diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2016-08-17 16:36:37 -0400 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2017-04-11 10:57:58 +0200 |
| commit | a7e027dca9eecbf6c02f91eb3f09c34136a8312f (patch) | |
| tree | cbf38921b53b02449e01ca61bc8f71bcb1213768 /include/asm-generic/uaccess.h | |
| parent | a8bf3beffe3b4f3b85dbfa98ec02ff2c67956642 (diff) | |
asm-generic: make copy_from_user() zero the destination properly
commit 2545e5da080b4839dd859e3b09343a884f6ab0e3 upstream.
... in all cases, including the failing access_ok()
Note that some architectures using asm-generic/uaccess.h have
__copy_from_user() not zeroing the tail on failure halfway
through. This variant works either way.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[wt: s/might_fault/might_sleep]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'include/asm-generic/uaccess.h')
| -rw-r--r-- | include/asm-generic/uaccess.h | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index fee282ab2..a8203040f 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -259,11 +259,13 @@ extern int __get_user_bad(void) __attribute__((noreturn)); static inline long copy_from_user(void *to, const void __user * from, unsigned long n) { + unsigned long res = n; might_sleep(); - if (access_ok(VERIFY_READ, from, n)) - return __copy_from_user(to, from, n); - else - return n; + if (likely(access_ok(VERIFY_READ, from, n))) + res = __copy_from_user(to, from, n); + if (unlikely(res)) + memset(to + (n - res), 0, res); + return res; } static inline long copy_to_user(void __user *to, |