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>

1 files changed, 0 insertions, 10 deletions

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;