blob: fb2cc1ab2ab1fe417997dd293174edae670507b3 [file] [log] [blame]
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 17 Aug 2016 23:19:01 -0400
Subject: asm-generic: make get_user() clear the destination on errors
commit 9ad18b75c2f6e4a78ce204e79f37781f8815c0fa upstream.
both for access_ok() failures and for faults halfway through
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
include/asm-generic/uaccess.h | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -228,14 +228,18 @@ extern int __put_user_bad(void) __attrib
might_fault(); \
access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \
__get_user(x, ptr) : \
- -EFAULT; \
+ ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
})
#ifndef __get_user_fn
static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
{
- size = __copy_from_user(x, ptr, size);
- return size ? -EFAULT : size;
+ size_t n = __copy_from_user(x, ptr, 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)