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

Eric Biggers
2026-03-02T08:01:33Z

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@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