Commit | Line | Data |
---|---|---|
17926a79 DH |
1 | /* Kerberos-based RxRPC security |
2 | * | |
3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
1afe593b | 12 | #include <crypto/skcipher.h> |
17926a79 DH |
13 | #include <linux/module.h> |
14 | #include <linux/net.h> | |
15 | #include <linux/skbuff.h> | |
16 | #include <linux/udp.h> | |
17926a79 DH |
17 | #include <linux/scatterlist.h> |
18 | #include <linux/ctype.h> | |
5a0e3ad6 | 19 | #include <linux/slab.h> |
17926a79 DH |
20 | #include <net/sock.h> |
21 | #include <net/af_rxrpc.h> | |
33941284 | 22 | #include <keys/rxrpc-type.h> |
17926a79 DH |
23 | #include "ar-internal.h" |
24 | ||
25 | #define RXKAD_VERSION 2 | |
26 | #define MAXKRB5TICKETLEN 1024 | |
27 | #define RXKAD_TKT_TYPE_KERBEROS_V5 256 | |
28 | #define ANAME_SZ 40 /* size of authentication name */ | |
29 | #define INST_SZ 40 /* size of principal's instance */ | |
30 | #define REALM_SZ 40 /* size of principal's auth domain */ | |
31 | #define SNAME_SZ 40 /* size of service name */ | |
32 | ||
17926a79 DH |
33 | struct rxkad_level1_hdr { |
34 | __be32 data_size; /* true data size (excluding padding) */ | |
35 | }; | |
36 | ||
37 | struct rxkad_level2_hdr { | |
38 | __be32 data_size; /* true data size (excluding padding) */ | |
39 | __be32 checksum; /* decrypted data checksum */ | |
40 | }; | |
41 | ||
17926a79 DH |
42 | /* |
43 | * this holds a pinned cipher so that keventd doesn't get called by the cipher | |
44 | * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE | |
45 | * packets | |
46 | */ | |
1afe593b | 47 | static struct crypto_skcipher *rxkad_ci; |
17926a79 DH |
48 | static DEFINE_MUTEX(rxkad_ci_mutex); |
49 | ||
50 | /* | |
51 | * initialise connection security | |
52 | */ | |
53 | static int rxkad_init_connection_security(struct rxrpc_connection *conn) | |
54 | { | |
1afe593b | 55 | struct crypto_skcipher *ci; |
33941284 | 56 | struct rxrpc_key_token *token; |
17926a79 DH |
57 | int ret; |
58 | ||
59 | _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key)); | |
60 | ||
146aa8b1 | 61 | token = conn->key->payload.data[0]; |
33941284 | 62 | conn->security_ix = token->security_index; |
17926a79 | 63 | |
1afe593b | 64 | ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC); |
17926a79 DH |
65 | if (IS_ERR(ci)) { |
66 | _debug("no cipher"); | |
67 | ret = PTR_ERR(ci); | |
68 | goto error; | |
69 | } | |
70 | ||
1afe593b HX |
71 | if (crypto_skcipher_setkey(ci, token->kad->session_key, |
72 | sizeof(token->kad->session_key)) < 0) | |
17926a79 DH |
73 | BUG(); |
74 | ||
75 | switch (conn->security_level) { | |
76 | case RXRPC_SECURITY_PLAIN: | |
77 | break; | |
78 | case RXRPC_SECURITY_AUTH: | |
79 | conn->size_align = 8; | |
80 | conn->security_size = sizeof(struct rxkad_level1_hdr); | |
81 | conn->header_size += sizeof(struct rxkad_level1_hdr); | |
82 | break; | |
83 | case RXRPC_SECURITY_ENCRYPT: | |
84 | conn->size_align = 8; | |
85 | conn->security_size = sizeof(struct rxkad_level2_hdr); | |
86 | conn->header_size += sizeof(struct rxkad_level2_hdr); | |
87 | break; | |
88 | default: | |
89 | ret = -EKEYREJECTED; | |
90 | goto error; | |
91 | } | |
92 | ||
93 | conn->cipher = ci; | |
94 | ret = 0; | |
95 | error: | |
96 | _leave(" = %d", ret); | |
97 | return ret; | |
98 | } | |
99 | ||
100 | /* | |
101 | * prime the encryption state with the invariant parts of a connection's | |
102 | * description | |
103 | */ | |
104 | static void rxkad_prime_packet_security(struct rxrpc_connection *conn) | |
105 | { | |
33941284 | 106 | struct rxrpc_key_token *token; |
1afe593b | 107 | SKCIPHER_REQUEST_ON_STACK(req, conn->cipher); |
17926a79 DH |
108 | struct scatterlist sg[2]; |
109 | struct rxrpc_crypt iv; | |
110 | struct { | |
111 | __be32 x[4]; | |
112 | } tmpbuf __attribute__((aligned(16))); /* must all be in same page */ | |
113 | ||
114 | _enter(""); | |
115 | ||
116 | if (!conn->key) | |
117 | return; | |
118 | ||
146aa8b1 | 119 | token = conn->key->payload.data[0]; |
33941284 | 120 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 121 | |
0d12f8a4 DH |
122 | tmpbuf.x[0] = htonl(conn->epoch); |
123 | tmpbuf.x[1] = htonl(conn->cid); | |
17926a79 DH |
124 | tmpbuf.x[2] = 0; |
125 | tmpbuf.x[3] = htonl(conn->security_ix); | |
126 | ||
68e3f5dd HX |
127 | sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf)); |
128 | sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf)); | |
1afe593b HX |
129 | |
130 | skcipher_request_set_tfm(req, conn->cipher); | |
131 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
132 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x); | |
133 | ||
134 | crypto_skcipher_encrypt(req); | |
135 | skcipher_request_zero(req); | |
17926a79 DH |
136 | |
137 | memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv)); | |
2b15ef15 | 138 | ASSERTCMP((u32 __force)conn->csum_iv.n[0], ==, (u32 __force)tmpbuf.x[2]); |
17926a79 DH |
139 | |
140 | _leave(""); | |
141 | } | |
142 | ||
143 | /* | |
144 | * partially encrypt a packet (level 1 security) | |
145 | */ | |
146 | static int rxkad_secure_packet_auth(const struct rxrpc_call *call, | |
147 | struct sk_buff *skb, | |
148 | u32 data_size, | |
149 | void *sechdr) | |
150 | { | |
151 | struct rxrpc_skb_priv *sp; | |
1afe593b | 152 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
153 | struct rxrpc_crypt iv; |
154 | struct scatterlist sg[2]; | |
155 | struct { | |
156 | struct rxkad_level1_hdr hdr; | |
157 | __be32 first; /* first four bytes of data and padding */ | |
158 | } tmpbuf __attribute__((aligned(8))); /* must all be in same page */ | |
159 | u16 check; | |
160 | ||
161 | sp = rxrpc_skb(skb); | |
162 | ||
163 | _enter(""); | |
164 | ||
0d12f8a4 DH |
165 | check = sp->hdr.seq ^ sp->hdr.callNumber; |
166 | data_size |= (u32)check << 16; | |
17926a79 DH |
167 | |
168 | tmpbuf.hdr.data_size = htonl(data_size); | |
169 | memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first)); | |
170 | ||
171 | /* start the encryption afresh */ | |
172 | memset(&iv, 0, sizeof(iv)); | |
17926a79 | 173 | |
68e3f5dd HX |
174 | sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf)); |
175 | sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf)); | |
1afe593b HX |
176 | |
177 | skcipher_request_set_tfm(req, call->conn->cipher); | |
178 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
179 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x); | |
180 | ||
181 | crypto_skcipher_encrypt(req); | |
182 | skcipher_request_zero(req); | |
17926a79 DH |
183 | |
184 | memcpy(sechdr, &tmpbuf, sizeof(tmpbuf)); | |
185 | ||
186 | _leave(" = 0"); | |
187 | return 0; | |
188 | } | |
189 | ||
190 | /* | |
191 | * wholly encrypt a packet (level 2 security) | |
192 | */ | |
193 | static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call, | |
b4f1342f DH |
194 | struct sk_buff *skb, |
195 | u32 data_size, | |
196 | void *sechdr) | |
17926a79 | 197 | { |
33941284 | 198 | const struct rxrpc_key_token *token; |
17926a79 DH |
199 | struct rxkad_level2_hdr rxkhdr |
200 | __attribute__((aligned(8))); /* must be all on one page */ | |
201 | struct rxrpc_skb_priv *sp; | |
1afe593b | 202 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
203 | struct rxrpc_crypt iv; |
204 | struct scatterlist sg[16]; | |
205 | struct sk_buff *trailer; | |
95c96174 | 206 | unsigned int len; |
17926a79 DH |
207 | u16 check; |
208 | int nsg; | |
1afe593b | 209 | int err; |
17926a79 DH |
210 | |
211 | sp = rxrpc_skb(skb); | |
212 | ||
213 | _enter(""); | |
214 | ||
0d12f8a4 | 215 | check = sp->hdr.seq ^ sp->hdr.callNumber; |
17926a79 | 216 | |
0d12f8a4 | 217 | rxkhdr.data_size = htonl(data_size | (u32)check << 16); |
17926a79 DH |
218 | rxkhdr.checksum = 0; |
219 | ||
220 | /* encrypt from the session key */ | |
146aa8b1 | 221 | token = call->conn->key->payload.data[0]; |
33941284 | 222 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 223 | |
68e3f5dd HX |
224 | sg_init_one(&sg[0], sechdr, sizeof(rxkhdr)); |
225 | sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr)); | |
1afe593b HX |
226 | |
227 | skcipher_request_set_tfm(req, call->conn->cipher); | |
228 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
229 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(rxkhdr), iv.x); | |
230 | ||
231 | crypto_skcipher_encrypt(req); | |
17926a79 DH |
232 | |
233 | /* we want to encrypt the skbuff in-place */ | |
234 | nsg = skb_cow_data(skb, 0, &trailer); | |
1afe593b | 235 | err = -ENOMEM; |
17926a79 | 236 | if (nsg < 0 || nsg > 16) |
1afe593b | 237 | goto out; |
17926a79 DH |
238 | |
239 | len = data_size + call->conn->size_align - 1; | |
240 | len &= ~(call->conn->size_align - 1); | |
241 | ||
51c739d1 DM |
242 | sg_init_table(sg, nsg); |
243 | skb_to_sgvec(skb, sg, 0, len); | |
1afe593b HX |
244 | |
245 | skcipher_request_set_crypt(req, sg, sg, len, iv.x); | |
246 | ||
247 | crypto_skcipher_encrypt(req); | |
17926a79 DH |
248 | |
249 | _leave(" = 0"); | |
1afe593b HX |
250 | err = 0; |
251 | ||
252 | out: | |
253 | skcipher_request_zero(req); | |
254 | return err; | |
17926a79 DH |
255 | } |
256 | ||
257 | /* | |
258 | * checksum an RxRPC packet header | |
259 | */ | |
260 | static int rxkad_secure_packet(const struct rxrpc_call *call, | |
b4f1342f DH |
261 | struct sk_buff *skb, |
262 | size_t data_size, | |
263 | void *sechdr) | |
17926a79 DH |
264 | { |
265 | struct rxrpc_skb_priv *sp; | |
1afe593b | 266 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
267 | struct rxrpc_crypt iv; |
268 | struct scatterlist sg[2]; | |
269 | struct { | |
270 | __be32 x[2]; | |
271 | } tmpbuf __attribute__((aligned(8))); /* must all be in same page */ | |
0d12f8a4 | 272 | u32 x, y; |
17926a79 DH |
273 | int ret; |
274 | ||
275 | sp = rxrpc_skb(skb); | |
276 | ||
277 | _enter("{%d{%x}},{#%u},%zu,", | |
0d12f8a4 | 278 | call->debug_id, key_serial(call->conn->key), sp->hdr.seq, |
17926a79 DH |
279 | data_size); |
280 | ||
281 | if (!call->conn->cipher) | |
282 | return 0; | |
283 | ||
284 | ret = key_validate(call->conn->key); | |
285 | if (ret < 0) | |
286 | return ret; | |
287 | ||
288 | /* continue encrypting from where we left off */ | |
289 | memcpy(&iv, call->conn->csum_iv.x, sizeof(iv)); | |
17926a79 DH |
290 | |
291 | /* calculate the security checksum */ | |
0d12f8a4 DH |
292 | x = call->channel << (32 - RXRPC_CIDSHIFT); |
293 | x |= sp->hdr.seq & 0x3fffffff; | |
294 | tmpbuf.x[0] = htonl(sp->hdr.callNumber); | |
295 | tmpbuf.x[1] = htonl(x); | |
17926a79 | 296 | |
68e3f5dd HX |
297 | sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf)); |
298 | sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf)); | |
1afe593b HX |
299 | |
300 | skcipher_request_set_tfm(req, call->conn->cipher); | |
301 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
302 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x); | |
303 | ||
304 | crypto_skcipher_encrypt(req); | |
305 | skcipher_request_zero(req); | |
17926a79 | 306 | |
91e916cf AV |
307 | y = ntohl(tmpbuf.x[1]); |
308 | y = (y >> 16) & 0xffff; | |
309 | if (y == 0) | |
310 | y = 1; /* zero checksums are not permitted */ | |
0d12f8a4 | 311 | sp->hdr.cksum = y; |
17926a79 DH |
312 | |
313 | switch (call->conn->security_level) { | |
314 | case RXRPC_SECURITY_PLAIN: | |
315 | ret = 0; | |
316 | break; | |
317 | case RXRPC_SECURITY_AUTH: | |
318 | ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr); | |
319 | break; | |
320 | case RXRPC_SECURITY_ENCRYPT: | |
321 | ret = rxkad_secure_packet_encrypt(call, skb, data_size, | |
322 | sechdr); | |
323 | break; | |
324 | default: | |
325 | ret = -EPERM; | |
326 | break; | |
327 | } | |
328 | ||
91e916cf | 329 | _leave(" = %d [set %hx]", ret, y); |
17926a79 DH |
330 | return ret; |
331 | } | |
332 | ||
333 | /* | |
334 | * decrypt partial encryption on a packet (level 1 security) | |
335 | */ | |
336 | static int rxkad_verify_packet_auth(const struct rxrpc_call *call, | |
337 | struct sk_buff *skb, | |
338 | u32 *_abort_code) | |
339 | { | |
340 | struct rxkad_level1_hdr sechdr; | |
341 | struct rxrpc_skb_priv *sp; | |
1afe593b | 342 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 | 343 | struct rxrpc_crypt iv; |
68e3f5dd | 344 | struct scatterlist sg[16]; |
17926a79 DH |
345 | struct sk_buff *trailer; |
346 | u32 data_size, buf; | |
347 | u16 check; | |
68e3f5dd | 348 | int nsg; |
17926a79 DH |
349 | |
350 | _enter(""); | |
351 | ||
352 | sp = rxrpc_skb(skb); | |
353 | ||
354 | /* we want to decrypt the skbuff in-place */ | |
68e3f5dd HX |
355 | nsg = skb_cow_data(skb, 0, &trailer); |
356 | if (nsg < 0 || nsg > 16) | |
17926a79 DH |
357 | goto nomem; |
358 | ||
68e3f5dd | 359 | sg_init_table(sg, nsg); |
51c739d1 | 360 | skb_to_sgvec(skb, sg, 0, 8); |
17926a79 DH |
361 | |
362 | /* start the decryption afresh */ | |
363 | memset(&iv, 0, sizeof(iv)); | |
17926a79 | 364 | |
1afe593b HX |
365 | skcipher_request_set_tfm(req, call->conn->cipher); |
366 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
367 | skcipher_request_set_crypt(req, sg, sg, 8, iv.x); | |
368 | ||
369 | crypto_skcipher_decrypt(req); | |
370 | skcipher_request_zero(req); | |
17926a79 DH |
371 | |
372 | /* remove the decrypted packet length */ | |
373 | if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0) | |
374 | goto datalen_error; | |
375 | if (!skb_pull(skb, sizeof(sechdr))) | |
376 | BUG(); | |
377 | ||
378 | buf = ntohl(sechdr.data_size); | |
379 | data_size = buf & 0xffff; | |
380 | ||
381 | check = buf >> 16; | |
0d12f8a4 | 382 | check ^= sp->hdr.seq ^ sp->hdr.callNumber; |
17926a79 DH |
383 | check &= 0xffff; |
384 | if (check != 0) { | |
385 | *_abort_code = RXKADSEALEDINCON; | |
386 | goto protocol_error; | |
387 | } | |
388 | ||
389 | /* shorten the packet to remove the padding */ | |
390 | if (data_size > skb->len) | |
391 | goto datalen_error; | |
392 | else if (data_size < skb->len) | |
393 | skb->len = data_size; | |
394 | ||
395 | _leave(" = 0 [dlen=%x]", data_size); | |
396 | return 0; | |
397 | ||
398 | datalen_error: | |
399 | *_abort_code = RXKADDATALEN; | |
400 | protocol_error: | |
401 | _leave(" = -EPROTO"); | |
402 | return -EPROTO; | |
403 | ||
404 | nomem: | |
405 | _leave(" = -ENOMEM"); | |
406 | return -ENOMEM; | |
407 | } | |
408 | ||
409 | /* | |
410 | * wholly decrypt a packet (level 2 security) | |
411 | */ | |
412 | static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call, | |
413 | struct sk_buff *skb, | |
414 | u32 *_abort_code) | |
415 | { | |
33941284 | 416 | const struct rxrpc_key_token *token; |
17926a79 DH |
417 | struct rxkad_level2_hdr sechdr; |
418 | struct rxrpc_skb_priv *sp; | |
1afe593b | 419 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
420 | struct rxrpc_crypt iv; |
421 | struct scatterlist _sg[4], *sg; | |
422 | struct sk_buff *trailer; | |
423 | u32 data_size, buf; | |
424 | u16 check; | |
425 | int nsg; | |
426 | ||
427 | _enter(",{%d}", skb->len); | |
428 | ||
429 | sp = rxrpc_skb(skb); | |
430 | ||
431 | /* we want to decrypt the skbuff in-place */ | |
432 | nsg = skb_cow_data(skb, 0, &trailer); | |
433 | if (nsg < 0) | |
434 | goto nomem; | |
435 | ||
436 | sg = _sg; | |
437 | if (unlikely(nsg > 4)) { | |
438 | sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO); | |
439 | if (!sg) | |
440 | goto nomem; | |
441 | } | |
442 | ||
68e3f5dd | 443 | sg_init_table(sg, nsg); |
51c739d1 | 444 | skb_to_sgvec(skb, sg, 0, skb->len); |
17926a79 DH |
445 | |
446 | /* decrypt from the session key */ | |
146aa8b1 | 447 | token = call->conn->key->payload.data[0]; |
33941284 | 448 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 449 | |
1afe593b HX |
450 | skcipher_request_set_tfm(req, call->conn->cipher); |
451 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
452 | skcipher_request_set_crypt(req, sg, sg, skb->len, iv.x); | |
453 | ||
454 | crypto_skcipher_decrypt(req); | |
455 | skcipher_request_zero(req); | |
17926a79 DH |
456 | if (sg != _sg) |
457 | kfree(sg); | |
458 | ||
459 | /* remove the decrypted packet length */ | |
460 | if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0) | |
461 | goto datalen_error; | |
462 | if (!skb_pull(skb, sizeof(sechdr))) | |
463 | BUG(); | |
464 | ||
465 | buf = ntohl(sechdr.data_size); | |
466 | data_size = buf & 0xffff; | |
467 | ||
468 | check = buf >> 16; | |
0d12f8a4 | 469 | check ^= sp->hdr.seq ^ sp->hdr.callNumber; |
17926a79 DH |
470 | check &= 0xffff; |
471 | if (check != 0) { | |
472 | *_abort_code = RXKADSEALEDINCON; | |
473 | goto protocol_error; | |
474 | } | |
475 | ||
476 | /* shorten the packet to remove the padding */ | |
477 | if (data_size > skb->len) | |
478 | goto datalen_error; | |
479 | else if (data_size < skb->len) | |
480 | skb->len = data_size; | |
481 | ||
482 | _leave(" = 0 [dlen=%x]", data_size); | |
483 | return 0; | |
484 | ||
485 | datalen_error: | |
486 | *_abort_code = RXKADDATALEN; | |
487 | protocol_error: | |
488 | _leave(" = -EPROTO"); | |
489 | return -EPROTO; | |
490 | ||
491 | nomem: | |
492 | _leave(" = -ENOMEM"); | |
493 | return -ENOMEM; | |
494 | } | |
495 | ||
496 | /* | |
497 | * verify the security on a received packet | |
498 | */ | |
499 | static int rxkad_verify_packet(const struct rxrpc_call *call, | |
500 | struct sk_buff *skb, | |
501 | u32 *_abort_code) | |
502 | { | |
1afe593b | 503 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
504 | struct rxrpc_skb_priv *sp; |
505 | struct rxrpc_crypt iv; | |
506 | struct scatterlist sg[2]; | |
507 | struct { | |
508 | __be32 x[2]; | |
509 | } tmpbuf __attribute__((aligned(8))); /* must all be in same page */ | |
0d12f8a4 DH |
510 | u16 cksum; |
511 | u32 x, y; | |
17926a79 DH |
512 | int ret; |
513 | ||
514 | sp = rxrpc_skb(skb); | |
515 | ||
516 | _enter("{%d{%x}},{#%u}", | |
0d12f8a4 | 517 | call->debug_id, key_serial(call->conn->key), sp->hdr.seq); |
17926a79 DH |
518 | |
519 | if (!call->conn->cipher) | |
520 | return 0; | |
521 | ||
8b815477 | 522 | if (sp->hdr.securityIndex != RXRPC_SECURITY_RXKAD) { |
17926a79 DH |
523 | *_abort_code = RXKADINCONSISTENCY; |
524 | _leave(" = -EPROTO [not rxkad]"); | |
525 | return -EPROTO; | |
526 | } | |
527 | ||
528 | /* continue encrypting from where we left off */ | |
529 | memcpy(&iv, call->conn->csum_iv.x, sizeof(iv)); | |
17926a79 DH |
530 | |
531 | /* validate the security checksum */ | |
0d12f8a4 DH |
532 | x = call->channel << (32 - RXRPC_CIDSHIFT); |
533 | x |= sp->hdr.seq & 0x3fffffff; | |
534 | tmpbuf.x[0] = htonl(call->call_id); | |
535 | tmpbuf.x[1] = htonl(x); | |
17926a79 | 536 | |
68e3f5dd HX |
537 | sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf)); |
538 | sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf)); | |
1afe593b HX |
539 | |
540 | skcipher_request_set_tfm(req, call->conn->cipher); | |
541 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
542 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x); | |
543 | ||
544 | crypto_skcipher_encrypt(req); | |
545 | skcipher_request_zero(req); | |
17926a79 | 546 | |
91e916cf | 547 | y = ntohl(tmpbuf.x[1]); |
0d12f8a4 DH |
548 | cksum = (y >> 16) & 0xffff; |
549 | if (cksum == 0) | |
550 | cksum = 1; /* zero checksums are not permitted */ | |
17926a79 | 551 | |
17926a79 DH |
552 | if (sp->hdr.cksum != cksum) { |
553 | *_abort_code = RXKADSEALEDINCON; | |
554 | _leave(" = -EPROTO [csum failed]"); | |
555 | return -EPROTO; | |
556 | } | |
557 | ||
558 | switch (call->conn->security_level) { | |
559 | case RXRPC_SECURITY_PLAIN: | |
560 | ret = 0; | |
561 | break; | |
562 | case RXRPC_SECURITY_AUTH: | |
563 | ret = rxkad_verify_packet_auth(call, skb, _abort_code); | |
564 | break; | |
565 | case RXRPC_SECURITY_ENCRYPT: | |
566 | ret = rxkad_verify_packet_encrypt(call, skb, _abort_code); | |
567 | break; | |
568 | default: | |
569 | ret = -ENOANO; | |
570 | break; | |
571 | } | |
572 | ||
573 | _leave(" = %d", ret); | |
574 | return ret; | |
575 | } | |
576 | ||
577 | /* | |
578 | * issue a challenge | |
579 | */ | |
580 | static int rxkad_issue_challenge(struct rxrpc_connection *conn) | |
581 | { | |
582 | struct rxkad_challenge challenge; | |
0d12f8a4 | 583 | struct rxrpc_wire_header whdr; |
17926a79 DH |
584 | struct msghdr msg; |
585 | struct kvec iov[2]; | |
586 | size_t len; | |
0d12f8a4 | 587 | u32 serial; |
17926a79 DH |
588 | int ret; |
589 | ||
590 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->key)); | |
591 | ||
592 | ret = key_validate(conn->key); | |
593 | if (ret < 0) | |
594 | return ret; | |
595 | ||
596 | get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce)); | |
597 | ||
598 | challenge.version = htonl(2); | |
599 | challenge.nonce = htonl(conn->security_nonce); | |
600 | challenge.min_level = htonl(0); | |
601 | challenge.__padding = 0; | |
602 | ||
603 | msg.msg_name = &conn->trans->peer->srx.transport.sin; | |
604 | msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin); | |
605 | msg.msg_control = NULL; | |
606 | msg.msg_controllen = 0; | |
607 | msg.msg_flags = 0; | |
608 | ||
0d12f8a4 DH |
609 | whdr.epoch = htonl(conn->epoch); |
610 | whdr.cid = htonl(conn->cid); | |
611 | whdr.callNumber = 0; | |
612 | whdr.seq = 0; | |
613 | whdr.type = RXRPC_PACKET_TYPE_CHALLENGE; | |
614 | whdr.flags = conn->out_clientflag; | |
615 | whdr.userStatus = 0; | |
616 | whdr.securityIndex = conn->security_ix; | |
617 | whdr._rsvd = 0; | |
618 | whdr.serviceId = htons(conn->service_id); | |
619 | ||
620 | iov[0].iov_base = &whdr; | |
621 | iov[0].iov_len = sizeof(whdr); | |
17926a79 DH |
622 | iov[1].iov_base = &challenge; |
623 | iov[1].iov_len = sizeof(challenge); | |
624 | ||
625 | len = iov[0].iov_len + iov[1].iov_len; | |
626 | ||
0d12f8a4 DH |
627 | serial = atomic_inc_return(&conn->serial); |
628 | whdr.serial = htonl(serial); | |
629 | _proto("Tx CHALLENGE %%%u", serial); | |
17926a79 DH |
630 | |
631 | ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len); | |
632 | if (ret < 0) { | |
633 | _debug("sendmsg failed: %d", ret); | |
634 | return -EAGAIN; | |
635 | } | |
636 | ||
637 | _leave(" = 0"); | |
638 | return 0; | |
639 | } | |
640 | ||
641 | /* | |
642 | * send a Kerberos security response | |
643 | */ | |
644 | static int rxkad_send_response(struct rxrpc_connection *conn, | |
0d12f8a4 | 645 | struct rxrpc_host_header *hdr, |
17926a79 DH |
646 | struct rxkad_response *resp, |
647 | const struct rxkad_key *s2) | |
648 | { | |
0d12f8a4 | 649 | struct rxrpc_wire_header whdr; |
17926a79 DH |
650 | struct msghdr msg; |
651 | struct kvec iov[3]; | |
652 | size_t len; | |
0d12f8a4 | 653 | u32 serial; |
17926a79 DH |
654 | int ret; |
655 | ||
656 | _enter(""); | |
657 | ||
658 | msg.msg_name = &conn->trans->peer->srx.transport.sin; | |
659 | msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin); | |
660 | msg.msg_control = NULL; | |
661 | msg.msg_controllen = 0; | |
662 | msg.msg_flags = 0; | |
663 | ||
0d12f8a4 DH |
664 | memset(&whdr, 0, sizeof(whdr)); |
665 | whdr.epoch = htonl(hdr->epoch); | |
666 | whdr.cid = htonl(hdr->cid); | |
667 | whdr.type = RXRPC_PACKET_TYPE_RESPONSE; | |
668 | whdr.flags = conn->out_clientflag; | |
669 | whdr.securityIndex = hdr->securityIndex; | |
670 | whdr.serviceId = htons(hdr->serviceId); | |
17926a79 | 671 | |
0d12f8a4 DH |
672 | iov[0].iov_base = &whdr; |
673 | iov[0].iov_len = sizeof(whdr); | |
17926a79 DH |
674 | iov[1].iov_base = resp; |
675 | iov[1].iov_len = sizeof(*resp); | |
0d12f8a4 | 676 | iov[2].iov_base = (void *)s2->ticket; |
17926a79 DH |
677 | iov[2].iov_len = s2->ticket_len; |
678 | ||
679 | len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len; | |
680 | ||
0d12f8a4 DH |
681 | serial = atomic_inc_return(&conn->serial); |
682 | whdr.serial = htonl(serial); | |
683 | _proto("Tx RESPONSE %%%u", serial); | |
17926a79 DH |
684 | |
685 | ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 3, len); | |
686 | if (ret < 0) { | |
687 | _debug("sendmsg failed: %d", ret); | |
688 | return -EAGAIN; | |
689 | } | |
690 | ||
691 | _leave(" = 0"); | |
692 | return 0; | |
693 | } | |
694 | ||
695 | /* | |
696 | * calculate the response checksum | |
697 | */ | |
698 | static void rxkad_calc_response_checksum(struct rxkad_response *response) | |
699 | { | |
700 | u32 csum = 1000003; | |
701 | int loop; | |
702 | u8 *p = (u8 *) response; | |
703 | ||
704 | for (loop = sizeof(*response); loop > 0; loop--) | |
705 | csum = csum * 0x10204081 + *p++; | |
706 | ||
707 | response->encrypted.checksum = htonl(csum); | |
708 | } | |
709 | ||
710 | /* | |
711 | * load a scatterlist with a potentially split-page buffer | |
712 | */ | |
713 | static void rxkad_sg_set_buf2(struct scatterlist sg[2], | |
714 | void *buf, size_t buflen) | |
715 | { | |
68e3f5dd | 716 | int nsg = 1; |
17926a79 | 717 | |
68e3f5dd | 718 | sg_init_table(sg, 2); |
17926a79 DH |
719 | |
720 | sg_set_buf(&sg[0], buf, buflen); | |
721 | if (sg[0].offset + buflen > PAGE_SIZE) { | |
722 | /* the buffer was split over two pages */ | |
723 | sg[0].length = PAGE_SIZE - sg[0].offset; | |
724 | sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length); | |
68e3f5dd | 725 | nsg++; |
17926a79 DH |
726 | } |
727 | ||
c46f2334 | 728 | sg_mark_end(&sg[nsg - 1]); |
68e3f5dd | 729 | |
17926a79 DH |
730 | ASSERTCMP(sg[0].length + sg[1].length, ==, buflen); |
731 | } | |
732 | ||
733 | /* | |
734 | * encrypt the response packet | |
735 | */ | |
736 | static void rxkad_encrypt_response(struct rxrpc_connection *conn, | |
737 | struct rxkad_response *resp, | |
738 | const struct rxkad_key *s2) | |
739 | { | |
1afe593b | 740 | SKCIPHER_REQUEST_ON_STACK(req, conn->cipher); |
17926a79 | 741 | struct rxrpc_crypt iv; |
68e3f5dd | 742 | struct scatterlist sg[2]; |
17926a79 DH |
743 | |
744 | /* continue encrypting from where we left off */ | |
745 | memcpy(&iv, s2->session_key, sizeof(iv)); | |
17926a79 | 746 | |
68e3f5dd | 747 | rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted)); |
1afe593b HX |
748 | |
749 | skcipher_request_set_tfm(req, conn->cipher); | |
750 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
751 | skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x); | |
752 | ||
753 | crypto_skcipher_encrypt(req); | |
754 | skcipher_request_zero(req); | |
17926a79 DH |
755 | } |
756 | ||
757 | /* | |
758 | * respond to a challenge packet | |
759 | */ | |
760 | static int rxkad_respond_to_challenge(struct rxrpc_connection *conn, | |
761 | struct sk_buff *skb, | |
762 | u32 *_abort_code) | |
763 | { | |
33941284 | 764 | const struct rxrpc_key_token *token; |
17926a79 DH |
765 | struct rxkad_challenge challenge; |
766 | struct rxkad_response resp | |
767 | __attribute__((aligned(8))); /* must be aligned for crypto */ | |
768 | struct rxrpc_skb_priv *sp; | |
769 | u32 version, nonce, min_level, abort_code; | |
770 | int ret; | |
771 | ||
772 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->key)); | |
773 | ||
774 | if (!conn->key) { | |
775 | _leave(" = -EPROTO [no key]"); | |
776 | return -EPROTO; | |
777 | } | |
778 | ||
779 | ret = key_validate(conn->key); | |
780 | if (ret < 0) { | |
781 | *_abort_code = RXKADEXPIRED; | |
782 | return ret; | |
783 | } | |
784 | ||
785 | abort_code = RXKADPACKETSHORT; | |
786 | sp = rxrpc_skb(skb); | |
787 | if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0) | |
788 | goto protocol_error; | |
789 | ||
790 | version = ntohl(challenge.version); | |
791 | nonce = ntohl(challenge.nonce); | |
792 | min_level = ntohl(challenge.min_level); | |
793 | ||
794 | _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }", | |
0d12f8a4 | 795 | sp->hdr.serial, version, nonce, min_level); |
17926a79 DH |
796 | |
797 | abort_code = RXKADINCONSISTENCY; | |
798 | if (version != RXKAD_VERSION) | |
799 | goto protocol_error; | |
800 | ||
801 | abort_code = RXKADLEVELFAIL; | |
802 | if (conn->security_level < min_level) | |
803 | goto protocol_error; | |
804 | ||
146aa8b1 | 805 | token = conn->key->payload.data[0]; |
17926a79 DH |
806 | |
807 | /* build the response packet */ | |
808 | memset(&resp, 0, sizeof(resp)); | |
809 | ||
098a2099 DH |
810 | resp.version = htonl(RXKAD_VERSION); |
811 | resp.encrypted.epoch = htonl(conn->epoch); | |
812 | resp.encrypted.cid = htonl(conn->cid); | |
813 | resp.encrypted.securityIndex = htonl(conn->security_ix); | |
814 | resp.encrypted.inc_nonce = htonl(nonce + 1); | |
815 | resp.encrypted.level = htonl(conn->security_level); | |
816 | resp.kvno = htonl(token->kad->kvno); | |
817 | resp.ticket_len = htonl(token->kad->ticket_len); | |
818 | ||
17926a79 | 819 | resp.encrypted.call_id[0] = |
0d12f8a4 | 820 | htonl(conn->channels[0] ? conn->channels[0]->call_id : 0); |
17926a79 | 821 | resp.encrypted.call_id[1] = |
0d12f8a4 | 822 | htonl(conn->channels[1] ? conn->channels[1]->call_id : 0); |
17926a79 | 823 | resp.encrypted.call_id[2] = |
0d12f8a4 | 824 | htonl(conn->channels[2] ? conn->channels[2]->call_id : 0); |
17926a79 | 825 | resp.encrypted.call_id[3] = |
0d12f8a4 | 826 | htonl(conn->channels[3] ? conn->channels[3]->call_id : 0); |
17926a79 DH |
827 | |
828 | /* calculate the response checksum and then do the encryption */ | |
829 | rxkad_calc_response_checksum(&resp); | |
33941284 DH |
830 | rxkad_encrypt_response(conn, &resp, token->kad); |
831 | return rxkad_send_response(conn, &sp->hdr, &resp, token->kad); | |
17926a79 DH |
832 | |
833 | protocol_error: | |
834 | *_abort_code = abort_code; | |
835 | _leave(" = -EPROTO [%d]", abort_code); | |
836 | return -EPROTO; | |
837 | } | |
838 | ||
839 | /* | |
840 | * decrypt the kerberos IV ticket in the response | |
841 | */ | |
842 | static int rxkad_decrypt_ticket(struct rxrpc_connection *conn, | |
843 | void *ticket, size_t ticket_len, | |
844 | struct rxrpc_crypt *_session_key, | |
845 | time_t *_expiry, | |
846 | u32 *_abort_code) | |
847 | { | |
1afe593b | 848 | struct skcipher_request *req; |
17926a79 | 849 | struct rxrpc_crypt iv, key; |
68e3f5dd | 850 | struct scatterlist sg[1]; |
17926a79 | 851 | struct in_addr addr; |
95c96174 | 852 | unsigned int life; |
17926a79 DH |
853 | time_t issue, now; |
854 | bool little_endian; | |
855 | int ret; | |
856 | u8 *p, *q, *name, *end; | |
857 | ||
858 | _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key)); | |
859 | ||
860 | *_expiry = 0; | |
861 | ||
862 | ret = key_validate(conn->server_key); | |
863 | if (ret < 0) { | |
864 | switch (ret) { | |
865 | case -EKEYEXPIRED: | |
866 | *_abort_code = RXKADEXPIRED; | |
867 | goto error; | |
868 | default: | |
869 | *_abort_code = RXKADNOAUTH; | |
870 | goto error; | |
871 | } | |
872 | } | |
873 | ||
146aa8b1 | 874 | ASSERT(conn->server_key->payload.data[0] != NULL); |
17926a79 DH |
875 | ASSERTCMP((unsigned long) ticket & 7UL, ==, 0); |
876 | ||
146aa8b1 | 877 | memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv)); |
17926a79 | 878 | |
1afe593b HX |
879 | req = skcipher_request_alloc(conn->server_key->payload.data[0], |
880 | GFP_NOFS); | |
881 | if (!req) { | |
882 | *_abort_code = RXKADNOAUTH; | |
883 | ret = -ENOMEM; | |
884 | goto error; | |
885 | } | |
17926a79 | 886 | |
68e3f5dd | 887 | sg_init_one(&sg[0], ticket, ticket_len); |
1afe593b HX |
888 | |
889 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
890 | skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x); | |
891 | ||
892 | crypto_skcipher_decrypt(req); | |
893 | skcipher_request_free(req); | |
17926a79 DH |
894 | |
895 | p = ticket; | |
896 | end = p + ticket_len; | |
897 | ||
898 | #define Z(size) \ | |
899 | ({ \ | |
900 | u8 *__str = p; \ | |
901 | q = memchr(p, 0, end - p); \ | |
902 | if (!q || q - p > (size)) \ | |
903 | goto bad_ticket; \ | |
904 | for (; p < q; p++) \ | |
905 | if (!isprint(*p)) \ | |
906 | goto bad_ticket; \ | |
907 | p++; \ | |
908 | __str; \ | |
909 | }) | |
910 | ||
911 | /* extract the ticket flags */ | |
912 | _debug("KIV FLAGS: %x", *p); | |
913 | little_endian = *p & 1; | |
914 | p++; | |
915 | ||
916 | /* extract the authentication name */ | |
917 | name = Z(ANAME_SZ); | |
918 | _debug("KIV ANAME: %s", name); | |
919 | ||
920 | /* extract the principal's instance */ | |
921 | name = Z(INST_SZ); | |
922 | _debug("KIV INST : %s", name); | |
923 | ||
924 | /* extract the principal's authentication domain */ | |
925 | name = Z(REALM_SZ); | |
926 | _debug("KIV REALM: %s", name); | |
927 | ||
928 | if (end - p < 4 + 8 + 4 + 2) | |
929 | goto bad_ticket; | |
930 | ||
931 | /* get the IPv4 address of the entity that requested the ticket */ | |
932 | memcpy(&addr, p, sizeof(addr)); | |
933 | p += 4; | |
21454aaa | 934 | _debug("KIV ADDR : %pI4", &addr); |
17926a79 DH |
935 | |
936 | /* get the session key from the ticket */ | |
937 | memcpy(&key, p, sizeof(key)); | |
938 | p += 8; | |
939 | _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1])); | |
940 | memcpy(_session_key, &key, sizeof(key)); | |
941 | ||
942 | /* get the ticket's lifetime */ | |
943 | life = *p++ * 5 * 60; | |
944 | _debug("KIV LIFE : %u", life); | |
945 | ||
946 | /* get the issue time of the ticket */ | |
947 | if (little_endian) { | |
948 | __le32 stamp; | |
949 | memcpy(&stamp, p, 4); | |
950 | issue = le32_to_cpu(stamp); | |
951 | } else { | |
952 | __be32 stamp; | |
953 | memcpy(&stamp, p, 4); | |
954 | issue = be32_to_cpu(stamp); | |
955 | } | |
956 | p += 4; | |
2c6b47de | 957 | now = get_seconds(); |
17926a79 DH |
958 | _debug("KIV ISSUE: %lx [%lx]", issue, now); |
959 | ||
960 | /* check the ticket is in date */ | |
961 | if (issue > now) { | |
962 | *_abort_code = RXKADNOAUTH; | |
963 | ret = -EKEYREJECTED; | |
964 | goto error; | |
965 | } | |
966 | ||
967 | if (issue < now - life) { | |
968 | *_abort_code = RXKADEXPIRED; | |
969 | ret = -EKEYEXPIRED; | |
970 | goto error; | |
971 | } | |
972 | ||
973 | *_expiry = issue + life; | |
974 | ||
975 | /* get the service name */ | |
976 | name = Z(SNAME_SZ); | |
977 | _debug("KIV SNAME: %s", name); | |
978 | ||
979 | /* get the service instance name */ | |
980 | name = Z(INST_SZ); | |
981 | _debug("KIV SINST: %s", name); | |
982 | ||
983 | ret = 0; | |
984 | error: | |
985 | _leave(" = %d", ret); | |
986 | return ret; | |
987 | ||
988 | bad_ticket: | |
989 | *_abort_code = RXKADBADTICKET; | |
990 | ret = -EBADMSG; | |
991 | goto error; | |
992 | } | |
993 | ||
994 | /* | |
995 | * decrypt the response packet | |
996 | */ | |
997 | static void rxkad_decrypt_response(struct rxrpc_connection *conn, | |
998 | struct rxkad_response *resp, | |
999 | const struct rxrpc_crypt *session_key) | |
1000 | { | |
1afe593b | 1001 | SKCIPHER_REQUEST_ON_STACK(req, rxkad_ci); |
68e3f5dd | 1002 | struct scatterlist sg[2]; |
17926a79 DH |
1003 | struct rxrpc_crypt iv; |
1004 | ||
1005 | _enter(",,%08x%08x", | |
1006 | ntohl(session_key->n[0]), ntohl(session_key->n[1])); | |
1007 | ||
1008 | ASSERT(rxkad_ci != NULL); | |
1009 | ||
1010 | mutex_lock(&rxkad_ci_mutex); | |
1afe593b HX |
1011 | if (crypto_skcipher_setkey(rxkad_ci, session_key->x, |
1012 | sizeof(*session_key)) < 0) | |
17926a79 DH |
1013 | BUG(); |
1014 | ||
1015 | memcpy(&iv, session_key, sizeof(iv)); | |
17926a79 | 1016 | |
68e3f5dd | 1017 | rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted)); |
1afe593b HX |
1018 | |
1019 | skcipher_request_set_tfm(req, rxkad_ci); | |
1020 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
1021 | skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x); | |
1022 | ||
1023 | crypto_skcipher_decrypt(req); | |
1024 | skcipher_request_zero(req); | |
1025 | ||
17926a79 DH |
1026 | mutex_unlock(&rxkad_ci_mutex); |
1027 | ||
1028 | _leave(""); | |
1029 | } | |
1030 | ||
1031 | /* | |
1032 | * verify a response | |
1033 | */ | |
1034 | static int rxkad_verify_response(struct rxrpc_connection *conn, | |
1035 | struct sk_buff *skb, | |
1036 | u32 *_abort_code) | |
1037 | { | |
1038 | struct rxkad_response response | |
1039 | __attribute__((aligned(8))); /* must be aligned for crypto */ | |
1040 | struct rxrpc_skb_priv *sp; | |
1041 | struct rxrpc_crypt session_key; | |
1042 | time_t expiry; | |
1043 | void *ticket; | |
91e916cf AV |
1044 | u32 abort_code, version, kvno, ticket_len, level; |
1045 | __be32 csum; | |
17926a79 DH |
1046 | int ret; |
1047 | ||
1048 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key)); | |
1049 | ||
1050 | abort_code = RXKADPACKETSHORT; | |
1051 | if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0) | |
1052 | goto protocol_error; | |
1053 | if (!pskb_pull(skb, sizeof(response))) | |
1054 | BUG(); | |
1055 | ||
1056 | version = ntohl(response.version); | |
1057 | ticket_len = ntohl(response.ticket_len); | |
1058 | kvno = ntohl(response.kvno); | |
1059 | sp = rxrpc_skb(skb); | |
1060 | _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }", | |
0d12f8a4 | 1061 | sp->hdr.serial, version, kvno, ticket_len); |
17926a79 DH |
1062 | |
1063 | abort_code = RXKADINCONSISTENCY; | |
1064 | if (version != RXKAD_VERSION) | |
4aa9cb32 | 1065 | goto protocol_error; |
17926a79 DH |
1066 | |
1067 | abort_code = RXKADTICKETLEN; | |
1068 | if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN) | |
1069 | goto protocol_error; | |
1070 | ||
1071 | abort_code = RXKADUNKNOWNKEY; | |
1072 | if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5) | |
1073 | goto protocol_error; | |
1074 | ||
1075 | /* extract the kerberos ticket and decrypt and decode it */ | |
1076 | ticket = kmalloc(ticket_len, GFP_NOFS); | |
1077 | if (!ticket) | |
1078 | return -ENOMEM; | |
1079 | ||
1080 | abort_code = RXKADPACKETSHORT; | |
1081 | if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0) | |
1082 | goto protocol_error_free; | |
1083 | ||
1084 | ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key, | |
1085 | &expiry, &abort_code); | |
1086 | if (ret < 0) { | |
1087 | *_abort_code = abort_code; | |
1088 | kfree(ticket); | |
1089 | return ret; | |
1090 | } | |
1091 | ||
1092 | /* use the session key from inside the ticket to decrypt the | |
1093 | * response */ | |
1094 | rxkad_decrypt_response(conn, &response, &session_key); | |
1095 | ||
1096 | abort_code = RXKADSEALEDINCON; | |
0d12f8a4 | 1097 | if (ntohl(response.encrypted.epoch) != conn->epoch) |
17926a79 | 1098 | goto protocol_error_free; |
0d12f8a4 | 1099 | if (ntohl(response.encrypted.cid) != conn->cid) |
17926a79 DH |
1100 | goto protocol_error_free; |
1101 | if (ntohl(response.encrypted.securityIndex) != conn->security_ix) | |
1102 | goto protocol_error_free; | |
1103 | csum = response.encrypted.checksum; | |
1104 | response.encrypted.checksum = 0; | |
1105 | rxkad_calc_response_checksum(&response); | |
1106 | if (response.encrypted.checksum != csum) | |
1107 | goto protocol_error_free; | |
1108 | ||
1109 | if (ntohl(response.encrypted.call_id[0]) > INT_MAX || | |
1110 | ntohl(response.encrypted.call_id[1]) > INT_MAX || | |
1111 | ntohl(response.encrypted.call_id[2]) > INT_MAX || | |
1112 | ntohl(response.encrypted.call_id[3]) > INT_MAX) | |
1113 | goto protocol_error_free; | |
1114 | ||
1115 | abort_code = RXKADOUTOFSEQUENCE; | |
0d12f8a4 | 1116 | if (ntohl(response.encrypted.inc_nonce) != conn->security_nonce + 1) |
17926a79 DH |
1117 | goto protocol_error_free; |
1118 | ||
1119 | abort_code = RXKADLEVELFAIL; | |
1120 | level = ntohl(response.encrypted.level); | |
1121 | if (level > RXRPC_SECURITY_ENCRYPT) | |
1122 | goto protocol_error_free; | |
1123 | conn->security_level = level; | |
1124 | ||
1125 | /* create a key to hold the security data and expiration time - after | |
1126 | * this the connection security can be handled in exactly the same way | |
1127 | * as for a client connection */ | |
1128 | ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno); | |
1129 | if (ret < 0) { | |
1130 | kfree(ticket); | |
1131 | return ret; | |
1132 | } | |
1133 | ||
1134 | kfree(ticket); | |
1135 | _leave(" = 0"); | |
1136 | return 0; | |
1137 | ||
1138 | protocol_error_free: | |
1139 | kfree(ticket); | |
1140 | protocol_error: | |
1141 | *_abort_code = abort_code; | |
1142 | _leave(" = -EPROTO [%d]", abort_code); | |
1143 | return -EPROTO; | |
1144 | } | |
1145 | ||
1146 | /* | |
1147 | * clear the connection security | |
1148 | */ | |
1149 | static void rxkad_clear(struct rxrpc_connection *conn) | |
1150 | { | |
1151 | _enter(""); | |
1152 | ||
1153 | if (conn->cipher) | |
1afe593b | 1154 | crypto_free_skcipher(conn->cipher); |
17926a79 DH |
1155 | } |
1156 | ||
648af7fc DH |
1157 | /* |
1158 | * Initialise the rxkad security service. | |
1159 | */ | |
1160 | static int rxkad_init(void) | |
1161 | { | |
1162 | /* pin the cipher we need so that the crypto layer doesn't invoke | |
1163 | * keventd to go get it */ | |
1164 | rxkad_ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC); | |
fa54cc70 | 1165 | return PTR_ERR_OR_ZERO(rxkad_ci); |
648af7fc DH |
1166 | } |
1167 | ||
1168 | /* | |
1169 | * Clean up the rxkad security service. | |
1170 | */ | |
1171 | static void rxkad_exit(void) | |
1172 | { | |
1173 | if (rxkad_ci) | |
1174 | crypto_free_skcipher(rxkad_ci); | |
1175 | } | |
1176 | ||
17926a79 DH |
1177 | /* |
1178 | * RxRPC Kerberos-based security | |
1179 | */ | |
648af7fc | 1180 | const struct rxrpc_security rxkad = { |
17926a79 | 1181 | .name = "rxkad", |
8b815477 | 1182 | .security_index = RXRPC_SECURITY_RXKAD, |
648af7fc DH |
1183 | .init = rxkad_init, |
1184 | .exit = rxkad_exit, | |
17926a79 DH |
1185 | .init_connection_security = rxkad_init_connection_security, |
1186 | .prime_packet_security = rxkad_prime_packet_security, | |
1187 | .secure_packet = rxkad_secure_packet, | |
1188 | .verify_packet = rxkad_verify_packet, | |
1189 | .issue_challenge = rxkad_issue_challenge, | |
1190 | .respond_to_challenge = rxkad_respond_to_challenge, | |
1191 | .verify_response = rxkad_verify_response, | |
1192 | .clear = rxkad_clear, | |
1193 | }; |