3.16.52-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Tested-by: Stephan Müller <smueller@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
crypto/shash.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -274,12 +274,14 @@ static int shash_async_finup(struct ahas
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));