[PATCH 4.14 016/156] crypto: inside-secure - fix hash when length is a multiple of a block

From: Greg Kroah-Hartman
Date: Fri Feb 02 2018 - 13:10:37 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Antoine Tenart <antoine.tenart@xxxxxxxxxxxxxxxxxx>

commit 809778e02cd45d0625439fee67688f655627bb3c upstream.

This patch fixes the hash support in the SafeXcel driver when the update
size is a multiple of a block size, and when a final call is made just
after with a size of 0. In such cases the driver should cache the last
block from the update to avoid handling 0 length data on the final call
(that's a hardware limitation).

Fixes: 1b44c5a60c13 ("crypto: inside-secure - add SafeXcel EIP197 crypto engine driver")
Signed-off-by: Antoine Tenart <antoine.tenart@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/crypto/inside-secure/safexcel_hash.c | 34 +++++++++++++++++++--------
1 file changed, 24 insertions(+), 10 deletions(-)

--- a/drivers/crypto/inside-secure/safexcel_hash.c
+++ b/drivers/crypto/inside-secure/safexcel_hash.c
@@ -185,17 +185,31 @@ static int safexcel_ahash_send(struct cr
else
cache_len = queued - areq->nbytes;

- /*
- * If this is not the last request and the queued data does not fit
- * into full blocks, cache it for the next send() call.
- */
- extra = queued & (crypto_ahash_blocksize(ahash) - 1);
- if (!req->last_req && extra) {
- sg_pcopy_to_buffer(areq->src, sg_nents(areq->src),
- req->cache_next, extra, areq->nbytes - extra);
+ if (!req->last_req) {
+ /* If this is not the last request and the queued data does not
+ * fit into full blocks, cache it for the next send() call.
+ */
+ extra = queued & (crypto_ahash_blocksize(ahash) - 1);
+ if (!extra)
+ /* If this is not the last request and the queued data
+ * is a multiple of a block, cache the last one for now.
+ */
+ extra = queued - crypto_ahash_blocksize(ahash);

- queued -= extra;
- len -= extra;
+ if (extra) {
+ sg_pcopy_to_buffer(areq->src, sg_nents(areq->src),
+ req->cache_next, extra,
+ areq->nbytes - extra);
+
+ queued -= extra;
+ len -= extra;
+
+ if (!queued) {
+ *commands = 0;
+ *results = 0;
+ return 0;
+ }
+ }
}

spin_lock_bh(&priv->ring[ring].egress_lock);