[PATCH 13/21] nvme-auth: host: use crypto library in nvme_auth_dhchap_setup_host_response()

[Eric Biggers]

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

Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
 drivers/nvme/host/auth.c | 59 ++++++++++++++--------------------------
 1 file changed, 21 insertions(+), 38 deletions(-)

diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index 47a1525e876e0..f22f17ad7e2f4 100644
--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -432,11 +432,11 @@ static int nvme_auth_set_dhchap_failure2_data(struct nvme_ctrl *ctrl,
 }
 
 static int nvme_auth_dhchap_setup_host_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;
 	u8 buf[4], *challenge = chap->c1;
 	int ret;
 
 	dev_dbg(ctrl->device, "%s: qid %d host response seq %u transaction %d\n",
 		__func__, chap->qid, chap->s1, chap->transaction);
@@ -452,17 +452,15 @@ static int nvme_auth_dhchap_setup_host_response(struct nvme_ctrl *ctrl,
 	} else {
 		dev_dbg(ctrl->device, "%s: qid %d re-using host response\n",
 			__func__, chap->qid);
 	}
 
-	ret = crypto_shash_setkey(chap->shash_tfm,
-			chap->transformed_key->key, chap->transformed_key->len);
-	if (ret) {
-		dev_warn(ctrl->device, "qid %d: failed to set key, error %d\n",
-			 chap->qid, ret);
+	ret = nvme_auth_hmac_init(&hmac, chap->hash_id,
+				  chap->transformed_key->key,
+				  chap->transformed_key->len);
+	if (ret)
 		goto out;
-	}
 
 	if (chap->dh_tfm) {
 		challenge = kmalloc(chap->hash_len, GFP_KERNEL);
 		if (!challenge) {
 			ret = -ENOMEM;
@@ -475,48 +473,33 @@ static int nvme_auth_dhchap_setup_host_response(struct nvme_ctrl *ctrl,
 						    chap->hash_len);
 		if (ret)
 			goto out;
 	}
 
-	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->s1, 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);
+
 	*buf = chap->sc_c;
-	ret = crypto_shash_update(shash, buf, 1);
-	if (ret)
-		goto out;
-	ret = crypto_shash_update(shash, "HostHost", 8);
-	if (ret)
-		goto out;
-	ret = crypto_shash_update(shash, ctrl->opts->host->nqn,
-				  strlen(ctrl->opts->host->nqn));
-	if (ret)
-		goto out;
+	nvme_auth_hmac_update(&hmac, buf, 1);
+	nvme_auth_hmac_update(&hmac, "HostHost", 8);
+	nvme_auth_hmac_update(&hmac, ctrl->opts->host->nqn,
+			      strlen(ctrl->opts->host->nqn));
 	memset(buf, 0, sizeof(buf));
-	ret = crypto_shash_update(shash, buf, 1);
-	if (ret)
-		goto out;
-	ret = crypto_shash_update(shash, ctrl->opts->subsysnqn,
-			    strlen(ctrl->opts->subsysnqn));
-	if (ret)
-		goto out;
-	ret = crypto_shash_final(shash, chap->response);
+	nvme_auth_hmac_update(&hmac, buf, 1);
+	nvme_auth_hmac_update(&hmac, ctrl->opts->subsysnqn,
+			      strlen(ctrl->opts->subsysnqn));
+	nvme_auth_hmac_final(&hmac, chap->response);
+	ret = 0;
 out:
 	if (challenge != chap->c1)
 		kfree(challenge);
+	memzero_explicit(&hmac, sizeof(hmac));
 	return ret;
 }
 
 static int nvme_auth_dhchap_setup_ctrl_response(struct nvme_ctrl *ctrl,
 		struct nvme_dhchap_queue_context *chap)
-- 
2.53.0