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| author | Al Viro <viro@zeniv.linux.org.uk> | 2016-08-17 23:19:01 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-11-20 01:01:38 +0000 |
| commit | 33734b78269e1d211cd1288c49756636042aa31e (patch) | |
| tree | 6429d4b59c15876300c5fc7e40bb1199efca8e17 | |
| parent | 87f3c8956e3fea2a704c3834e0666e8fae5a529e (diff) | |
| download | lwn-33734b78269e1d211cd1288c49756636042aa31e.tar.gz lwn-33734b78269e1d211cd1288c49756636042aa31e.zip | |
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 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | include/asm-generic/uaccess.h | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 61dada277520..5ba2c4570bd3 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -221,13 +221,17 @@ extern int __put_user_bad(void) __attribute__((noreturn)); 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)); |