crypto: ccree - make AEAD sgl iterator well behaved

Fix some scatter list interation code was not handling scatter lists
being shorter than expected in a graceful manner.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 17 insertions, 38 deletions

diff --git a/drivers/crypto/ccree/cc_buffer_mgr.c b/drivers/crypto/ccree/cc_buffer_mgr.c
index 86e498bee0bb..fa625bdde3f9 100644
--- a/drivers/crypto/ccree/cc_buffer_mgr.c
+++ b/drivers/crypto/ccree/cc_buffer_mgr.c
@@ -659,11 +659,9 @@ static int cc_aead_chain_assoc(struct cc_drvdata *drvdata,
 {
         struct aead_req_ctx *areq_ctx = aead_request_ctx(req);
         int rc = 0;
-        u32 mapped_nents = 0;
-        struct scatterlist *current_sg = req->src;
+        int mapped_nents = 0;
         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
-        unsigned int sg_index = 0;
-        u32 size_of_assoc = areq_ctx->assoclen;
+        unsigned int size_of_assoc = areq_ctx->assoclen;
         struct device *dev = drvdata_to_dev(drvdata);
 
         if (areq_ctx->is_gcm4543)
@@ -684,26 +682,10 @@ static int cc_aead_chain_assoc(struct cc_drvdata *drvdata,
                 goto chain_assoc_exit;
         }
 
-        //iterate over the sgl to see how many entries are for associated data
-        //it is assumed that if we reach here , the sgl is already mapped
-        sg_index = current_sg->length;
-        //the first entry in the scatter list contains all the associated data
-        if (sg_index > size_of_assoc) {
-                mapped_nents++;
-        } else {
-                while (sg_index <= size_of_assoc) {
-                        current_sg = sg_next(current_sg);
-                        /* if have reached the end of the sgl, then this is
-                         * unexpected
-                         */
-                        if (!current_sg) {
-                                dev_err(dev, "reached end of sg list. unexpected\n");
-                                return -EINVAL;
-                        }
-                        sg_index += current_sg->length;
-                        mapped_nents++;
-                }
-        }
+        mapped_nents = sg_nents_for_len(req->src, size_of_assoc);
+        if (mapped_nents < 0)
+                return mapped_nents;
+
         if (mapped_nents > LLI_MAX_NUM_OF_ASSOC_DATA_ENTRIES) {
                 dev_err(dev, "Too many fragments. current %d max %d\n",
                         mapped_nents, LLI_MAX_NUM_OF_ASSOC_DATA_ENTRIES);
@@ -898,6 +880,7 @@ static int cc_aead_chain_data(struct cc_drvdata *drvdata,
         u32 sg_index = 0;
         bool is_gcm4543 = areq_ctx->is_gcm4543;
         u32 size_to_skip = areq_ctx->assoclen;
+        struct scatterlist *sgl;
 
         if (is_gcm4543)
                 size_to_skip += crypto_aead_ivsize(tfm);
@@ -920,15 +903,13 @@ static int cc_aead_chain_data(struct cc_drvdata *drvdata,
         sg_index = areq_ctx->src_sgl->length;
         //check where the data starts
         while (sg_index <= size_to_skip) {
+                src_mapped_nents--;
                 offset -= areq_ctx->src_sgl->length;
-                areq_ctx->src_sgl = sg_next(areq_ctx->src_sgl);
-                //if have reached the end of the sgl, then this is unexpected
-                if (!areq_ctx->src_sgl) {
-                        dev_err(dev, "reached end of sg list. unexpected\n");
-                        return -EINVAL;
-                }
+                sgl = sg_next(areq_ctx->src_sgl);
+                if (!sgl)
+                        break;
+                areq_ctx->src_sgl = sgl;
                 sg_index += areq_ctx->src_sgl->length;
-                src_mapped_nents--;
         }
         if (src_mapped_nents > LLI_MAX_NUM_OF_DATA_ENTRIES) {
                 dev_err(dev, "Too many fragments. current %d max %d\n",
@@ -962,15 +943,13 @@ static int cc_aead_chain_data(struct cc_drvdata *drvdata,
 
         //check where the data starts
         while (sg_index <= size_to_skip) {
+                dst_mapped_nents--;
                 offset -= areq_ctx->dst_sgl->length;
-                areq_ctx->dst_sgl = sg_next(areq_ctx->dst_sgl);
-                //if have reached the end of the sgl, then this is unexpected
-                if (!areq_ctx->dst_sgl) {
-                        dev_err(dev, "reached end of sg list. unexpected\n");
-                        return -EINVAL;
-                }
+                sgl = sg_next(areq_ctx->dst_sgl);
+                if (!sgl)
+                        break;
+                areq_ctx->dst_sgl = sgl;
                 sg_index += areq_ctx->dst_sgl->length;
-                dst_mapped_nents--;
         }
         if (dst_mapped_nents > LLI_MAX_NUM_OF_DATA_ENTRIES) {
                 dev_err(dev, "Too many fragments. current %d max %d\n",