1 files changed, 83 insertions, 49 deletions

diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c
index db0cf7c8add..ab4915c0d93 100644
--- a/drivers/target/iscsi/iscsi_target_auth.c
+++ b/drivers/target/iscsi/iscsi_target_auth.c
@@ -1,9 +1,7 @@
 /*******************************************************************************
  * This file houses the main functions for the iSCSI CHAP support
  *
- * \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
- *
- * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
+ * (c) Copyright 2007-2013 Datera, Inc.
  *
  * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
  *
@@ -49,32 +47,6 @@ static void chap_binaryhex_to_asciihex(char *dst, char *src, int src_len)
 	}
 }
 
-static void chap_set_random(char *data, int length)
-{
-	long r;
-	unsigned n;
-
-	while (length > 0) {
-		get_random_bytes(&r, sizeof(long));
-		r = r ^ (r >> 8);
-		r = r ^ (r >> 4);
-		n = r & 0x7;
-
-		get_random_bytes(&r, sizeof(long));
-		r = r ^ (r >> 8);
-		r = r ^ (r >> 5);
-		n = (n << 3) | (r & 0x7);
-
-		get_random_bytes(&r, sizeof(long));
-		r = r ^ (r >> 8);
-		r = r ^ (r >> 5);
-		n = (n << 2) | (r & 0x3);
-
-		*data++ = n;
-		length--;
-	}
-}
-
 static void chap_gen_challenge(
 	struct iscsi_conn *conn,
 	int caller,
@@ -86,7 +58,7 @@ static void chap_gen_challenge(
 
 	memset(challenge_asciihex, 0, CHAP_CHALLENGE_LENGTH * 2 + 1);
 
-	chap_set_random(chap->challenge, CHAP_CHALLENGE_LENGTH);
+	get_random_bytes(chap->challenge, CHAP_CHALLENGE_LENGTH);
 	chap_binaryhex_to_asciihex(challenge_asciihex, chap->challenge,
 				CHAP_CHALLENGE_LENGTH);
 	/*
@@ -99,6 +71,40 @@ static void chap_gen_challenge(
 			challenge_asciihex);
 }
 
+static int chap_check_algorithm(const char *a_str)
+{
+	char *tmp, *orig, *token;
+
+	tmp = kstrdup(a_str, GFP_KERNEL);
+	if (!tmp) {
+		pr_err("Memory allocation failed for CHAP_A temporary buffer\n");
+		return CHAP_DIGEST_UNKNOWN;
+	}
+	orig = tmp;
+
+	token = strsep(&tmp, "=");
+	if (!token)
+		goto out;
+
+	if (strcmp(token, "CHAP_A")) {
+		pr_err("Unable to locate CHAP_A key\n");
+		goto out;
+	}
+	while (token) {
+		token = strsep(&tmp, ",");
+		if (!token)
+			goto out;
+
+		if (!strncmp(token, "5", 1)) {
+			pr_debug("Selected MD5 Algorithm\n");
+			kfree(orig);
+			return CHAP_DIGEST_MD5;
+		}
+	}
+out:
+	kfree(orig);
+	return CHAP_DIGEST_UNKNOWN;
+}
 
 static struct iscsi_chap *chap_server_open(
 	struct iscsi_conn *conn,
@@ -107,6 +113,7 @@ static struct iscsi_chap *chap_server_open(
 	char *aic_str,
 	unsigned int *aic_len)
 {
+	int ret;
 	struct iscsi_chap *chap;
 
 	if (!(auth->naf_flags & NAF_USERID_SET) ||
@@ -121,25 +128,28 @@ static struct iscsi_chap *chap_server_open(
 		return NULL;
 
 	chap = conn->auth_protocol;
-	/*
-	 * We only support MD5 MDA presently.
-	 */
-	if (strncmp(a_str, "CHAP_A=5", 8)) {
-		pr_err("CHAP_A is not MD5.\n");
+	ret = chap_check_algorithm(a_str);
+	switch (ret) {
+	case CHAP_DIGEST_MD5:
+		pr_debug("[server] Got CHAP_A=5\n");
+		/*
+		 * Send back CHAP_A set to MD5.
+		*/
+		*aic_len = sprintf(aic_str, "CHAP_A=5");
+		*aic_len += 1;
+		chap->digest_type = CHAP_DIGEST_MD5;
+		pr_debug("[server] Sending CHAP_A=%d\n", chap->digest_type);
+		break;
+	case CHAP_DIGEST_UNKNOWN:
+	default:
+		pr_err("Unsupported CHAP_A value\n");
 		return NULL;
 	}
-	pr_debug("[server] Got CHAP_A=5\n");
-	/*
-	 * Send back CHAP_A set to MD5.
-	 */
-	*aic_len = sprintf(aic_str, "CHAP_A=5");
-	*aic_len += 1;
-	chap->digest_type = CHAP_DIGEST_MD5;
-	pr_debug("[server] Sending CHAP_A=%d\n", chap->digest_type);
+
 	/*
 	 * Set Identifier.
 	 */
-	chap->id = ISCSI_TPG_C(conn)->tpg_chap_id++;
+	chap->id = conn->tpg->tpg_chap_id++;
 	*aic_len += sprintf(aic_str + *aic_len, "CHAP_I=%d", chap->id);
 	*aic_len += 1;
 	pr_debug("[server] Sending CHAP_I=%d\n", chap->id);
@@ -164,8 +174,8 @@ static int chap_server_compute_md5(
 	char *nr_out_ptr,
 	unsigned int *nr_out_len)
 {
-	char *endptr;
 	unsigned long id;
+	unsigned char id_as_uchar;
 	unsigned char digest[MD5_SIGNATURE_SIZE];
 	unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
 	unsigned char identifier[10], *challenge = NULL;
@@ -173,6 +183,7 @@ static int chap_server_compute_md5(
 	unsigned char client_digest[MD5_SIGNATURE_SIZE];
 	unsigned char server_digest[MD5_SIGNATURE_SIZE];
 	unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
+	size_t compare_len;
 	struct iscsi_chap *chap = conn->auth_protocol;
 	struct crypto_hash *tfm;
 	struct hash_desc desc;
@@ -211,7 +222,9 @@ static int chap_server_compute_md5(
 		goto out;
 	}
 
-	if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 0) {
+	/* Include the terminating NULL in the compare */
+	compare_len = strlen(auth->userid) + 1;
+	if (strncmp(chap_n, auth->userid, compare_len) != 0) {
 		pr_err("CHAP_N values do not match!\n");
 		goto out;
 	}
@@ -306,9 +319,14 @@ static int chap_server_compute_md5(
 	}
 
 	if (type == HEX)
-		id = simple_strtoul(&identifier[2], &endptr, 0);
+		ret = kstrtoul(&identifier[2], 0, &id);
 	else
-		id = simple_strtoul(identifier, &endptr, 0);
+		ret = kstrtoul(identifier, 0, &id);
+
+	if (ret < 0) {
+		pr_err("kstrtoul() failed for CHAP identifier: %d\n", ret);
+		goto out;
+	}
 	if (id > 255) {
 		pr_err("chap identifier: %lu greater than 255\n", id);
 		goto out;
@@ -337,6 +355,20 @@ static int chap_server_compute_md5(
 		pr_err("Unable to convert incoming challenge\n");
 		goto out;
 	}
+	if (challenge_len > 1024) {
+		pr_err("CHAP_C exceeds maximum binary size of 1024 bytes\n");
+		goto out;
+	}
+	/*
+	 * During mutual authentication, the CHAP_C generated by the
+	 * initiator must not match the original CHAP_C generated by
+	 * the target.
+	 */
+	if (!memcmp(challenge_binhex, chap->challenge, CHAP_CHALLENGE_LENGTH)) {
+		pr_err("initiator CHAP_C matches target CHAP_C, failing"
+		       " login attempt\n");
+		goto out;
+	}
 	/*
 	 * Generate CHAP_N and CHAP_R for mutual authentication.
 	 */
@@ -355,7 +387,9 @@ static int chap_server_compute_md5(
 		goto out;
 	}
 
-	sg_init_one(&sg, &id, 1);
+	/* To handle both endiannesses */
+	id_as_uchar = id;
+	sg_init_one(&sg, &id_as_uchar, 1);
 	ret = crypto_hash_update(&desc, &sg, 1);
 	if (ret < 0) {
 		pr_err("crypto_hash_update() failed for id\n");