[deliverable/linux.git] / drivers / target / iscsi / iscsi_target_auth.c

/*******************************************************************************
 * This file houses the main functions for the iSCSI CHAP support
 *
 * (c) Copyright 2007-2013 Datera, Inc.
 *
 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 ******************************************************************************/

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <linux/scatterlist.h>

#include <target/iscsi/iscsi_target_core.h>
#include "iscsi_target_nego.h"
#include "iscsi_target_auth.h"

static int chap_string_to_hex(unsigned char *dst, unsigned char *src, int len)
{
	int j = DIV_ROUND_UP(len, 2), rc;

	rc = hex2bin(dst, src, j);
	if (rc < 0)
		pr_debug("CHAP string contains non hex digit symbols\n");

	dst[j] = '\0';
	return j;
}

static void chap_binaryhex_to_asciihex(char *dst, char *src, int src_len)
{
	int i;

	for (i = 0; i < src_len; i++) {
		sprintf(&dst[i*2], "%02x", (int) src[i] & 0xff);
	}
}

static void chap_gen_challenge(
	struct iscsi_conn *conn,
	int caller,
	char *c_str,
	unsigned int *c_len)
{
	unsigned char challenge_asciihex[CHAP_CHALLENGE_LENGTH * 2 + 1];
	struct iscsi_chap *chap = conn->auth_protocol;

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

	get_random_bytes(chap->challenge, CHAP_CHALLENGE_LENGTH);
	chap_binaryhex_to_asciihex(challenge_asciihex, chap->challenge,
				CHAP_CHALLENGE_LENGTH);
	/*
	 * Set CHAP_C, and copy the generated challenge into c_str.
	 */
	*c_len += sprintf(c_str + *c_len, "CHAP_C=0x%s", challenge_asciihex);
	*c_len += 1;

	pr_debug("[%s] Sending CHAP_C=0x%s\n\n", (caller) ? "server" : "client",
			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,
	struct iscsi_node_auth *auth,
	const char *a_str,
	char *aic_str,
	unsigned int *aic_len)
{
	int ret;
	struct iscsi_chap *chap;

	if (!(auth->naf_flags & NAF_USERID_SET) ||
	    !(auth->naf_flags & NAF_PASSWORD_SET)) {
		pr_err("CHAP user or password not set for"
				" Initiator ACL\n");
		return NULL;
	}

	conn->auth_protocol = kzalloc(sizeof(struct iscsi_chap), GFP_KERNEL);
	if (!conn->auth_protocol)
		return NULL;

	chap = conn->auth_protocol;
	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;
	}

	/*
	 * Set Identifier.
	 */
	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);
	/*
	 * Generate Challenge.
	 */
	chap_gen_challenge(conn, 1, aic_str, aic_len);

	return chap;
}

static void chap_close(struct iscsi_conn *conn)
{
	kfree(conn->auth_protocol);
	conn->auth_protocol = NULL;
}

static int chap_server_compute_md5(
	struct iscsi_conn *conn,
	struct iscsi_node_auth *auth,
	char *nr_in_ptr,
	char *nr_out_ptr,
	unsigned int *nr_out_len)
{
	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;
	unsigned char *challenge_binhex = NULL;
	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;
	struct scatterlist sg;
	int auth_ret = -1, ret, challenge_len;

	memset(identifier, 0, 10);
	memset(chap_n, 0, MAX_CHAP_N_SIZE);
	memset(chap_r, 0, MAX_RESPONSE_LENGTH);
	memset(digest, 0, MD5_SIGNATURE_SIZE);
	memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
	memset(client_digest, 0, MD5_SIGNATURE_SIZE);
	memset(server_digest, 0, MD5_SIGNATURE_SIZE);

	challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
	if (!challenge) {
		pr_err("Unable to allocate challenge buffer\n");
		goto out;
	}

	challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
	if (!challenge_binhex) {
		pr_err("Unable to allocate challenge_binhex buffer\n");
		goto out;
	}
	/*
	 * Extract CHAP_N.
	 */
	if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
				&type) < 0) {
		pr_err("Could not find CHAP_N.\n");
		goto out;
	}
	if (type == HEX) {
		pr_err("Could not find CHAP_N.\n");
		goto out;
	}

	/* 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;
	}
	pr_debug("[server] Got CHAP_N=%s\n", chap_n);
	/*
	 * Extract CHAP_R.
	 */
	if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
				&type) < 0) {
		pr_err("Could not find CHAP_R.\n");
		goto out;
	}
	if (type != HEX) {
		pr_err("Could not find CHAP_R.\n");
		goto out;
	}

	pr_debug("[server] Got CHAP_R=%s\n", chap_r);
	chap_string_to_hex(client_digest, chap_r, strlen(chap_r));

	tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(tfm)) {
		pr_err("Unable to allocate struct crypto_hash\n");
		goto out;
	}
	desc.tfm = tfm;
	desc.flags = 0;

	ret = crypto_hash_init(&desc);
	if (ret < 0) {
		pr_err("crypto_hash_init() failed\n");
		crypto_free_hash(tfm);
		goto out;
	}

	sg_init_one(&sg, &chap->id, 1);
	ret = crypto_hash_update(&desc, &sg, 1);
	if (ret < 0) {
		pr_err("crypto_hash_update() failed for id\n");
		crypto_free_hash(tfm);
		goto out;
	}

	sg_init_one(&sg, &auth->password, strlen(auth->password));
	ret = crypto_hash_update(&desc, &sg, strlen(auth->password));
	if (ret < 0) {
		pr_err("crypto_hash_update() failed for password\n");
		crypto_free_hash(tfm);
		goto out;
	}

	sg_init_one(&sg, chap->challenge, CHAP_CHALLENGE_LENGTH);
	ret = crypto_hash_update(&desc, &sg, CHAP_CHALLENGE_LENGTH);
	if (ret < 0) {
		pr_err("crypto_hash_update() failed for challenge\n");
		crypto_free_hash(tfm);
		goto out;
	}

	ret = crypto_hash_final(&desc, server_digest);
	if (ret < 0) {
		pr_err("crypto_hash_final() failed for server digest\n");
		crypto_free_hash(tfm);
		goto out;
	}
	crypto_free_hash(tfm);

	chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
	pr_debug("[server] MD5 Server Digest: %s\n", response);

	if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
		pr_debug("[server] MD5 Digests do not match!\n\n");
		goto out;
	} else
		pr_debug("[server] MD5 Digests match, CHAP connetication"
				" successful.\n\n");
	/*
	 * One way authentication has succeeded, return now if mutual
	 * authentication is not enabled.
	 */
	if (!auth->authenticate_target) {
		kfree(challenge);
		kfree(challenge_binhex);
		return 0;
	}
	/*
	 * Get CHAP_I.
	 */
	if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
		pr_err("Could not find CHAP_I.\n");
		goto out;
	}

	if (type == HEX)
		ret = kstrtoul(&identifier[2], 0, &id);
	else
		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;
	}
	/*
	 * RFC 1994 says Identifier is no more than octet (8 bits).
	 */
	pr_debug("[server] Got CHAP_I=%lu\n", id);
	/*
	 * Get CHAP_C.
	 */
	if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
			challenge, &type) < 0) {
		pr_err("Could not find CHAP_C.\n");
		goto out;
	}

	if (type != HEX) {
		pr_err("Could not find CHAP_C.\n");
		goto out;
	}
	pr_debug("[server] Got CHAP_C=%s\n", challenge);
	challenge_len = chap_string_to_hex(challenge_binhex, challenge,
				strlen(challenge));
	if (!challenge_len) {
		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.
	 */
	tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(tfm)) {
		pr_err("Unable to allocate struct crypto_hash\n");
		goto out;
	}
	desc.tfm = tfm;
	desc.flags = 0;

	ret = crypto_hash_init(&desc);
	if (ret < 0) {
		pr_err("crypto_hash_init() failed\n");
		crypto_free_hash(tfm);
		goto out;
	}

	/* 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");
		crypto_free_hash(tfm);
		goto out;
	}

	sg_init_one(&sg, auth->password_mutual,
				strlen(auth->password_mutual));
	ret = crypto_hash_update(&desc, &sg, strlen(auth->password_mutual));
	if (ret < 0) {
		pr_err("crypto_hash_update() failed for"
				" password_mutual\n");
		crypto_free_hash(tfm);
		goto out;
	}
	/*
	 * Convert received challenge to binary hex.
	 */
	sg_init_one(&sg, challenge_binhex, challenge_len);
	ret = crypto_hash_update(&desc, &sg, challenge_len);
	if (ret < 0) {
		pr_err("crypto_hash_update() failed for ma challenge\n");
		crypto_free_hash(tfm);
		goto out;
	}

	ret = crypto_hash_final(&desc, digest);
	if (ret < 0) {
		pr_err("crypto_hash_final() failed for ma digest\n");
		crypto_free_hash(tfm);
		goto out;
	}
	crypto_free_hash(tfm);
	/*
	 * Generate CHAP_N and CHAP_R.
	 */
	*nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
	*nr_out_len += 1;
	pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
	/*
	 * Convert response from binary hex to ascii hext.
	 */
	chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
	*nr_out_len += sprintf(nr_out_ptr + *nr_out_len, "CHAP_R=0x%s",
			response);
	*nr_out_len += 1;
	pr_debug("[server] Sending CHAP_R=0x%s\n", response);
	auth_ret = 0;
out:
	kfree(challenge);
	kfree(challenge_binhex);
	return auth_ret;
}

static int chap_got_response(
	struct iscsi_conn *conn,
	struct iscsi_node_auth *auth,
	char *nr_in_ptr,
	char *nr_out_ptr,
	unsigned int *nr_out_len)
{
	struct iscsi_chap *chap = conn->auth_protocol;

	switch (chap->digest_type) {
	case CHAP_DIGEST_MD5:
		if (chap_server_compute_md5(conn, auth, nr_in_ptr,
				nr_out_ptr, nr_out_len) < 0)
			return -1;
		return 0;
	default:
		pr_err("Unknown CHAP digest type %d!\n",
				chap->digest_type);
		return -1;
	}
}

u32 chap_main_loop(
	struct iscsi_conn *conn,
	struct iscsi_node_auth *auth,
	char *in_text,
	char *out_text,
	int *in_len,
	int *out_len)
{
	struct iscsi_chap *chap = conn->auth_protocol;

	if (!chap) {
		chap = chap_server_open(conn, auth, in_text, out_text, out_len);
		if (!chap)
			return 2;
		chap->chap_state = CHAP_STAGE_SERVER_AIC;
		return 0;
	} else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
		convert_null_to_semi(in_text, *in_len);
		if (chap_got_response(conn, auth, in_text, out_text,
				out_len) < 0) {
			chap_close(conn);
			return 2;
		}
		if (auth->authenticate_target)
			chap->chap_state = CHAP_STAGE_SERVER_NR;
		else
			*out_len = 0;
		chap_close(conn);
		return 1;
	}

	return 2;
}
Commit	Line	Data
e48354ce NB	1	/*******************************************************************************
	2	* This file houses the main functions for the iSCSI CHAP support
	3	*
4c76251e	4	* (c) Copyright 2007-2013 Datera, Inc.
e48354ce NB	5	*
	6	* Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	******************************************************************************/
	18
f2b56afd	19	#include <linux/kernel.h>
e48354ce NB	20	#include <linux/string.h>
	21	#include <linux/crypto.h>
	22	#include <linux/err.h>
	23	#include <linux/scatterlist.h>
	24
67f091f2	25	#include <target/iscsi/iscsi_target_core.h>
e48354ce NB	26	#include "iscsi_target_nego.h"
	27	#include "iscsi_target_auth.h"
	28
e48354ce NB	29	static int chap_string_to_hex(unsigned char dst, unsigned char src, int len)
e48354ce NB	30	{
ddca8f3e	31	int j = DIV_ROUND_UP(len, 2), rc;
e48354ce	32
ddca8f3e NB	33	rc = hex2bin(dst, src, j);
	34	if (rc < 0)
	35	pr_debug("CHAP string contains non hex digit symbols\n");
e48354ce NB	36
	37	dst[j] = '\0';
	38	return j;
	39	}
	40
	41	static void chap_binaryhex_to_asciihex(char dst, char src, int src_len)
	42	{
	43	int i;
	44
	45	for (i = 0; i < src_len; i++) {
	46	sprintf(&dst[i*2], "%02x", (int) src[i] & 0xff);
	47	}
	48	}
	49
e48354ce NB	50	static void chap_gen_challenge(
	51	struct iscsi_conn *conn,
	52	int caller,
	53	char *c_str,
	54	unsigned int *c_len)
	55	{
	56	unsigned char challenge_asciihex[CHAP_CHALLENGE_LENGTH * 2 + 1];
8359cf43	57	struct iscsi_chap *chap = conn->auth_protocol;
e48354ce NB	58
	59	memset(challenge_asciihex, 0, CHAP_CHALLENGE_LENGTH * 2 + 1);
	60
98e2eeb3	61	get_random_bytes(chap->challenge, CHAP_CHALLENGE_LENGTH);
e48354ce NB	62	chap_binaryhex_to_asciihex(challenge_asciihex, chap->challenge,
	63	CHAP_CHALLENGE_LENGTH);
	64	/*
	65	* Set CHAP_C, and copy the generated challenge into c_str.
	66	*/
	67	c_len += sprintf(c_str + c_len, "CHAP_C=0x%s", challenge_asciihex);
	68	*c_len += 1;
	69
	70	pr_debug("[%s] Sending CHAP_C=0x%s\n\n", (caller) ? "server" : "client",
	71	challenge_asciihex);
	72	}
	73
3160723c TV	74	static int chap_check_algorithm(const char *a_str)
	75	{
	76	char tmp, orig, *token;
	77
	78	tmp = kstrdup(a_str, GFP_KERNEL);
	79	if (!tmp) {
	80	pr_err("Memory allocation failed for CHAP_A temporary buffer\n");
	81	return CHAP_DIGEST_UNKNOWN;
	82	}
	83	orig = tmp;
	84
	85	token = strsep(&tmp, "=");
	86	if (!token)
	87	goto out;
	88
	89	if (strcmp(token, "CHAP_A")) {
	90	pr_err("Unable to locate CHAP_A key\n");
	91	goto out;
	92	}
	93	while (token) {
	94	token = strsep(&tmp, ",");
	95	if (!token)
	96	goto out;
	97
	98	if (!strncmp(token, "5", 1)) {
	99	pr_debug("Selected MD5 Algorithm\n");
	100	kfree(orig);
	101	return CHAP_DIGEST_MD5;
	102	}
	103	}
	104	out:
	105	kfree(orig);
	106	return CHAP_DIGEST_UNKNOWN;
	107	}
e48354ce NB	108
	109	static struct iscsi_chap *chap_server_open(
	110	struct iscsi_conn *conn,
	111	struct iscsi_node_auth *auth,
	112	const char *a_str,
	113	char *aic_str,
	114	unsigned int *aic_len)
	115	{
3160723c	116	int ret;
e48354ce NB	117	struct iscsi_chap *chap;
	118
	119	if (!(auth->naf_flags & NAF_USERID_SET) \|\|
	120	!(auth->naf_flags & NAF_PASSWORD_SET)) {
	121	pr_err("CHAP user or password not set for"
	122	" Initiator ACL\n");
	123	return NULL;
	124	}
	125
	126	conn->auth_protocol = kzalloc(sizeof(struct iscsi_chap), GFP_KERNEL);
	127	if (!conn->auth_protocol)
	128	return NULL;
	129
8359cf43	130	chap = conn->auth_protocol;
3160723c TV	131	ret = chap_check_algorithm(a_str);
	132	switch (ret) {
	133	case CHAP_DIGEST_MD5:
	134	pr_debug("[server] Got CHAP_A=5\n");
	135	/*
	136	* Send back CHAP_A set to MD5.
	137	*/
	138	*aic_len = sprintf(aic_str, "CHAP_A=5");
	139	*aic_len += 1;
	140	chap->digest_type = CHAP_DIGEST_MD5;
	141	pr_debug("[server] Sending CHAP_A=%d\n", chap->digest_type);
	142	break;
	143	case CHAP_DIGEST_UNKNOWN:
	144	default:
	145	pr_err("Unsupported CHAP_A value\n");
e48354ce NB	146	return NULL;
e48354ce NB	147	}
3160723c	148
e48354ce NB	149	/*
	150	* Set Identifier.
	151	*/
60bfcf8e	152	chap->id = conn->tpg->tpg_chap_id++;
e48354ce NB	153	aic_len += sprintf(aic_str + aic_len, "CHAP_I=%d", chap->id);
	154	*aic_len += 1;
	155	pr_debug("[server] Sending CHAP_I=%d\n", chap->id);
	156	/*
	157	* Generate Challenge.
	158	*/
	159	chap_gen_challenge(conn, 1, aic_str, aic_len);
	160
	161	return chap;
	162	}
	163
	164	static void chap_close(struct iscsi_conn *conn)
	165	{
	166	kfree(conn->auth_protocol);
	167	conn->auth_protocol = NULL;
	168	}
	169
	170	static int chap_server_compute_md5(
	171	struct iscsi_conn *conn,
	172	struct iscsi_node_auth *auth,
	173	char *nr_in_ptr,
	174	char *nr_out_ptr,
	175	unsigned int *nr_out_len)
	176	{
bc704fb5	177	unsigned long id;
7ac9ad11	178	unsigned char id_as_uchar;
bc704fb5	179	unsigned char digest[MD5_SIGNATURE_SIZE];
e48354ce NB	180	unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
	181	unsigned char identifier[10], *challenge = NULL;
	182	unsigned char *challenge_binhex = NULL;
	183	unsigned char client_digest[MD5_SIGNATURE_SIZE];
	184	unsigned char server_digest[MD5_SIGNATURE_SIZE];
	185	unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
86784c6b	186	size_t compare_len;
8359cf43	187	struct iscsi_chap *chap = conn->auth_protocol;
e48354ce NB	188	struct crypto_hash *tfm;
	189	struct hash_desc desc;
	190	struct scatterlist sg;
	191	int auth_ret = -1, ret, challenge_len;
	192
	193	memset(identifier, 0, 10);
	194	memset(chap_n, 0, MAX_CHAP_N_SIZE);
	195	memset(chap_r, 0, MAX_RESPONSE_LENGTH);
	196	memset(digest, 0, MD5_SIGNATURE_SIZE);
	197	memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
	198	memset(client_digest, 0, MD5_SIGNATURE_SIZE);
	199	memset(server_digest, 0, MD5_SIGNATURE_SIZE);
	200
	201	challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
	202	if (!challenge) {
	203	pr_err("Unable to allocate challenge buffer\n");
	204	goto out;
	205	}
	206
	207	challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
	208	if (!challenge_binhex) {
	209	pr_err("Unable to allocate challenge_binhex buffer\n");
	210	goto out;
	211	}
	212	/*
	213	* Extract CHAP_N.
	214	*/
	215	if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
	216	&type) < 0) {
	217	pr_err("Could not find CHAP_N.\n");
	218	goto out;
	219	}
	220	if (type == HEX) {
	221	pr_err("Could not find CHAP_N.\n");
	222	goto out;
	223	}
	224
86784c6b ES	225	/* Include the terminating NULL in the compare */
	226	compare_len = strlen(auth->userid) + 1;
	227	if (strncmp(chap_n, auth->userid, compare_len) != 0) {
e48354ce NB	228	pr_err("CHAP_N values do not match!\n");
	229	goto out;
	230	}
	231	pr_debug("[server] Got CHAP_N=%s\n", chap_n);
	232	/*
	233	* Extract CHAP_R.
	234	*/
	235	if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
	236	&type) < 0) {
	237	pr_err("Could not find CHAP_R.\n");
	238	goto out;
	239	}
	240	if (type != HEX) {
	241	pr_err("Could not find CHAP_R.\n");
	242	goto out;
	243	}
	244
	245	pr_debug("[server] Got CHAP_R=%s\n", chap_r);
	246	chap_string_to_hex(client_digest, chap_r, strlen(chap_r));
	247
	248	tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
	249	if (IS_ERR(tfm)) {
	250	pr_err("Unable to allocate struct crypto_hash\n");
	251	goto out;
	252	}
	253	desc.tfm = tfm;
	254	desc.flags = 0;
	255
	256	ret = crypto_hash_init(&desc);
	257	if (ret < 0) {
	258	pr_err("crypto_hash_init() failed\n");
	259	crypto_free_hash(tfm);
	260	goto out;
	261	}
	262
8359cf43	263	sg_init_one(&sg, &chap->id, 1);
e48354ce NB	264	ret = crypto_hash_update(&desc, &sg, 1);
	265	if (ret < 0) {
	266	pr_err("crypto_hash_update() failed for id\n");
	267	crypto_free_hash(tfm);
	268	goto out;
	269	}
	270
8359cf43	271	sg_init_one(&sg, &auth->password, strlen(auth->password));
e48354ce NB	272	ret = crypto_hash_update(&desc, &sg, strlen(auth->password));
	273	if (ret < 0) {
	274	pr_err("crypto_hash_update() failed for password\n");
	275	crypto_free_hash(tfm);
	276	goto out;
	277	}
	278
8359cf43	279	sg_init_one(&sg, chap->challenge, CHAP_CHALLENGE_LENGTH);
e48354ce NB	280	ret = crypto_hash_update(&desc, &sg, CHAP_CHALLENGE_LENGTH);
	281	if (ret < 0) {
	282	pr_err("crypto_hash_update() failed for challenge\n");
	283	crypto_free_hash(tfm);
	284	goto out;
	285	}
	286
	287	ret = crypto_hash_final(&desc, server_digest);
	288	if (ret < 0) {
	289	pr_err("crypto_hash_final() failed for server digest\n");
	290	crypto_free_hash(tfm);
	291	goto out;
	292	}
	293	crypto_free_hash(tfm);
	294
	295	chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
	296	pr_debug("[server] MD5 Server Digest: %s\n", response);
	297
	298	if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
	299	pr_debug("[server] MD5 Digests do not match!\n\n");
	300	goto out;
	301	} else
	302	pr_debug("[server] MD5 Digests match, CHAP connetication"
	303	" successful.\n\n");
	304	/*
	305	* One way authentication has succeeded, return now if mutual
	306	* authentication is not enabled.
	307	*/
	308	if (!auth->authenticate_target) {
	309	kfree(challenge);
	310	kfree(challenge_binhex);
	311	return 0;
	312	}
	313	/*
	314	* Get CHAP_I.
	315	*/
	316	if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
	317	pr_err("Could not find CHAP_I.\n");
	318	goto out;
	319	}
	320
	321	if (type == HEX)
b06eef6e	322	ret = kstrtoul(&identifier[2], 0, &id);
e48354ce	323	else
b06eef6e NB	324	ret = kstrtoul(identifier, 0, &id);
	325
	326	if (ret < 0) {
	327	pr_err("kstrtoul() failed for CHAP identifier: %d\n", ret);
	328	goto out;
	329	}
bc704fb5 NB	330	if (id > 255) {
	331	pr_err("chap identifier: %lu greater than 255\n", id);
	332	goto out;
	333	}
e48354ce NB	334	/*
	335	* RFC 1994 says Identifier is no more than octet (8 bits).
	336	*/
bc704fb5	337	pr_debug("[server] Got CHAP_I=%lu\n", id);
e48354ce NB	338	/*
	339	* Get CHAP_C.
	340	*/
	341	if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
	342	challenge, &type) < 0) {
	343	pr_err("Could not find CHAP_C.\n");
	344	goto out;
	345	}
	346
	347	if (type != HEX) {
	348	pr_err("Could not find CHAP_C.\n");
	349	goto out;
	350	}
	351	pr_debug("[server] Got CHAP_C=%s\n", challenge);
	352	challenge_len = chap_string_to_hex(challenge_binhex, challenge,
	353	strlen(challenge));
	354	if (!challenge_len) {
	355	pr_err("Unable to convert incoming challenge\n");
	356	goto out;
	357	}
e4fae231 NB	358	if (challenge_len > 1024) {
	359	pr_err("CHAP_C exceeds maximum binary size of 1024 bytes\n");
	360	goto out;
	361	}
1d2b60a5 NB	362	/*
	363	* During mutual authentication, the CHAP_C generated by the
	364	* initiator must not match the original CHAP_C generated by
	365	* the target.
	366	*/
	367	if (!memcmp(challenge_binhex, chap->challenge, CHAP_CHALLENGE_LENGTH)) {
	368	pr_err("initiator CHAP_C matches target CHAP_C, failing"
	369	" login attempt\n");
	370	goto out;
	371	}
e48354ce NB	372	/*
	373	* Generate CHAP_N and CHAP_R for mutual authentication.
	374	*/
	375	tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
	376	if (IS_ERR(tfm)) {
	377	pr_err("Unable to allocate struct crypto_hash\n");
	378	goto out;
	379	}
	380	desc.tfm = tfm;
	381	desc.flags = 0;
	382
	383	ret = crypto_hash_init(&desc);
	384	if (ret < 0) {
	385	pr_err("crypto_hash_init() failed\n");
	386	crypto_free_hash(tfm);
	387	goto out;
	388	}
	389
7ac9ad11 AG	390	/* To handle both endiannesses */
	391	id_as_uchar = id;
	392	sg_init_one(&sg, &id_as_uchar, 1);
e48354ce NB	393	ret = crypto_hash_update(&desc, &sg, 1);
	394	if (ret < 0) {
	395	pr_err("crypto_hash_update() failed for id\n");
	396	crypto_free_hash(tfm);
	397	goto out;
	398	}
	399
8359cf43	400	sg_init_one(&sg, auth->password_mutual,
e48354ce NB	401	strlen(auth->password_mutual));
	402	ret = crypto_hash_update(&desc, &sg, strlen(auth->password_mutual));
	403	if (ret < 0) {
	404	pr_err("crypto_hash_update() failed for"
	405	" password_mutual\n");
	406	crypto_free_hash(tfm);
	407	goto out;
	408	}
	409	/*
	410	* Convert received challenge to binary hex.
	411	*/
8359cf43	412	sg_init_one(&sg, challenge_binhex, challenge_len);
e48354ce NB	413	ret = crypto_hash_update(&desc, &sg, challenge_len);
	414	if (ret < 0) {
	415	pr_err("crypto_hash_update() failed for ma challenge\n");
	416	crypto_free_hash(tfm);
	417	goto out;
	418	}
	419
	420	ret = crypto_hash_final(&desc, digest);
	421	if (ret < 0) {
	422	pr_err("crypto_hash_final() failed for ma digest\n");
	423	crypto_free_hash(tfm);
	424	goto out;
	425	}
	426	crypto_free_hash(tfm);
	427	/*
	428	* Generate CHAP_N and CHAP_R.
	429	*/
	430	*nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
	431	*nr_out_len += 1;
	432	pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
	433	/*
	434	* Convert response from binary hex to ascii hext.
	435	*/
	436	chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
	437	nr_out_len += sprintf(nr_out_ptr + nr_out_len, "CHAP_R=0x%s",
	438	response);
	439	*nr_out_len += 1;
	440	pr_debug("[server] Sending CHAP_R=0x%s\n", response);
	441	auth_ret = 0;
	442	out:
	443	kfree(challenge);
	444	kfree(challenge_binhex);
	445	return auth_ret;
	446	}
	447
	448	static int chap_got_response(
	449	struct iscsi_conn *conn,
	450	struct iscsi_node_auth *auth,
	451	char *nr_in_ptr,
	452	char *nr_out_ptr,
	453	unsigned int *nr_out_len)
	454	{
8359cf43	455	struct iscsi_chap *chap = conn->auth_protocol;
e48354ce NB	456
	457	switch (chap->digest_type) {
	458	case CHAP_DIGEST_MD5:
	459	if (chap_server_compute_md5(conn, auth, nr_in_ptr,
	460	nr_out_ptr, nr_out_len) < 0)
	461	return -1;
	462	return 0;
	463	default:
	464	pr_err("Unknown CHAP digest type %d!\n",
	465	chap->digest_type);
	466	return -1;
	467	}
	468	}
	469
	470	u32 chap_main_loop(
	471	struct iscsi_conn *conn,
	472	struct iscsi_node_auth *auth,
	473	char *in_text,
	474	char *out_text,
	475	int *in_len,
	476	int *out_len)
	477	{
8359cf43	478	struct iscsi_chap *chap = conn->auth_protocol;
e48354ce NB	479
	480	if (!chap) {
	481	chap = chap_server_open(conn, auth, in_text, out_text, out_len);
	482	if (!chap)
	483	return 2;
	484	chap->chap_state = CHAP_STAGE_SERVER_AIC;
	485	return 0;
	486	} else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
	487	convert_null_to_semi(in_text, *in_len);
	488	if (chap_got_response(conn, auth, in_text, out_text,
	489	out_len) < 0) {
	490	chap_close(conn);
	491	return 2;
	492	}
	493	if (auth->authenticate_target)
	494	chap->chap_state = CHAP_STAGE_SERVER_NR;
	495	else
	496	*out_len = 0;
	497	chap_close(conn);
	498	return 1;
	499	}
	500
	501	return 2;
	502	}