crypto: caam - use len instead of nents for bulding HW S/G table

Currently, conversion of SW S/G table into HW S/G layout relies on
nents returned by sg_nents_for_len(sg, len).
However this leaves the possibility of HW S/G referencing more data
then needed: since buffer length in HW S/G entries is filled using
sg_dma_len(sg), the last entry in HW S/G table might have a length
that is bigger than needed for the crypto request.

This way of S/G table conversion is fine, unless after converting a table
more entries have to be appended to the HW S/G table.
In this case, crypto engine would access data from the S/G entry having
the incorrect length, instead of advancing in the S/G table.
This situation doesn't exist, but the upcoming implementation of
IV update for skcipher algorithms needs to add a S/G entry after
req->dst S/G (corresponding to output IV).

Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 29 insertions, 31 deletions

diff --git a/drivers/crypto/caam/caamalg_qi2.c b/drivers/crypto/caam/caamalg_qi2.c
index 2621d657048a..1652fa26cf96 100644
--- a/drivers/crypto/caam/caamalg_qi2.c
+++ b/drivers/crypto/caam/caamalg_qi2.c
@@ -371,6 +371,7 @@ static struct aead_edesc *aead_edesc_alloc(struct aead_request *req,
 	gfp_t flags = (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 		      GFP_KERNEL : GFP_ATOMIC;
 	int src_nents, mapped_src_nents, dst_nents = 0, mapped_dst_nents = 0;
+	int src_len, dst_len = 0;
 	struct aead_edesc *edesc;
 	dma_addr_t qm_sg_dma, iv_dma = 0;
 	int ivsize = 0;
@@ -387,23 +388,21 @@ static struct aead_edesc *aead_edesc_alloc(struct aead_request *req,
 	}
 
 	if (unlikely(req->dst != req->src)) {
-		src_nents = sg_nents_for_len(req->src, req->assoclen +
-					     req->cryptlen);
+		src_len = req->assoclen + req->cryptlen;
+		dst_len = src_len + (encrypt ? authsize : (-authsize));
+
+		src_nents = sg_nents_for_len(req->src, src_len);
 		if (unlikely(src_nents < 0)) {
 			dev_err(dev, "Insufficient bytes (%d) in src S/G\n",
-				req->assoclen + req->cryptlen);
+				src_len);
 			qi_cache_free(edesc);
 			return ERR_PTR(src_nents);
 		}
 
-		dst_nents = sg_nents_for_len(req->dst, req->assoclen +
-					     req->cryptlen +
-					     (encrypt ? authsize :
-							(-authsize)));
+		dst_nents = sg_nents_for_len(req->dst, dst_len);
 		if (unlikely(dst_nents < 0)) {
 			dev_err(dev, "Insufficient bytes (%d) in dst S/G\n",
-				req->assoclen + req->cryptlen +
-				(encrypt ? authsize : (-authsize)));
+				dst_len);
 			qi_cache_free(edesc);
 			return ERR_PTR(dst_nents);
 		}
@@ -434,13 +433,13 @@ static struct aead_edesc *aead_edesc_alloc(struct aead_request *req,
 			mapped_dst_nents = 0;
 		}
 	} else {
-		src_nents = sg_nents_for_len(req->src, req->assoclen +
-					     req->cryptlen +
-						(encrypt ? authsize : 0));
+		src_len = req->assoclen + req->cryptlen +
+			  (encrypt ? authsize : 0);
+
+		src_nents = sg_nents_for_len(req->src, src_len);
 		if (unlikely(src_nents < 0)) {
 			dev_err(dev, "Insufficient bytes (%d) in src S/G\n",
-				req->assoclen + req->cryptlen +
-				(encrypt ? authsize : 0));
+				src_len);
 			qi_cache_free(edesc);
 			return ERR_PTR(src_nents);
 		}
@@ -536,12 +535,11 @@ static struct aead_edesc *aead_edesc_alloc(struct aead_request *req,
 		dma_to_qm_sg_one(sg_table + qm_sg_index, iv_dma, ivsize, 0);
 		qm_sg_index++;
 	}
-	sg_to_qm_sg_last(req->src, mapped_src_nents, sg_table + qm_sg_index, 0);
+	sg_to_qm_sg_last(req->src, src_len, sg_table + qm_sg_index, 0);
 	qm_sg_index += mapped_src_nents;
 
 	if (mapped_dst_nents > 1)
-		sg_to_qm_sg_last(req->dst, mapped_dst_nents, sg_table +
-				 qm_sg_index, 0);
+		sg_to_qm_sg_last(req->dst, dst_len, sg_table + qm_sg_index, 0);
 
 	qm_sg_dma = dma_map_single(dev, sg_table, qm_sg_bytes, DMA_TO_DEVICE);
 	if (dma_mapping_error(dev, qm_sg_dma)) {
@@ -1159,10 +1157,10 @@ static struct skcipher_edesc *skcipher_edesc_alloc(struct skcipher_request *req)
 	edesc->qm_sg_bytes = qm_sg_bytes;
 
 	dma_to_qm_sg_one(sg_table, iv_dma, ivsize, 0);
-	sg_to_qm_sg_last(req->src, mapped_src_nents, sg_table + 1, 0);
+	sg_to_qm_sg_last(req->src, req->cryptlen, sg_table + 1, 0);
 
 	if (mapped_dst_nents > 1)
-		sg_to_qm_sg_last(req->dst, mapped_dst_nents, sg_table +
+		sg_to_qm_sg_last(req->dst, req->cryptlen, sg_table +
 				 dst_sg_idx, 0);
 
 	edesc->qm_sg_dma = dma_map_single(dev, sg_table, edesc->qm_sg_bytes,
@@ -3422,9 +3420,9 @@ static int ahash_update_ctx(struct ahash_request *req)
 
 	if (to_hash) {
 		struct dpaa2_sg_entry *sg_table;
+		int src_len = req->nbytes - *next_buflen;
 
-		src_nents = sg_nents_for_len(req->src,
-					     req->nbytes - (*next_buflen));
+		src_nents = sg_nents_for_len(req->src, src_len);
 		if (src_nents < 0) {
 			dev_err(ctx->dev, "Invalid number of src SG.\n");
 			return src_nents;
@@ -3465,7 +3463,7 @@ static int ahash_update_ctx(struct ahash_request *req)
 			goto unmap_ctx;
 
 		if (mapped_nents) {
-			sg_to_qm_sg_last(req->src, mapped_nents,
+			sg_to_qm_sg_last(req->src, src_len,
 					 sg_table + qm_sg_src_index, 0);
 			if (*next_buflen)
 				scatterwalk_map_and_copy(next_buf, req->src,
@@ -3653,7 +3651,7 @@ static int ahash_finup_ctx(struct ahash_request *req)
 	if (ret)
 		goto unmap_ctx;
 
-	sg_to_qm_sg_last(req->src, mapped_nents, sg_table + qm_sg_src_index, 0);
+	sg_to_qm_sg_last(req->src, req->nbytes, sg_table + qm_sg_src_index, 0);
 
 	edesc->qm_sg_dma = dma_map_single(ctx->dev, sg_table, qm_sg_bytes,
 					  DMA_TO_DEVICE);
@@ -3739,7 +3737,7 @@ static int ahash_digest(struct ahash_request *req)
 		struct dpaa2_sg_entry *sg_table = &edesc->sgt[0];
 
 		qm_sg_bytes = pad_sg_nents(mapped_nents) * sizeof(*sg_table);
-		sg_to_qm_sg_last(req->src, mapped_nents, sg_table, 0);
+		sg_to_qm_sg_last(req->src, req->nbytes, sg_table, 0);
 		edesc->qm_sg_dma = dma_map_single(ctx->dev, sg_table,
 						  qm_sg_bytes, DMA_TO_DEVICE);
 		if (dma_mapping_error(ctx->dev, edesc->qm_sg_dma)) {
@@ -3882,9 +3880,9 @@ static int ahash_update_no_ctx(struct ahash_request *req)
 
 	if (to_hash) {
 		struct dpaa2_sg_entry *sg_table;
+		int src_len = req->nbytes - *next_buflen;
 
-		src_nents = sg_nents_for_len(req->src,
-					     req->nbytes - *next_buflen);
+		src_nents = sg_nents_for_len(req->src, src_len);
 		if (src_nents < 0) {
 			dev_err(ctx->dev, "Invalid number of src SG.\n");
 			return src_nents;
@@ -3918,7 +3916,7 @@ static int ahash_update_no_ctx(struct ahash_request *req)
 		if (ret)
 			goto unmap_ctx;
 
-		sg_to_qm_sg_last(req->src, mapped_nents, sg_table + 1, 0);
+		sg_to_qm_sg_last(req->src, src_len, sg_table + 1, 0);
 
 		if (*next_buflen)
 			scatterwalk_map_and_copy(next_buf, req->src,
@@ -4037,7 +4035,7 @@ static int ahash_finup_no_ctx(struct ahash_request *req)
 	if (ret)
 		goto unmap;
 
-	sg_to_qm_sg_last(req->src, mapped_nents, sg_table + 1, 0);
+	sg_to_qm_sg_last(req->src, req->nbytes, sg_table + 1, 0);
 
 	edesc->qm_sg_dma = dma_map_single(ctx->dev, sg_table, qm_sg_bytes,
 					  DMA_TO_DEVICE);
@@ -4107,9 +4105,9 @@ static int ahash_update_first(struct ahash_request *req)
 
 	if (to_hash) {
 		struct dpaa2_sg_entry *sg_table;
+		int src_len = req->nbytes - *next_buflen;
 
-		src_nents = sg_nents_for_len(req->src,
-					     req->nbytes - (*next_buflen));
+		src_nents = sg_nents_for_len(req->src, src_len);
 		if (src_nents < 0) {
 			dev_err(ctx->dev, "Invalid number of src SG.\n");
 			return src_nents;
@@ -4144,7 +4142,7 @@ static int ahash_update_first(struct ahash_request *req)
 		if (mapped_nents > 1) {
 			int qm_sg_bytes;
 
-			sg_to_qm_sg_last(req->src, mapped_nents, sg_table, 0);
+			sg_to_qm_sg_last(req->src, src_len, sg_table, 0);
 			qm_sg_bytes = pad_sg_nents(mapped_nents) *
 				      sizeof(*sg_table);
 			edesc->qm_sg_dma = dma_map_single(ctx->dev, sg_table,