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authorHerbert Xu <herbert@gondor.apana.org.au>2017-10-09 23:30:02 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2017-10-11 00:34:07 +0800
commitb61907bb42409adf9b3120f741af7c57dd7e3db2 (patch)
tree5e2e631bddf0f13336e2c52ac93cbce361bfcbd7 /crypto
parent0cabf2af6f5ac3c88cb106c4e06087a5a39b8e1e (diff)
downloadlinux-stericsson-b61907bb42409adf9b3120f741af7c57dd7e3db2.tar.gz
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')
-rw-r--r--crypto/shash.c8
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));