nvme-auth: update sc_c in host response

The sc_c field is currently not updated in the host response to the
controller challenge leading to failures while attempting secure
channel concatenation. Fix this by adding a new sc_c variable to the
dhchap queue context structure which is appropriately set during
negotiate and then used in the host response.

Fixes: e88a759 ("nvme-tcp: request secure channel concatenation")
Signed-off-by: Martin George <marting@netapp.com>
Signed-off-by: Prashanth Adurthi <prashana@netapp.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: martin-gpy

drivers/nvme/host/auth.c

@@ -36,6 +36,7 @@ struct nvme_dhchap_queue_context {
 	u8 status;
 	u8 dhgroup_id;
 	u8 hash_id;
+	u8 sc_c;
 	size_t hash_len;
 	u8 c1[64];
 	u8 c2[64];
@@ -154,6 +155,8 @@ static int nvme_auth_set_dhchap_negotiate_data(struct nvme_ctrl *ctrl,
 	data->auth_protocol[0].dhchap.idlist[34] = NVME_AUTH_DHGROUP_6144;
 	data->auth_protocol[0].dhchap.idlist[35] = NVME_AUTH_DHGROUP_8192;
 
+	chap->sc_c = data->sc_c;
+
 	return size;
 }
 
@@ -489,7 +492,7 @@ static int nvme_auth_dhchap_setup_host_response(struct nvme_ctrl *ctrl,
 	ret = crypto_shash_update(shash, buf, 2);
 	if (ret)
 		goto out;
-	memset(buf, 0, sizeof(buf));
+	*buf = chap->sc_c;
 	ret = crypto_shash_update(shash, buf, 1);
 	if (ret)
 		goto out;
@@ -500,6 +503,7 @@ static int nvme_auth_dhchap_setup_host_response(struct nvme_ctrl *ctrl,
 				  strlen(ctrl->opts->host->nqn));
 	if (ret)
 		goto out;
+	memset(buf, 0, sizeof(buf));
 	ret = crypto_shash_update(shash, buf, 1);
 	if (ret)
 		goto out;