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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
21#include <linux/string.h>
22#include <linux/crypto.h>
23#include <linux/err.h>
24#include <linux/scatterlist.h>
25
26#include "iscsi_target_core.h"
27#include "iscsi_target_nego.h"
28#include "iscsi_target_auth.h"
29
30static unsigned char chap_asciihex_to_binaryhex(unsigned char val[2])
31{
32 unsigned char result = 0;
33 /*
34 * MSB
35 */
36 if ((val[0] >= 'a') && (val[0] <= 'f'))
37 result = ((val[0] - 'a' + 10) & 0xf) << 4;
38 else
39 if ((val[0] >= 'A') && (val[0] <= 'F'))
40 result = ((val[0] - 'A' + 10) & 0xf) << 4;
41 else /* digit */
42 result = ((val[0] - '0') & 0xf) << 4;
43 /*
44 * LSB
45 */
46 if ((val[1] >= 'a') && (val[1] <= 'f'))
47 result |= ((val[1] - 'a' + 10) & 0xf);
48 else
49 if ((val[1] >= 'A') && (val[1] <= 'F'))
50 result |= ((val[1] - 'A' + 10) & 0xf);
51 else /* digit */
52 result |= ((val[1] - '0') & 0xf);
53
54 return result;
55}
56
57static int chap_string_to_hex(unsigned char *dst, unsigned char *src, int len)
58{
59 int i, j = 0;
60
61 for (i = 0; i < len; i += 2) {
62 dst[j++] = (unsigned char) chap_asciihex_to_binaryhex(&src[i]);
63 }
64
65 dst[j] = '\0';
66 return j;
67}
68
69static void chap_binaryhex_to_asciihex(char *dst, char *src, int src_len)
70{
71 int i;
72
73 for (i = 0; i < src_len; i++) {
74 sprintf(&dst[i*2], "%02x", (int) src[i] & 0xff);
75 }
76}
77
78static void chap_set_random(char *data, int length)
79{
80 long r;
81 unsigned n;
82
83 while (length > 0) {
84 get_random_bytes(&r, sizeof(long));
85 r = r ^ (r >> 8);
86 r = r ^ (r >> 4);
87 n = r & 0x7;
88
89 get_random_bytes(&r, sizeof(long));
90 r = r ^ (r >> 8);
91 r = r ^ (r >> 5);
92 n = (n << 3) | (r & 0x7);
93
94 get_random_bytes(&r, sizeof(long));
95 r = r ^ (r >> 8);
96 r = r ^ (r >> 5);
97 n = (n << 2) | (r & 0x3);
98
99 *data++ = n;
100 length--;
101 }
102}
103
104static void chap_gen_challenge(
105 struct iscsi_conn *conn,
106 int caller,
107 char *c_str,
108 unsigned int *c_len)
109{
110 unsigned char challenge_asciihex[CHAP_CHALLENGE_LENGTH * 2 + 1];
111 struct iscsi_chap *chap = (struct iscsi_chap *) conn->auth_protocol;
112
113 memset(challenge_asciihex, 0, CHAP_CHALLENGE_LENGTH * 2 + 1);
114
115 chap_set_random(chap->challenge, CHAP_CHALLENGE_LENGTH);
116 chap_binaryhex_to_asciihex(challenge_asciihex, chap->challenge,
117 CHAP_CHALLENGE_LENGTH);
118 /*
119 * Set CHAP_C, and copy the generated challenge into c_str.
120 */
121 *c_len += sprintf(c_str + *c_len, "CHAP_C=0x%s", challenge_asciihex);
122 *c_len += 1;
123
124 pr_debug("[%s] Sending CHAP_C=0x%s\n\n", (caller) ? "server" : "client",
125 challenge_asciihex);
126}
127
128
129static struct iscsi_chap *chap_server_open(
130 struct iscsi_conn *conn,
131 struct iscsi_node_auth *auth,
132 const char *a_str,
133 char *aic_str,
134 unsigned int *aic_len)
135{
136 struct iscsi_chap *chap;
137
138 if (!(auth->naf_flags & NAF_USERID_SET) ||
139 !(auth->naf_flags & NAF_PASSWORD_SET)) {
140 pr_err("CHAP user or password not set for"
141 " Initiator ACL\n");
142 return NULL;
143 }
144
145 conn->auth_protocol = kzalloc(sizeof(struct iscsi_chap), GFP_KERNEL);
146 if (!conn->auth_protocol)
147 return NULL;
148
149 chap = (struct iscsi_chap *) conn->auth_protocol;
150 /*
151 * We only support MD5 MDA presently.
152 */
153 if (strncmp(a_str, "CHAP_A=5", 8)) {
154 pr_err("CHAP_A is not MD5.\n");
155 return NULL;
156 }
157 pr_debug("[server] Got CHAP_A=5\n");
158 /*
159 * Send back CHAP_A set to MD5.
160 */
161 *aic_len = sprintf(aic_str, "CHAP_A=5");
162 *aic_len += 1;
163 chap->digest_type = CHAP_DIGEST_MD5;
164 pr_debug("[server] Sending CHAP_A=%d\n", chap->digest_type);
165 /*
166 * Set Identifier.
167 */
168 chap->id = ISCSI_TPG_C(conn)->tpg_chap_id++;
169 *aic_len += sprintf(aic_str + *aic_len, "CHAP_I=%d", chap->id);
170 *aic_len += 1;
171 pr_debug("[server] Sending CHAP_I=%d\n", chap->id);
172 /*
173 * Generate Challenge.
174 */
175 chap_gen_challenge(conn, 1, aic_str, aic_len);
176
177 return chap;
178}
179
180static void chap_close(struct iscsi_conn *conn)
181{
182 kfree(conn->auth_protocol);
183 conn->auth_protocol = NULL;
184}
185
186static int chap_server_compute_md5(
187 struct iscsi_conn *conn,
188 struct iscsi_node_auth *auth,
189 char *nr_in_ptr,
190 char *nr_out_ptr,
191 unsigned int *nr_out_len)
192{
193 char *endptr;
194 unsigned char id, digest[MD5_SIGNATURE_SIZE];
195 unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
196 unsigned char identifier[10], *challenge = NULL;
197 unsigned char *challenge_binhex = NULL;
198 unsigned char client_digest[MD5_SIGNATURE_SIZE];
199 unsigned char server_digest[MD5_SIGNATURE_SIZE];
200 unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
201 struct iscsi_chap *chap = (struct iscsi_chap *) conn->auth_protocol;
202 struct crypto_hash *tfm;
203 struct hash_desc desc;
204 struct scatterlist sg;
205 int auth_ret = -1, ret, challenge_len;
206
207 memset(identifier, 0, 10);
208 memset(chap_n, 0, MAX_CHAP_N_SIZE);
209 memset(chap_r, 0, MAX_RESPONSE_LENGTH);
210 memset(digest, 0, MD5_SIGNATURE_SIZE);
211 memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
212 memset(client_digest, 0, MD5_SIGNATURE_SIZE);
213 memset(server_digest, 0, MD5_SIGNATURE_SIZE);
214
215 challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
216 if (!challenge) {
217 pr_err("Unable to allocate challenge buffer\n");
218 goto out;
219 }
220
221 challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
222 if (!challenge_binhex) {
223 pr_err("Unable to allocate challenge_binhex buffer\n");
224 goto out;
225 }
226 /*
227 * Extract CHAP_N.
228 */
229 if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
230 &type) < 0) {
231 pr_err("Could not find CHAP_N.\n");
232 goto out;
233 }
234 if (type == HEX) {
235 pr_err("Could not find CHAP_N.\n");
236 goto out;
237 }
238
239 if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 0) {
240 pr_err("CHAP_N values do not match!\n");
241 goto out;
242 }
243 pr_debug("[server] Got CHAP_N=%s\n", chap_n);
244 /*
245 * Extract CHAP_R.
246 */
247 if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
248 &type) < 0) {
249 pr_err("Could not find CHAP_R.\n");
250 goto out;
251 }
252 if (type != HEX) {
253 pr_err("Could not find CHAP_R.\n");
254 goto out;
255 }
256
257 pr_debug("[server] Got CHAP_R=%s\n", chap_r);
258 chap_string_to_hex(client_digest, chap_r, strlen(chap_r));
259
260 tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
261 if (IS_ERR(tfm)) {
262 pr_err("Unable to allocate struct crypto_hash\n");
263 goto out;
264 }
265 desc.tfm = tfm;
266 desc.flags = 0;
267
268 ret = crypto_hash_init(&desc);
269 if (ret < 0) {
270 pr_err("crypto_hash_init() failed\n");
271 crypto_free_hash(tfm);
272 goto out;
273 }
274
275 sg_init_one(&sg, (void *)&chap->id, 1);
276 ret = crypto_hash_update(&desc, &sg, 1);
277 if (ret < 0) {
278 pr_err("crypto_hash_update() failed for id\n");
279 crypto_free_hash(tfm);
280 goto out;
281 }
282
283 sg_init_one(&sg, (void *)&auth->password, strlen(auth->password));
284 ret = crypto_hash_update(&desc, &sg, strlen(auth->password));
285 if (ret < 0) {
286 pr_err("crypto_hash_update() failed for password\n");
287 crypto_free_hash(tfm);
288 goto out;
289 }
290
291 sg_init_one(&sg, (void *)chap->challenge, CHAP_CHALLENGE_LENGTH);
292 ret = crypto_hash_update(&desc, &sg, CHAP_CHALLENGE_LENGTH);
293 if (ret < 0) {
294 pr_err("crypto_hash_update() failed for challenge\n");
295 crypto_free_hash(tfm);
296 goto out;
297 }
298
299 ret = crypto_hash_final(&desc, server_digest);
300 if (ret < 0) {
301 pr_err("crypto_hash_final() failed for server digest\n");
302 crypto_free_hash(tfm);
303 goto out;
304 }
305 crypto_free_hash(tfm);
306
307 chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
308 pr_debug("[server] MD5 Server Digest: %s\n", response);
309
310 if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
311 pr_debug("[server] MD5 Digests do not match!\n\n");
312 goto out;
313 } else
314 pr_debug("[server] MD5 Digests match, CHAP connetication"
315 " successful.\n\n");
316 /*
317 * One way authentication has succeeded, return now if mutual
318 * authentication is not enabled.
319 */
320 if (!auth->authenticate_target) {
321 kfree(challenge);
322 kfree(challenge_binhex);
323 return 0;
324 }
325 /*
326 * Get CHAP_I.
327 */
328 if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
329 pr_err("Could not find CHAP_I.\n");
330 goto out;
331 }
332
333 if (type == HEX)
334 id = (unsigned char)simple_strtoul((char *)&identifier[2],
335 &endptr, 0);
336 else
337 id = (unsigned char)simple_strtoul(identifier, &endptr, 0);
338 /*
339 * RFC 1994 says Identifier is no more than octet (8 bits).
340 */
341 pr_debug("[server] Got CHAP_I=%d\n", id);
342 /*
343 * Get CHAP_C.
344 */
345 if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
346 challenge, &type) < 0) {
347 pr_err("Could not find CHAP_C.\n");
348 goto out;
349 }
350
351 if (type != HEX) {
352 pr_err("Could not find CHAP_C.\n");
353 goto out;
354 }
355 pr_debug("[server] Got CHAP_C=%s\n", challenge);
356 challenge_len = chap_string_to_hex(challenge_binhex, challenge,
357 strlen(challenge));
358 if (!challenge_len) {
359 pr_err("Unable to convert incoming challenge\n");
360 goto out;
361 }
362 /*
363 * Generate CHAP_N and CHAP_R for mutual authentication.
364 */
365 tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
366 if (IS_ERR(tfm)) {
367 pr_err("Unable to allocate struct crypto_hash\n");
368 goto out;
369 }
370 desc.tfm = tfm;
371 desc.flags = 0;
372
373 ret = crypto_hash_init(&desc);
374 if (ret < 0) {
375 pr_err("crypto_hash_init() failed\n");
376 crypto_free_hash(tfm);
377 goto out;
378 }
379
380 sg_init_one(&sg, (void *)&id, 1);
381 ret = crypto_hash_update(&desc, &sg, 1);
382 if (ret < 0) {
383 pr_err("crypto_hash_update() failed for id\n");
384 crypto_free_hash(tfm);
385 goto out;
386 }
387
388 sg_init_one(&sg, (void *)auth->password_mutual,
389 strlen(auth->password_mutual));
390 ret = crypto_hash_update(&desc, &sg, strlen(auth->password_mutual));
391 if (ret < 0) {
392 pr_err("crypto_hash_update() failed for"
393 " password_mutual\n");
394 crypto_free_hash(tfm);
395 goto out;
396 }
397 /*
398 * Convert received challenge to binary hex.
399 */
400 sg_init_one(&sg, (void *)challenge_binhex, challenge_len);
401 ret = crypto_hash_update(&desc, &sg, challenge_len);
402 if (ret < 0) {
403 pr_err("crypto_hash_update() failed for ma challenge\n");
404 crypto_free_hash(tfm);
405 goto out;
406 }
407
408 ret = crypto_hash_final(&desc, digest);
409 if (ret < 0) {
410 pr_err("crypto_hash_final() failed for ma digest\n");
411 crypto_free_hash(tfm);
412 goto out;
413 }
414 crypto_free_hash(tfm);
415 /*
416 * Generate CHAP_N and CHAP_R.
417 */
418 *nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
419 *nr_out_len += 1;
420 pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
421 /*
422 * Convert response from binary hex to ascii hext.
423 */
424 chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
425 *nr_out_len += sprintf(nr_out_ptr + *nr_out_len, "CHAP_R=0x%s",
426 response);
427 *nr_out_len += 1;
428 pr_debug("[server] Sending CHAP_R=0x%s\n", response);
429 auth_ret = 0;
430out:
431 kfree(challenge);
432 kfree(challenge_binhex);
433 return auth_ret;
434}
435
436static int chap_got_response(
437 struct iscsi_conn *conn,
438 struct iscsi_node_auth *auth,
439 char *nr_in_ptr,
440 char *nr_out_ptr,
441 unsigned int *nr_out_len)
442{
443 struct iscsi_chap *chap = (struct iscsi_chap *) conn->auth_protocol;
444
445 switch (chap->digest_type) {
446 case CHAP_DIGEST_MD5:
447 if (chap_server_compute_md5(conn, auth, nr_in_ptr,
448 nr_out_ptr, nr_out_len) < 0)
449 return -1;
450 return 0;
451 default:
452 pr_err("Unknown CHAP digest type %d!\n",
453 chap->digest_type);
454 return -1;
455 }
456}
457
458u32 chap_main_loop(
459 struct iscsi_conn *conn,
460 struct iscsi_node_auth *auth,
461 char *in_text,
462 char *out_text,
463 int *in_len,
464 int *out_len)
465{
466 struct iscsi_chap *chap = (struct iscsi_chap *) conn->auth_protocol;
467
468 if (!chap) {
469 chap = chap_server_open(conn, auth, in_text, out_text, out_len);
470 if (!chap)
471 return 2;
472 chap->chap_state = CHAP_STAGE_SERVER_AIC;
473 return 0;
474 } else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
475 convert_null_to_semi(in_text, *in_len);
476 if (chap_got_response(conn, auth, in_text, out_text,
477 out_len) < 0) {
478 chap_close(conn);
479 return 2;
480 }
481 if (auth->authenticate_target)
482 chap->chap_state = CHAP_STAGE_SERVER_NR;
483 else
484 *out_len = 0;
485 chap_close(conn);
486 return 1;
487 }
488
489 return 2;
490}
1/*******************************************************************************
2 * This file houses the main functions for the iSCSI CHAP support
3 *
4 * (c) Copyright 2007-2013 Datera, Inc.
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
19#include <crypto/hash.h>
20#include <linux/kernel.h>
21#include <linux/string.h>
22#include <linux/err.h>
23#include <linux/scatterlist.h>
24
25#include <target/iscsi/iscsi_target_core.h>
26#include "iscsi_target_nego.h"
27#include "iscsi_target_auth.h"
28
29static int chap_string_to_hex(unsigned char *dst, unsigned char *src, int len)
30{
31 int j = DIV_ROUND_UP(len, 2), rc;
32
33 rc = hex2bin(dst, src, j);
34 if (rc < 0)
35 pr_debug("CHAP string contains non hex digit symbols\n");
36
37 dst[j] = '\0';
38 return j;
39}
40
41static 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
50static 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];
57 struct iscsi_chap *chap = conn->auth_protocol;
58
59 memset(challenge_asciihex, 0, CHAP_CHALLENGE_LENGTH * 2 + 1);
60
61 get_random_bytes(chap->challenge, CHAP_CHALLENGE_LENGTH);
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
74static 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 }
104out:
105 kfree(orig);
106 return CHAP_DIGEST_UNKNOWN;
107}
108
109static 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{
116 int ret;
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
130 chap = conn->auth_protocol;
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");
146 return NULL;
147 }
148
149 /*
150 * Set Identifier.
151 */
152 chap->id = conn->tpg->tpg_chap_id++;
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
164static void chap_close(struct iscsi_conn *conn)
165{
166 kfree(conn->auth_protocol);
167 conn->auth_protocol = NULL;
168}
169
170static 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{
177 unsigned long id;
178 unsigned char id_as_uchar;
179 unsigned char digest[MD5_SIGNATURE_SIZE];
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];
186 size_t compare_len;
187 struct iscsi_chap *chap = conn->auth_protocol;
188 struct crypto_shash *tfm = NULL;
189 struct shash_desc *desc = NULL;
190 int auth_ret = -1, ret, challenge_len;
191
192 memset(identifier, 0, 10);
193 memset(chap_n, 0, MAX_CHAP_N_SIZE);
194 memset(chap_r, 0, MAX_RESPONSE_LENGTH);
195 memset(digest, 0, MD5_SIGNATURE_SIZE);
196 memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
197 memset(client_digest, 0, MD5_SIGNATURE_SIZE);
198 memset(server_digest, 0, MD5_SIGNATURE_SIZE);
199
200 challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
201 if (!challenge) {
202 pr_err("Unable to allocate challenge buffer\n");
203 goto out;
204 }
205
206 challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
207 if (!challenge_binhex) {
208 pr_err("Unable to allocate challenge_binhex buffer\n");
209 goto out;
210 }
211 /*
212 * Extract CHAP_N.
213 */
214 if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
215 &type) < 0) {
216 pr_err("Could not find CHAP_N.\n");
217 goto out;
218 }
219 if (type == HEX) {
220 pr_err("Could not find CHAP_N.\n");
221 goto out;
222 }
223
224 /* Include the terminating NULL in the compare */
225 compare_len = strlen(auth->userid) + 1;
226 if (strncmp(chap_n, auth->userid, compare_len) != 0) {
227 pr_err("CHAP_N values do not match!\n");
228 goto out;
229 }
230 pr_debug("[server] Got CHAP_N=%s\n", chap_n);
231 /*
232 * Extract CHAP_R.
233 */
234 if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
235 &type) < 0) {
236 pr_err("Could not find CHAP_R.\n");
237 goto out;
238 }
239 if (type != HEX) {
240 pr_err("Could not find CHAP_R.\n");
241 goto out;
242 }
243
244 pr_debug("[server] Got CHAP_R=%s\n", chap_r);
245 chap_string_to_hex(client_digest, chap_r, strlen(chap_r));
246
247 tfm = crypto_alloc_shash("md5", 0, 0);
248 if (IS_ERR(tfm)) {
249 tfm = NULL;
250 pr_err("Unable to allocate struct crypto_shash\n");
251 goto out;
252 }
253
254 desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(tfm), GFP_KERNEL);
255 if (!desc) {
256 pr_err("Unable to allocate struct shash_desc\n");
257 goto out;
258 }
259
260 desc->tfm = tfm;
261 desc->flags = 0;
262
263 ret = crypto_shash_init(desc);
264 if (ret < 0) {
265 pr_err("crypto_shash_init() failed\n");
266 goto out;
267 }
268
269 ret = crypto_shash_update(desc, &chap->id, 1);
270 if (ret < 0) {
271 pr_err("crypto_shash_update() failed for id\n");
272 goto out;
273 }
274
275 ret = crypto_shash_update(desc, (char *)&auth->password,
276 strlen(auth->password));
277 if (ret < 0) {
278 pr_err("crypto_shash_update() failed for password\n");
279 goto out;
280 }
281
282 ret = crypto_shash_finup(desc, chap->challenge,
283 CHAP_CHALLENGE_LENGTH, server_digest);
284 if (ret < 0) {
285 pr_err("crypto_shash_finup() failed for challenge\n");
286 goto out;
287 }
288
289 chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
290 pr_debug("[server] MD5 Server Digest: %s\n", response);
291
292 if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
293 pr_debug("[server] MD5 Digests do not match!\n\n");
294 goto out;
295 } else
296 pr_debug("[server] MD5 Digests match, CHAP connetication"
297 " successful.\n\n");
298 /*
299 * One way authentication has succeeded, return now if mutual
300 * authentication is not enabled.
301 */
302 if (!auth->authenticate_target) {
303 auth_ret = 0;
304 goto out;
305 }
306 /*
307 * Get CHAP_I.
308 */
309 if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
310 pr_err("Could not find CHAP_I.\n");
311 goto out;
312 }
313
314 if (type == HEX)
315 ret = kstrtoul(&identifier[2], 0, &id);
316 else
317 ret = kstrtoul(identifier, 0, &id);
318
319 if (ret < 0) {
320 pr_err("kstrtoul() failed for CHAP identifier: %d\n", ret);
321 goto out;
322 }
323 if (id > 255) {
324 pr_err("chap identifier: %lu greater than 255\n", id);
325 goto out;
326 }
327 /*
328 * RFC 1994 says Identifier is no more than octet (8 bits).
329 */
330 pr_debug("[server] Got CHAP_I=%lu\n", id);
331 /*
332 * Get CHAP_C.
333 */
334 if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
335 challenge, &type) < 0) {
336 pr_err("Could not find CHAP_C.\n");
337 goto out;
338 }
339
340 if (type != HEX) {
341 pr_err("Could not find CHAP_C.\n");
342 goto out;
343 }
344 pr_debug("[server] Got CHAP_C=%s\n", challenge);
345 challenge_len = chap_string_to_hex(challenge_binhex, challenge,
346 strlen(challenge));
347 if (!challenge_len) {
348 pr_err("Unable to convert incoming challenge\n");
349 goto out;
350 }
351 if (challenge_len > 1024) {
352 pr_err("CHAP_C exceeds maximum binary size of 1024 bytes\n");
353 goto out;
354 }
355 /*
356 * During mutual authentication, the CHAP_C generated by the
357 * initiator must not match the original CHAP_C generated by
358 * the target.
359 */
360 if (!memcmp(challenge_binhex, chap->challenge, CHAP_CHALLENGE_LENGTH)) {
361 pr_err("initiator CHAP_C matches target CHAP_C, failing"
362 " login attempt\n");
363 goto out;
364 }
365 /*
366 * Generate CHAP_N and CHAP_R for mutual authentication.
367 */
368 ret = crypto_shash_init(desc);
369 if (ret < 0) {
370 pr_err("crypto_shash_init() failed\n");
371 goto out;
372 }
373
374 /* To handle both endiannesses */
375 id_as_uchar = id;
376 ret = crypto_shash_update(desc, &id_as_uchar, 1);
377 if (ret < 0) {
378 pr_err("crypto_shash_update() failed for id\n");
379 goto out;
380 }
381
382 ret = crypto_shash_update(desc, auth->password_mutual,
383 strlen(auth->password_mutual));
384 if (ret < 0) {
385 pr_err("crypto_shash_update() failed for"
386 " password_mutual\n");
387 goto out;
388 }
389 /*
390 * Convert received challenge to binary hex.
391 */
392 ret = crypto_shash_finup(desc, challenge_binhex, challenge_len,
393 digest);
394 if (ret < 0) {
395 pr_err("crypto_shash_finup() failed for ma challenge\n");
396 goto out;
397 }
398
399 /*
400 * Generate CHAP_N and CHAP_R.
401 */
402 *nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
403 *nr_out_len += 1;
404 pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
405 /*
406 * Convert response from binary hex to ascii hext.
407 */
408 chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
409 *nr_out_len += sprintf(nr_out_ptr + *nr_out_len, "CHAP_R=0x%s",
410 response);
411 *nr_out_len += 1;
412 pr_debug("[server] Sending CHAP_R=0x%s\n", response);
413 auth_ret = 0;
414out:
415 kzfree(desc);
416 crypto_free_shash(tfm);
417 kfree(challenge);
418 kfree(challenge_binhex);
419 return auth_ret;
420}
421
422static int chap_got_response(
423 struct iscsi_conn *conn,
424 struct iscsi_node_auth *auth,
425 char *nr_in_ptr,
426 char *nr_out_ptr,
427 unsigned int *nr_out_len)
428{
429 struct iscsi_chap *chap = conn->auth_protocol;
430
431 switch (chap->digest_type) {
432 case CHAP_DIGEST_MD5:
433 if (chap_server_compute_md5(conn, auth, nr_in_ptr,
434 nr_out_ptr, nr_out_len) < 0)
435 return -1;
436 return 0;
437 default:
438 pr_err("Unknown CHAP digest type %d!\n",
439 chap->digest_type);
440 return -1;
441 }
442}
443
444u32 chap_main_loop(
445 struct iscsi_conn *conn,
446 struct iscsi_node_auth *auth,
447 char *in_text,
448 char *out_text,
449 int *in_len,
450 int *out_len)
451{
452 struct iscsi_chap *chap = conn->auth_protocol;
453
454 if (!chap) {
455 chap = chap_server_open(conn, auth, in_text, out_text, out_len);
456 if (!chap)
457 return 2;
458 chap->chap_state = CHAP_STAGE_SERVER_AIC;
459 return 0;
460 } else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
461 convert_null_to_semi(in_text, *in_len);
462 if (chap_got_response(conn, auth, in_text, out_text,
463 out_len) < 0) {
464 chap_close(conn);
465 return 2;
466 }
467 if (auth->authenticate_target)
468 chap->chap_state = CHAP_STAGE_SERVER_NR;
469 else
470 *out_len = 0;
471 chap_close(conn);
472 return 1;
473 }
474
475 return 2;
476}