3.16.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Herbert Xu herbert@gondor.apana.org.au
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 Müllersmueller@chronox.de Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Tested-by: Stephan Müller smueller@chronox.de Signed-off-by: Ben Hutchings ben@decadent.org.uk --- 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));