Commit 19f5f88e authored by Maurizio Lombardi's avatar Maurizio Lombardi Committed by Martin K. Petersen
Browse files

scsi: target: iscsi: tie the challenge length to the hash digest size 

Link: https://lore.kernel.org/r/20191017131037.9903-3-mlombard@redhat.com


Signed-off-by: default avatarMaurizio Lombardi <mlombard@redhat.com>
Tested-by: default avatarChris Leech <cleech@redhat.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent a572d24a

drivers/target/iscsi/iscsi_target_auth.c

+26 −11
Original line number Diff line number Diff line
@@ -41,16 +41,21 @@ static int chap_gen_challenge( 
	unsigned int *c_len)

{

	int ret;

	unsigned char challenge_asciihex[CHAP_CHALLENGE_LENGTH * 2 + 1];

	unsigned char *challenge_asciihex;

	struct iscsi_chap *chap = conn->auth_protocol;



	memset(challenge_asciihex, 0, CHAP_CHALLENGE_LENGTH * 2 + 1);

	challenge_asciihex = kzalloc(chap->challenge_len * 2 + 1, GFP_KERNEL);

	if (!challenge_asciihex)

		return -ENOMEM;



	ret = get_random_bytes_wait(chap->challenge, CHAP_CHALLENGE_LENGTH);

	memset(chap->challenge, 0, MAX_CHAP_CHALLENGE_LEN);



	ret = get_random_bytes_wait(chap->challenge, chap->challenge_len);

	if (unlikely(ret))

		return ret;

		goto out;



	bin2hex(challenge_asciihex, chap->challenge,

				CHAP_CHALLENGE_LENGTH);

				chap->challenge_len);

	/*

	 * Set CHAP_C, and copy the generated challenge into c_str.

	 */
@@ -59,7 +64,10 @@ static int chap_gen_challenge( 


	pr_debug("[%s] Sending CHAP_C=0x%s\n\n", (caller) ? "server" : "client",

			challenge_asciihex);

	return 0;



out:

	kfree(challenge_asciihex);

	return ret;

}



static int chap_test_algorithm(const char *name)
@@ -171,6 +179,9 @@ static struct iscsi_chap *chap_server_open( 


	chap->digest_name = chap_get_digest_name(digest_type);



	/* Tie the challenge length to the digest size */

	chap->challenge_len = chap->digest_size;



	pr_debug("[server] Got CHAP_A=%d\n", digest_type);

	*aic_len = sprintf(aic_str, "CHAP_A=%d", digest_type);

	*aic_len += 1;
@@ -334,21 +345,23 @@ static int chap_server_compute_hash( 
	}



	ret = crypto_shash_finup(desc, chap->challenge,

				 CHAP_CHALLENGE_LENGTH, server_digest);

				 chap->challenge_len, server_digest);

	if (ret < 0) {

		pr_err("crypto_shash_finup() failed for challenge\n");

		goto out;

	}



	bin2hex(response, server_digest, chap->digest_size);

	pr_debug("[server] %s Server Digest: %s\n", hash_name, response);

	pr_debug("[server] %s Server Digest: %s\n",

		chap->digest_name, response);



	if (memcmp(server_digest, client_digest, chap->digest_size) != 0) {

		pr_debug("[server] %s Digests do not match!\n\n", hash_name);

		pr_debug("[server] %s Digests do not match!\n\n",

			chap->digest_name);

		goto out;

	} else

		pr_debug("[server] %s Digests match, CHAP connection"

				" successful.\n\n", hash_name);

				" successful.\n\n", chap->digest_name);

	/*

	 * One way authentication has succeeded, return now if mutual

	 * authentication is not enabled.
@@ -414,7 +427,9 @@ static int chap_server_compute_hash( 
	 * initiator must not match the original CHAP_C generated by

	 * the target.

	 */

	if (!memcmp(challenge_binhex, chap->challenge, CHAP_CHALLENGE_LENGTH)) {

	if (challenge_len == chap->challenge_len &&

				!memcmp(challenge_binhex, chap->challenge,

				challenge_len)) {

		pr_err("initiator CHAP_C matches target CHAP_C, failing"

		       " login attempt\n");

		goto out;

drivers/target/iscsi/iscsi_target_auth.h

+2 −2
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ 
#define CHAP_DIGEST_SHA256	7

#define CHAP_DIGEST_SHA3_256	8



#define CHAP_CHALLENGE_LENGTH	16

#define MAX_CHAP_CHALLENGE_LEN	32

#define CHAP_CHALLENGE_STR_LEN	4096

#define MAX_RESPONSE_LENGTH	128	/* sufficient for SHA3 256 */

#define	MAX_CHAP_N_SIZE		512
@@ -34,7 +34,7 @@ extern u32 chap_main_loop(struct iscsi_conn *, struct iscsi_node_auth *, char *, 


struct iscsi_chap {

	unsigned char	id;

	unsigned char	challenge[CHAP_CHALLENGE_LENGTH];

	unsigned char	challenge[MAX_CHAP_CHALLENGE_LEN];

	unsigned int	challenge_len;

	unsigned char	*digest_name;

	unsigned int	digest_size;