| From | Ben Hutchings <> | Date | Mon, 14 Nov 2016 00:14:07 +0000 | Subject | [PATCH 3.2 106/152] asm-generic: make get_user() clear the destination on errors |
| |
3.2.84-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Al Viro <viro@zeniv.linux.org.uk>
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 3.2: 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 @@ -221,13 +221,17 @@ extern int __put_user_bad(void) __attrib might_sleep(); \ access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \ __get_user(x, ptr) : \ - -EFAULT; \ + ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ }) 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; } extern int __get_user_bad(void) __attribute__((noreturn));
|