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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
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
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
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
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
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
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
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
293
294
295 if (!auth->authenticate_target) {
296 kfree(challenge);
297 kfree(challenge_binhex);
298 return 0;
299 }
300
301
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
318
319 pr_debug("[server] Got CHAP_I=%lu\n", id);
320
321
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
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
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
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
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}
469
