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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2017-10-09 23:30:02 +0800 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2017-10-11 00:34:07 +0800 |
| commit | b61907bb42409adf9b3120f741af7c57dd7e3db2 (patch) | |
| tree | 5e2e631bddf0f13336e2c52ac93cbce361bfcbd7 /crypto/shash.c | |
| parent | 0cabf2af6f5ac3c88cb106c4e06087a5a39b8e1e (diff) | |
| download | lwn-b61907bb42409adf9b3120f741af7c57dd7e3db2.tar.gz lwn-b61907bb42409adf9b3120f741af7c57dd7e3db2.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 'crypto/shash.c')
| -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 8fcecc66741d..325a14da5827 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)); |