On Sat, Oct 07, 2017 at 02:56:24PM +0200, Stephan Müller wrote:
>
> Though, this opens up the shash issue I tried to fix.
Does this patch fix the crash?
---8<---
Subject: 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@xxxxxxxxxxxxxxx>
Reported-by: Stephan Müller<smueller@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
diff --git a/crypto/shash.c b/crypto/shash.c
index 8fcecc6..a8322b0 100644
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -275,11 +275,17 @@ 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)
+ return 0;
+
+ sg = req->src;
+ offset = sg->offset;
+
if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
void *data;
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
