From patchwork Thu Mar 9 01:24:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Garnier X-Patchwork-Id: 9612177 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6F18F60414 for ; Thu, 9 Mar 2017 01:25:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4F57628645 for ; Thu, 9 Mar 2017 01:25:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4394C2864B; Thu, 9 Mar 2017 01:25:48 +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=-4.1 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID 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 2FF5A28645 for ; Thu, 9 Mar 2017 01:25:47 +0000 (UTC) Received: (qmail 16091 invoked by uid 550); 9 Mar 2017 01:25:38 -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 16039 invoked from network); 9 Mar 2017 01:25:36 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=HC+ONBbvC1qcpc7QjMhjEyeoPRKLYUUl5sANbADuK38=; b=DLkJOwNcOzX0ni6QgiPCARF9Z0BL6pk5wSEOJsBzBU/LZjRSEYJgC11gnD0O901gJE vRTwwWnDS23IOzn6qsBVLrb1a2u15ce3YqVng0hyVnthZx0smJD2ZiZrHZklHlXZ5+bA hf1qGu+G0aWay4mRZGE2vOl+pWOZrN+oYIxh6se7GaeATaG370PV9IdRpaz1jqUIdnuU yIDJql+k5X7tDIPvGAuac0aQXFPKENbxOQ5vT12SjWpxi6TiZ+9L8HfkL44+s+0KCtgb 0/lG0UbK7k+Y0VGENfsdo8ItqBiBW7WJDj3avyU68FeGHOd3imdDMOtRJlDR2m+qeJZU KMXg== 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=HC+ONBbvC1qcpc7QjMhjEyeoPRKLYUUl5sANbADuK38=; b=I9rNW+KW//EeJ/1nTHv5aCdDMlo5LqxuS63dCuHvWK7Q0xrYSnFeLvnQHZPp8/ITsk xl+9aCLU/GZOeDX+L7r13hRqdskcJoqHcy/pd0JRVZfJfmt3bkzKkQnohEfdCrTePV+W 7LpAK4bBATO4RhgCO/4l6NPTlOaEalkCAY4ExR0fYQGhgWjw3kb9LJp3lGx7MNcIhObR 9hJqj+lJ73c4Xvj8KwN7DyKM/Wd3ADda6de8YZ/YntZ0CBFftQFHJwGRSbezTXpdFR1O oh0BC9hmaiA3TEixxSneVGsT2XTl3weVovtYo9Fb3jbGgQmbO4y0qQtZ3PCrJNqkhu9G DG8Q== X-Gm-Message-State: AMke39nacgPyVQSMG+xpabqPMxb28hMIIz1gO8NtvYfkwLhqrv+ExMKoyH+GidRPdaRHyykh X-Received: by 10.84.164.106 with SMTP id m39mr13188862plg.9.1489022724685; Wed, 08 Mar 2017 17:25:24 -0800 (PST) From: Thomas Garnier To: David Howells , Dave Hansen , Arnd Bergmann , Al Viro , =?UTF-8?q?Ren=C3=A9=20Nyffenegger?= , Thomas Garnier , Andrew Morton , Kees Cook , "Paul E . McKenney" , "David S . Miller" , Andy Lutomirski , Ard Biesheuvel , Nicolas Pitre , Petr Mladek , Sebastian Andrzej Siewior , Sergey Senozhatsky , Helge Deller , Rik van Riel , Ingo Molnar , Oleg Nesterov , John Stultz , Thomas Gleixner , Pavel Tikhomirov , Frederic Weisbecker , Stephen Smalley , Stanislav Kinsburskiy , Ingo Molnar , "H . Peter Anvin" , Paolo Bonzini , Borislav Petkov , Josh Poimboeuf , Brian Gerst , Jan Beulich , Christian Borntraeger , "Luis R . Rodriguez" , He Chen , Russell King , Will Deacon , Catalin Marinas , Mark Rutland , James Morse , Pratyush Anand , Vladimir Murzin , Chris Metcalf , Andre Przywara Cc: linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, kernel-hardening@lists.openwall.com Date: Wed, 8 Mar 2017 17:24:54 -0800 Message-Id: <20170309012456.5631-2-thgarnie@google.com> X-Mailer: git-send-email 2.12.0.246.ga2ecc84866-goog In-Reply-To: <20170309012456.5631-1-thgarnie@google.com> References: <20170309012456.5631-1-thgarnie@google.com> Subject: [kernel-hardening] [PATCH v2 2/4] x86/syscalls: Specific usage of verify_pre_usermode_state X-Virus-Scanned: ClamAV using ClamSMTP Implement specific usage of verify_pre_usermode_state for user-mode returns for x86. --- Based on next-20170308 --- arch/x86/Kconfig | 1 + arch/x86/entry/common.c | 3 +++ arch/x86/entry/entry_64.S | 19 +++++++++++++++++++ arch/x86/include/asm/pgtable_64_types.h | 11 +++++++++++ arch/x86/include/asm/processor.h | 11 ----------- 5 files changed, 34 insertions(+), 11 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 005df7c825f5..6d48e18e6f09 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -63,6 +63,7 @@ config X86 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_SERIO + select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 370c42c7f046..525edbb77f03 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -180,6 +181,8 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs) struct thread_info *ti = current_thread_info(); u32 cached_flags; + verify_pre_usermode_state(); + if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled())) local_irq_disable(); diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index d2b2a2948ffe..b3527d31b91b 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -96,6 +96,19 @@ ENDPROC(native_usergs_sysret64) # define TRACE_IRQS_IRETQ_DEBUG TRACE_IRQS_IRETQ #endif +#ifdef CONFIG_BUG_ON_DATA_CORRUPTION +.macro VERIFY_PRE_USERMODE_STATE + call verify_pre_usermode_state +.endm +#else +/* Similar to set_fs(USER_DS) in verify_pre_usermode_state without a warning. */ +.macro VERIFY_PRE_USERMODE_STATE + movq PER_CPU_VAR(current_task), %rax + movq $TASK_SIZE_MAX, %rcx + movq %rcx, TASK_addr_limit(%rax) +.endm +#endif + /* * 64-bit SYSCALL instruction entry. Up to 6 arguments in registers. * @@ -201,6 +214,7 @@ entry_SYSCALL_64_fastpath: * It might end up jumping to the slow path. If it jumps, RAX * and all argument registers are clobbered. */ + call *sys_call_table(, %rax, 8) .Lentry_SYSCALL_64_after_fastpath_call: @@ -218,6 +232,11 @@ entry_SYSCALL_64_fastpath: testl $_TIF_ALLWORK_MASK, TASK_TI_flags(%r11) jnz 1f + /* + * Check user-mode state on fast path return, the same check is done + * under the slow path through syscall_return_slowpath. + */ + VERIFY_PRE_USERMODE_STATE LOCKDEP_SYS_EXIT TRACE_IRQS_ON /* user mode is traced as IRQs on */ movq RIP(%rsp), %rcx diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h index 3a264200c62f..0fbbb79d058c 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -76,4 +76,15 @@ typedef struct { pteval_t pte; } pte_t; #define EARLY_DYNAMIC_PAGE_TABLES 64 +/* + * User space process size. 47bits minus one guard page. The guard + * page is necessary on Intel CPUs: if a SYSCALL instruction is at + * the highest possible canonical userspace address, then that + * syscall will enter the kernel with a non-canonical return + * address, and SYSRET will explode dangerously. We avoid this + * particular problem by preventing anything from being mapped + * at the maximum canonical address. + */ +#define TASK_SIZE_MAX ((_AC(1, UL) << 47) - PAGE_SIZE) + #endif /* _ASM_X86_PGTABLE_64_DEFS_H */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index f385eca5407a..9bc99d37133e 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -829,17 +829,6 @@ static inline void spin_lock_prefetch(const void *x) #define KSTK_ESP(task) (task_pt_regs(task)->sp) #else -/* - * User space process size. 47bits minus one guard page. The guard - * page is necessary on Intel CPUs: if a SYSCALL instruction is at - * the highest possible canonical userspace address, then that - * syscall will enter the kernel with a non-canonical return - * address, and SYSRET will explode dangerously. We avoid this - * particular problem by preventing anything from being mapped - * at the maximum canonical address. - */ -#define TASK_SIZE_MAX ((1UL << 47) - PAGE_SIZE) - /* This decides where the kernel will search for a free chunk of vm * space during mmap's. */