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| author | Andy Lutomirski <luto@kernel.org> | 2016-07-27 09:12:22 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-07-27 12:09:43 +0300 |
| commit | 609c19a385c8744c41f944e2a2d8afe8e8fb860e (patch) | |
| tree | 34e6a36adf4ec420dca05a5cf2c7d83c2a195ca3 /arch/x86/include | |
| parent | 37e13a1ebe32c4fbfbdb5413f42eb6e71d8b28a4 (diff) | |
| download | linux-609c19a385c8744c41f944e2a2d8afe8e8fb860e.tar.xz | |
x86/ptrace: Stop setting TS_COMPAT in ptrace code
Setting TS_COMPAT in ptrace is wrong: if we happen to do it during
syscall entry, then we'll confuse seccomp and audit. (The former
isn't a security problem: seccomp is currently entirely insecure if a
malicious ptracer is attached.) As a minimal fix, this patch adds a
new flag TS_I386_REGS_POKED that handles the ptrace special case.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5383ebed38b39fa37462139e337aff7f2314d1ca.1469599803.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/syscall.h | 5 | ||||
| -rw-r--r-- | arch/x86/include/asm/thread_info.h | 3 |
2 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h index 999b7cd2e78c..4e23dd15c661 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_info(task)->status & (TS_COMPAT|TS_I386_REGS_POKED)) /* * Sign-extend the value so (int)-EFOO becomes (long)-EFOO * and will match correctly in comparisons. @@ -239,9 +239,6 @@ static inline int syscall_get_arch(void) * 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) diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 89bff044a6f5..f856c590c309 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -219,6 +219,9 @@ static inline unsigned long current_stack_pointer(void) * have to worry about atomic accesses. */ #define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ +#ifdef CONFIG_COMPAT +#define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */ +#endif #define TS_RESTORE_SIGMASK 0x0008 /* restore signal mask in do_signal() */ #ifndef __ASSEMBLY__ |