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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 * \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/kernel.h>
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
31static int chap_string_to_hex(unsigned char *dst, unsigned char *src, int len)
32{
33 int j = DIV_ROUND_UP(len, 2), rc;
34
35 rc = hex2bin(dst, src, j);
36 if (rc < 0)
37 pr_debug("CHAP string contains non hex digit symbols\n");
38
39 dst[j] = '\0';
40 return j;
41}
42
43static 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
52static 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
78static 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 = 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
103static 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 = 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
154static void chap_close(struct iscsi_conn *conn)
155{
156 kfree(conn->auth_protocol);
157 conn->auth_protocol = NULL;
158}
159
160static 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 long id;
169 unsigned char digest[MD5_SIGNATURE_SIZE];
170 unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
171 unsigned char identifier[10], *challenge = NULL;
172 unsigned char *challenge_binhex = NULL;
173 unsigned char client_digest[MD5_SIGNATURE_SIZE];
174 unsigned char server_digest[MD5_SIGNATURE_SIZE];
175 unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
176 struct iscsi_chap *chap = conn->auth_protocol;
177 struct crypto_hash *tfm;
178 struct hash_desc desc;
179 struct scatterlist sg;
180 int auth_ret = -1, ret, challenge_len;
181
182 memset(identifier, 0, 10);
183 memset(chap_n, 0, MAX_CHAP_N_SIZE);
184 memset(chap_r, 0, MAX_RESPONSE_LENGTH);
185 memset(digest, 0, MD5_SIGNATURE_SIZE);
186 memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
187 memset(client_digest, 0, MD5_SIGNATURE_SIZE);
188 memset(server_digest, 0, MD5_SIGNATURE_SIZE);
189
190 challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
191 if (!challenge) {
192 pr_err("Unable to allocate challenge buffer\n");
193 goto out;
194 }
195
196 challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
197 if (!challenge_binhex) {
198 pr_err("Unable to allocate challenge_binhex buffer\n");
199 goto out;
200 }
201 /*
202 * Extract CHAP_N.
203 */
204 if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
205 &type) < 0) {
206 pr_err("Could not find CHAP_N.\n");
207 goto out;
208 }
209 if (type == HEX) {
210 pr_err("Could not find CHAP_N.\n");
211 goto out;
212 }
213
214 if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 0) {
215 pr_err("CHAP_N values do not match!\n");
216 goto out;
217 }
218 pr_debug("[server] Got CHAP_N=%s\n", chap_n);
219 /*
220 * Extract CHAP_R.
221 */
222 if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
223 &type) < 0) {
224 pr_err("Could not find CHAP_R.\n");
225 goto out;
226 }
227 if (type != HEX) {
228 pr_err("Could not find CHAP_R.\n");
229 goto out;
230 }
231
232 pr_debug("[server] Got CHAP_R=%s\n", chap_r);
233 chap_string_to_hex(client_digest, chap_r, strlen(chap_r));
234
235 tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
236 if (IS_ERR(tfm)) {
237 pr_err("Unable to allocate struct crypto_hash\n");
238 goto out;
239 }
240 desc.tfm = tfm;
241 desc.flags = 0;
242
243 ret = crypto_hash_init(&desc);
244 if (ret < 0) {
245 pr_err("crypto_hash_init() failed\n");
246 crypto_free_hash(tfm);
247 goto out;
248 }
249
250 sg_init_one(&sg, &chap->id, 1);
251 ret = crypto_hash_update(&desc, &sg, 1);
252 if (ret < 0) {
253 pr_err("crypto_hash_update() failed for id\n");
254 crypto_free_hash(tfm);
255 goto out;
256 }
257
258 sg_init_one(&sg, &auth->password, strlen(auth->password));
259 ret = crypto_hash_update(&desc, &sg, strlen(auth->password));
260 if (ret < 0) {
261 pr_err("crypto_hash_update() failed for password\n");
262 crypto_free_hash(tfm);
263 goto out;
264 }
265
266 sg_init_one(&sg, chap->challenge, CHAP_CHALLENGE_LENGTH);
267 ret = crypto_hash_update(&desc, &sg, CHAP_CHALLENGE_LENGTH);
268 if (ret < 0) {
269 pr_err("crypto_hash_update() failed for challenge\n");
270 crypto_free_hash(tfm);
271 goto out;
272 }
273
274 ret = crypto_hash_final(&desc, server_digest);
275 if (ret < 0) {
276 pr_err("crypto_hash_final() failed for server digest\n");
277 crypto_free_hash(tfm);
278 goto out;
279 }
280 crypto_free_hash(tfm);
281
282 chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
283 pr_debug("[server] MD5 Server Digest: %s\n", response);
284
285 if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
286 pr_debug("[server] MD5 Digests do not match!\n\n");
287 goto out;
288 } else
289 pr_debug("[server] MD5 Digests match, CHAP connetication"
290 " successful.\n\n");
291 /*
292 * One way authentication has succeeded, return now if mutual
293 * authentication is not enabled.
294 */
295 if (!auth->authenticate_target) {
296 kfree(challenge);
297 kfree(challenge_binhex);
298 return 0;
299 }
300 /*
301 * Get CHAP_I.
302 */
303 if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
304 pr_err("Could not find CHAP_I.\n");
305 goto out;
306 }
307
308 if (type == HEX)
309 id = simple_strtoul(&identifier[2], &endptr, 0);
310 else
311 id = simple_strtoul(identifier, &endptr, 0);
312 if (id > 255) {
313 pr_err("chap identifier: %lu greater than 255\n", id);
314 goto out;
315 }
316 /*
317 * RFC 1994 says Identifier is no more than octet (8 bits).
318 */
319 pr_debug("[server] Got CHAP_I=%lu\n", id);
320 /*
321 * Get CHAP_C.
322 */
323 if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
324 challenge, &type) < 0) {
325 pr_err("Could not find CHAP_C.\n");
326 goto out;
327 }
328
329 if (type != HEX) {
330 pr_err("Could not find CHAP_C.\n");
331 goto out;
332 }
333 pr_debug("[server] Got CHAP_C=%s\n", challenge);
334 challenge_len = chap_string_to_hex(challenge_binhex, challenge,
335 strlen(challenge));
336 if (!challenge_len) {
337 pr_err("Unable to convert incoming challenge\n");
338 goto out;
339 }
340 /*
341 * Generate CHAP_N and CHAP_R for mutual authentication.
342 */
343 tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
344 if (IS_ERR(tfm)) {
345 pr_err("Unable to allocate struct crypto_hash\n");
346 goto out;
347 }
348 desc.tfm = tfm;
349 desc.flags = 0;
350
351 ret = crypto_hash_init(&desc);
352 if (ret < 0) {
353 pr_err("crypto_hash_init() failed\n");
354 crypto_free_hash(tfm);
355 goto out;
356 }
357
358 sg_init_one(&sg, &id, 1);
359 ret = crypto_hash_update(&desc, &sg, 1);
360 if (ret < 0) {
361 pr_err("crypto_hash_update() failed for id\n");
362 crypto_free_hash(tfm);
363 goto out;
364 }
365
366 sg_init_one(&sg, auth->password_mutual,
367 strlen(auth->password_mutual));
368 ret = crypto_hash_update(&desc, &sg, strlen(auth->password_mutual));
369 if (ret < 0) {
370 pr_err("crypto_hash_update() failed for"
371 " password_mutual\n");
372 crypto_free_hash(tfm);
373 goto out;
374 }
375 /*
376 * Convert received challenge to binary hex.
377 */
378 sg_init_one(&sg, challenge_binhex, challenge_len);
379 ret = crypto_hash_update(&desc, &sg, challenge_len);
380 if (ret < 0) {
381 pr_err("crypto_hash_update() failed for ma challenge\n");
382 crypto_free_hash(tfm);
383 goto out;
384 }
385
386 ret = crypto_hash_final(&desc, digest);
387 if (ret < 0) {
388 pr_err("crypto_hash_final() failed for ma digest\n");
389 crypto_free_hash(tfm);
390 goto out;
391 }
392 crypto_free_hash(tfm);
393 /*
394 * Generate CHAP_N and CHAP_R.
395 */
396 *nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
397 *nr_out_len += 1;
398 pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
399 /*
400 * Convert response from binary hex to ascii hext.
401 */
402 chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
403 *nr_out_len += sprintf(nr_out_ptr + *nr_out_len, "CHAP_R=0x%s",
404 response);
405 *nr_out_len += 1;
406 pr_debug("[server] Sending CHAP_R=0x%s\n", response);
407 auth_ret = 0;
408out:
409 kfree(challenge);
410 kfree(challenge_binhex);
411 return auth_ret;
412}
413
414static int chap_got_response(
415 struct iscsi_conn *conn,
416 struct iscsi_node_auth *auth,
417 char *nr_in_ptr,
418 char *nr_out_ptr,
419 unsigned int *nr_out_len)
420{
421 struct iscsi_chap *chap = conn->auth_protocol;
422
423 switch (chap->digest_type) {
424 case CHAP_DIGEST_MD5:
425 if (chap_server_compute_md5(conn, auth, nr_in_ptr,
426 nr_out_ptr, nr_out_len) < 0)
427 return -1;
428 return 0;
429 default:
430 pr_err("Unknown CHAP digest type %d!\n",
431 chap->digest_type);
432 return -1;
433 }
434}
435
436u32 chap_main_loop(
437 struct iscsi_conn *conn,
438 struct iscsi_node_auth *auth,
439 char *in_text,
440 char *out_text,
441 int *in_len,
442 int *out_len)
443{
444 struct iscsi_chap *chap = conn->auth_protocol;
445
446 if (!chap) {
447 chap = chap_server_open(conn, auth, in_text, out_text, out_len);
448 if (!chap)
449 return 2;
450 chap->chap_state = CHAP_STAGE_SERVER_AIC;
451 return 0;
452 } else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
453 convert_null_to_semi(in_text, *in_len);
454 if (chap_got_response(conn, auth, in_text, out_text,
455 out_len) < 0) {
456 chap_close(conn);
457 return 2;
458 }
459 if (auth->authenticate_target)
460 chap->chap_state = CHAP_STAGE_SERVER_NR;
461 else
462 *out_len = 0;
463 chap_close(conn);
464 return 1;
465 }
466
467 return 2;
468}