nvme-auth: common: use crypto library in nvme_auth_generate_psk()

For the HMAC computation in nvme_auth_generate_psk(), 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.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
index be5bc5fcafc63d2b7d5608e894251e044c74d452..781d1d5d46dd3bdb87ddb04e7f802d5688fcae7b 100644 (file)
--- a/drivers/nvme/common/auth.c
+++ b/drivers/nvme/common/auth.c
@@ -497,63 +497,28 @@ int nvme_auth_generate_psk(u8 hmac_id, const u8 *skey, size_t skey_len,
                           const u8 *c1, const u8 *c2, size_t hash_len,
                           u8 **ret_psk, size_t *ret_len)
 {
-       struct crypto_shash *tfm;
-       SHASH_DESC_ON_STACK(shash, tfm);
+       size_t psk_len = nvme_auth_hmac_hash_len(hmac_id);
+       struct nvme_auth_hmac_ctx hmac;
        u8 *psk;
-       const char *hmac_name;
-       int ret, psk_len;
+       int ret;
 
        if (!c1 || !c2)
                return -EINVAL;
 
-       hmac_name = nvme_auth_hmac_name(hmac_id);
-       if (!hmac_name) {
-               pr_warn("%s: invalid hash algorithm %d\n",
-                       __func__, hmac_id);
-               return -EINVAL;
-       }
-
-       tfm = crypto_alloc_shash(hmac_name, 0, 0);
-       if (IS_ERR(tfm))
-               return PTR_ERR(tfm);
-
-       psk_len = crypto_shash_digestsize(tfm);
+       ret = nvme_auth_hmac_init(&hmac, hmac_id, skey, skey_len);
+       if (ret)
+               return ret;
        psk = kzalloc(psk_len, GFP_KERNEL);
        if (!psk) {
-               ret = -ENOMEM;
-               goto out_free_tfm;
-       }
-
-       shash->tfm = tfm;
-       ret = crypto_shash_setkey(tfm, skey, skey_len);
-       if (ret)
-               goto out_free_psk;
-
-       ret = crypto_shash_init(shash);
-       if (ret)
-               goto out_free_psk;
-
-       ret = crypto_shash_update(shash, c1, hash_len);
-       if (ret)
-               goto out_free_psk;
-
-       ret = crypto_shash_update(shash, c2, hash_len);
-       if (ret)
-               goto out_free_psk;
-
-       ret = crypto_shash_final(shash, psk);
-       if (!ret) {
-               *ret_psk = psk;
-               *ret_len = psk_len;
+               memzero_explicit(&hmac, sizeof(hmac));
+               return -ENOMEM;
        }
-
-out_free_psk:
-       if (ret)
-               kfree_sensitive(psk);
-out_free_tfm:
-       crypto_free_shash(tfm);
-
-       return ret;
+       nvme_auth_hmac_update(&hmac, c1, hash_len);
+       nvme_auth_hmac_update(&hmac, c2, hash_len);
+       nvme_auth_hmac_final(&hmac, psk);
+       *ret_psk = psk;
+       *ret_len = psk_len;
+       return 0;
 }
 EXPORT_SYMBOL_GPL(nvme_auth_generate_psk);