crypto: caam - check return value of sg_nents_for_len

The sg_nents_for_len() function could fail, this patch add a check for
its return value.
We do the same for sg_count since it use sg_nents_for_len().

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/caamhash.c

@@ -803,6 +803,10 @@ static int ahash_update_ctx(struct ahash_request *req)
 	if (to_hash) {
 		src_nents = sg_nents_for_len(req->src,
 					     req->nbytes - (*next_buflen));
+		if (src_nents < 0) {
+			dev_err(jrdev, "Invalid number of src SG.\n");
+			return src_nents;
+		}
 		sec4_sg_src_index = 1 + (*buflen ? 1 : 0);
 		sec4_sg_bytes = (sec4_sg_src_index + src_nents) *
 				 sizeof(struct sec4_sg_entry);
@@ -1002,6 +1006,10 @@ static int ahash_finup_ctx(struct ahash_request *req)
 	int sh_len;
 
 	src_nents = sg_nents_for_len(req->src, req->nbytes);
+	if (src_nents < 0) {
+		dev_err(jrdev, "Invalid number of src SG.\n");
+		return src_nents;
+	}
 	sec4_sg_src_index = 1 + (buflen ? 1 : 0);
 	sec4_sg_bytes = (sec4_sg_src_index + src_nents) *
 			 sizeof(struct sec4_sg_entry);
@@ -1086,6 +1094,10 @@ static int ahash_digest(struct ahash_request *req)
 	int sh_len;
 
 	src_nents = sg_count(req->src, req->nbytes);
+	if (src_nents < 0) {
+		dev_err(jrdev, "Invalid number of src SG.\n");
+		return src_nents;
+	}
 	dma_map_sg(jrdev, req->src, src_nents ? : 1, DMA_TO_DEVICE);
 	sec4_sg_bytes = src_nents * sizeof(struct sec4_sg_entry);
 
@@ -1234,6 +1246,10 @@ static int ahash_update_no_ctx(struct ahash_request *req)
 	if (to_hash) {
 		src_nents = sg_nents_for_len(req->src,
 					     req->nbytes - (*next_buflen));
+		if (src_nents < 0) {
+			dev_err(jrdev, "Invalid number of src SG.\n");
+			return src_nents;
+		}
 		sec4_sg_bytes = (1 + src_nents) *
 				sizeof(struct sec4_sg_entry);
 
@@ -1342,6 +1358,10 @@ static int ahash_finup_no_ctx(struct ahash_request *req)
 	int ret = 0;
 
 	src_nents = sg_nents_for_len(req->src, req->nbytes);
+	if (src_nents < 0) {
+		dev_err(jrdev, "Invalid number of src SG.\n");
+		return src_nents;
+	}
 	sec4_sg_src_index = 2;
 	sec4_sg_bytes = (sec4_sg_src_index + src_nents) *
 			 sizeof(struct sec4_sg_entry);
@@ -1430,6 +1450,10 @@ static int ahash_update_first(struct ahash_request *req)
 
 	if (to_hash) {
 		src_nents = sg_count(req->src, req->nbytes - (*next_buflen));
+		if (src_nents < 0) {
+			dev_err(jrdev, "Invalid number of src SG.\n");
+			return src_nents;
+		}
 		dma_map_sg(jrdev, req->src, src_nents ? : 1, DMA_TO_DEVICE);
 		sec4_sg_bytes = src_nents * sizeof(struct sec4_sg_entry);