diff options
author | Herbert Xu <herbert@gondor.apana.org.au> | 2007-09-11 10:31:59 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-09-26 10:54:41 -0700 |
commit | 01add92dd4be6b4641219ea616bc31e6337cbd6c (patch) | |
tree | 1a693dcadabeb90b5dc7ebd42391ef9ffceee12a | |
parent | d2f7a9bf48930c25bbd293c28641a8f251c44474 (diff) |
crypto: blkcipher_get_spot() handling of buffer at end of page
This corresponds to upstream changesets
e4630f9fd8cdc14eb1caa08dafe649eb5ae09985 and
32528d0fbda1093eeeaa7d0a2c498bbb5154099d.
[CRYPTO] blkcipher: Fix handling of kmalloc page straddling
The function blkcipher_get_spot tries to return a buffer of
the specified length that does not straddle a page. It has
an off-by-one bug so it may advance a page unnecessarily.
What's worse, one of its callers doesn't provide a buffer
that's sufficiently long for this operation.
This patch fixes both problems. Thanks to Bob Gilligan for
diagnosing this problem and providing a fix.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r-- | crypto/blkcipher.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c index 8edf40c835a7..cce92365de36 100644 --- a/crypto/blkcipher.c +++ b/crypto/blkcipher.c @@ -59,11 +59,13 @@ static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk) scatterwalk_unmap(walk->dst.virt.addr, 1); } +/* Get a spot of the specified length that does not straddle a page. + * The caller needs to ensure that there is enough space for this operation. + */ static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len) { - if (offset_in_page(start + len) < len) - return (u8 *)((unsigned long)(start + len) & PAGE_MASK); - return start; + u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK); + return start > end_page ? start : end_page; } static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm, @@ -155,7 +157,8 @@ static inline int blkcipher_next_slow(struct blkcipher_desc *desc, if (walk->buffer) goto ok; - n = bsize * 2 + (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); + n = bsize * 3 - (alignmask + 1) + + (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); walk->buffer = kmalloc(n, GFP_ATOMIC); if (!walk->buffer) return blkcipher_walk_done(desc, walk, -ENOMEM); |