[PATCH 11/21] nvme-auth: common: use crypto library in nvme_auth_generate_digest()

Eric Biggers
2026-03-02T08:01:30Z

For the HMAC computation in nvme_auth_generate_digest(), use the crypto
library instead of crypto_shash. This is simpler, faster, and more
reliable. Notably, this eliminates the crypto transformation object
allocation for every call, which was very slow.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
drivers/nvme/common/auth.c | 87 +++++++++++---------------------------
1 file changed, 25 insertions(+), 62 deletions(-)

diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
index 781d1d5d46dd3..f0b4e1c6ade7e 100644
--- a/drivers/nvme/common/auth.c
+++ b/drivers/nvme/common/auth.c
@@ -559,103 +559,66 @@ EXPORT_SYMBOL_GPL(nvme_auth_generate_psk);
*/
int nvme_auth_generate_digest(u8 hmac_id, const u8 *psk, size_t psk_len,
const char *subsysnqn, const char *hostnqn,
char **ret_digest)
{
- struct crypto_shash *tfm;
- SHASH_DESC_ON_STACK(shash, tfm);
- u8 *digest;
+ struct nvme_auth_hmac_ctx hmac;
+ u8 digest[NVME_AUTH_MAX_DIGEST_SIZE];
+ size_t hash_len = nvme_auth_hmac_hash_len(hmac_id);
char *enc;
- const char *hmac_name;
- size_t digest_len, hmac_len;
+ size_t enc_len;
int ret;

if (WARN_ON(!subsysnqn || !hostnqn))
return -EINVAL;

- hmac_name = nvme_auth_hmac_name(hmac_id);
- if (!hmac_name) {
+ if (hash_len == 0) {
pr_warn("%s: invalid hash algorithm %d\n",
__func__, hmac_id);
return -EINVAL;
}

- switch (nvme_auth_hmac_hash_len(hmac_id)) {
+ switch (hash_len) {
case 32:
- hmac_len = 44;
+ enc_len = 44;
break;
case 48:
- hmac_len = 64;
+ enc_len = 64;
break;
default:
pr_warn("%s: invalid hash algorithm '%s'\n",
- __func__, hmac_name);
+ __func__, nvme_auth_hmac_name(hmac_id));
return -EINVAL;
}

- enc = kzalloc(hmac_len + 1, GFP_KERNEL);
- if (!enc)
- return -ENOMEM;
-
- tfm = crypto_alloc_shash(hmac_name, 0, 0);
- if (IS_ERR(tfm)) {
- ret = PTR_ERR(tfm);
- goto out_free_enc;
- }
-
- digest_len = crypto_shash_digestsize(tfm);
- digest = kzalloc(digest_len, GFP_KERNEL);
- if (!digest) {
+ enc = kzalloc(enc_len + 1, GFP_KERNEL);
+ if (!enc) {
ret = -ENOMEM;
- goto out_free_tfm;
+ goto out;
}

- shash->tfm = tfm;
- ret = crypto_shash_setkey(tfm, psk, psk_len);
+ ret = nvme_auth_hmac_init(&hmac, hmac_id, psk, psk_len);
if (ret)
- goto out_free_digest;
-
- ret = crypto_shash_init(shash);
- if (ret)
- goto out_free_digest;
-
- ret = crypto_shash_update(shash, hostnqn, strlen(hostnqn));
- if (ret)
- goto out_free_digest;
-
- ret = crypto_shash_update(shash, " ", 1);
- if (ret)
- goto out_free_digest;
-
- ret = crypto_shash_update(shash, subsysnqn, strlen(subsysnqn));
- if (ret)
- goto out_free_digest;
-
- ret = crypto_shash_update(shash, " NVMe-over-Fabrics", 18);
- if (ret)
- goto out_free_digest;
-
- ret = crypto_shash_final(shash, digest);
- if (ret)
- goto out_free_digest;
-
- ret = base64_encode(digest, digest_len, enc, true, BASE64_STD);
- if (ret < hmac_len) {
+ goto out;
+ nvme_auth_hmac_update(&hmac, hostnqn, strlen(hostnqn));
+ nvme_auth_hmac_update(&hmac, " ", 1);
+ nvme_auth_hmac_update(&hmac, subsysnqn, strlen(subsysnqn));
+ nvme_auth_hmac_update(&hmac, " NVMe-over-Fabrics", 18);
+ nvme_auth_hmac_final(&hmac, digest);
+
+ ret = base64_encode(digest, hash_len, enc, true, BASE64_STD);
+ if (ret < enc_len) {
ret = -ENOKEY;
- goto out_free_digest;
+ goto out;
}
*ret_digest = enc;
ret = 0;

-out_free_digest:
- kfree_sensitive(digest);
-out_free_tfm:
- crypto_free_shash(tfm);
-out_free_enc:
+out:
if (ret)
kfree_sensitive(enc);
-
+ memzero_explicit(digest, sizeof(digest));
return ret;
}
EXPORT_SYMBOL_GPL(nvme_auth_generate_digest);

/**
--
2.53.0