Messages in this thread Patch in this message | | | From | Mike Frysinger <> | Subject | [PATCH 2/4] asm-generic: uaccess: add missing access_ok() check to strnlen_user() | Date | Sun, 14 Jun 2009 02:00:02 -0400 |
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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> --- 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 cf3cb73..d299557 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -296,6 +296,8 @@ 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 -- 1.6.3.1
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