From patchwork Mon Jul 11 20:53:54 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Lutomirski X-Patchwork-Id: 9224169 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 CF15060572 for ; Mon, 11 Jul 2016 20:56:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C021727D76 for ; Mon, 11 Jul 2016 20:56:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B465327E33; Mon, 11 Jul 2016 20:56:52 +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=-4.2 required=2.0 tests=BAYES_00, 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 7FCEA27D76 for ; Mon, 11 Jul 2016 20:56:51 +0000 (UTC) Received: (qmail 25764 invoked by uid 550); 11 Jul 2016 20:54:49 -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: Reply-To: kernel-hardening@lists.openwall.com Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 24515 invoked from network); 11 Jul 2016 20:54:44 -0000 From: Andy Lutomirski To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, Borislav Petkov , Nadav Amit , Kees Cook , Brian Gerst , "kernel-hardening@lists.openwall.com" , Linus Torvalds , Josh Poimboeuf , Jann Horn , Heiko Carstens , Andy Lutomirski Date: Mon, 11 Jul 2016 13:53:54 -0700 Message-Id: <905d951956bee9ae58a6312ad21aa7a52503d368.1468270393.git.luto@kernel.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: X-Virus-Scanned: ClamAV using ClamSMTP Subject: [kernel-hardening] [PATCH v5 21/32] x86/asm: Move 'status' from struct thread_info to struct thread_struct X-Virus-Scanned: ClamAV using ClamSMTP Becuase sched.h and thread_info.h are a tangled mess, I turned in_compat_syscall into a macro. If we had current_thread_struct() or similar and we could use it from thread_info.h, then this would be a bit cleaner. Signed-off-by: Andy Lutomirski --- arch/x86/entry/common.c | 4 ++-- arch/x86/include/asm/processor.h | 12 ++++++++++++ arch/x86/include/asm/syscall.h | 23 +++++------------------ arch/x86/include/asm/thread_info.h | 23 ++++------------------- arch/x86/kernel/asm-offsets.c | 1 - arch/x86/kernel/fpu/init.c | 1 - arch/x86/kernel/process_64.c | 4 ++-- arch/x86/kernel/ptrace.c | 2 +- 8 files changed, 26 insertions(+), 44 deletions(-) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index ec138e538c44..c4150bec7982 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -271,7 +271,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs) * syscalls. The fixup is exercised by the ptrace_syscall_32 * selftest. */ - ti->status &= ~TS_COMPAT; + current->thread.status &= ~TS_COMPAT; #endif user_enter(); @@ -369,7 +369,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs) unsigned int nr = (unsigned int)regs->orig_ax; #ifdef CONFIG_IA32_EMULATION - ti->status |= TS_COMPAT; + current->thread.status |= TS_COMPAT; #endif if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) { diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index a2e20d6d01fe..a75e720f6402 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -388,6 +388,9 @@ struct thread_struct { unsigned short fsindex; unsigned short gsindex; #endif + + u32 status; /* thread synchronous flags */ + #ifdef CONFIG_X86_32 unsigned long ip; #endif @@ -437,6 +440,15 @@ struct thread_struct { }; /* + * Thread-synchronous status. + * + * This is different from the flags in that nobody else + * ever touches our thread-synchronous status, so we don't + * have to worry about atomic accesses. + */ +#define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ + +/* * Set IOPL bits in EFLAGS from given mask */ static inline void native_set_iopl_mask(unsigned mask) diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h index 999b7cd2e78c..17229e7e2a1c 100644 --- a/arch/x86/include/asm/syscall.h +++ b/arch/x86/include/asm/syscall.h @@ -60,7 +60,7 @@ static inline long syscall_get_error(struct task_struct *task, * TS_COMPAT is set for 32-bit syscall entries and then * remains set until we return to user mode. */ - if (task_thread_info(task)->status & TS_COMPAT) + if (task->thread.status & TS_COMPAT) /* * Sign-extend the value so (int)-EFOO becomes (long)-EFOO * and will match correctly in comparisons. @@ -116,7 +116,7 @@ static inline void syscall_get_arguments(struct task_struct *task, unsigned long *args) { # ifdef CONFIG_IA32_EMULATION - if (task_thread_info(task)->status & TS_COMPAT) + if (task->thread.status & TS_COMPAT) switch (i) { case 0: if (!n--) break; @@ -177,7 +177,7 @@ static inline void syscall_set_arguments(struct task_struct *task, const unsigned long *args) { # ifdef CONFIG_IA32_EMULATION - if (task_thread_info(task)->status & TS_COMPAT) + if (task->thread.status & TS_COMPAT) switch (i) { case 0: if (!n--) break; @@ -234,21 +234,8 @@ static inline void syscall_set_arguments(struct task_struct *task, static inline int syscall_get_arch(void) { -#ifdef CONFIG_IA32_EMULATION - /* - * TS_COMPAT is set for 32-bit syscall entry and then - * remains set until we return to user mode. - * - * TIF_IA32 tasks should always have TS_COMPAT set at - * system call time. - * - * x32 tasks should be considered AUDIT_ARCH_X86_64. - */ - if (task_thread_info(current)->status & TS_COMPAT) - return AUDIT_ARCH_I386; -#endif - /* Both x32 and x86_64 are considered "64-bit". */ - return AUDIT_ARCH_X86_64; + /* x32 tasks should be considered AUDIT_ARCH_X86_64. */ + return in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64; } #endif /* CONFIG_X86_32 */ diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index b45ffdda3549..7b42c1e462ac 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -55,7 +55,6 @@ struct task_struct; struct thread_info { struct task_struct *task; /* main task structure */ __u32 flags; /* low level flags */ - __u32 status; /* thread synchronous flags */ __u32 cpu; /* current CPU */ }; @@ -211,28 +210,14 @@ static inline unsigned long current_stack_pointer(void) #endif -/* - * Thread-synchronous status. - * - * This is different from the flags in that nobody else - * ever touches our thread-synchronous status, so we don't - * have to worry about atomic accesses. - */ -#define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ - #ifndef __ASSEMBLY__ -static inline bool in_ia32_syscall(void) -{ #ifdef CONFIG_X86_32 - return true; -#endif -#ifdef CONFIG_IA32_EMULATION - if (current_thread_info()->status & TS_COMPAT) - return true; +#define in_ia32_syscall() true +#else +#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \ + current->thread.status & TS_COMPAT) #endif - return false; -} /* * Force syscall return via IRET by making it look as if there was diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 2bd5c6ff7ee7..a91a6ead24a2 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -30,7 +30,6 @@ void common(void) { BLANK(); OFFSET(TI_flags, thread_info, flags); - OFFSET(TI_status, thread_info, status); BLANK(); OFFSET(TASK_addr_limit, task_struct, thread.addr_limit); diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index aacfd7a82cec..4579c1544ed1 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -327,7 +327,6 @@ static void __init fpu__init_system_ctx_switch(void) on_boot_cpu = 0; WARN_ON_FPU(current->thread.fpu.fpstate_active); - current_thread_info()->status = 0; if (boot_cpu_has(X86_FEATURE_XSAVEOPT) && eagerfpu != DISABLE) eagerfpu = ENABLE; diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 6e789ca1f841..e6d53b641ef0 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -511,7 +511,7 @@ void set_personality_ia32(bool x32) current->personality &= ~READ_IMPLIES_EXEC; /* in_compat_syscall() uses the presence of the x32 syscall bit flag to determine compat status */ - current_thread_info()->status &= ~TS_COMPAT; + current->thread.status &= ~TS_COMPAT; } else { set_thread_flag(TIF_IA32); clear_thread_flag(TIF_X32); @@ -519,7 +519,7 @@ void set_personality_ia32(bool x32) current->mm->context.ia32_compat = TIF_IA32; current->personality |= force_personality32; /* Prepare the first "return" to user space */ - current_thread_info()->status |= TS_COMPAT; + current->thread.status |= TS_COMPAT; } } EXPORT_SYMBOL_GPL(set_personality_ia32); diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 600edd225e81..4f03301ecfbe 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -931,7 +931,7 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value) */ regs->orig_ax = value; if (syscall_get_nr(child, regs) >= 0) - task_thread_info(child)->status |= TS_COMPAT; + child->thread.status |= TS_COMPAT; break; case offsetof(struct user32, regs.eflags):