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asm-generic: make get_user() clear the destination on errors 

both for access_ok() failures and for faults halfway through

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-08-17 23:19:01 -04:00
parent 2545e5da08
commit 9ad18b75c2
1 changed files with 7 additions and 3 deletions
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10
include/asm-generic/uaccess.h
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@ -230,14 +230,18 @@ extern int __put_user_bad(void) __attribute__((noreturn));
might_fault(); \ might_fault(); \
access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \ access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \
__get_user((x), (__typeof__(*(ptr)) *)__p) : \ __get_user((x), (__typeof__(*(ptr)) *)__p) : \
-EFAULT; \ ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
}) })
#ifndef __get_user_fn #ifndef __get_user_fn
static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
{ {
size = __copy_from_user(x, ptr, size); size_t n = __copy_from_user(x, ptr, size);
return size ? -EFAULT : size; if (unlikely(n)) {
memset(x + (size - n), 0, n);
return -EFAULT;
}
return 0;
} }
#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)