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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2017-10-09 23:30:02 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-18 09:35:38 +0200 |
| commit | 91daaefbe5df9da88589ffc2a9c448d771d1bbe7 (patch) | |
| tree | 6d8a13a41e9276045b0960272f41de6ca56924e7 | |
| parent | 57265cddde308292af881ce634a5378dd4e25900 (diff) | |
| download | linux-4.9-exynos9110-91daaefbe5df9da88589ffc2a9c448d771d1bbe7.tar.gz linux-4.9-exynos9110-91daaefbe5df9da88589ffc2a9c448d771d1bbe7.tar.bz2 linux-4.9-exynos9110-91daaefbe5df9da88589ffc2a9c448d771d1bbe7.zip | |
crypto: shash - Fix zero-length shash ahash digest crash
commit b61907bb42409adf9b3120f741af7c57dd7e3db2 upstream.
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.
Reported-by: Stephan Müller<smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Stephan Müller <smueller@chronox.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 a051541a4a17..4d8a671d1614 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -274,12 +274,14 @@ 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)); |