crypto: talitos - fix ahash for multiple of blocksize

Correct ahash_process_req() to properly handle cases
where the total hash amount is a multiple of the blocksize.
The SEC must have some data to hash during the very last
descriptor operation; so up to one whole blocksize
of data is buffered until the final hash.

Signed-off-by: Lee Nipper <lee.nipper@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 40 insertions, 37 deletions

diff --git a/drivers/crypto/talitos.c b/drivers/crypto/talitos.c
index 637c105f53d2..0f2483e221ad 100644
--- a/drivers/crypto/talitos.c
+++ b/drivers/crypto/talitos.c
@@ -720,7 +720,6 @@ struct talitos_ctx {
 #define TALITOS_MDEU_MAX_CONTEXT_SIZE   TALITOS_MDEU_CONTEXT_SIZE_SHA384_SHA512
 
 struct talitos_ahash_req_ctx {
-        u64 count;
         u32 hw_context[TALITOS_MDEU_MAX_CONTEXT_SIZE / sizeof(u32)];
         unsigned int hw_context_size;
         u8 buf[HASH_MAX_BLOCK_SIZE];
@@ -729,6 +728,7 @@ struct talitos_ahash_req_ctx {
         unsigned int first;
         unsigned int last;
         unsigned int to_hash_later;
+        u64 nbuf;
         struct scatterlist bufsl[2];
         struct scatterlist *psrc;
 };
@@ -1609,6 +1609,7 @@ static void ahash_done(struct device *dev,
         if (!req_ctx->last && req_ctx->to_hash_later) {
                 /* Position any partial block for next update/final/finup */
                 memcpy(req_ctx->buf, req_ctx->bufnext, req_ctx->to_hash_later);
+                req_ctx->nbuf = req_ctx->to_hash_later;
         }
         common_nonsnoop_hash_unmap(dev, edesc, areq);
 
@@ -1724,7 +1725,7 @@ static int ahash_init(struct ahash_request *areq)
         struct talitos_ahash_req_ctx *req_ctx = ahash_request_ctx(areq);
 
         /* Initialize the context */
-        req_ctx->count = 0;
+        req_ctx->nbuf = 0;
         req_ctx->first = 1; /* first indicates h/w must init its context */
         req_ctx->swinit = 0; /* assume h/w init of context */
         req_ctx->hw_context_size =
@@ -1772,52 +1773,54 @@ static int ahash_process_req(struct ahash_request *areq, unsigned int nbytes)
                         crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
         unsigned int nbytes_to_hash;
         unsigned int to_hash_later;
-        unsigned int index;
+        unsigned int nsg;
         int chained;
 
-        index = req_ctx->count & (blocksize - 1);
-        req_ctx->count += nbytes;
-
-        if (!req_ctx->last && (index + nbytes) < blocksize) {
-                /* Buffer the partial block */
+        if (!req_ctx->last && (nbytes + req_ctx->nbuf <= blocksize)) {
+                /* Buffer up to one whole block */
                 sg_copy_to_buffer(areq->src,
                                   sg_count(areq->src, nbytes, &chained),
-                                  req_ctx->buf + index, nbytes);
+                                  req_ctx->buf + req_ctx->nbuf, nbytes);
+                req_ctx->nbuf += nbytes;
                 return 0;
         }
 
-        if (index) {
-                /* partial block from previous update; chain it in. */
-                sg_init_table(req_ctx->bufsl, (nbytes) ? 2 : 1);
-                sg_set_buf(req_ctx->bufsl, req_ctx->buf, index);
-                if (nbytes)
-                        scatterwalk_sg_chain(req_ctx->bufsl, 2,
-                                             areq->src);
+        /* At least (blocksize + 1) bytes are available to hash */
+        nbytes_to_hash = nbytes + req_ctx->nbuf;
+        to_hash_later = nbytes_to_hash & (blocksize - 1);
+
+        if (req_ctx->last)
+                to_hash_later = 0;
+        else if (to_hash_later)
+                /* There is a partial block. Hash the full block(s) now */
+                nbytes_to_hash -= to_hash_later;
+        else {
+                /* Keep one block buffered */
+                nbytes_to_hash -= blocksize;
+                to_hash_later = blocksize;
+        }
+
+        /* Chain in any previously buffered data */
+        if (req_ctx->nbuf) {
+                nsg = (req_ctx->nbuf < nbytes_to_hash) ? 2 : 1;
+                sg_init_table(req_ctx->bufsl, nsg);
+                sg_set_buf(req_ctx->bufsl, req_ctx->buf, req_ctx->nbuf);
+                if (nsg > 1)
+                        scatterwalk_sg_chain(req_ctx->bufsl, 2, areq->src);
                 req_ctx->psrc = req_ctx->bufsl;
-        } else {
+        } else
                 req_ctx->psrc = areq->src;
+
+        if (to_hash_later) {
+                int nents = sg_count(areq->src, nbytes, &chained);
+                sg_copy_end_to_buffer(areq->src, nents,
+                                      req_ctx->bufnext,
+                                      to_hash_later,
+                                      nbytes - to_hash_later);
         }
-        nbytes_to_hash =  index + nbytes;
-        if (!req_ctx->last) {
-                to_hash_later = (nbytes_to_hash & (blocksize - 1));
-                if (to_hash_later) {
-                        int nents;
-                        /* Must copy to_hash_later bytes from the end
-                         * to bufnext (a partial block) for later.
-                         */
-                        nents = sg_count(areq->src, nbytes, &chained);
-                        sg_copy_end_to_buffer(areq->src, nents,
-                                              req_ctx->bufnext,
-                                              to_hash_later,
-                                              nbytes - to_hash_later);
-
-                        /* Adjust count for what will be hashed now */
-                        nbytes_to_hash -= to_hash_later;
-                }
-                req_ctx->to_hash_later = to_hash_later;
-        }
+        req_ctx->to_hash_later = to_hash_later;
 
-        /* allocate extended descriptor */
+        /* Allocate extended descriptor */
         edesc = ahash_edesc_alloc(areq, nbytes_to_hash);
         if (IS_ERR(edesc))
                 return PTR_ERR(edesc);