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Subject[PATCH 3/4] crypto: qce: Ensure QCE receives no zero-sized updates
Date
From: Voker57 <voker57@gmail.com>

Zero-sized updates lock QCE, so ensure there's always some data left
for the final update, up to blocksize.
Signed-off-by: Iaroslav Gridin <voker57@gmail.com>
---
drivers/crypto/qce/sha.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/qce/sha.c b/drivers/crypto/qce/sha.c
index a068d39..f199f28 100644
--- a/drivers/crypto/qce/sha.c
+++ b/drivers/crypto/qce/sha.c
@@ -240,9 +240,11 @@ static int qce_ahash_update(struct ahash_request *req)
struct qce_device *qce = tmpl->qce;
struct scatterlist *sg_last, *sg;
unsigned int total, len;
+ unsigned int tmpbuflen = 0;
unsigned int hash_later;
unsigned int nbytes;
unsigned int blocksize;
+ unsigned int src_offset;

blocksize = crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
rctx->count += req->nbytes;
@@ -265,21 +267,30 @@ static int qce_ahash_update(struct ahash_request *req)
* if we have data from previous update copy them on buffer. The old
* data will be combined with current request bytes.
*/
- if (rctx->buflen)
+ if (rctx->buflen) {
memcpy(rctx->tmpbuf, rctx->buf, rctx->buflen);
+ tmpbuflen = rctx->buflen;
+ }

/* calculate how many bytes will be hashed later */
hash_later = total % blocksize;
- if (hash_later) {
- unsigned int src_offset = req->nbytes - hash_later;
- scatterwalk_map_and_copy(rctx->buf, req->src, src_offset,
- hash_later, 0);
- }
+ /* ensure we always have something on buffer */
+ if (hash_later == 0)
+ hash_later = blocksize;
+ src_offset = req->nbytes - hash_later;
+ scatterwalk_map_and_copy(rctx->buf, req->src, src_offset,
+ hash_later, 0);
+ rctx->buflen = hash_later;

/* here nbytes is multiple of blocksize */
nbytes = total - hash_later;

- len = rctx->buflen;
+ len = tmpbuflen;
+
+ /* Zero-length update is a no-op */
+ if (nbytes == 0)
+ return 0;
+
sg = sg_last = req->src;

while (len < nbytes && sg) {
@@ -293,15 +304,14 @@ static int qce_ahash_update(struct ahash_request *req)

sg_mark_end(sg_last);

- if (rctx->buflen) {
+ if (tmpbuflen) {
sg_init_table(rctx->sg, 2);
- sg_set_buf(rctx->sg, rctx->tmpbuf, rctx->buflen);
+ sg_set_buf(rctx->sg, rctx->tmpbuf, tmpbuflen);
sg_chain(rctx->sg, 2, req->src);
req->src = rctx->sg;
}

req->nbytes = nbytes;
- rctx->buflen = hash_later;

return qce->async_req_enqueue(tmpl->qce, &req->base);
}
--
2.9.3
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