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frv: fix clear_user() 

It should check access_ok().  Otherwise a bunch of places turn into
trivially exploitable rootholes.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-08-18 20:54:02 -04:00
parent eb47e0293b
commit 3b8767a8f0
1 changed files with 9 additions and 3 deletions
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12
arch/frv/include/asm/uaccess.h
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@ -263,19 +263,25 @@ do { \
extern long __memset_user(void *dst, unsigned long count);
extern long __memcpy_user(void *dst, const void *src, unsigned long count);
#define clear_user(dst,count) __memset_user(____force(dst), (count))
#define __clear_user(dst,count) __memset_user(____force(dst), (count))
#define __copy_from_user_inatomic(to, from, n) __memcpy_user((to), ____force(from), (n))
#define __copy_to_user_inatomic(to, from, n) __memcpy_user(____force(to), (from), (n))
#else
#define clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
#define __clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
#define __copy_from_user_inatomic(to, from, n) (memcpy((to), ____force(from), (n)), 0)
#define __copy_to_user_inatomic(to, from, n) (memcpy(____force(to), (from), (n)), 0)
#endif
#define __clear_user clear_user
static inline unsigned long __must_check
clear_user(void __user *to, unsigned long n)
{
if (likely(__access_ok(to, n)))
n = __clear_user(to, n);
return n;
}
static inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)