) { + set_memory_nx(addr, area->nr_pages); + set_memory_rw(addr, area->nr_pages); + } + + remove_vm_area(area->addr); + + /* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */ + if (!flush_reset) + return; + + /* + * If not deallocating pages, just do the flush of the VM area and + * return. + */ + if (!deallocate_pages) { + vm_unmap_aliases(); + return; + } + + /* + * If execution gets here, flush the vm mapping and reset the direct + * map. Find the start and end range of the direct mappings to make sure + * the vm_unmap_aliases() flush includes the direct map. + */ + for (i = 0; i < area->nr_pages; i++) { + if (page_address(area->pages[i])) { + start = min(addr, start); + end = max(addr, end); + } + } + + /* + * Set direct map to something invalid so that it won't be cached if + * there are any accesses after the TLB flush, then flush the TLB and + * reset the direct map permissions to the default. + */ + set_area_direct_map(area, set_direct_map_invalid_noflush); + _vm_unmap_aliases(start, end, 1); + set_area_direct_map(area, set_direct_map_default_noflush); +} + static void __vunmap(const void *addr, int deallocate_pages) { struct vm_struct *area; @@ -1526,7 +1599,8 @@ static void __vunmap(const void *addr, int deallocate_pages) debug_check_no_locks_freed(area->addr, get_vm_area_size(area)); debug_check_no_obj_freed(area->addr, get_vm_area_size(area)); - remove_vm_area(addr); + vm_remove_mappings(area, deallocate_pages); + if (deallocate_pages) { int i; @@ -1961,8 +2035,9 @@ EXPORT_SYMBOL(vzalloc_node); */ void *vmalloc_exec(unsigned long size) { - return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL_EXEC, - NUMA_NO_NODE, __builtin_return_address(0)); + return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, + GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, + NUMA_NO_NODE, __builtin_return_address(0)); } #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32) From patchwork Fri Apr 26 23:22:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920099 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0782D912 for ; Sat, 27 Apr 2019 06:47:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EB03328BC3 for ; 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Fri, 26 Apr 2019 23:43:30 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Jessica Yu , Steven Rostedt Subject: [PATCH v6 18/24] modules: Use vmalloc special flag Date: Fri, 26 Apr 2019 16:22:57 -0700 Message-Id: <20190426232303.28381-19-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Rick Edgecombe Use new flag for handling freeing of special permissioned memory in vmalloc and remove places where memory was set RW before freeing which is no longer needed. Since freeing of VM_FLUSH_RESET_PERMS memory is not supported in an interrupt by vmalloc, the freeing of init sections is moved to a work queue. Instead of call_rcu it now uses synchronize_rcu() in the work queue. Lastly, there is now a WARN_ON in module_memfree since it should not be called in an interrupt with special memory as is required for VM_FLUSH_RESET_PERMS. Cc: Jessica Yu Cc: Steven Rostedt Signed-off-by: Rick Edgecombe --- kernel/module.c | 77 +++++++++++++++++++++++++------------------------ 1 file changed, 39 insertions(+), 38 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index 2b2845ae983e..a9020bdd4cf6 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -98,6 +98,10 @@ DEFINE_MUTEX(module_mutex); EXPORT_SYMBOL_GPL(module_mutex); static LIST_HEAD(modules); +/* Work queue for freeing init sections in success case */ +static struct work_struct init_free_wq; +static struct llist_head init_free_list; + #ifdef CONFIG_MODULES_TREE_LOOKUP /* @@ -1949,6 +1953,8 @@ void module_enable_ro(const struct module *mod, bool after_init) if (!rodata_enabled) return; + set_vm_flush_reset_perms(mod->core_layout.base); + set_vm_flush_reset_perms(mod->init_layout.base); frob_text(&mod->core_layout, set_memory_ro); frob_text(&mod->core_layout, set_memory_x); @@ -1972,15 +1978,6 @@ static void module_enable_nx(const struct module *mod) frob_writable_data(&mod->init_layout, set_memory_nx); } -static void module_disable_nx(const struct module *mod) -{ - frob_rodata(&mod->core_layout, set_memory_x); - frob_ro_after_init(&mod->core_layout, set_memory_x); - frob_writable_data(&mod->core_layout, set_memory_x); - frob_rodata(&mod->init_layout, set_memory_x); - frob_writable_data(&mod->init_layout, set_memory_x); -} - /* Iterate through all modules and set each module's text as RW */ void set_all_modules_text_rw(void) { @@ -2024,23 +2021,8 @@ void set_all_modules_text_ro(void) } mutex_unlock(&module_mutex); } - -static void disable_ro_nx(const struct module_layout *layout) -{ - if (rodata_enabled) { - frob_text(layout, set_memory_rw); - frob_rodata(layout, set_memory_rw); - frob_ro_after_init(layout, set_memory_rw); - } - frob_rodata(layout, set_memory_x); - frob_ro_after_init(layout, set_memory_x); - frob_writable_data(layout, set_memory_x); -} - #else -static void disable_ro_nx(const struct module_layout *layout) { } static void module_enable_nx(const struct module *mod) { } -static void module_disable_nx(const struct module *mod) { } #endif #ifdef CONFIG_LIVEPATCH @@ -2120,6 +2102,11 @@ static void free_module_elf(struct module *mod) void __weak module_memfree(void *module_region) { + /* + * This memory may be RO, and freeing RO memory in an interrupt is not + * supported by vmalloc. + */ + WARN_ON(in_interrupt()); vfree(module_region); } @@ -2171,7 +2158,6 @@ static void free_module(struct module *mod) mutex_unlock(&module_mutex); /* This may be empty, but that's OK */ - disable_ro_nx(&mod->init_layout); module_arch_freeing_init(mod); module_memfree(mod->init_layout.base); kfree(mod->args); @@ -2181,7 +2167,6 @@ static void free_module(struct module *mod) lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size); /* Finally, free the core (containing the module structure) */ - disable_ro_nx(&mod->core_layout); module_memfree(mod->core_layout.base); } @@ -3420,17 +3405,34 @@ static void do_mod_ctors(struct module *mod) /* For freeing module_init on success, in case kallsyms traversing */ struct mod_initfree { - struct rcu_head rcu; + struct llist_node node; void *module_init; }; -static void do_free_init(struct rcu_head *head) +static void do_free_init(struct work_struct *w) { - struct mod_initfree *m = container_of(head, struct mod_initfree, rcu); - module_memfree(m->module_init); - kfree(m); + struct llist_node *pos, *n, *list; + struct mod_initfree *initfree; + + list = llist_del_all(&init_free_list); + + synchronize_rcu(); + + llist_for_each_safe(pos, n, list) { + initfree = container_of(pos, struct mod_initfree, node); + module_memfree(initfree->module_init); + kfree(initfree); + } } +static int __init modules_wq_init(void) +{ + INIT_WORK(&init_free_wq, do_free_init); + init_llist_head(&init_free_list); + return 0; +} +module_init(modules_wq_init); + /* * This is where the real work happens. * @@ -3507,7 +3509,6 @@ static noinline int do_init_module(struct module *mod) #endif module_enable_ro(mod, true); mod_tree_remove_init(mod); - disable_ro_nx(&mod->init_layout); module_arch_freeing_init(mod); mod->init_layout.base = NULL; mod->init_layout.size = 0; @@ -3518,14 +3519,18 @@ static noinline int do_init_module(struct module *mod) * We want to free module_init, but be aware that kallsyms may be * walking this with preempt disabled. In all the failure paths, we * call synchronize_rcu(), but we don't want to slow down the success - * path, so use actual RCU here. + * path. module_memfree() cannot be called in an interrupt, so do the + * work and call synchronize_rcu() in a work queue. + * * Note that module_alloc() on most architectures creates W+X page * mappings which won't be cleaned up until do_free_init() runs. Any * code such as mark_rodata_ro() which depends on those mappings to * be cleaned up needs to sync with the queued work - ie * rcu_barrier() */ - call_rcu(&freeinit->rcu, do_free_init); + if (llist_add(&freeinit->node, &init_free_list)) + schedule_work(&init_free_wq); + mutex_unlock(&module_mutex); wake_up_all(&module_wq); @@ -3822,10 +3827,6 @@ static int load_module(struct load_info *info, const char __user *uargs, module_bug_cleanup(mod); mutex_unlock(&module_mutex); - /* we can't deallocate the module until we clear memory protection */ - module_disable_ro(mod); - module_disable_nx(mod); - ddebug_cleanup: ftrace_release_mod(mod); dynamic_debug_remove(mod, info->debug); From patchwork Fri Apr 26 23:22:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920101 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D836114D5 for ; Sat, 27 Apr 2019 06:47:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C954228BC3 for ; Sat, 27 Apr 2019 06:47:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BCA9528E78; Sat, 27 Apr 2019 06:47:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id E2D7728BC3 for ; Sat, 27 Apr 2019 06:47:30 +0000 (UTC) Received: (qmail 5860 invoked by uid 550); 27 Apr 2019 06:43:46 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 5680 invoked from network); 27 Apr 2019 06:43:43 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=03x8MyH4ONo6RL8TDAuJcYQYBUTk8Xfu5EMEl5vv8zs=; b=Q470hKxCA0zkhL+IQMRmPe5UQg42Gi+l2RRmW947taZyL//Jesf10pqg7iknajn5cM 6MahwRUBormFC9ROtXZzOCBPO1osFE8XuHCncIgLvsCHxLcNuXntyLIPTNUxNKWwnbuS YivKpxFXT45f055xbj7gqKyZeZCL6izznlo4y+QcynGiNpgPJSJn6cIDoQUEWR8q3NIV QQ28y5mhdxTCv3ZGyzW3vgvH+5eRIAil3M9uo1sFkym+2/eXjUEbYhGGuoRIn6PGQ204 szqozT+L1TEHgWXr+gjrabBNVx0fQWsxwFBogU0RCWe7qqaev2wbboj0cmVtOcpDQP9M I7SA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=03x8MyH4ONo6RL8TDAuJcYQYBUTk8Xfu5EMEl5vv8zs=; b=NBjXLgr4g1hFQ9fygVdhfLVjqFpBh6x3hRpd1s78vtj1il6G6qiXolf/9ZNOI1lViH /oCOfBIYu6HapzG7bSE9Pl/5SsaAMQqA9pPpPVh7NQSDIbnTEN4Haokic2KdJWRrEApW 45OLRM/fBHATgFIowWUk/eE6GlIXIAsUnQJtlMXN9AwwX6cYc/pzyDUZwulXWaHccS+2 fIPdHqMLUYH/iwz1aj8dXfQcKFUNCzEpOBPTHFQy0M7v5GZq+UIpUCCb0T/vtZN7AvFC ImnDL225tAoNwTDBjROHUky6x68SGqnSDlQBJOrbPlOrGHgMtREEga9lNys8bF1EJW+I wWlA== X-Gm-Message-State: APjAAAVq0fXOZJa1zdIJRt7or5s3+ieW72AiEqQcl4Y7KLyJd3W8aFCF h2lrImlbiUXViX4iHLwvGDQ= X-Google-Smtp-Source: APXvYqwS9mBb6vrC0DhVyMmyRT5ZRdKwezrJErmAVG/FEmt+6AsmQkMSAz9lRez80K2MggQYstDNlg== X-Received: by 2002:a17:902:bd0c:: with SMTP id p12mr17355851pls.50.1556347411683; Fri, 26 Apr 2019 23:43:31 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Daniel Borkmann , Alexei Starovoitov Subject: [PATCH v6 19/24] bpf: Use vmalloc special flag Date: Fri, 26 Apr 2019 16:22:58 -0700 Message-Id: <20190426232303.28381-20-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Rick Edgecombe Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special permissioned memory in vmalloc and remove places where memory was set RW before freeing which is no longer needed. Don't track if the memory is RO anymore because it is now tracked in vmalloc. Cc: Daniel Borkmann Cc: Alexei Starovoitov Signed-off-by: Rick Edgecombe --- include/linux/filter.h | 17 +++-------------- kernel/bpf/core.c | 1 - 2 files changed, 3 insertions(+), 15 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 14ec3bdad9a9..7d3abde3f183 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -20,6 +20,7 @@ #include #include #include +#include #include @@ -503,7 +504,6 @@ struct bpf_prog { u16 pages; /* Number of allocated pages */ u16 jited:1, /* Is our filter JIT'ed? */ jit_requested:1,/* archs need to JIT the prog */ - undo_set_mem:1, /* Passed set_memory_ro() checkpoint */ gpl_compatible:1, /* Is filter GPL compatible? */ cb_access:1, /* Is control block accessed? */ dst_needed:1, /* Do we need dst entry? */ @@ -733,27 +733,17 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) static inline void bpf_prog_lock_ro(struct bpf_prog *fp) { - fp->undo_set_mem = 1; + set_vm_flush_reset_perms(fp); set_memory_ro((unsigned long)fp, fp->pages); } -static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) -{ - if (fp->undo_set_mem) - set_memory_rw((unsigned long)fp, fp->pages); -} - static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) { + set_vm_flush_reset_perms(hdr); set_memory_ro((unsigned long)hdr, hdr->pages); set_memory_x((unsigned long)hdr, hdr->pages); } -static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) -{ - set_memory_rw((unsigned long)hdr, hdr->pages); -} - static inline struct bpf_binary_header * bpf_jit_binary_hdr(const struct bpf_prog *fp) { @@ -789,7 +779,6 @@ void __bpf_prog_free(struct bpf_prog *fp); static inline void bpf_prog_unlock_free(struct bpf_prog *fp) { - bpf_prog_unlock_ro(fp); __bpf_prog_free(fp); } diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index ff09d32a8a1b..c605397c79f0 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -848,7 +848,6 @@ void __weak bpf_jit_free(struct bpf_prog *fp) if (fp->jited) { struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); - bpf_jit_binary_unlock_ro(hdr); bpf_jit_binary_free(hdr); WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); From patchwork Fri Apr 26 23:22:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920103 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1BA4214D5 for ; Sat, 27 Apr 2019 06:47:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0886B28BC3 for ; Sat, 27 Apr 2019 06:47:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id ED53728E78; Sat, 27 Apr 2019 06:47:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 2114A28BC3 for ; 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d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=RIE66crRSFais2XMEreovT7cuc4aWzwk2c6XjFrsy1k=; b=l4IS+IX1N2uniQwCxQU1ZjEJIi5tcvhtUkx8lmm4fx9YARa0DekVO+ApDhTFtIVt2P Yvpx4N6WUY5JvStgH87tNpnDyJ072Iayukof6kT+LQ5SH1P9nXrqZSrrMT4oCGhUYNib btc6yy2Lq8ghKbLCqGlgoJMfseY2VFXFQGrUigNZnQf4k4G7ed8XnWnR59Ml6mLqJQaD unCi27mT9hiUjrpNsSI+WfKnuvawItnSHzqoGNlF54e41MrJuMb/oMwdspr3KYF3n1NX LXurrIPmeZao3QmkVPRe06T8SEYFTwxmYY/o9fGpusWJGmBcB3o7GI3Uravux4NNw62i EaUg== X-Gm-Message-State: APjAAAWEOIzpkWVOT/49TFKFznRHHe2rU6tOJXPc5RLe9EKBPfgAGiUg rClBQFEpRV4hFAZTESp9F60= X-Google-Smtp-Source: APXvYqwLfbRywYDBLBkn2s5QjOy7Ake8UGyhjw6r9cFTnOHwE2KsORvL/Fy4JLKSQeWsUj9Okam5Jg== X-Received: by 2002:a17:902:b68e:: with SMTP id c14mr52282678pls.49.1556347412993; Fri, 26 Apr 2019 23:43:32 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe Subject: [PATCH v6 20/24] x86/ftrace: Use vmalloc special flag Date: Fri, 26 Apr 2019 16:22:59 -0700 Message-Id: <20190426232303.28381-21-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Rick Edgecombe Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special permissioned memory in vmalloc and remove places where memory was set NX and RW before freeing which is no longer needed. Acked-by: Steven Rostedt (VMware) Tested-by: Steven Rostedt (VMware) Signed-off-by: Rick Edgecombe --- arch/x86/kernel/ftrace.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 53ba1aa3a01f..0caf8122d680 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -678,12 +678,8 @@ static inline void *alloc_tramp(unsigned long size) { return module_alloc(size); } -static inline void tramp_free(void *tramp, int size) +static inline void tramp_free(void *tramp) { - int npages = PAGE_ALIGN(size) >> PAGE_SHIFT; - - set_memory_nx((unsigned long)tramp, npages); - set_memory_rw((unsigned long)tramp, npages); module_memfree(tramp); } #else @@ -692,7 +688,7 @@ static inline void *alloc_tramp(unsigned long size) { return NULL; } -static inline void tramp_free(void *tramp, int size) { } +static inline void tramp_free(void *tramp) { } #endif /* Defined as markers to the end of the ftrace default trampolines */ @@ -808,6 +804,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) /* ALLOC_TRAMP flags lets us know we created it */ ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP; + set_vm_flush_reset_perms(trampoline); + /* * Module allocation needs to be completed by making the page * executable. The page is still writable, which is a security hazard, @@ -816,7 +814,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) set_memory_x((unsigned long)trampoline, npages); return (unsigned long)trampoline; fail: - tramp_free(trampoline, *tramp_size); + tramp_free(trampoline); return 0; } @@ -947,7 +945,7 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops) if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) return; - tramp_free((void *)ops->trampoline, ops->trampoline_size); + tramp_free((void *)ops->trampoline); ops->trampoline = 0; } From patchwork Fri Apr 26 23:23:00 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920105 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 80593912 for ; Sat, 27 Apr 2019 06:48:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6F8FD28BC3 for ; Sat, 27 Apr 2019 06:48:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6239C28E78; Sat, 27 Apr 2019 06:48:01 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 986BE28BC3 for ; Sat, 27 Apr 2019 06:48:00 +0000 (UTC) Received: (qmail 5918 invoked by uid 550); 27 Apr 2019 06:43:48 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 5813 invoked from network); 27 Apr 2019 06:43:46 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=PMP2Cxb893S0prGS0vCi085zHCDPTtmjtSNHdboWACs=; b=K41kvx1t6SFhhfzncmYY1HeK2Igm+/jVQYVM/IJLmHXShsg5nGe8rTKsYo4rZoZPC/ 6zju36lQj+i8uBKtds/aE0HT690JXiZHzsJ4iG2ZVbGtv1+m8Rexp2qGC4WzKGij4mJY pS0wLymSfhipDrS8/jIS0cMHQRk/GDuPBjL2K/M1OnR2vxv4YrIebnQ2xexSNHS3XdIV svsj4+MI3xf9ZC2zePDJQy6e/n2bUI0eeL3ftgtEvNDNqK6/0DUPSoZt2Ss6m6/VX3rn 2cMMuSy1cr6XBfOuPS4wxZ/91yZ1FLcgw2kClZNZEQvPCdnBiT4UNc5YyXetyq58UhjO W5iw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=PMP2Cxb893S0prGS0vCi085zHCDPTtmjtSNHdboWACs=; b=hZ7ZvWpkTdPNCE1MrHK3i0Gj+gG57IpVuqMuj2HDenSSR1niqv6k7eNPHzXcg5ROyW umNAGM4ZbFqgk/sSJAdOCmMKDaeJjgqy91nROqyajhrtdhIdTNcsCG1k3mJPJlEZzxR3 C4zNuu+1UmqygiGKmsEElgTNWEztbTk1oxWMDRSsd/SOVHkVZ1kN5aA3hg8lRUxVbYyg KiRH7f649ikabnW5+yz0t5yoHxz8d2OhR6eZY8irid3I8K4ZiGh/O57rfp6WbjqkBk1K 70R3qNMewcO13AwFZ1FKP1Uw++4XJSeLl/TQsSvOHgOMSKJx6HUVxmHgdf3xnGc8r2A2 5xig== X-Gm-Message-State: APjAAAUqW4eLoe/1BrEhMCEv6SaYhr08xGbB1EtQEMFd0nP4dvTaiY6B GlJParvNkvw/BmY2lO9NZco= X-Google-Smtp-Source: APXvYqzt81NaHzE4N6lgOn1CEEv66yygls114EGZnoMMrIlsI1R4+4jwMYRUYyyw4vMJxMCD0c6n8g== X-Received: by 2002:a17:902:f094:: with SMTP id go20mr50490988plb.159.1556347414288; Fri, 26 Apr 2019 23:43:34 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Masami Hiramatsu Subject: [PATCH v6 21/24] x86/kprobes: Use vmalloc special flag Date: Fri, 26 Apr 2019 16:23:00 -0700 Message-Id: <20190426232303.28381-22-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Rick Edgecombe Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special permissioned memory in vmalloc and remove places where memory was set NX and RW before freeing which is no longer needed. Cc: Masami Hiramatsu Signed-off-by: Rick Edgecombe --- arch/x86/kernel/kprobes/core.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 1591852d3ac4..136695e4434a 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -434,6 +434,7 @@ void *alloc_insn_page(void) if (!page) return NULL; + set_vm_flush_reset_perms(page); /* * First make the page read-only, and only then make it executable to * prevent it from being W+X in between. @@ -452,12 +453,6 @@ void *alloc_insn_page(void) /* Recover page to RW mode before releasing it */ void free_insn_page(void *page) { - /* - * First make the page non-executable, and only then make it writable to - * prevent it from being W+X in between. - */ - set_memory_nx((unsigned long)page, 1); - set_memory_rw((unsigned long)page, 1); module_memfree(page); } From patchwork Fri Apr 26 23:23:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920107 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2D92214D5 for ; Sat, 27 Apr 2019 06:48:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 200D728BC3 for ; Sat, 27 Apr 2019 06:48:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1431628E78; Sat, 27 Apr 2019 06:48:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 3879F28BC3 for ; Sat, 27 Apr 2019 06:48:10 +0000 (UTC) Received: (qmail 5998 invoked by uid 550); 27 Apr 2019 06:43:50 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 5869 invoked from network); 27 Apr 2019 06:43:47 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Mq726et3FUsm8L5SG93p+KUhd7ShOgthVM8qUN29ytY=; b=ZcHDpG5oI881U7Ra0/L2O5huO2cwDn2YrdsQ5hiAWkm6WdBzN67nlkJvfLDLJC5q+X UOCeP+9RydbCT4dO6iGp4lZQdm3+sXHNSQC0G0grGB6NOlnyKbwZn5NdDqZwDHIXRDud 3mNZu1J6RFiZozyuuSJ7f0wBAoiYQFhmUfj5tGkTm8jduQKjEFGn6AF04k5qQYjIWsXY 4YzLX+ZgfiYxaYFVUDUXXbJdfkkMMJKkcbeIB+VGTLlKKEI2dS4TTD29m/lBt3TdxyYa a4fp8LYLp6QEbTAIinVcBUAwlwg+TwtnzyGC3pPfhsUXM3/E24y9pQ9Ah5nWVdchzhK2 LMJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Mq726et3FUsm8L5SG93p+KUhd7ShOgthVM8qUN29ytY=; b=oAQWjpSciax+TzbTXU51s2v8Btlf7mVOVDvaMFDjM9OimhL4DDXcvfB1XUSfEQppSk NQuauI+oY5GP3At+CeRFeOh4NnsLLo/PubNZbSLT0Gw2oC7Nel+DxwCeGnpv6yJ/6YJ+ idg17dZOhj1Xl1E2bZBByUJ1dlLa27RSV7UJe7xWu6IjmWt3o9AmnGb1jEiBpfPT3/yo iZnRF/EfzB/or5yg0nMbVEymWceGXfUrGRyL1uJ99Nx2v1RhWrbAjD8Kqih6RTCPEwUA gIiE08kok59cc9p6++0JEIqk3kVvxUWKSj1NxI5tD7Nh8qLdnehCHYP2qOHC5BELssHB vUuQ== X-Gm-Message-State: APjAAAUvQ6YGQUvw/zSh0fqy9JG7LqPkk55n8eXSbupmGZDfvnvLzVNm spn5CKyJwMADD97M76uEiEY= X-Google-Smtp-Source: APXvYqz6QdLKu0nIIJYQFhptNQ/c9BRHYqidvmm2brorovTM3Ggu9E591UYxGE1lKlV0dGgfmeOtWg== X-Received: by 2002:a63:e051:: with SMTP id n17mr5092049pgj.19.1556347415619; Fri, 26 Apr 2019 23:43:35 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Masami Hiramatsu Subject: [PATCH v6 22/24] x86/alternative: Comment about module removal races Date: Fri, 26 Apr 2019 16:23:01 -0700 Message-Id: <20190426232303.28381-23-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit Add a comment to clarify that users of text_poke() must ensure that no races with module removal take place. Cc: Masami Hiramatsu Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/kernel/alternative.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 18f959975ea0..7b9b49dfc05a 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -810,6 +810,11 @@ static void *__text_poke(void *addr, const void *opcode, size_t len) * It means the size must be writable atomically and the address must be aligned * in a way that permits an atomic write. It also makes sure we fit on a single * page. + * + * Note that the caller must ensure that if the modified code is part of a + * module, the module would not be removed during poking. This can be achieved + * by registering a module notifier, and ordering module removal and patching + * trough a mutex. */ void *text_poke(void *addr, const void *opcode, size_t len) { From patchwork Fri Apr 26 23:23:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920109 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 79983912 for ; Sat, 27 Apr 2019 06:48:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6AE1728BC3 for ; Sat, 27 Apr 2019 06:48:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5EBEA28E78; Sat, 27 Apr 2019 06:48:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 83B2428E85 for ; Sat, 27 Apr 2019 06:48:26 +0000 (UTC) Received: (qmail 6027 invoked by uid 550); 27 Apr 2019 06:43:50 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 5943 invoked from network); 27 Apr 2019 06:43:48 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=p6XVxxmeId6Fyrw7m3B0ifgQzW6nhwdk5H1SAhfRKS0=; b=JScJif310IMh72ZohwOauSCAwdoUkuEv8bR6xdhJcKtk1RynLwO3Yk/O8uL4tZE53n NrQxpNK4N1uzjciA1sdkWWtPp8ycpHXFn7qqLzJr7tYIRLsxhiosMqxmPVmHzIChx8+N dySb7k6fhrhmrpcilrlJoW9blvaY3Q+PCSiONh6FBKvoxbL7qSMy7/IzPS7lXjYYk3R/ KYc3BtX2zUuYUpbQToVTJQ3xLcXFtZGa0gKnazTNuB9oRgES+e5Dt6lyOMWvmuEim8L6 0oOzDDk8SIoEGUBtvVZ7G2upgHOvvdwFGoH6Y4DMveFflSyOioLkC8F7etEF6M59+eVc h1Dg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=p6XVxxmeId6Fyrw7m3B0ifgQzW6nhwdk5H1SAhfRKS0=; b=e9b/3NjnP81EDhT74+OlRW2b/cpxLTTW4Lmv+2sG2uuy7KaSSI963qV1U1GoFdYCA5 p1y1YUIkiLFj5fWpayizOymBWldzPvwWoayvw5sld7buV7ntUmrGFXtVDm5alhzyKD9h 8miTaxZHUI0Q8nBNecSslEh6RXKIqa0YT4IaQZThXlzRqMHG95lRxv3tG36oq4WaIbVI OIwWnZCITkJzJIfINqfpymneI045Gzf5JsLNjnA75wt3DSS8E4RcjsJFfcmJgpNh8MME QdGGGpWHlddjNNqtAEJMYqS6uI4oYm8ll5/3z8gwuhabw2Nk55JXr0AKnribsElLghs0 uZdg== X-Gm-Message-State: APjAAAUbTQcH6TAUBxxkNLORJqodHT+DuZXPVYamfG47ftANYbnAnll3 3yYtpamrs/4rgidH05we/HY= X-Google-Smtp-Source: APXvYqy73yIN4FITPLecL8eRrrVFTQfYnIM8wwU5XCBZXYl3CE93cW/V+JNeu8zKe2r7aDykFyaZUg== X-Received: by 2002:a17:902:d83:: with SMTP id 3mr52113119plv.125.1556347416975; Fri, 26 Apr 2019 23:43:36 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit Subject: [PATCH v6 23/24] mm/tlb: Provide default nmi_uaccess_okay() Date: Fri, 26 Apr 2019 16:23:02 -0700 Message-Id: <20190426232303.28381-24-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit x86 has an nmi_uaccess_okay(), but other architectures do not. Arch-independent code might need to know whether access to user addresses is ok in an NMI context or in other code whose execution context is unknown. Specifically, this function is needed for bpf_probe_write_user(). Add a default implementation of nmi_uaccess_okay() for architectures that do not have such a function. Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/include/asm/tlbflush.h | 2 ++ include/asm-generic/tlb.h | 9 +++++++++ 2 files changed, 11 insertions(+) diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 90926e8dd1f8..dee375831962 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -274,6 +274,8 @@ static inline bool nmi_uaccess_okay(void) return true; } +#define nmi_uaccess_okay nmi_uaccess_okay + /* Initialize cr4 shadow for this CPU. */ static inline void cr4_init_shadow(void) { diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index b9edc7608d90..480e5b2a5748 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -21,6 +21,15 @@ #include #include +/* + * Blindly accessing user memory from NMI context can be dangerous + * if we're in the middle of switching the current user task or switching + * the loaded mm. + */ +#ifndef nmi_uaccess_okay +# define nmi_uaccess_okay() true +#endif + #ifdef CONFIG_MMU /* From patchwork Fri Apr 26 23:23:03 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10920111 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AA5E2912 for ; Sat, 27 Apr 2019 06:48:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9B42C28BC3 for ; Sat, 27 Apr 2019 06:48:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8EA9128E78; Sat, 27 Apr 2019 06:48:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id B5EF928BC3 for ; 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d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=TdxUBqKvjD04gvlVW2fqTrr9rgpG7ttN99ifXgy4wJ0=; b=PuhGYb1CxO1LqqhnkkUlNAtnW10uzSHwaE6U7aZ5iIN8qczbgjLmHe2jBTMgb2JAuy o/pMgGJUFS092CiGkIqmxGjM1QBxrwGyvN7ZXs5kfY0QaLITs5EsxsdxGs16jDP8obEv gQ53g74Q09OjXZyhZKs3cqL4xmEiwTzq0TJKwi7ySV8xcCeEP6GL1tUyvxod94bM8B4c 9xP8YB2Hoz6qXWeQeDp/O6v7/9y2zmV6y/+H1FZYE+prxhO8YLKls0Y0GlZ5Q4jCTx6z mcP8SVEDryLqJiJBOSh/YbWkHfCjBS8Z0A4iAcdCOgiwmSnHNG9wAs0AaBWtHy79HUN/ S9MQ== X-Gm-Message-State: APjAAAUoAZx3LhD8q/NjQaQ/N+lm0GNBSOyWaXUf0MNSuFwHHAQWfOtl srvzVhyYgLKiCx4iZD4VcDQ= X-Google-Smtp-Source: APXvYqwkqefi+5wlFbKz/qeJ/65fu9i/qlczB3LZREQFaY/+lFjrw+S/8uXGcd/aBtDXpy5vBsJ5Xg== X-Received: by 2002:a17:902:b715:: with SMTP id d21mr50699394pls.103.1556347418251; Fri, 26 Apr 2019 23:43:38 -0700 (PDT) From: nadav.amit@gmail.com To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , Nadav Amit , Daniel Borkmann , Alexei Starovoitov Subject: [PATCH v6 24/24] bpf: Fail bpf_probe_write_user() while mm is switched Date: Fri, 26 Apr 2019 16:23:03 -0700 Message-Id: <20190426232303.28381-25-nadav.amit@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com> References: <20190426232303.28381-1-nadav.amit@gmail.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Nadav Amit When using a temporary mm, bpf_probe_write_user() should not be able to write to user memory, since user memory addresses may be used to map kernel memory. Detect these cases and fail bpf_probe_write_user() in such cases. Cc: Daniel Borkmann Cc: Alexei Starovoitov Reported-by: Jann Horn Suggested-by: Jann Horn Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- kernel/trace/bpf_trace.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d64c00afceb5..94b0e37d90ef 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -14,6 +14,8 @@ #include #include +#include + #include "trace_probe.h" #include "trace.h" @@ -163,6 +165,10 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, * access_ok() should prevent writing to non-user memory, but in * some situations (nommu, temporary switch, etc) access_ok() does * not provide enough validation, hence the check on KERNEL_DS. + * + * nmi_uaccess_okay() ensures the probe is not run in an interim + * state, when the task or mm are switched. This is specifically + * required to prevent the use of temporary mm. */ if (unlikely(in_interrupt() || @@ -170,6 +176,8 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, return -EPERM; if (unlikely(uaccess_kernel())) return -EPERM; + if (unlikely(!nmi_uaccess_okay())) + return -EPERM; if (!access_ok(unsafe_ptr, size)) return -EPERM;