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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 id_as_uchar;
170 unsigned char digest[MD5_SIGNATURE_SIZE];
171 unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
172 unsigned char identifier[10], *challenge = NULL;
173 unsigned char *challenge_binhex = NULL;
174 unsigned char client_digest[MD5_SIGNATURE_SIZE];
175 unsigned char server_digest[MD5_SIGNATURE_SIZE];
176 unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
177 struct iscsi_chap *chap = conn->auth_protocol;
178 struct crypto_hash *tfm;
179 struct hash_desc desc;
180 struct scatterlist sg;
181 int auth_ret = -1, ret, challenge_len;
182
183 memset(identifier, 0, 10);
184 memset(chap_n, 0, MAX_CHAP_N_SIZE);
185 memset(chap_r, 0, MAX_RESPONSE_LENGTH);
186 memset(digest, 0, MD5_SIGNATURE_SIZE);
187 memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
188 memset(client_digest, 0, MD5_SIGNATURE_SIZE);
189 memset(server_digest, 0, MD5_SIGNATURE_SIZE);
190
191 challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
192 if (!challenge) {
193 pr_err("Unable to allocate challenge buffer\n");
194 goto out;
195 }
196
197 challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
198 if (!challenge_binhex) {
199 pr_err("Unable to allocate challenge_binhex buffer\n");
200 goto out;
201 }
202
203
204
205 if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
206 &type) < 0) {
207 pr_err("Could not find CHAP_N.\n");
208 goto out;
209 }
210 if (type == HEX) {
211 pr_err("Could not find CHAP_N.\n");
212 goto out;
213 }
214
215 if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 0) {
216 pr_err("CHAP_N values do not match!\n");
217 goto out;
218 }
219 pr_debug("[server] Got CHAP_N=%s\n", chap_n);
220
221
222
223 if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
224 &type) < 0) {
225 pr_err("Could not find CHAP_R.\n");
226 goto out;
227 }
228 if (type != HEX) {
229 pr_err("Could not find CHAP_R.\n");
230 goto out;
231 }
232
233 pr_debug("[server] Got CHAP_R=%s\n", chap_r);
234 chap_string_to_hex(client_digest, chap_r, strlen(chap_r));
235
236 tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
237 if (IS_ERR(tfm)) {
238 pr_err("Unable to allocate struct crypto_hash\n");
239 goto out;
240 }
241 desc.tfm = tfm;
242 desc.flags = 0;
243
244 ret = crypto_hash_init(&desc);
245 if (ret < 0) {
246 pr_err("crypto_hash_init() failed\n");
247 crypto_free_hash(tfm);
248 goto out;
249 }
250
251 sg_init_one(&sg, &chap->id, 1);
252 ret = crypto_hash_update(&desc, &sg, 1);
253 if (ret < 0) {
254 pr_err("crypto_hash_update() failed for id\n");
255 crypto_free_hash(tfm);
256 goto out;
257 }
258
259 sg_init_one(&sg, &auth->password, strlen(auth->password));
260 ret = crypto_hash_update(&desc, &sg, strlen(auth->password));
261 if (ret < 0) {
262 pr_err("crypto_hash_update() failed for password\n");
263 crypto_free_hash(tfm);
264 goto out;
265 }
266
267 sg_init_one(&sg, chap->challenge, CHAP_CHALLENGE_LENGTH);
268 ret = crypto_hash_update(&desc, &sg, CHAP_CHALLENGE_LENGTH);
269 if (ret < 0) {
270 pr_err("crypto_hash_update() failed for challenge\n");
271 crypto_free_hash(tfm);
272 goto out;
273 }
274
275 ret = crypto_hash_final(&desc, server_digest);
276 if (ret < 0) {
277 pr_err("crypto_hash_final() failed for server digest\n");
278 crypto_free_hash(tfm);
279 goto out;
280 }
281 crypto_free_hash(tfm);
282
283 chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
284 pr_debug("[server] MD5 Server Digest: %s\n", response);
285
286 if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
287 pr_debug("[server] MD5 Digests do not match!\n\n");
288 goto out;
289 } else
290 pr_debug("[server] MD5 Digests match, CHAP connetication"
291 " successful.\n\n");
292
293
294
295
296 if (!auth->authenticate_target) {
297 kfree(challenge);
298 kfree(challenge_binhex);
299 return 0;
300 }
301
302
303
304 if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
305 pr_err("Could not find CHAP_I.\n");
306 goto out;
307 }
308
309 if (type == HEX)
310 id = simple_strtoul(&identifier[2], &endptr, 0);
311 else
312 id = simple_strtoul(identifier, &endptr, 0);
313 if (id > 255) {
314 pr_err("chap identifier: %lu greater than 255\n", id);
315 goto out;
316 }
317
318
319
320 pr_debug("[server] Got CHAP_I=%lu\n", id);
321
322
323
324 if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
325 challenge, &type) < 0) {
326 pr_err("Could not find CHAP_C.\n");
327 goto out;
328 }
329
330 if (type != HEX) {
331 pr_err("Could not find CHAP_C.\n");
332 goto out;
333 }
334 pr_debug("[server] Got CHAP_C=%s\n", challenge);
335 challenge_len = chap_string_to_hex(challenge_binhex, challenge,
336 strlen(challenge));
337 if (!challenge_len) {
338 pr_err("Unable to convert incoming challenge\n");
339 goto out;
340 }
341
342
343
344 tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
345 if (IS_ERR(tfm)) {
346 pr_err("Unable to allocate struct crypto_hash\n");
347 goto out;
348 }
349 desc.tfm = tfm;
350 desc.flags = 0;
351
352 ret = crypto_hash_init(&desc);
353 if (ret < 0) {
354 pr_err("crypto_hash_init() failed\n");
355 crypto_free_hash(tfm);
356 goto out;
357 }
358
359
360 id_as_uchar = id;
361 sg_init_one(&sg, &id_as_uchar, 1);
362 ret = crypto_hash_update(&desc, &sg, 1);
363 if (ret < 0) {
364 pr_err("crypto_hash_update() failed for id\n");
365 crypto_free_hash(tfm);
366 goto out;
367 }
368
369 sg_init_one(&sg, auth->password_mutual,
370 strlen(auth->password_mutual));
371 ret = crypto_hash_update(&desc, &sg, strlen(auth->password_mutual));
372 if (ret < 0) {
373 pr_err("crypto_hash_update() failed for"
374 " password_mutual\n");
375 crypto_free_hash(tfm);
376 goto out;
377 }
378
379
380
381 sg_init_one(&sg, challenge_binhex, challenge_len);
382 ret = crypto_hash_update(&desc, &sg, challenge_len);
383 if (ret < 0) {
384 pr_err("crypto_hash_update() failed for ma challenge\n");
385 crypto_free_hash(tfm);
386 goto out;
387 }
388
389 ret = crypto_hash_final(&desc, digest);
390 if (ret < 0) {
391 pr_err("crypto_hash_final() failed for ma digest\n");
392 crypto_free_hash(tfm);
393 goto out;
394 }
395 crypto_free_hash(tfm);
396
397
398
399 *nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
400 *nr_out_len += 1;
401 pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
402
403
404
405 chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
406 *nr_out_len += sprintf(nr_out_ptr + *nr_out_len, "CHAP_R=0x%s",
407 response);
408 *nr_out_len += 1;
409 pr_debug("[server] Sending CHAP_R=0x%s\n", response);
410 auth_ret = 0;
411out:
412 kfree(challenge);
413 kfree(challenge_binhex);
414 return auth_ret;
415}
416
417static int chap_got_response(
418 struct iscsi_conn *conn,
419 struct iscsi_node_auth *auth,
420 char *nr_in_ptr,
421 char *nr_out_ptr,
422 unsigned int *nr_out_len)
423{
424 struct iscsi_chap *chap = conn->auth_protocol;
425
426 switch (chap->digest_type) {
427 case CHAP_DIGEST_MD5:
428 if (chap_server_compute_md5(conn, auth, nr_in_ptr,
429 nr_out_ptr, nr_out_len) < 0)
430 return -1;
431 return 0;
432 default:
433 pr_err("Unknown CHAP digest type %d!\n",
434 chap->digest_type);
435 return -1;
436 }
437}
438
439u32 chap_main_loop(
440 struct iscsi_conn *conn,
441 struct iscsi_node_auth *auth,
442 char *in_text,
443 char *out_text,
444 int *in_len,
445 int *out_len)
446{
447 struct iscsi_chap *chap = conn->auth_protocol;
448
449 if (!chap) {
450 chap = chap_server_open(conn, auth, in_text, out_text, out_len);
451 if (!chap)
452 return 2;
453 chap->chap_state = CHAP_STAGE_SERVER_AIC;
454 return 0;
455 } else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
456 convert_null_to_semi(in_text, *in_len);
457 if (chap_got_response(conn, auth, in_text, out_text,
458 out_len) < 0) {
459 chap_close(conn);
460 return 2;
461 }
462 if (auth->authenticate_target)
463 chap->chap_state = CHAP_STAGE_SERVER_NR;
464 else
465 *out_len = 0;
466 chap_close(conn);
467 return 1;
468 }
469
470 return 2;
471}
472
