[PATCH 14/21] nvme-auth: host: use crypto library in nvme_auth_dhchap_setup_ctrl_response()

[Eric Biggers]

For the HMAC computation in nvme_auth_dhchap_setup_ctrl_response(), use
the crypto library instead of crypto_shash.  This is simpler, faster,
and more reliable.

Signed-off-by: Eric Biggers <ebiggers at kernel.org>
---
 drivers/nvme/host/auth.c | 56 +++++++++++++++-------------------------
 1 file changed, 21 insertions(+), 35 deletions(-)

diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index f22f17ad7e2f4..2f27f550a7442 100644
--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -502,11 +502,11 @@ static int nvme_auth_dhchap_setup_host_response(struct nvme_ctrl *ctrl,
 }
 
 static int nvme_auth_dhchap_setup_ctrl_response(struct nvme_ctrl *ctrl,
 		struct nvme_dhchap_queue_context *chap)
 {
-	SHASH_DESC_ON_STACK(shash, chap->shash_tfm);
+	struct nvme_auth_hmac_ctx hmac;
 	struct nvme_dhchap_key *transformed_key;
 	u8 buf[4], *challenge = chap->c2;
 	int ret;
 
 	transformed_key = nvme_auth_transform_key(ctrl->ctrl_key,
@@ -514,14 +514,14 @@ static int nvme_auth_dhchap_setup_ctrl_response(struct nvme_ctrl *ctrl,
 	if (IS_ERR(transformed_key)) {
 		ret = PTR_ERR(transformed_key);
 		return ret;
 	}
 
-	ret = crypto_shash_setkey(chap->shash_tfm,
-			transformed_key->key, transformed_key->len);
+	ret = nvme_auth_hmac_init(&hmac, chap->hash_id, transformed_key->key,
+				  transformed_key->len);
 	if (ret) {
-		dev_warn(ctrl->device, "qid %d: failed to set key, error %d\n",
+		dev_warn(ctrl->device, "qid %d: failed to init hmac, error %d\n",
 			 chap->qid, ret);
 		goto out;
 	}
 
 	if (chap->dh_tfm) {
@@ -544,47 +544,33 @@ static int nvme_auth_dhchap_setup_ctrl_response(struct nvme_ctrl *ctrl,
 		__func__, chap->qid, (int)chap->hash_len, challenge);
 	dev_dbg(ctrl->device, "%s: qid %d subsysnqn %s\n",
 		__func__, chap->qid, ctrl->opts->subsysnqn);
 	dev_dbg(ctrl->device, "%s: qid %d hostnqn %s\n",
 		__func__, chap->qid, ctrl->opts->host->nqn);
-	shash->tfm = chap->shash_tfm;
-	ret = crypto_shash_init(shash);
-	if (ret)
-		goto out;
-	ret = crypto_shash_update(shash, challenge, chap->hash_len);
-	if (ret)
-		goto out;
+
+	nvme_auth_hmac_update(&hmac, challenge, chap->hash_len);
+
 	put_unaligned_le32(chap->s2, buf);
-	ret = crypto_shash_update(shash, buf, 4);
-	if (ret)
-		goto out;
+	nvme_auth_hmac_update(&hmac, buf, 4);
+
 	put_unaligned_le16(chap->transaction, buf);
-	ret = crypto_shash_update(shash, buf, 2);
-	if (ret)
-		goto out;
+	nvme_auth_hmac_update(&hmac, buf, 2);
+
 	memset(buf, 0, 4);
-	ret = crypto_shash_update(shash, buf, 1);
-	if (ret)
-		goto out;
-	ret = crypto_shash_update(shash, "Controller", 10);
-	if (ret)
-		goto out;
-	ret = crypto_shash_update(shash, ctrl->opts->subsysnqn,
-				  strlen(ctrl->opts->subsysnqn));
-	if (ret)
-		goto out;
-	ret = crypto_shash_update(shash, buf, 1);
-	if (ret)
-		goto out;
-	ret = crypto_shash_update(shash, ctrl->opts->host->nqn,
-				  strlen(ctrl->opts->host->nqn));
-	if (ret)
-		goto out;
-	ret = crypto_shash_final(shash, chap->response);
+	nvme_auth_hmac_update(&hmac, buf, 1);
+	nvme_auth_hmac_update(&hmac, "Controller", 10);
+	nvme_auth_hmac_update(&hmac, ctrl->opts->subsysnqn,
+			      strlen(ctrl->opts->subsysnqn));
+	nvme_auth_hmac_update(&hmac, buf, 1);
+	nvme_auth_hmac_update(&hmac, ctrl->opts->host->nqn,
+			      strlen(ctrl->opts->host->nqn));
+	nvme_auth_hmac_final(&hmac, chap->response);
+	ret = 0;
 out:
 	if (challenge != chap->c2)
 		kfree(challenge);
+	memzero_explicit(&hmac, sizeof(hmac));
 	nvme_auth_free_key(transformed_key);
 	return ret;
 }
 
 static int nvme_auth_dhchap_exponential(struct nvme_ctrl *ctrl,
-- 
2.53.0