From 19f5f88ed779180f16e236949e18389a0dca4aae Mon Sep 17 00:00:00 2001 From: Maurizio Lombardi Date: Thu, 17 Oct 2019 15:10:36 +0200 Subject: 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: Maurizio Lombardi Tested-by: Chris Leech Signed-off-by: Martin K. Petersen --- drivers/target/iscsi/iscsi_target_auth.c | 37 ++++++++++++++++++++++---------- drivers/target/iscsi/iscsi_target_auth.h | 4 ++-- 2 files changed, 28 insertions(+), 13 deletions(-) (limited to 'drivers/target') diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c index b09f20842e40..f3973ab19da2 100644 --- a/drivers/target/iscsi/iscsi_target_auth.c +++ b/drivers/target/iscsi/iscsi_target_auth.c @@ -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; diff --git a/drivers/target/iscsi/iscsi_target_auth.h b/drivers/target/iscsi/iscsi_target_auth.h index 93db1ab5516c..fc75c1c20e23 100644 --- a/drivers/target/iscsi/iscsi_target_auth.h +++ b/drivers/target/iscsi/iscsi_target_auth.h @@ -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; -- cgit v1.2.3