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19#include <linux/kernel.h>
20#include <linux/string.h>
21#include <linux/crypto.h>
22#include <linux/err.h>
23#include <linux/scatterlist.h>
24
25#include "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
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
74
75static struct iscsi_chap *chap_server_open(
76 struct iscsi_conn *conn,
77 struct iscsi_node_auth *auth,
78 const char *a_str,
79 char *aic_str,
80 unsigned int *aic_len)
81{
82 struct iscsi_chap *chap;
83
84 if (!(auth->naf_flags & NAF_USERID_SET) ||
85 !(auth->naf_flags & NAF_PASSWORD_SET)) {
86 pr_err("CHAP user or password not set for"
87 " Initiator ACL\n");
88 return NULL;
89 }
90
91 conn->auth_protocol = kzalloc(sizeof(struct iscsi_chap), GFP_KERNEL);
92 if (!conn->auth_protocol)
93 return NULL;
94
95 chap = conn->auth_protocol;
96
97
98
99 if (strncmp(a_str, "CHAP_A=5", 8)) {
100 pr_err("CHAP_A is not MD5.\n");
101 return NULL;
102 }
103 pr_debug("[server] Got CHAP_A=5\n");
104
105
106
107 *aic_len = sprintf(aic_str, "CHAP_A=5");
108 *aic_len += 1;
109 chap->digest_type = CHAP_DIGEST_MD5;
110 pr_debug("[server] Sending CHAP_A=%d\n", chap->digest_type);
111
112
113
114 chap->id = ISCSI_TPG_C(conn)->tpg_chap_id++;
115 *aic_len += sprintf(aic_str + *aic_len, "CHAP_I=%d", chap->id);
116 *aic_len += 1;
117 pr_debug("[server] Sending CHAP_I=%d\n", chap->id);
118
119
120
121 chap_gen_challenge(conn, 1, aic_str, aic_len);
122
123 return chap;
124}
125
126static void chap_close(struct iscsi_conn *conn)
127{
128 kfree(conn->auth_protocol);
129 conn->auth_protocol = NULL;
130}
131
132static int chap_server_compute_md5(
133 struct iscsi_conn *conn,
134 struct iscsi_node_auth *auth,
135 char *nr_in_ptr,
136 char *nr_out_ptr,
137 unsigned int *nr_out_len)
138{
139 char *endptr;
140 unsigned long id;
141 unsigned char id_as_uchar;
142 unsigned char digest[MD5_SIGNATURE_SIZE];
143 unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
144 unsigned char identifier[10], *challenge = NULL;
145 unsigned char *challenge_binhex = NULL;
146 unsigned char client_digest[MD5_SIGNATURE_SIZE];
147 unsigned char server_digest[MD5_SIGNATURE_SIZE];
148 unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
149 struct iscsi_chap *chap = conn->auth_protocol;
150 struct crypto_hash *tfm;
151 struct hash_desc desc;
152 struct scatterlist sg;
153 int auth_ret = -1, ret, challenge_len;
154
155 memset(identifier, 0, 10);
156 memset(chap_n, 0, MAX_CHAP_N_SIZE);
157 memset(chap_r, 0, MAX_RESPONSE_LENGTH);
158 memset(digest, 0, MD5_SIGNATURE_SIZE);
159 memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
160 memset(client_digest, 0, MD5_SIGNATURE_SIZE);
161 memset(server_digest, 0, MD5_SIGNATURE_SIZE);
162
163 challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
164 if (!challenge) {
165 pr_err("Unable to allocate challenge buffer\n");
166 goto out;
167 }
168
169 challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
170 if (!challenge_binhex) {
171 pr_err("Unable to allocate challenge_binhex buffer\n");
172 goto out;
173 }
174
175
176
177 if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
178 &type) < 0) {
179 pr_err("Could not find CHAP_N.\n");
180 goto out;
181 }
182 if (type == HEX) {
183 pr_err("Could not find CHAP_N.\n");
184 goto out;
185 }
186
187 if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 0) {
188 pr_err("CHAP_N values do not match!\n");
189 goto out;
190 }
191 pr_debug("[server] Got CHAP_N=%s\n", chap_n);
192
193
194
195 if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
196 &type) < 0) {
197 pr_err("Could not find CHAP_R.\n");
198 goto out;
199 }
200 if (type != HEX) {
201 pr_err("Could not find CHAP_R.\n");
202 goto out;
203 }
204
205 pr_debug("[server] Got CHAP_R=%s\n", chap_r);
206 chap_string_to_hex(client_digest, chap_r, strlen(chap_r));
207
208 tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
209 if (IS_ERR(tfm)) {
210 pr_err("Unable to allocate struct crypto_hash\n");
211 goto out;
212 }
213 desc.tfm = tfm;
214 desc.flags = 0;
215
216 ret = crypto_hash_init(&desc);
217 if (ret < 0) {
218 pr_err("crypto_hash_init() failed\n");
219 crypto_free_hash(tfm);
220 goto out;
221 }
222
223 sg_init_one(&sg, &chap->id, 1);
224 ret = crypto_hash_update(&desc, &sg, 1);
225 if (ret < 0) {
226 pr_err("crypto_hash_update() failed for id\n");
227 crypto_free_hash(tfm);
228 goto out;
229 }
230
231 sg_init_one(&sg, &auth->password, strlen(auth->password));
232 ret = crypto_hash_update(&desc, &sg, strlen(auth->password));
233 if (ret < 0) {
234 pr_err("crypto_hash_update() failed for password\n");
235 crypto_free_hash(tfm);
236 goto out;
237 }
238
239 sg_init_one(&sg, chap->challenge, CHAP_CHALLENGE_LENGTH);
240 ret = crypto_hash_update(&desc, &sg, CHAP_CHALLENGE_LENGTH);
241 if (ret < 0) {
242 pr_err("crypto_hash_update() failed for challenge\n");
243 crypto_free_hash(tfm);
244 goto out;
245 }
246
247 ret = crypto_hash_final(&desc, server_digest);
248 if (ret < 0) {
249 pr_err("crypto_hash_final() failed for server digest\n");
250 crypto_free_hash(tfm);
251 goto out;
252 }
253 crypto_free_hash(tfm);
254
255 chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
256 pr_debug("[server] MD5 Server Digest: %s\n", response);
257
258 if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
259 pr_debug("[server] MD5 Digests do not match!\n\n");
260 goto out;
261 } else
262 pr_debug("[server] MD5 Digests match, CHAP connetication"
263 " successful.\n\n");
264
265
266
267
268 if (!auth->authenticate_target) {
269 kfree(challenge);
270 kfree(challenge_binhex);
271 return 0;
272 }
273
274
275
276 if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
277 pr_err("Could not find CHAP_I.\n");
278 goto out;
279 }
280
281 if (type == HEX)
282 id = simple_strtoul(&identifier[2], &endptr, 0);
283 else
284 id = simple_strtoul(identifier, &endptr, 0);
285 if (id > 255) {
286 pr_err("chap identifier: %lu greater than 255\n", id);
287 goto out;
288 }
289
290
291
292 pr_debug("[server] Got CHAP_I=%lu\n", id);
293
294
295
296 if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
297 challenge, &type) < 0) {
298 pr_err("Could not find CHAP_C.\n");
299 goto out;
300 }
301
302 if (type != HEX) {
303 pr_err("Could not find CHAP_C.\n");
304 goto out;
305 }
306 pr_debug("[server] Got CHAP_C=%s\n", challenge);
307 challenge_len = chap_string_to_hex(challenge_binhex, challenge,
308 strlen(challenge));
309 if (!challenge_len) {
310 pr_err("Unable to convert incoming challenge\n");
311 goto out;
312 }
313
314
315
316 tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
317 if (IS_ERR(tfm)) {
318 pr_err("Unable to allocate struct crypto_hash\n");
319 goto out;
320 }
321 desc.tfm = tfm;
322 desc.flags = 0;
323
324 ret = crypto_hash_init(&desc);
325 if (ret < 0) {
326 pr_err("crypto_hash_init() failed\n");
327 crypto_free_hash(tfm);
328 goto out;
329 }
330
331
332 id_as_uchar = id;
333 sg_init_one(&sg, &id_as_uchar, 1);
334 ret = crypto_hash_update(&desc, &sg, 1);
335 if (ret < 0) {
336 pr_err("crypto_hash_update() failed for id\n");
337 crypto_free_hash(tfm);
338 goto out;
339 }
340
341 sg_init_one(&sg, auth->password_mutual,
342 strlen(auth->password_mutual));
343 ret = crypto_hash_update(&desc, &sg, strlen(auth->password_mutual));
344 if (ret < 0) {
345 pr_err("crypto_hash_update() failed for"
346 " password_mutual\n");
347 crypto_free_hash(tfm);
348 goto out;
349 }
350
351
352
353 sg_init_one(&sg, challenge_binhex, challenge_len);
354 ret = crypto_hash_update(&desc, &sg, challenge_len);
355 if (ret < 0) {
356 pr_err("crypto_hash_update() failed for ma challenge\n");
357 crypto_free_hash(tfm);
358 goto out;
359 }
360
361 ret = crypto_hash_final(&desc, digest);
362 if (ret < 0) {
363 pr_err("crypto_hash_final() failed for ma digest\n");
364 crypto_free_hash(tfm);
365 goto out;
366 }
367 crypto_free_hash(tfm);
368
369
370
371 *nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
372 *nr_out_len += 1;
373 pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
374
375
376
377 chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
378 *nr_out_len += sprintf(nr_out_ptr + *nr_out_len, "CHAP_R=0x%s",
379 response);
380 *nr_out_len += 1;
381 pr_debug("[server] Sending CHAP_R=0x%s\n", response);
382 auth_ret = 0;
383out:
384 kfree(challenge);
385 kfree(challenge_binhex);
386 return auth_ret;
387}
388
389static int chap_got_response(
390 struct iscsi_conn *conn,
391 struct iscsi_node_auth *auth,
392 char *nr_in_ptr,
393 char *nr_out_ptr,
394 unsigned int *nr_out_len)
395{
396 struct iscsi_chap *chap = conn->auth_protocol;
397
398 switch (chap->digest_type) {
399 case CHAP_DIGEST_MD5:
400 if (chap_server_compute_md5(conn, auth, nr_in_ptr,
401 nr_out_ptr, nr_out_len) < 0)
402 return -1;
403 return 0;
404 default:
405 pr_err("Unknown CHAP digest type %d!\n",
406 chap->digest_type);
407 return -1;
408 }
409}
410
411u32 chap_main_loop(
412 struct iscsi_conn *conn,
413 struct iscsi_node_auth *auth,
414 char *in_text,
415 char *out_text,
416 int *in_len,
417 int *out_len)
418{
419 struct iscsi_chap *chap = conn->auth_protocol;
420
421 if (!chap) {
422 chap = chap_server_open(conn, auth, in_text, out_text, out_len);
423 if (!chap)
424 return 2;
425 chap->chap_state = CHAP_STAGE_SERVER_AIC;
426 return 0;
427 } else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
428 convert_null_to_semi(in_text, *in_len);
429 if (chap_got_response(conn, auth, in_text, out_text,
430 out_len) < 0) {
431 chap_close(conn);
432 return 2;
433 }
434 if (auth->authenticate_target)
435 chap->chap_state = CHAP_STAGE_SERVER_NR;
436 else
437 *out_len = 0;
438 chap_close(conn);
439 return 1;
440 }
441
442 return 2;
443}
444
