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author | Herbert Xu <herbert@gondor.apana.org.au> | 2017-10-09 23:30:02 +0800 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2017-10-11 00:34:07 +0800 |
commit | 58425dc5a756e7d9cab4d4f0632c0455e1419279 (patch) | |
tree | 607fa71fd8932c2657db62de8db0679197e2b894 | |
parent | 75b192a19c70ec09e68484d7741a99438bbef306 (diff) | |
download | linux-crypto-58425dc5a756e7d9cab4d4f0632c0455e1419279.tar.gz linux-crypto-58425dc5a756e7d9cab4d4f0632c0455e1419279.zip |
crypto: shash - Fix zero-length shash ahash digest crash
The shash ahash digest adaptor function may crash if given a
zero-length input together with a null SG list. This is because
it tries to read the SG list before looking at the length.
This patch fixes it by checking the length first.
Cc: <stable@vger.kernel.org>
Reported-by: Stephan Müller<smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Stephan Müller <smueller@chronox.de>
Diffstat (limited to '')
-rw-r--r-- | crypto/shash.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/crypto/shash.c b/crypto/shash.c index 8fcecc66..325a14da 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -275,12 +275,14 @@ static int shash_async_finup(struct ahash_request *req) int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc) { - struct scatterlist *sg = req->src; - unsigned int offset = sg->offset; unsigned int nbytes = req->nbytes; + struct scatterlist *sg; + unsigned int offset; int err; - if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) { + if (nbytes && + (sg = req->src, offset = sg->offset, + nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset))) { void *data; data = kmap_atomic(sg_page(sg)); |