Messages in this thread Patch in this message | | | From | Marcin Slusarz <> | Subject | [PATCH] ERR_PTR: if errno value is known at compile time, make sure it's valid | Date | Thu, 22 May 2008 18:50:18 +0200 |
| |
ERR_PTR is easy to call with wrong argument (positive errno), and this error lead to catastrophic event - oops or kernel panic (dereference of invalid pointer).
As most of error handling code paths are rarely tested, this kind of bug can be hidden for years. Currently there are > 1400 calls of ERR_PTR with constant argument.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Johannes Weiner <hannes@saeurebad.de> --- include/linux/err.h | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/include/linux/err.h b/include/linux/err.h index ec87f31..4773ed3 100644 --- a/include/linux/err.h +++ b/include/linux/err.h @@ -18,12 +18,21 @@ #ifndef __ASSEMBLY__ #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO) +#define VALID_ERR_PTR_ARG(error) (error == 0 || IS_ERR_VALUE(error)) -static inline void *ERR_PTR(long error) +static inline void *__ERR_PTR(long error) { return (void *) error; } +/* + * implementation note: we have to make it a macro, otherwise + * gcc won't break the build on wrong argument + */ +#define ERR_PTR(error) (BUILD_BUG_ON(__builtin_constant_p(error) && \ + !VALID_ERR_PTR_ARG(error)), \ + __ERR_PTR(error)) + static inline long PTR_ERR(const void *ptr) { return (long) ptr; -- 1.5.4.5
| |