[PATCH] libceph: Use HMAC-SHA256 library instead of crypto_shash

Eric Biggers
2025-07-31T19:03:41Z

Use the HMAC-SHA256 library functions instead of crypto_shash. This is
simpler and faster.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
include/linux/ceph/messenger.h | 4 +-
net/ceph/Kconfig | 3 +-
net/ceph/messenger_v2.c | 77 ++++++++++------------------------
3 files changed, 26 insertions(+), 58 deletions(-)

diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index 1717cc57cdacd..4b49592a738fc 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -1,9 +1,10 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __FS_CEPH_MESSENGER_H
#define __FS_CEPH_MESSENGER_H

+#include <crypto/sha2.h>
#include <linux/bvec.h>
#include <linux/crypto.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/net.h>
@@ -410,11 +411,12 @@ struct ceph_connection_v2_info {

struct ceph_frame_desc in_desc;
struct ceph_msg_data_cursor in_cursor;
struct ceph_msg_data_cursor out_cursor;

- struct crypto_shash *hmac_tfm; /* post-auth signature */
+ struct hmac_sha256_key hmac_key; /* post-auth signature */
+ bool hmac_key_set;
struct crypto_aead *gcm_tfm; /* on-wire encryption */
struct aead_request *gcm_req;
struct crypto_wait gcm_wait;
struct ceph_gcm_nonce in_gcm_nonce;
struct ceph_gcm_nonce out_gcm_nonce;
diff --git a/net/ceph/Kconfig b/net/ceph/Kconfig
index 0aa21fcbf6ece..ea60e3ef08343 100644
--- a/net/ceph/Kconfig
+++ b/net/ceph/Kconfig
@@ -4,12 +4,11 @@ config CEPH_LIB
depends on INET
select CRC32
select CRYPTO_AES
select CRYPTO_CBC
select CRYPTO_GCM
- select CRYPTO_HMAC
- select CRYPTO_SHA256
+ select CRYPTO_LIB_SHA256
select CRYPTO
select KEYS
default n
help
Choose Y or M here to include cephlib, which provides the
diff --git a/net/ceph/messenger_v2.c b/net/ceph/messenger_v2.c
index 5483b4eed94e1..c54c8b5a65261 100644
--- a/net/ceph/messenger_v2.c
+++ b/net/ceph/messenger_v2.c
@@ -707,11 +707,11 @@ static int setup_crypto(struct ceph_connection *con,
unsigned int noio_flag;
int ret;

dout("%s con %p con_mode %d session_key_len %d con_secret_len %d\n",
__func__, con, con->v2.con_mode, session_key_len, con_secret_len);
- WARN_ON(con->v2.hmac_tfm || con->v2.gcm_tfm || con->v2.gcm_req);
+ WARN_ON(con->v2.hmac_key_set || con->v2.gcm_tfm || con->v2.gcm_req);

if (con->v2.con_mode != CEPH_CON_MODE_CRC &&
con->v2.con_mode != CEPH_CON_MODE_SECURE) {
pr_err("bad con_mode %d\n", con->v2.con_mode);
return -EINVAL;
@@ -721,26 +721,12 @@ static int setup_crypto(struct ceph_connection *con,
WARN_ON(con->v2.con_mode != CEPH_CON_MODE_CRC);
WARN_ON(con_secret_len);
return 0; /* auth_none */
}

- noio_flag = memalloc_noio_save();
- con->v2.hmac_tfm = crypto_alloc_shash("hmac(sha256)", 0, 0);
- memalloc_noio_restore(noio_flag);
- if (IS_ERR(con->v2.hmac_tfm)) {
- ret = PTR_ERR(con->v2.hmac_tfm);
- con->v2.hmac_tfm = NULL;
- pr_err("failed to allocate hmac tfm context: %d\n", ret);
- return ret;
- }
-
- ret = crypto_shash_setkey(con->v2.hmac_tfm, session_key,
- session_key_len);
- if (ret) {
- pr_err("failed to set hmac key: %d\n", ret);
- return ret;
- }
+ hmac_sha256_preparekey(&con->v2.hmac_key, session_key, session_key_len);
+ con->v2.hmac_key_set = true;

if (con->v2.con_mode == CEPH_CON_MODE_CRC) {
WARN_ON(con_secret_len);
return 0; /* auth_x, plain mode */
}
@@ -791,42 +777,30 @@ static int setup_crypto(struct ceph_connection *con,
con_secret + CEPH_GCM_KEY_LEN + CEPH_GCM_IV_LEN,
CEPH_GCM_IV_LEN);
return 0; /* auth_x, secure mode */
}

-static int ceph_hmac_sha256(struct ceph_connection *con,
- const struct kvec *kvecs, int kvec_cnt, u8 *hmac)
+static void ceph_hmac_sha256(struct ceph_connection *con,
+ const struct kvec *kvecs, int kvec_cnt,
+ u8 hmac[SHA256_DIGEST_SIZE])
{
- SHASH_DESC_ON_STACK(desc, con->v2.hmac_tfm); /* tfm arg is ignored */
- int ret;
+ struct hmac_sha256_ctx ctx;
int i;

- dout("%s con %p hmac_tfm %p kvec_cnt %d\n", __func__, con,
- con->v2.hmac_tfm, kvec_cnt);
+ dout("%s con %p hmac_key_set %d kvec_cnt %d\n", __func__, con,
+ con->v2.hmac_key_set, kvec_cnt);

- if (!con->v2.hmac_tfm) {
+ if (!con->v2.hmac_key_set) {
memset(hmac, 0, SHA256_DIGEST_SIZE);
- return 0; /* auth_none */
+ return; /* auth_none */
}

- desc->tfm = con->v2.hmac_tfm;
- ret = crypto_shash_init(desc);
- if (ret)
- goto out;
-
- for (i = 0; i < kvec_cnt; i++) {
- ret = crypto_shash_update(desc, kvecs[i].iov_base,
- kvecs[i].iov_len);
- if (ret)
- goto out;
- }
-
- ret = crypto_shash_final(desc, hmac);
-
-out:
- shash_desc_zero(desc);
- return ret; /* auth_x, both plain and secure modes */
+ /* auth_x, both plain and secure modes */
+ hmac_sha256_init(&ctx, &con->v2.hmac_key);
+ for (i = 0; i < kvec_cnt; i++)
+ hmac_sha256_update(&ctx, kvecs[i].iov_base, kvecs[i].iov_len);
+ hmac_sha256_final(&ctx, hmac);
}

static void gcm_inc_nonce(struct ceph_gcm_nonce *nonce)
{
u64 counter;
@@ -1453,21 +1427,18 @@ static int prepare_auth_request_more(struct ceph_connection *con,
}

static int prepare_auth_signature(struct ceph_connection *con)
{
void *buf;
- int ret;

buf = alloc_conn_buf(con, head_onwire_len(SHA256_DIGEST_SIZE,
con_secure(con)));
if (!buf)
return -ENOMEM;

- ret = ceph_hmac_sha256(con, con->v2.in_sign_kvecs,
- con->v2.in_sign_kvec_cnt, CTRL_BODY(buf));
- if (ret)
- return ret;
+ ceph_hmac_sha256(con, con->v2.in_sign_kvecs, con->v2.in_sign_kvec_cnt,
+ CTRL_BODY(buf));

return prepare_control(con, FRAME_TAG_AUTH_SIGNATURE, buf,
SHA256_DIGEST_SIZE);
}

@@ -2458,14 +2429,12 @@ static int process_auth_signature(struct ceph_connection *con,
if (con->state != CEPH_CON_S_V2_AUTH_SIGNATURE) {
con->error_msg = "protocol error, unexpected auth_signature";
return -EINVAL;
}

- ret = ceph_hmac_sha256(con, con->v2.out_sign_kvecs,
- con->v2.out_sign_kvec_cnt, hmac);
- if (ret)
- return ret;
+ ceph_hmac_sha256(con, con->v2.out_sign_kvecs, con->v2.out_sign_kvec_cnt,
+ hmac);

ceph_decode_need(&p, end, SHA256_DIGEST_SIZE, bad);
if (crypto_memneq(p, hmac, SHA256_DIGEST_SIZE)) {
con->error_msg = "integrity error, bad auth signature";
return -EBADMSG;
@@ -3812,14 +3781,12 @@ void ceph_con_v2_reset_protocol(struct ceph_connection *con)

con->v2.con_mode = CEPH_CON_MODE_UNKNOWN;
memzero_explicit(&con->v2.in_gcm_nonce, CEPH_GCM_IV_LEN);
memzero_explicit(&con->v2.out_gcm_nonce, CEPH_GCM_IV_LEN);

- if (con->v2.hmac_tfm) {
- crypto_free_shash(con->v2.hmac_tfm);
- con->v2.hmac_tfm = NULL;
- }
+ memzero_explicit(&con->v2.hmac_key, sizeof(con->v2.hmac_key));
+ con->v2.hmac_key_set = false;
if (con->v2.gcm_req) {
aead_request_free(con->v2.gcm_req);
con->v2.gcm_req = NULL;
}
if (con->v2.gcm_tfm) {

base-commit: d6084bb815c453de27af8071a23163a711586a6c
--
2.50.1