3.2.97-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Herbert Xu <[email protected]> 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<[email protected]> Signed-off-by: Herbert Xu <[email protected]> Tested-by: Stephan Müller <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- crypto/shash.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/crypto/shash.c +++ b/crypto/shash.c @@ -273,12 +273,14 @@ 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 = crypto_kmap(sg_page(sg), 0);
