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authorJan Beulich <JBeulich@suse.com>2013-10-21 10:44:37 +0200
committerIngo Molnar <mingo@kernel.org>2013-10-26 12:27:37 +0200
commit7a3d9b0f3abbea957b829cdfff8169872c575642 (patch)
tree905bb8d2f62b5bee5b1523ed6dff08dc81551763 /arch/x86/include
parentx86: Unify copy_from_user() size checking (diff)
downloadlinux-7a3d9b0f3abbea957b829cdfff8169872c575642.tar.xz
linux-7a3d9b0f3abbea957b829cdfff8169872c575642.zip
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')
-rw-r--r--arch/x86/include/asm/uaccess.h30
-rw-r--r--arch/x86/include/asm/uaccess_32.h3
-rw-r--r--arch/x86/include/asm/uaccess_64.h10
3 files changed, 30 insertions, 13 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 */
diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h
index c348c87cefc8..3c03a5de64d3 100644
--- a/arch/x86/include/asm/uaccess_32.h
+++ b/arch/x86/include/asm/uaccess_32.h
@@ -184,7 +184,4 @@ __copy_from_user_inatomic_nocache(void *to, const void __user *from,
return __copy_from_user_ll_nocache_nozero(to, from, n);
}
-unsigned long __must_check copy_to_user(void __user *to,
- const void *from, unsigned long n);
-
#endif /* _ASM_X86_UACCESS_32_H */
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index 4df93c46852b..0acae710fa00 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -46,19 +46,9 @@ copy_user_generic(void *to, const void *from, unsigned len)
}
__must_check unsigned long
-_copy_to_user(void __user *to, const void *from, unsigned len);
-__must_check unsigned long
copy_in_user(void __user *to, const void __user *from, unsigned len);
static __always_inline __must_check
-int copy_to_user(void __user *dst, const void *src, unsigned size)
-{
- might_fault();
-
- return _copy_to_user(dst, src, size);
-}
-
-static __always_inline __must_check
int __copy_from_user(void *dst, const void __user *src, unsigned size)
{
int ret = 0;