[mirror_ubuntu-eoan-kernel.git] / drivers / target / iscsi / iscsi_target_auth.c

/*******************************************************************************
 * 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.
 *
 * 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 "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_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,
	char *c_str,
	unsigned int *c_len)
{
	unsigned char challenge_asciihex[CHAP_CHALLENGE_LENGTH * 2 + 1];
	struct iscsi_chap *chap = (struct iscsi_chap *) conn->auth_protocol;

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

	chap_set_random(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 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)
{
	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 = (struct iscsi_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");
		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++;
	*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)
{
	char *endptr;
	unsigned char id, 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];
	struct iscsi_chap *chap = (struct iscsi_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;
	}

	if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 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, (void *)&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, (void *)&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, (void *)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)
		id = (unsigned char)simple_strtoul((char *)&identifier[2],
					&endptr, 0);
	else
		id = (unsigned char)simple_strtoul(identifier, &endptr, 0);
	/*
	 * RFC 1994 says Identifier is no more than octet (8 bits).
	 */
	pr_debug("[server] Got CHAP_I=%d\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;
	}
	/*
	 * 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;
	}

	sg_init_one(&sg, (void *)&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, (void *)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, (void *)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 = (struct iscsi_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 = (struct iscsi_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	*
	4	* \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
	5	*
	6	* Licensed to the Linux Foundation under the General Public License (GPL) version 2.
	7	*
	8	* Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
	9	*
	10	* This program is free software; you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License as published by
	12	* the Free Software Foundation; either version 2 of the License, or
	13	* (at your option) any later version.
	14	*
	15	* This program is distributed in the hope that it will be useful,
	16	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	17	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	18	* GNU General Public License for more details.
	19	******************************************************************************/
	20
f2b56afd	21	#include <linux/kernel.h>
e48354ce NB	22	#include <linux/string.h>
	23	#include <linux/crypto.h>
	24	#include <linux/err.h>
	25	#include <linux/scatterlist.h>
	26
	27	#include "iscsi_target_core.h"
	28	#include "iscsi_target_nego.h"
	29	#include "iscsi_target_auth.h"
	30
e48354ce NB	31	static int chap_string_to_hex(unsigned char dst, unsigned char src, int len)
e48354ce NB	32	{
ddca8f3e	33	int j = DIV_ROUND_UP(len, 2), rc;
e48354ce	34
ddca8f3e NB	35	rc = hex2bin(dst, src, j);
	36	if (rc < 0)
	37	pr_debug("CHAP string contains non hex digit symbols\n");
e48354ce NB	38
	39	dst[j] = '\0';
	40	return j;
	41	}
	42
	43	static void chap_binaryhex_to_asciihex(char dst, char src, int src_len)
	44	{
	45	int i;
	46
	47	for (i = 0; i < src_len; i++) {
	48	sprintf(&dst[i*2], "%02x", (int) src[i] & 0xff);
	49	}
	50	}
	51
	52	static void chap_set_random(char *data, int length)
	53	{
	54	long r;
	55	unsigned n;
	56
	57	while (length > 0) {
	58	get_random_bytes(&r, sizeof(long));
	59	r = r ^ (r >> 8);
	60	r = r ^ (r >> 4);
	61	n = r & 0x7;
	62
	63	get_random_bytes(&r, sizeof(long));
	64	r = r ^ (r >> 8);
	65	r = r ^ (r >> 5);
	66	n = (n << 3) \| (r & 0x7);
	67
	68	get_random_bytes(&r, sizeof(long));
	69	r = r ^ (r >> 8);
	70	r = r ^ (r >> 5);
	71	n = (n << 2) \| (r & 0x3);
	72
	73	*data++ = n;
	74	length--;
	75	}
	76	}
	77
	78	static void chap_gen_challenge(
	79	struct iscsi_conn *conn,
	80	int caller,
	81	char *c_str,
	82	unsigned int *c_len)
	83	{
	84	unsigned char challenge_asciihex[CHAP_CHALLENGE_LENGTH * 2 + 1];
	85	struct iscsi_chap chap = (struct iscsi_chap ) conn->auth_protocol;
	86
	87	memset(challenge_asciihex, 0, CHAP_CHALLENGE_LENGTH * 2 + 1);
	88
	89	chap_set_random(chap->challenge, CHAP_CHALLENGE_LENGTH);
	90	chap_binaryhex_to_asciihex(challenge_asciihex, chap->challenge,
	91	CHAP_CHALLENGE_LENGTH);
	92	/*
	93	* Set CHAP_C, and copy the generated challenge into c_str.
	94	*/
	95	c_len += sprintf(c_str + c_len, "CHAP_C=0x%s", challenge_asciihex);
	96	*c_len += 1;
	97
	98	pr_debug("[%s] Sending CHAP_C=0x%s\n\n", (caller) ? "server" : "client",
	99	challenge_asciihex);
	100	}
	101
102
103	static struct iscsi_chap *chap_server_open(
104	struct iscsi_conn *conn,
105	struct iscsi_node_auth *auth,
106	const char *a_str,
107	char *aic_str,
108	unsigned int *aic_len)
109	{
110	struct iscsi_chap *chap;
111
112	if (!(auth->naf_flags & NAF_USERID_SET) \|\|
113	!(auth->naf_flags & NAF_PASSWORD_SET)) {
114	pr_err("CHAP user or password not set for"
115	" Initiator ACL\n");
116	return NULL;
117	}
118
119	conn->auth_protocol = kzalloc(sizeof(struct iscsi_chap), GFP_KERNEL);
120	if (!conn->auth_protocol)
121	return NULL;
122
123	chap = (struct iscsi_chap *) conn->auth_protocol;
124	/*
125	* We only support MD5 MDA presently.
126	*/
127	if (strncmp(a_str, "CHAP_A=5", 8)) {
128	pr_err("CHAP_A is not MD5.\n");
129	return NULL;
130	}
131	pr_debug("[server] Got CHAP_A=5\n");
132	/*
133	* Send back CHAP_A set to MD5.
134	*/
135	*aic_len = sprintf(aic_str, "CHAP_A=5");
136	*aic_len += 1;
137	chap->digest_type = CHAP_DIGEST_MD5;
138	pr_debug("[server] Sending CHAP_A=%d\n", chap->digest_type);
139	/*
140	* Set Identifier.
141	*/
142	chap->id = ISCSI_TPG_C(conn)->tpg_chap_id++;
143	aic_len += sprintf(aic_str + aic_len, "CHAP_I=%d", chap->id);
144	*aic_len += 1;
145	pr_debug("[server] Sending CHAP_I=%d\n", chap->id);
146	/*
147	* Generate Challenge.
148	*/
149	chap_gen_challenge(conn, 1, aic_str, aic_len);
150
151	return chap;
152	}
153
154	static void chap_close(struct iscsi_conn *conn)
155	{
156	kfree(conn->auth_protocol);
157	conn->auth_protocol = NULL;
158	}
159
160	static int chap_server_compute_md5(
161	struct iscsi_conn *conn,
162	struct iscsi_node_auth *auth,
163	char *nr_in_ptr,
164	char *nr_out_ptr,
165	unsigned int *nr_out_len)
166	{
167	char *endptr;
168	unsigned char id, digest[MD5_SIGNATURE_SIZE];
169	unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
170	unsigned char identifier[10], *challenge = NULL;
171	unsigned char *challenge_binhex = NULL;
172	unsigned char client_digest[MD5_SIGNATURE_SIZE];
173	unsigned char server_digest[MD5_SIGNATURE_SIZE];
174	unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
175	struct iscsi_chap chap = (struct iscsi_chap ) conn->auth_protocol;
176	struct crypto_hash *tfm;
177	struct hash_desc desc;
178	struct scatterlist sg;
179	int auth_ret = -1, ret, challenge_len;
180
181	memset(identifier, 0, 10);
182	memset(chap_n, 0, MAX_CHAP_N_SIZE);
183	memset(chap_r, 0, MAX_RESPONSE_LENGTH);
184	memset(digest, 0, MD5_SIGNATURE_SIZE);
185	memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
186	memset(client_digest, 0, MD5_SIGNATURE_SIZE);
187	memset(server_digest, 0, MD5_SIGNATURE_SIZE);
188
189	challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
190	if (!challenge) {
191	pr_err("Unable to allocate challenge buffer\n");
192	goto out;
193	}
194
195	challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
196	if (!challenge_binhex) {
197	pr_err("Unable to allocate challenge_binhex buffer\n");
198	goto out;
199	}
200	/*
201	* Extract CHAP_N.
202	*/
203	if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
204	&type) < 0) {
205	pr_err("Could not find CHAP_N.\n");
206	goto out;
207	}
208	if (type == HEX) {
209	pr_err("Could not find CHAP_N.\n");
210	goto out;
211	}
212
213	if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 0) {
214	pr_err("CHAP_N values do not match!\n");
215	goto out;
216	}
217	pr_debug("[server] Got CHAP_N=%s\n", chap_n);
218	/*
219	* Extract CHAP_R.
220	*/
221	if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
222	&type) < 0) {
223	pr_err("Could not find CHAP_R.\n");
224	goto out;
225	}
226	if (type != HEX) {
227	pr_err("Could not find CHAP_R.\n");
228	goto out;
229	}
230
231	pr_debug("[server] Got CHAP_R=%s\n", chap_r);
232	chap_string_to_hex(client_digest, chap_r, strlen(chap_r));
233
234	tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
235	if (IS_ERR(tfm)) {
236	pr_err("Unable to allocate struct crypto_hash\n");
237	goto out;
238	}
239	desc.tfm = tfm;
240	desc.flags = 0;
241
242	ret = crypto_hash_init(&desc);
243	if (ret < 0) {
244	pr_err("crypto_hash_init() failed\n");
245	crypto_free_hash(tfm);
246	goto out;
247	}
248
249	sg_init_one(&sg, (void *)&chap->id, 1);
250	ret = crypto_hash_update(&desc, &sg, 1);
251	if (ret < 0) {
252	pr_err("crypto_hash_update() failed for id\n");
253	crypto_free_hash(tfm);
254	goto out;
255	}
256
257	sg_init_one(&sg, (void *)&auth->password, strlen(auth->password));
258	ret = crypto_hash_update(&desc, &sg, strlen(auth->password));
259	if (ret < 0) {
260	pr_err("crypto_hash_update() failed for password\n");
261	crypto_free_hash(tfm);
262	goto out;
263	}
264
265	sg_init_one(&sg, (void *)chap->challenge, CHAP_CHALLENGE_LENGTH);
266	ret = crypto_hash_update(&desc, &sg, CHAP_CHALLENGE_LENGTH);
267	if (ret < 0) {
268	pr_err("crypto_hash_update() failed for challenge\n");
269	crypto_free_hash(tfm);
270	goto out;
271	}
272
273	ret = crypto_hash_final(&desc, server_digest);
274	if (ret < 0) {
275	pr_err("crypto_hash_final() failed for server digest\n");
276	crypto_free_hash(tfm);
277	goto out;
278	}
279	crypto_free_hash(tfm);
280
281	chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
282	pr_debug("[server] MD5 Server Digest: %s\n", response);
283
284	if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
285	pr_debug("[server] MD5 Digests do not match!\n\n");
286	goto out;
287	} else
288	pr_debug("[server] MD5 Digests match, CHAP connetication"
289	" successful.\n\n");
290	/*
291	* One way authentication has succeeded, return now if mutual
292	* authentication is not enabled.
293	*/
294	if (!auth->authenticate_target) {
295	kfree(challenge);
296	kfree(challenge_binhex);
297	return 0;
298	}
299	/*
300	* Get CHAP_I.
301	*/
302	if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
303	pr_err("Could not find CHAP_I.\n");
304	goto out;
305	}
306
307	if (type == HEX)
308	id = (unsigned char)simple_strtoul((char *)&identifier[2],
309	&endptr, 0);
310	else
311	id = (unsigned char)simple_strtoul(identifier, &endptr, 0);
312	/*
313	* RFC 1994 says Identifier is no more than octet (8 bits).
314	*/
315	pr_debug("[server] Got CHAP_I=%d\n", id);
316	/*
317	* Get CHAP_C.
318	*/
319	if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
320	challenge, &type) < 0) {
321	pr_err("Could not find CHAP_C.\n");
322	goto out;
323	}
324
325	if (type != HEX) {
326	pr_err("Could not find CHAP_C.\n");
327	goto out;
328	}
329	pr_debug("[server] Got CHAP_C=%s\n", challenge);
330	challenge_len = chap_string_to_hex(challenge_binhex, challenge,
331	strlen(challenge));
332	if (!challenge_len) {
333	pr_err("Unable to convert incoming challenge\n");
334	goto out;
335	}
336	/*
337	* Generate CHAP_N and CHAP_R for mutual authentication.
338	*/
339	tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
340	if (IS_ERR(tfm)) {
341	pr_err("Unable to allocate struct crypto_hash\n");
342	goto out;
343	}
344	desc.tfm = tfm;
345	desc.flags = 0;
346
347	ret = crypto_hash_init(&desc);
348	if (ret < 0) {
349	pr_err("crypto_hash_init() failed\n");
350	crypto_free_hash(tfm);
351	goto out;
352	}
353
354	sg_init_one(&sg, (void *)&id, 1);
355	ret = crypto_hash_update(&desc, &sg, 1);
356	if (ret < 0) {
357	pr_err("crypto_hash_update() failed for id\n");
358	crypto_free_hash(tfm);
359	goto out;
360	}
361
362	sg_init_one(&sg, (void *)auth->password_mutual,
363	strlen(auth->password_mutual));
364	ret = crypto_hash_update(&desc, &sg, strlen(auth->password_mutual));
365	if (ret < 0) {
366	pr_err("crypto_hash_update() failed for"
367	" password_mutual\n");
368	crypto_free_hash(tfm);
369	goto out;
370	}
371	/*
372	* Convert received challenge to binary hex.
373	*/
374	sg_init_one(&sg, (void *)challenge_binhex, challenge_len);
375	ret = crypto_hash_update(&desc, &sg, challenge_len);
376	if (ret < 0) {
377	pr_err("crypto_hash_update() failed for ma challenge\n");
378	crypto_free_hash(tfm);
379	goto out;
380	}
381
382	ret = crypto_hash_final(&desc, digest);
383	if (ret < 0) {
384	pr_err("crypto_hash_final() failed for ma digest\n");
385	crypto_free_hash(tfm);
386	goto out;
387	}
388	crypto_free_hash(tfm);
389	/*
390	* Generate CHAP_N and CHAP_R.
391	*/
392	*nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
393	*nr_out_len += 1;
394	pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
395	/*
396	* Convert response from binary hex to ascii hext.
397	*/
398	chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
399	nr_out_len += sprintf(nr_out_ptr + nr_out_len, "CHAP_R=0x%s",
400	response);
401	*nr_out_len += 1;
402	pr_debug("[server] Sending CHAP_R=0x%s\n", response);
403	auth_ret = 0;
404	out:
405	kfree(challenge);
406	kfree(challenge_binhex);
407	return auth_ret;
408	}
409
410	static int chap_got_response(
411	struct iscsi_conn *conn,
412	struct iscsi_node_auth *auth,
413	char *nr_in_ptr,
414	char *nr_out_ptr,
415	unsigned int *nr_out_len)
416	{
417	struct iscsi_chap chap = (struct iscsi_chap ) conn->auth_protocol;
418
419	switch (chap->digest_type) {
420	case CHAP_DIGEST_MD5:
421	if (chap_server_compute_md5(conn, auth, nr_in_ptr,
422	nr_out_ptr, nr_out_len) < 0)
423	return -1;
424	return 0;
425	default:
426	pr_err("Unknown CHAP digest type %d!\n",
427	chap->digest_type);
428	return -1;
429	}
430	}
431
432	u32 chap_main_loop(
433	struct iscsi_conn *conn,
434	struct iscsi_node_auth *auth,
435	char *in_text,
436	char *out_text,
437	int *in_len,
438	int *out_len)
439	{
440	struct iscsi_chap chap = (struct iscsi_chap ) conn->auth_protocol;
441
442	if (!chap) {
443	chap = chap_server_open(conn, auth, in_text, out_text, out_len);
444	if (!chap)
445	return 2;
446	chap->chap_state = CHAP_STAGE_SERVER_AIC;
447	return 0;
448	} else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
449	convert_null_to_semi(in_text, *in_len);
450	if (chap_got_response(conn, auth, in_text, out_text,
451	out_len) < 0) {
452	chap_close(conn);
453	return 2;
454	}
455	if (auth->authenticate_target)
456	chap->chap_state = CHAP_STAGE_SERVER_NR;
457	else
458	*out_len = 0;
459	chap_close(conn);
460	return 1;
461	}
462
463	return 2;
464	}