Commit 10f42b3e authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

libceph: zero out session key and connection secret 



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: default avatarIlya Dryomov <idryomov@gmail.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
parent e71ba945

net/ceph/auth_x.c

+34 −23
Original line number Diff line number Diff line
@@ -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;

net/ceph/crypto.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

net/ceph/messenger_v2.c

+26 −19
Original line number Diff line number Diff line
@@ -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);