On Wed, 2020-12-30 at 18:27 +0100, Ilya Dryomov wrote:
> Try and avoid leaving bits and pieces of session key and connection
> secret (gets split into GCM key and a pair of GCM IVs) around.
>
> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
> ---
> net/ceph/auth_x.c | 57 ++++++++++++++++++++++++-----------------
> net/ceph/crypto.c | 3 ++-
> net/ceph/messenger_v2.c | 45 ++++++++++++++++++--------------
> 3 files changed, 62 insertions(+), 43 deletions(-)
>
> diff --git a/net/ceph/auth_x.c b/net/ceph/auth_x.c
> index 9815cfe42af0..ca44c327bace 100644
> --- a/net/ceph/auth_x.c
> +++ b/net/ceph/auth_x.c
> @@ -569,6 +569,34 @@ static int ceph_x_build_request(struct ceph_auth_client *ac,
> return -ERANGE;
> }
>
>
> +static int decode_con_secret(void **p, void *end, u8 *con_secret,
> + int *con_secret_len)
> +{
> + int len;
> +
> + ceph_decode_32_safe(p, end, len, bad);
> + ceph_decode_need(p, end, len, bad);
> +
> + dout("%s len %d\n", __func__, len);
> + if (con_secret) {
> + if (len > CEPH_MAX_CON_SECRET_LEN) {
> + pr_err("connection secret too big %d\n", len);
> + goto bad_memzero;
> + }
> + memcpy(con_secret, *p, len);
> + *con_secret_len = len;
> + }
> + memzero_explicit(*p, len);
> + *p += len;
> + return 0;
> +
> +bad_memzero:
> + memzero_explicit(*p, len);
> +bad:
> + pr_err("failed to decode connection secret\n");
> + return -EINVAL;
> +}
> +
> static int handle_auth_session_key(struct ceph_auth_client *ac,
> void **p, void *end,
> u8 *session_key, int *session_key_len,
> @@ -612,17 +640,9 @@ static int handle_auth_session_key(struct ceph_auth_client *ac,
> dout("%s decrypted %d bytes\n", __func__, ret);
> dend = dp + ret;
>
>
> - ceph_decode_32_safe(&dp, dend, len, e_inval);
> - if (len > CEPH_MAX_CON_SECRET_LEN) {
> - pr_err("connection secret too big %d\n", len);
> - return -EINVAL;
> - }
> -
> - dout("%s connection secret len %d\n", __func__, len);
> - if (con_secret) {
> - memcpy(con_secret, dp, len);
> - *con_secret_len = len;
> - }
> + ret = decode_con_secret(&dp, dend, con_secret, con_secret_len);
> + if (ret)
> + return ret;
> }
>
>
> /* service tickets */
> @@ -828,7 +848,6 @@ static int decrypt_authorizer_reply(struct ceph_crypto_key *secret,
> {
> void *dp, *dend;
> u8 struct_v;
> - int len;
> int ret;
>
>
> dp = *p + ceph_x_encrypt_offset();
> @@ -843,17 +862,9 @@ static int decrypt_authorizer_reply(struct ceph_crypto_key *secret,
> ceph_decode_64_safe(&dp, dend, *nonce_plus_one, e_inval);
> dout("%s nonce_plus_one %llu\n", __func__, *nonce_plus_one);
> if (struct_v >= 2) {
> - ceph_decode_32_safe(&dp, dend, len, e_inval);
> - if (len > CEPH_MAX_CON_SECRET_LEN) {
> - pr_err("connection secret too big %d\n", len);
> - return -EINVAL;
> - }
> -
> - dout("%s connection secret len %d\n", __func__, len);
> - if (con_secret) {
> - memcpy(con_secret, dp, len);
> - *con_secret_len = len;
> - }
> + ret = decode_con_secret(&dp, dend, con_secret, con_secret_len);
> + if (ret)
> + return ret;
> }
>
>
> return 0;
> diff --git a/net/ceph/crypto.c b/net/ceph/crypto.c
> index 4f75df40fb12..92d89b331645 100644
> --- a/net/ceph/crypto.c
> +++ b/net/ceph/crypto.c
> @@ -96,6 +96,7 @@ int ceph_crypto_key_decode(struct ceph_crypto_key *key, void **p, void *end)
> key->len = ceph_decode_16(p);
> ceph_decode_need(p, end, key->len, bad);
> ret = set_secret(key, *p);
> + memzero_explicit(*p, key->len);
> *p += key->len;
> return ret;
>
>
> @@ -134,7 +135,7 @@ int ceph_crypto_key_unarmor(struct ceph_crypto_key *key, const char *inkey)
> void ceph_crypto_key_destroy(struct ceph_crypto_key *key)
> {
> if (key) {
> - kfree(key->key);
> + kfree_sensitive(key->key);
> key->key = NULL;
> if (key->tfm) {
> crypto_free_sync_skcipher(key->tfm);
> diff --git a/net/ceph/messenger_v2.c b/net/ceph/messenger_v2.c
> index c38d8de93836..cc40ce4e02fb 100644
> --- a/net/ceph/messenger_v2.c
> +++ b/net/ceph/messenger_v2.c
> @@ -689,11 +689,10 @@ static int verify_epilogue_crcs(struct ceph_connection *con, u32 front_crc,
> }
>
>
> static int setup_crypto(struct ceph_connection *con,
> - u8 *session_key, int session_key_len,
> - u8 *con_secret, int con_secret_len)
> + const u8 *session_key, int session_key_len,
> + const u8 *con_secret, int con_secret_len)
> {
> unsigned int noio_flag;
> - void *p;
> int ret;
>
>
> dout("%s con %p con_mode %d session_key_len %d con_secret_len %d\n",
> @@ -751,15 +750,14 @@ static int setup_crypto(struct ceph_connection *con,
> return ret;
> }
>
>
> - p = con_secret;
> - WARN_ON((unsigned long)p & crypto_aead_alignmask(con->v2.gcm_tfm));
> - ret = crypto_aead_setkey(con->v2.gcm_tfm, p, CEPH_GCM_KEY_LEN);
> + WARN_ON((unsigned long)con_secret &
> + crypto_aead_alignmask(con->v2.gcm_tfm));
> + ret = crypto_aead_setkey(con->v2.gcm_tfm, con_secret, CEPH_GCM_KEY_LEN);
> if (ret) {
> pr_err("failed to set gcm key: %d\n", ret);
> return ret;
> }
>
>
> - p += CEPH_GCM_KEY_LEN;
> WARN_ON(crypto_aead_ivsize(con->v2.gcm_tfm) != CEPH_GCM_IV_LEN);
> ret = crypto_aead_setauthsize(con->v2.gcm_tfm, CEPH_GCM_TAG_LEN);
> if (ret) {
> @@ -777,8 +775,11 @@ static int setup_crypto(struct ceph_connection *con,
> aead_request_set_callback(con->v2.gcm_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
> crypto_req_done, &con->v2.gcm_wait);
>
>
> - memcpy(&con->v2.in_gcm_nonce, p, CEPH_GCM_IV_LEN);
> - memcpy(&con->v2.out_gcm_nonce, p + CEPH_GCM_IV_LEN, CEPH_GCM_IV_LEN);
> + memcpy(&con->v2.in_gcm_nonce, con_secret + CEPH_GCM_KEY_LEN,
> + CEPH_GCM_IV_LEN);
> + memcpy(&con->v2.out_gcm_nonce,
> + con_secret + CEPH_GCM_KEY_LEN + CEPH_GCM_IV_LEN,
> + CEPH_GCM_IV_LEN);
> return 0; /* auth_x, secure mode */
> }
>
>
> @@ -800,7 +801,7 @@ static int hmac_sha256(struct ceph_connection *con, const struct kvec *kvecs,
> desc->tfm = con->v2.hmac_tfm;
> ret = crypto_shash_init(desc);
> if (ret)
> - return ret;
> + goto out;
>
>
> for (i = 0; i < kvec_cnt; i++) {
> WARN_ON((unsigned long)kvecs[i].iov_base &
> @@ -808,15 +809,14 @@ static int hmac_sha256(struct ceph_connection *con, const struct kvec *kvecs,
> ret = crypto_shash_update(desc, kvecs[i].iov_base,
> kvecs[i].iov_len);
> if (ret)
> - return ret;
> + goto out;
> }
>
>
> ret = crypto_shash_final(desc, hmac);
> - if (ret)
> - return ret;
>
>
> +out:
> shash_desc_zero(desc);
> - return 0; /* auth_x, both plain and secure modes */
> + return ret; /* auth_x, both plain and secure modes */
> }
>
>
> static void gcm_inc_nonce(struct ceph_gcm_nonce *nonce)
> @@ -2072,27 +2072,32 @@ static int process_auth_done(struct ceph_connection *con, void *p, void *end)
> if (con->state != CEPH_CON_S_V2_AUTH) {
> dout("%s con %p state changed to %d\n", __func__, con,
> con->state);
> - return -EAGAIN;
> + ret = -EAGAIN;
> + goto out;
> }
>
>
> dout("%s con %p handle_auth_done ret %d\n", __func__, con, ret);
> if (ret)
> - return ret;
> + goto out;
>
>
> ret = setup_crypto(con, session_key, session_key_len, con_secret,
> con_secret_len);
> if (ret)
> - return ret;
> + goto out;
>
>
> reset_out_kvecs(con);
> ret = prepare_auth_signature(con);
> if (ret) {
> pr_err("prepare_auth_signature failed: %d\n", ret);
> - return ret;
> + goto out;
> }
>
>
> con->state = CEPH_CON_S_V2_AUTH_SIGNATURE;
> - return 0;
> +
> +out:
> + memzero_explicit(session_key_buf, sizeof(session_key_buf));
> + memzero_explicit(con_secret_buf, sizeof(con_secret_buf));
> + return ret;
>
>
> bad:
> pr_err("failed to decode auth_done\n");
> @@ -3436,6 +3441,8 @@ 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);
Looks like a reasonable thing to do:
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
