diff options
| author |   Mike Frysinger <vapier@gentoo.org> | 2009-06-14 02:00:02 -0400 |
|---|---|---|
| committer |   Arnd Bergmann <arnd@arndb.de> | 2009-06-19 14:58:07 +0200 |
| commit | 9844813f226f6d07e1544e915529cb88f4fcb868 (patch) | |
| tree | cdf051b38220c6d99a6f4aac372d7b95eda26c6a | |
| parent | Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 (diff) | |
asm-generic: uaccess: add missing access_ok() check to strnlen_user()
The strnlen_user() function was missing a access_ok() check on the pointer
given. We've had cases on Blackfin systems where test programs caused
kernel crashes here because userspace passed up a NULL/-1 pointer and the
kernel gladly attempted to run strlen() on it.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
| -rw-r--r-- | include/asm-generic/uaccess.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 6d8cab22e294..5dd511b62ce9 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -291,6 +291,8 @@ strncpy_from_user(char *dst, const char __user *src, long count) #ifndef strnlen_user static inline long strnlen_user(const char __user *src, long n) { + if (!access_ok(VERIFY_READ, src, 1)) + return 0; return strlen((void * __force)src) + 1; } #endif |