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| author | Xi Wang <xi.wang@gmail.com> | 2012-04-20 15:49:44 -0500 |
|---|---|---|
| committer | Alex Elder <elder@dreamhost.com> | 2012-05-14 12:12:27 -0500 |
| commit | 76aa542fb90e3e91edb1146d10ca7cf2cae8e7e9 (patch) | |
| tree | d01a137e60126d140790c64f1a3994c62792b61e /include/linux/ceph | |
| parent | 065a68f9167e20f321a62d044cb2c3024393d455 (diff) | |
| download | lwn-76aa542fb90e3e91edb1146d10ca7cf2cae8e7e9.tar.gz lwn-76aa542fb90e3e91edb1146d10ca7cf2cae8e7e9.zip | |
ceph: fix bounds check in ceph_decode_need and ceph_encode_need
Given a large n, the bounds check (*p + n > end) can be bypassed due to
pointer wraparound. A safer check is (n > end - *p).
[elder@dreamhost.com: inverted test and renamed ceph_has_room()]
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Reviewed-by: Alex Elder <elder@dreamhost.com>
Diffstat (limited to 'include/linux/ceph')
| -rw-r--r-- | include/linux/ceph/decode.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/include/linux/ceph/decode.h b/include/linux/ceph/decode.h index c5b6939fb32a..ecf324eb2c9a 100644 --- a/include/linux/ceph/decode.h +++ b/include/linux/ceph/decode.h @@ -45,9 +45,14 @@ static inline void ceph_decode_copy(void **p, void *pv, size_t n) /* * bounds check input. */ +static inline int ceph_has_room(void **p, void *end, size_t n) +{ + return end >= *p && n <= end - *p; +} + #define ceph_decode_need(p, end, n, bad) \ do { \ - if (unlikely(*(p) + (n) > (end))) \ + if (!likely(ceph_has_room(p, end, n))) \ goto bad; \ } while (0) @@ -166,7 +171,7 @@ static inline void ceph_encode_string(void **p, void *end, #define ceph_encode_need(p, end, n, bad) \ do { \ - if (unlikely(*(p) + (n) > (end))) \ + if (!likely(ceph_has_room(p, end, n))) \ goto bad; \ } while (0) |