UBUNTU: Ubuntu-raspi2-4.13.0-1014.15

[mirror_ubuntu-artful-kernel.git] / crypto / shash.c

diff --git a/crypto/shash.c b/crypto/shash.c
index 5e31c8d776dfc8a144f25e70122ee77d335e196a..f4161f3cfed6fd20fa8db8513566e9771526c42f 100644 (file)
--- 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));