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>

diff --git a/drivers/crypto/ccree/cc_buffer_mgr.c b/drivers/crypto/ccree/cc_buffer_mgr.c
index 86e498bee0bb1a19e9d671607f661dc7572c3a6b..fa625bdde3f94a70565e3b55f0655506aed130a4 100644 (file)
--- 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",