diff options
| author | Jan Beulich <JBeulich@suse.com> | 2013-10-21 09:44:37 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-10-26 12:27:37 +0200 |
| commit | 7a3d9b0f3abbea957b829cdfff8169872c575642 (patch) | |
| tree | 905bb8d2f62b5bee5b1523ed6dff08dc81551763 /arch/x86/include/asm/uaccess.h | |
| parent | 3df7b41aa5e7797f391d0a41f8b0dce1fe366a09 (diff) | |
x86: Unify copy_to_user() and add size checking to it
Similarly to copy_from_user(), where the range check is to
protect against kernel memory corruption, copy_to_user() can
benefit from such checking too: Here it protects against kernel
information leaks.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: <arjan@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/5265059502000078000FC4F6@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index c9799ed208a8..8ec57c07b125 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -544,6 +544,8 @@ extern struct movsl_mask { unsigned long __must_check _copy_from_user(void *to, const void __user *from, unsigned n); +unsigned long __must_check _copy_to_user(void __user *to, const void *from, + unsigned n); #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS # define copy_user_diag __compiletime_error @@ -553,6 +555,8 @@ unsigned long __must_check _copy_from_user(void *to, const void __user *from, extern void copy_user_diag("copy_from_user() buffer size is too small") copy_from_user_overflow(void); +extern void copy_user_diag("copy_to_user() buffer size is too small") +copy_to_user_overflow(void) __asm__("copy_from_user_overflow"); #undef copy_user_diag @@ -563,6 +567,11 @@ __compiletime_warning("copy_from_user() buffer size is not provably correct") __copy_from_user_overflow(void) __asm__("copy_from_user_overflow"); #define __copy_from_user_overflow(size, count) __copy_from_user_overflow() +extern void +__compiletime_warning("copy_to_user() buffer size is not provably correct") +__copy_to_user_overflow(void) __asm__("copy_from_user_overflow"); +#define __copy_to_user_overflow(size, count) __copy_to_user_overflow() + #else static inline void @@ -571,6 +580,8 @@ __copy_from_user_overflow(int size, unsigned long count) WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count); } +#define __copy_to_user_overflow __copy_from_user_overflow + #endif static inline unsigned long __must_check @@ -608,7 +619,26 @@ copy_from_user(void *to, const void __user *from, unsigned long n) return n; } +static inline unsigned long __must_check +copy_to_user(void __user *to, const void *from, unsigned long n) +{ + int sz = __compiletime_object_size(from); + + might_fault(); + + /* See the comment in copy_from_user() above. */ + if (likely(sz < 0 || sz >= n)) + n = _copy_to_user(to, from, n); + else if(__builtin_constant_p(n)) + copy_to_user_overflow(); + else + __copy_to_user_overflow(sz, n); + + return n; +} + #undef __copy_from_user_overflow +#undef __copy_to_user_overflow #endif /* _ASM_X86_UACCESS_H */ |