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> |
b1bdb691 | 23 | #define rxrpc_debug rxkad_debug |
17926a79 DH |
24 | #include "ar-internal.h" |
25 | ||
26 | #define RXKAD_VERSION 2 | |
27 | #define MAXKRB5TICKETLEN 1024 | |
28 | #define RXKAD_TKT_TYPE_KERBEROS_V5 256 | |
29 | #define ANAME_SZ 40 /* size of authentication name */ | |
30 | #define INST_SZ 40 /* size of principal's instance */ | |
31 | #define REALM_SZ 40 /* size of principal's auth domain */ | |
32 | #define SNAME_SZ 40 /* size of service name */ | |
33 | ||
95c96174 | 34 | unsigned int rxrpc_debug; |
17926a79 | 35 | module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO); |
424b00e2 | 36 | MODULE_PARM_DESC(debug, "rxkad debugging mask"); |
17926a79 DH |
37 | |
38 | struct rxkad_level1_hdr { | |
39 | __be32 data_size; /* true data size (excluding padding) */ | |
40 | }; | |
41 | ||
42 | struct rxkad_level2_hdr { | |
43 | __be32 data_size; /* true data size (excluding padding) */ | |
44 | __be32 checksum; /* decrypted data checksum */ | |
45 | }; | |
46 | ||
8b815477 | 47 | MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos 4)"); |
17926a79 DH |
48 | MODULE_AUTHOR("Red Hat, Inc."); |
49 | MODULE_LICENSE("GPL"); | |
50 | ||
51 | /* | |
52 | * this holds a pinned cipher so that keventd doesn't get called by the cipher | |
53 | * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE | |
54 | * packets | |
55 | */ | |
1afe593b | 56 | static struct crypto_skcipher *rxkad_ci; |
17926a79 DH |
57 | static DEFINE_MUTEX(rxkad_ci_mutex); |
58 | ||
59 | /* | |
60 | * initialise connection security | |
61 | */ | |
62 | static int rxkad_init_connection_security(struct rxrpc_connection *conn) | |
63 | { | |
1afe593b | 64 | struct crypto_skcipher *ci; |
33941284 | 65 | struct rxrpc_key_token *token; |
17926a79 DH |
66 | int ret; |
67 | ||
68 | _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key)); | |
69 | ||
146aa8b1 | 70 | token = conn->key->payload.data[0]; |
33941284 | 71 | conn->security_ix = token->security_index; |
17926a79 | 72 | |
1afe593b | 73 | ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC); |
17926a79 DH |
74 | if (IS_ERR(ci)) { |
75 | _debug("no cipher"); | |
76 | ret = PTR_ERR(ci); | |
77 | goto error; | |
78 | } | |
79 | ||
1afe593b HX |
80 | if (crypto_skcipher_setkey(ci, token->kad->session_key, |
81 | sizeof(token->kad->session_key)) < 0) | |
17926a79 DH |
82 | BUG(); |
83 | ||
84 | switch (conn->security_level) { | |
85 | case RXRPC_SECURITY_PLAIN: | |
86 | break; | |
87 | case RXRPC_SECURITY_AUTH: | |
88 | conn->size_align = 8; | |
89 | conn->security_size = sizeof(struct rxkad_level1_hdr); | |
90 | conn->header_size += sizeof(struct rxkad_level1_hdr); | |
91 | break; | |
92 | case RXRPC_SECURITY_ENCRYPT: | |
93 | conn->size_align = 8; | |
94 | conn->security_size = sizeof(struct rxkad_level2_hdr); | |
95 | conn->header_size += sizeof(struct rxkad_level2_hdr); | |
96 | break; | |
97 | default: | |
98 | ret = -EKEYREJECTED; | |
99 | goto error; | |
100 | } | |
101 | ||
102 | conn->cipher = ci; | |
103 | ret = 0; | |
104 | error: | |
105 | _leave(" = %d", ret); | |
106 | return ret; | |
107 | } | |
108 | ||
109 | /* | |
110 | * prime the encryption state with the invariant parts of a connection's | |
111 | * description | |
112 | */ | |
113 | static void rxkad_prime_packet_security(struct rxrpc_connection *conn) | |
114 | { | |
33941284 | 115 | struct rxrpc_key_token *token; |
1afe593b | 116 | SKCIPHER_REQUEST_ON_STACK(req, conn->cipher); |
17926a79 DH |
117 | struct scatterlist sg[2]; |
118 | struct rxrpc_crypt iv; | |
119 | struct { | |
120 | __be32 x[4]; | |
121 | } tmpbuf __attribute__((aligned(16))); /* must all be in same page */ | |
122 | ||
123 | _enter(""); | |
124 | ||
125 | if (!conn->key) | |
126 | return; | |
127 | ||
146aa8b1 | 128 | token = conn->key->payload.data[0]; |
33941284 | 129 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 130 | |
0d12f8a4 DH |
131 | tmpbuf.x[0] = htonl(conn->epoch); |
132 | tmpbuf.x[1] = htonl(conn->cid); | |
17926a79 DH |
133 | tmpbuf.x[2] = 0; |
134 | tmpbuf.x[3] = htonl(conn->security_ix); | |
135 | ||
68e3f5dd HX |
136 | sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf)); |
137 | sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf)); | |
1afe593b HX |
138 | |
139 | skcipher_request_set_tfm(req, conn->cipher); | |
140 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
141 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x); | |
142 | ||
143 | crypto_skcipher_encrypt(req); | |
144 | skcipher_request_zero(req); | |
17926a79 DH |
145 | |
146 | memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv)); | |
2b15ef15 | 147 | ASSERTCMP((u32 __force)conn->csum_iv.n[0], ==, (u32 __force)tmpbuf.x[2]); |
17926a79 DH |
148 | |
149 | _leave(""); | |
150 | } | |
151 | ||
152 | /* | |
153 | * partially encrypt a packet (level 1 security) | |
154 | */ | |
155 | static int rxkad_secure_packet_auth(const struct rxrpc_call *call, | |
156 | struct sk_buff *skb, | |
157 | u32 data_size, | |
158 | void *sechdr) | |
159 | { | |
160 | struct rxrpc_skb_priv *sp; | |
1afe593b | 161 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
162 | struct rxrpc_crypt iv; |
163 | struct scatterlist sg[2]; | |
164 | struct { | |
165 | struct rxkad_level1_hdr hdr; | |
166 | __be32 first; /* first four bytes of data and padding */ | |
167 | } tmpbuf __attribute__((aligned(8))); /* must all be in same page */ | |
168 | u16 check; | |
169 | ||
170 | sp = rxrpc_skb(skb); | |
171 | ||
172 | _enter(""); | |
173 | ||
0d12f8a4 DH |
174 | check = sp->hdr.seq ^ sp->hdr.callNumber; |
175 | data_size |= (u32)check << 16; | |
17926a79 DH |
176 | |
177 | tmpbuf.hdr.data_size = htonl(data_size); | |
178 | memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first)); | |
179 | ||
180 | /* start the encryption afresh */ | |
181 | memset(&iv, 0, sizeof(iv)); | |
17926a79 | 182 | |
68e3f5dd HX |
183 | sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf)); |
184 | sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf)); | |
1afe593b HX |
185 | |
186 | skcipher_request_set_tfm(req, call->conn->cipher); | |
187 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
188 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x); | |
189 | ||
190 | crypto_skcipher_encrypt(req); | |
191 | skcipher_request_zero(req); | |
17926a79 DH |
192 | |
193 | memcpy(sechdr, &tmpbuf, sizeof(tmpbuf)); | |
194 | ||
195 | _leave(" = 0"); | |
196 | return 0; | |
197 | } | |
198 | ||
199 | /* | |
200 | * wholly encrypt a packet (level 2 security) | |
201 | */ | |
202 | static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call, | |
b4f1342f DH |
203 | struct sk_buff *skb, |
204 | u32 data_size, | |
205 | void *sechdr) | |
17926a79 | 206 | { |
33941284 | 207 | const struct rxrpc_key_token *token; |
17926a79 DH |
208 | struct rxkad_level2_hdr rxkhdr |
209 | __attribute__((aligned(8))); /* must be all on one page */ | |
210 | struct rxrpc_skb_priv *sp; | |
1afe593b | 211 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
212 | struct rxrpc_crypt iv; |
213 | struct scatterlist sg[16]; | |
214 | struct sk_buff *trailer; | |
95c96174 | 215 | unsigned int len; |
17926a79 DH |
216 | u16 check; |
217 | int nsg; | |
1afe593b | 218 | int err; |
17926a79 DH |
219 | |
220 | sp = rxrpc_skb(skb); | |
221 | ||
222 | _enter(""); | |
223 | ||
0d12f8a4 | 224 | check = sp->hdr.seq ^ sp->hdr.callNumber; |
17926a79 | 225 | |
0d12f8a4 | 226 | rxkhdr.data_size = htonl(data_size | (u32)check << 16); |
17926a79 DH |
227 | rxkhdr.checksum = 0; |
228 | ||
229 | /* encrypt from the session key */ | |
146aa8b1 | 230 | token = call->conn->key->payload.data[0]; |
33941284 | 231 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 232 | |
68e3f5dd HX |
233 | sg_init_one(&sg[0], sechdr, sizeof(rxkhdr)); |
234 | sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr)); | |
1afe593b HX |
235 | |
236 | skcipher_request_set_tfm(req, call->conn->cipher); | |
237 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
238 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(rxkhdr), iv.x); | |
239 | ||
240 | crypto_skcipher_encrypt(req); | |
17926a79 DH |
241 | |
242 | /* we want to encrypt the skbuff in-place */ | |
243 | nsg = skb_cow_data(skb, 0, &trailer); | |
1afe593b | 244 | err = -ENOMEM; |
17926a79 | 245 | if (nsg < 0 || nsg > 16) |
1afe593b | 246 | goto out; |
17926a79 DH |
247 | |
248 | len = data_size + call->conn->size_align - 1; | |
249 | len &= ~(call->conn->size_align - 1); | |
250 | ||
51c739d1 DM |
251 | sg_init_table(sg, nsg); |
252 | skb_to_sgvec(skb, sg, 0, len); | |
1afe593b HX |
253 | |
254 | skcipher_request_set_crypt(req, sg, sg, len, iv.x); | |
255 | ||
256 | crypto_skcipher_encrypt(req); | |
17926a79 DH |
257 | |
258 | _leave(" = 0"); | |
1afe593b HX |
259 | err = 0; |
260 | ||
261 | out: | |
262 | skcipher_request_zero(req); | |
263 | return err; | |
17926a79 DH |
264 | } |
265 | ||
266 | /* | |
267 | * checksum an RxRPC packet header | |
268 | */ | |
269 | static int rxkad_secure_packet(const struct rxrpc_call *call, | |
b4f1342f DH |
270 | struct sk_buff *skb, |
271 | size_t data_size, | |
272 | void *sechdr) | |
17926a79 DH |
273 | { |
274 | struct rxrpc_skb_priv *sp; | |
1afe593b | 275 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
276 | struct rxrpc_crypt iv; |
277 | struct scatterlist sg[2]; | |
278 | struct { | |
279 | __be32 x[2]; | |
280 | } tmpbuf __attribute__((aligned(8))); /* must all be in same page */ | |
0d12f8a4 | 281 | u32 x, y; |
17926a79 DH |
282 | int ret; |
283 | ||
284 | sp = rxrpc_skb(skb); | |
285 | ||
286 | _enter("{%d{%x}},{#%u},%zu,", | |
0d12f8a4 | 287 | call->debug_id, key_serial(call->conn->key), sp->hdr.seq, |
17926a79 DH |
288 | data_size); |
289 | ||
290 | if (!call->conn->cipher) | |
291 | return 0; | |
292 | ||
293 | ret = key_validate(call->conn->key); | |
294 | if (ret < 0) | |
295 | return ret; | |
296 | ||
297 | /* continue encrypting from where we left off */ | |
298 | memcpy(&iv, call->conn->csum_iv.x, sizeof(iv)); | |
17926a79 DH |
299 | |
300 | /* calculate the security checksum */ | |
0d12f8a4 DH |
301 | x = call->channel << (32 - RXRPC_CIDSHIFT); |
302 | x |= sp->hdr.seq & 0x3fffffff; | |
303 | tmpbuf.x[0] = htonl(sp->hdr.callNumber); | |
304 | tmpbuf.x[1] = htonl(x); | |
17926a79 | 305 | |
68e3f5dd HX |
306 | sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf)); |
307 | sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf)); | |
1afe593b HX |
308 | |
309 | skcipher_request_set_tfm(req, call->conn->cipher); | |
310 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
311 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x); | |
312 | ||
313 | crypto_skcipher_encrypt(req); | |
314 | skcipher_request_zero(req); | |
17926a79 | 315 | |
91e916cf AV |
316 | y = ntohl(tmpbuf.x[1]); |
317 | y = (y >> 16) & 0xffff; | |
318 | if (y == 0) | |
319 | y = 1; /* zero checksums are not permitted */ | |
0d12f8a4 | 320 | sp->hdr.cksum = y; |
17926a79 DH |
321 | |
322 | switch (call->conn->security_level) { | |
323 | case RXRPC_SECURITY_PLAIN: | |
324 | ret = 0; | |
325 | break; | |
326 | case RXRPC_SECURITY_AUTH: | |
327 | ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr); | |
328 | break; | |
329 | case RXRPC_SECURITY_ENCRYPT: | |
330 | ret = rxkad_secure_packet_encrypt(call, skb, data_size, | |
331 | sechdr); | |
332 | break; | |
333 | default: | |
334 | ret = -EPERM; | |
335 | break; | |
336 | } | |
337 | ||
91e916cf | 338 | _leave(" = %d [set %hx]", ret, y); |
17926a79 DH |
339 | return ret; |
340 | } | |
341 | ||
342 | /* | |
343 | * decrypt partial encryption on a packet (level 1 security) | |
344 | */ | |
345 | static int rxkad_verify_packet_auth(const struct rxrpc_call *call, | |
346 | struct sk_buff *skb, | |
347 | u32 *_abort_code) | |
348 | { | |
349 | struct rxkad_level1_hdr sechdr; | |
350 | struct rxrpc_skb_priv *sp; | |
1afe593b | 351 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 | 352 | struct rxrpc_crypt iv; |
68e3f5dd | 353 | struct scatterlist sg[16]; |
17926a79 DH |
354 | struct sk_buff *trailer; |
355 | u32 data_size, buf; | |
356 | u16 check; | |
68e3f5dd | 357 | int nsg; |
17926a79 DH |
358 | |
359 | _enter(""); | |
360 | ||
361 | sp = rxrpc_skb(skb); | |
362 | ||
363 | /* we want to decrypt the skbuff in-place */ | |
68e3f5dd HX |
364 | nsg = skb_cow_data(skb, 0, &trailer); |
365 | if (nsg < 0 || nsg > 16) | |
17926a79 DH |
366 | goto nomem; |
367 | ||
68e3f5dd | 368 | sg_init_table(sg, nsg); |
51c739d1 | 369 | skb_to_sgvec(skb, sg, 0, 8); |
17926a79 DH |
370 | |
371 | /* start the decryption afresh */ | |
372 | memset(&iv, 0, sizeof(iv)); | |
17926a79 | 373 | |
1afe593b HX |
374 | skcipher_request_set_tfm(req, call->conn->cipher); |
375 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
376 | skcipher_request_set_crypt(req, sg, sg, 8, iv.x); | |
377 | ||
378 | crypto_skcipher_decrypt(req); | |
379 | skcipher_request_zero(req); | |
17926a79 DH |
380 | |
381 | /* remove the decrypted packet length */ | |
382 | if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0) | |
383 | goto datalen_error; | |
384 | if (!skb_pull(skb, sizeof(sechdr))) | |
385 | BUG(); | |
386 | ||
387 | buf = ntohl(sechdr.data_size); | |
388 | data_size = buf & 0xffff; | |
389 | ||
390 | check = buf >> 16; | |
0d12f8a4 | 391 | check ^= sp->hdr.seq ^ sp->hdr.callNumber; |
17926a79 DH |
392 | check &= 0xffff; |
393 | if (check != 0) { | |
394 | *_abort_code = RXKADSEALEDINCON; | |
395 | goto protocol_error; | |
396 | } | |
397 | ||
398 | /* shorten the packet to remove the padding */ | |
399 | if (data_size > skb->len) | |
400 | goto datalen_error; | |
401 | else if (data_size < skb->len) | |
402 | skb->len = data_size; | |
403 | ||
404 | _leave(" = 0 [dlen=%x]", data_size); | |
405 | return 0; | |
406 | ||
407 | datalen_error: | |
408 | *_abort_code = RXKADDATALEN; | |
409 | protocol_error: | |
410 | _leave(" = -EPROTO"); | |
411 | return -EPROTO; | |
412 | ||
413 | nomem: | |
414 | _leave(" = -ENOMEM"); | |
415 | return -ENOMEM; | |
416 | } | |
417 | ||
418 | /* | |
419 | * wholly decrypt a packet (level 2 security) | |
420 | */ | |
421 | static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call, | |
422 | struct sk_buff *skb, | |
423 | u32 *_abort_code) | |
424 | { | |
33941284 | 425 | const struct rxrpc_key_token *token; |
17926a79 DH |
426 | struct rxkad_level2_hdr sechdr; |
427 | struct rxrpc_skb_priv *sp; | |
1afe593b | 428 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
429 | struct rxrpc_crypt iv; |
430 | struct scatterlist _sg[4], *sg; | |
431 | struct sk_buff *trailer; | |
432 | u32 data_size, buf; | |
433 | u16 check; | |
434 | int nsg; | |
435 | ||
436 | _enter(",{%d}", skb->len); | |
437 | ||
438 | sp = rxrpc_skb(skb); | |
439 | ||
440 | /* we want to decrypt the skbuff in-place */ | |
441 | nsg = skb_cow_data(skb, 0, &trailer); | |
442 | if (nsg < 0) | |
443 | goto nomem; | |
444 | ||
445 | sg = _sg; | |
446 | if (unlikely(nsg > 4)) { | |
447 | sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO); | |
448 | if (!sg) | |
449 | goto nomem; | |
450 | } | |
451 | ||
68e3f5dd | 452 | sg_init_table(sg, nsg); |
51c739d1 | 453 | skb_to_sgvec(skb, sg, 0, skb->len); |
17926a79 DH |
454 | |
455 | /* decrypt from the session key */ | |
146aa8b1 | 456 | token = call->conn->key->payload.data[0]; |
33941284 | 457 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 458 | |
1afe593b HX |
459 | skcipher_request_set_tfm(req, call->conn->cipher); |
460 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
461 | skcipher_request_set_crypt(req, sg, sg, skb->len, iv.x); | |
462 | ||
463 | crypto_skcipher_decrypt(req); | |
464 | skcipher_request_zero(req); | |
17926a79 DH |
465 | if (sg != _sg) |
466 | kfree(sg); | |
467 | ||
468 | /* remove the decrypted packet length */ | |
469 | if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0) | |
470 | goto datalen_error; | |
471 | if (!skb_pull(skb, sizeof(sechdr))) | |
472 | BUG(); | |
473 | ||
474 | buf = ntohl(sechdr.data_size); | |
475 | data_size = buf & 0xffff; | |
476 | ||
477 | check = buf >> 16; | |
0d12f8a4 | 478 | check ^= sp->hdr.seq ^ sp->hdr.callNumber; |
17926a79 DH |
479 | check &= 0xffff; |
480 | if (check != 0) { | |
481 | *_abort_code = RXKADSEALEDINCON; | |
482 | goto protocol_error; | |
483 | } | |
484 | ||
485 | /* shorten the packet to remove the padding */ | |
486 | if (data_size > skb->len) | |
487 | goto datalen_error; | |
488 | else if (data_size < skb->len) | |
489 | skb->len = data_size; | |
490 | ||
491 | _leave(" = 0 [dlen=%x]", data_size); | |
492 | return 0; | |
493 | ||
494 | datalen_error: | |
495 | *_abort_code = RXKADDATALEN; | |
496 | protocol_error: | |
497 | _leave(" = -EPROTO"); | |
498 | return -EPROTO; | |
499 | ||
500 | nomem: | |
501 | _leave(" = -ENOMEM"); | |
502 | return -ENOMEM; | |
503 | } | |
504 | ||
505 | /* | |
506 | * verify the security on a received packet | |
507 | */ | |
508 | static int rxkad_verify_packet(const struct rxrpc_call *call, | |
509 | struct sk_buff *skb, | |
510 | u32 *_abort_code) | |
511 | { | |
1afe593b | 512 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
513 | struct rxrpc_skb_priv *sp; |
514 | struct rxrpc_crypt iv; | |
515 | struct scatterlist sg[2]; | |
516 | struct { | |
517 | __be32 x[2]; | |
518 | } tmpbuf __attribute__((aligned(8))); /* must all be in same page */ | |
0d12f8a4 DH |
519 | u16 cksum; |
520 | u32 x, y; | |
17926a79 DH |
521 | int ret; |
522 | ||
523 | sp = rxrpc_skb(skb); | |
524 | ||
525 | _enter("{%d{%x}},{#%u}", | |
0d12f8a4 | 526 | call->debug_id, key_serial(call->conn->key), sp->hdr.seq); |
17926a79 DH |
527 | |
528 | if (!call->conn->cipher) | |
529 | return 0; | |
530 | ||
8b815477 | 531 | if (sp->hdr.securityIndex != RXRPC_SECURITY_RXKAD) { |
17926a79 DH |
532 | *_abort_code = RXKADINCONSISTENCY; |
533 | _leave(" = -EPROTO [not rxkad]"); | |
534 | return -EPROTO; | |
535 | } | |
536 | ||
537 | /* continue encrypting from where we left off */ | |
538 | memcpy(&iv, call->conn->csum_iv.x, sizeof(iv)); | |
17926a79 DH |
539 | |
540 | /* validate the security checksum */ | |
0d12f8a4 DH |
541 | x = call->channel << (32 - RXRPC_CIDSHIFT); |
542 | x |= sp->hdr.seq & 0x3fffffff; | |
543 | tmpbuf.x[0] = htonl(call->call_id); | |
544 | tmpbuf.x[1] = htonl(x); | |
17926a79 | 545 | |
68e3f5dd HX |
546 | sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf)); |
547 | sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf)); | |
1afe593b HX |
548 | |
549 | skcipher_request_set_tfm(req, call->conn->cipher); | |
550 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
551 | skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x); | |
552 | ||
553 | crypto_skcipher_encrypt(req); | |
554 | skcipher_request_zero(req); | |
17926a79 | 555 | |
91e916cf | 556 | y = ntohl(tmpbuf.x[1]); |
0d12f8a4 DH |
557 | cksum = (y >> 16) & 0xffff; |
558 | if (cksum == 0) | |
559 | cksum = 1; /* zero checksums are not permitted */ | |
17926a79 | 560 | |
17926a79 DH |
561 | if (sp->hdr.cksum != cksum) { |
562 | *_abort_code = RXKADSEALEDINCON; | |
563 | _leave(" = -EPROTO [csum failed]"); | |
564 | return -EPROTO; | |
565 | } | |
566 | ||
567 | switch (call->conn->security_level) { | |
568 | case RXRPC_SECURITY_PLAIN: | |
569 | ret = 0; | |
570 | break; | |
571 | case RXRPC_SECURITY_AUTH: | |
572 | ret = rxkad_verify_packet_auth(call, skb, _abort_code); | |
573 | break; | |
574 | case RXRPC_SECURITY_ENCRYPT: | |
575 | ret = rxkad_verify_packet_encrypt(call, skb, _abort_code); | |
576 | break; | |
577 | default: | |
578 | ret = -ENOANO; | |
579 | break; | |
580 | } | |
581 | ||
582 | _leave(" = %d", ret); | |
583 | return ret; | |
584 | } | |
585 | ||
586 | /* | |
587 | * issue a challenge | |
588 | */ | |
589 | static int rxkad_issue_challenge(struct rxrpc_connection *conn) | |
590 | { | |
591 | struct rxkad_challenge challenge; | |
0d12f8a4 | 592 | struct rxrpc_wire_header whdr; |
17926a79 DH |
593 | struct msghdr msg; |
594 | struct kvec iov[2]; | |
595 | size_t len; | |
0d12f8a4 | 596 | u32 serial; |
17926a79 DH |
597 | int ret; |
598 | ||
599 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->key)); | |
600 | ||
601 | ret = key_validate(conn->key); | |
602 | if (ret < 0) | |
603 | return ret; | |
604 | ||
605 | get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce)); | |
606 | ||
607 | challenge.version = htonl(2); | |
608 | challenge.nonce = htonl(conn->security_nonce); | |
609 | challenge.min_level = htonl(0); | |
610 | challenge.__padding = 0; | |
611 | ||
612 | msg.msg_name = &conn->trans->peer->srx.transport.sin; | |
613 | msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin); | |
614 | msg.msg_control = NULL; | |
615 | msg.msg_controllen = 0; | |
616 | msg.msg_flags = 0; | |
617 | ||
0d12f8a4 DH |
618 | whdr.epoch = htonl(conn->epoch); |
619 | whdr.cid = htonl(conn->cid); | |
620 | whdr.callNumber = 0; | |
621 | whdr.seq = 0; | |
622 | whdr.type = RXRPC_PACKET_TYPE_CHALLENGE; | |
623 | whdr.flags = conn->out_clientflag; | |
624 | whdr.userStatus = 0; | |
625 | whdr.securityIndex = conn->security_ix; | |
626 | whdr._rsvd = 0; | |
627 | whdr.serviceId = htons(conn->service_id); | |
628 | ||
629 | iov[0].iov_base = &whdr; | |
630 | iov[0].iov_len = sizeof(whdr); | |
17926a79 DH |
631 | iov[1].iov_base = &challenge; |
632 | iov[1].iov_len = sizeof(challenge); | |
633 | ||
634 | len = iov[0].iov_len + iov[1].iov_len; | |
635 | ||
0d12f8a4 DH |
636 | serial = atomic_inc_return(&conn->serial); |
637 | whdr.serial = htonl(serial); | |
638 | _proto("Tx CHALLENGE %%%u", serial); | |
17926a79 DH |
639 | |
640 | ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len); | |
641 | if (ret < 0) { | |
642 | _debug("sendmsg failed: %d", ret); | |
643 | return -EAGAIN; | |
644 | } | |
645 | ||
646 | _leave(" = 0"); | |
647 | return 0; | |
648 | } | |
649 | ||
650 | /* | |
651 | * send a Kerberos security response | |
652 | */ | |
653 | static int rxkad_send_response(struct rxrpc_connection *conn, | |
0d12f8a4 | 654 | struct rxrpc_host_header *hdr, |
17926a79 DH |
655 | struct rxkad_response *resp, |
656 | const struct rxkad_key *s2) | |
657 | { | |
0d12f8a4 | 658 | struct rxrpc_wire_header whdr; |
17926a79 DH |
659 | struct msghdr msg; |
660 | struct kvec iov[3]; | |
661 | size_t len; | |
0d12f8a4 | 662 | u32 serial; |
17926a79 DH |
663 | int ret; |
664 | ||
665 | _enter(""); | |
666 | ||
667 | msg.msg_name = &conn->trans->peer->srx.transport.sin; | |
668 | msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin); | |
669 | msg.msg_control = NULL; | |
670 | msg.msg_controllen = 0; | |
671 | msg.msg_flags = 0; | |
672 | ||
0d12f8a4 DH |
673 | memset(&whdr, 0, sizeof(whdr)); |
674 | whdr.epoch = htonl(hdr->epoch); | |
675 | whdr.cid = htonl(hdr->cid); | |
676 | whdr.type = RXRPC_PACKET_TYPE_RESPONSE; | |
677 | whdr.flags = conn->out_clientflag; | |
678 | whdr.securityIndex = hdr->securityIndex; | |
679 | whdr.serviceId = htons(hdr->serviceId); | |
17926a79 | 680 | |
0d12f8a4 DH |
681 | iov[0].iov_base = &whdr; |
682 | iov[0].iov_len = sizeof(whdr); | |
17926a79 DH |
683 | iov[1].iov_base = resp; |
684 | iov[1].iov_len = sizeof(*resp); | |
0d12f8a4 | 685 | iov[2].iov_base = (void *)s2->ticket; |
17926a79 DH |
686 | iov[2].iov_len = s2->ticket_len; |
687 | ||
688 | len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len; | |
689 | ||
0d12f8a4 DH |
690 | serial = atomic_inc_return(&conn->serial); |
691 | whdr.serial = htonl(serial); | |
692 | _proto("Tx RESPONSE %%%u", serial); | |
17926a79 DH |
693 | |
694 | ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 3, len); | |
695 | if (ret < 0) { | |
696 | _debug("sendmsg failed: %d", ret); | |
697 | return -EAGAIN; | |
698 | } | |
699 | ||
700 | _leave(" = 0"); | |
701 | return 0; | |
702 | } | |
703 | ||
704 | /* | |
705 | * calculate the response checksum | |
706 | */ | |
707 | static void rxkad_calc_response_checksum(struct rxkad_response *response) | |
708 | { | |
709 | u32 csum = 1000003; | |
710 | int loop; | |
711 | u8 *p = (u8 *) response; | |
712 | ||
713 | for (loop = sizeof(*response); loop > 0; loop--) | |
714 | csum = csum * 0x10204081 + *p++; | |
715 | ||
716 | response->encrypted.checksum = htonl(csum); | |
717 | } | |
718 | ||
719 | /* | |
720 | * load a scatterlist with a potentially split-page buffer | |
721 | */ | |
722 | static void rxkad_sg_set_buf2(struct scatterlist sg[2], | |
723 | void *buf, size_t buflen) | |
724 | { | |
68e3f5dd | 725 | int nsg = 1; |
17926a79 | 726 | |
68e3f5dd | 727 | sg_init_table(sg, 2); |
17926a79 DH |
728 | |
729 | sg_set_buf(&sg[0], buf, buflen); | |
730 | if (sg[0].offset + buflen > PAGE_SIZE) { | |
731 | /* the buffer was split over two pages */ | |
732 | sg[0].length = PAGE_SIZE - sg[0].offset; | |
733 | sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length); | |
68e3f5dd | 734 | nsg++; |
17926a79 DH |
735 | } |
736 | ||
c46f2334 | 737 | sg_mark_end(&sg[nsg - 1]); |
68e3f5dd | 738 | |
17926a79 DH |
739 | ASSERTCMP(sg[0].length + sg[1].length, ==, buflen); |
740 | } | |
741 | ||
742 | /* | |
743 | * encrypt the response packet | |
744 | */ | |
745 | static void rxkad_encrypt_response(struct rxrpc_connection *conn, | |
746 | struct rxkad_response *resp, | |
747 | const struct rxkad_key *s2) | |
748 | { | |
1afe593b | 749 | SKCIPHER_REQUEST_ON_STACK(req, conn->cipher); |
17926a79 | 750 | struct rxrpc_crypt iv; |
68e3f5dd | 751 | struct scatterlist sg[2]; |
17926a79 DH |
752 | |
753 | /* continue encrypting from where we left off */ | |
754 | memcpy(&iv, s2->session_key, sizeof(iv)); | |
17926a79 | 755 | |
68e3f5dd | 756 | rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted)); |
1afe593b HX |
757 | |
758 | skcipher_request_set_tfm(req, conn->cipher); | |
759 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
760 | skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x); | |
761 | ||
762 | crypto_skcipher_encrypt(req); | |
763 | skcipher_request_zero(req); | |
17926a79 DH |
764 | } |
765 | ||
766 | /* | |
767 | * respond to a challenge packet | |
768 | */ | |
769 | static int rxkad_respond_to_challenge(struct rxrpc_connection *conn, | |
770 | struct sk_buff *skb, | |
771 | u32 *_abort_code) | |
772 | { | |
33941284 | 773 | const struct rxrpc_key_token *token; |
17926a79 DH |
774 | struct rxkad_challenge challenge; |
775 | struct rxkad_response resp | |
776 | __attribute__((aligned(8))); /* must be aligned for crypto */ | |
777 | struct rxrpc_skb_priv *sp; | |
778 | u32 version, nonce, min_level, abort_code; | |
779 | int ret; | |
780 | ||
781 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->key)); | |
782 | ||
783 | if (!conn->key) { | |
784 | _leave(" = -EPROTO [no key]"); | |
785 | return -EPROTO; | |
786 | } | |
787 | ||
788 | ret = key_validate(conn->key); | |
789 | if (ret < 0) { | |
790 | *_abort_code = RXKADEXPIRED; | |
791 | return ret; | |
792 | } | |
793 | ||
794 | abort_code = RXKADPACKETSHORT; | |
795 | sp = rxrpc_skb(skb); | |
796 | if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0) | |
797 | goto protocol_error; | |
798 | ||
799 | version = ntohl(challenge.version); | |
800 | nonce = ntohl(challenge.nonce); | |
801 | min_level = ntohl(challenge.min_level); | |
802 | ||
803 | _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }", | |
0d12f8a4 | 804 | sp->hdr.serial, version, nonce, min_level); |
17926a79 DH |
805 | |
806 | abort_code = RXKADINCONSISTENCY; | |
807 | if (version != RXKAD_VERSION) | |
808 | goto protocol_error; | |
809 | ||
810 | abort_code = RXKADLEVELFAIL; | |
811 | if (conn->security_level < min_level) | |
812 | goto protocol_error; | |
813 | ||
146aa8b1 | 814 | token = conn->key->payload.data[0]; |
17926a79 DH |
815 | |
816 | /* build the response packet */ | |
817 | memset(&resp, 0, sizeof(resp)); | |
818 | ||
098a2099 DH |
819 | resp.version = htonl(RXKAD_VERSION); |
820 | resp.encrypted.epoch = htonl(conn->epoch); | |
821 | resp.encrypted.cid = htonl(conn->cid); | |
822 | resp.encrypted.securityIndex = htonl(conn->security_ix); | |
823 | resp.encrypted.inc_nonce = htonl(nonce + 1); | |
824 | resp.encrypted.level = htonl(conn->security_level); | |
825 | resp.kvno = htonl(token->kad->kvno); | |
826 | resp.ticket_len = htonl(token->kad->ticket_len); | |
827 | ||
17926a79 | 828 | resp.encrypted.call_id[0] = |
0d12f8a4 | 829 | htonl(conn->channels[0] ? conn->channels[0]->call_id : 0); |
17926a79 | 830 | resp.encrypted.call_id[1] = |
0d12f8a4 | 831 | htonl(conn->channels[1] ? conn->channels[1]->call_id : 0); |
17926a79 | 832 | resp.encrypted.call_id[2] = |
0d12f8a4 | 833 | htonl(conn->channels[2] ? conn->channels[2]->call_id : 0); |
17926a79 | 834 | resp.encrypted.call_id[3] = |
0d12f8a4 | 835 | htonl(conn->channels[3] ? conn->channels[3]->call_id : 0); |
17926a79 DH |
836 | |
837 | /* calculate the response checksum and then do the encryption */ | |
838 | rxkad_calc_response_checksum(&resp); | |
33941284 DH |
839 | rxkad_encrypt_response(conn, &resp, token->kad); |
840 | return rxkad_send_response(conn, &sp->hdr, &resp, token->kad); | |
17926a79 DH |
841 | |
842 | protocol_error: | |
843 | *_abort_code = abort_code; | |
844 | _leave(" = -EPROTO [%d]", abort_code); | |
845 | return -EPROTO; | |
846 | } | |
847 | ||
848 | /* | |
849 | * decrypt the kerberos IV ticket in the response | |
850 | */ | |
851 | static int rxkad_decrypt_ticket(struct rxrpc_connection *conn, | |
852 | void *ticket, size_t ticket_len, | |
853 | struct rxrpc_crypt *_session_key, | |
854 | time_t *_expiry, | |
855 | u32 *_abort_code) | |
856 | { | |
1afe593b | 857 | struct skcipher_request *req; |
17926a79 | 858 | struct rxrpc_crypt iv, key; |
68e3f5dd | 859 | struct scatterlist sg[1]; |
17926a79 | 860 | struct in_addr addr; |
95c96174 | 861 | unsigned int life; |
17926a79 DH |
862 | time_t issue, now; |
863 | bool little_endian; | |
864 | int ret; | |
865 | u8 *p, *q, *name, *end; | |
866 | ||
867 | _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key)); | |
868 | ||
869 | *_expiry = 0; | |
870 | ||
871 | ret = key_validate(conn->server_key); | |
872 | if (ret < 0) { | |
873 | switch (ret) { | |
874 | case -EKEYEXPIRED: | |
875 | *_abort_code = RXKADEXPIRED; | |
876 | goto error; | |
877 | default: | |
878 | *_abort_code = RXKADNOAUTH; | |
879 | goto error; | |
880 | } | |
881 | } | |
882 | ||
146aa8b1 | 883 | ASSERT(conn->server_key->payload.data[0] != NULL); |
17926a79 DH |
884 | ASSERTCMP((unsigned long) ticket & 7UL, ==, 0); |
885 | ||
146aa8b1 | 886 | memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv)); |
17926a79 | 887 | |
1afe593b HX |
888 | req = skcipher_request_alloc(conn->server_key->payload.data[0], |
889 | GFP_NOFS); | |
890 | if (!req) { | |
891 | *_abort_code = RXKADNOAUTH; | |
892 | ret = -ENOMEM; | |
893 | goto error; | |
894 | } | |
17926a79 | 895 | |
68e3f5dd | 896 | sg_init_one(&sg[0], ticket, ticket_len); |
1afe593b HX |
897 | |
898 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
899 | skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x); | |
900 | ||
901 | crypto_skcipher_decrypt(req); | |
902 | skcipher_request_free(req); | |
17926a79 DH |
903 | |
904 | p = ticket; | |
905 | end = p + ticket_len; | |
906 | ||
907 | #define Z(size) \ | |
908 | ({ \ | |
909 | u8 *__str = p; \ | |
910 | q = memchr(p, 0, end - p); \ | |
911 | if (!q || q - p > (size)) \ | |
912 | goto bad_ticket; \ | |
913 | for (; p < q; p++) \ | |
914 | if (!isprint(*p)) \ | |
915 | goto bad_ticket; \ | |
916 | p++; \ | |
917 | __str; \ | |
918 | }) | |
919 | ||
920 | /* extract the ticket flags */ | |
921 | _debug("KIV FLAGS: %x", *p); | |
922 | little_endian = *p & 1; | |
923 | p++; | |
924 | ||
925 | /* extract the authentication name */ | |
926 | name = Z(ANAME_SZ); | |
927 | _debug("KIV ANAME: %s", name); | |
928 | ||
929 | /* extract the principal's instance */ | |
930 | name = Z(INST_SZ); | |
931 | _debug("KIV INST : %s", name); | |
932 | ||
933 | /* extract the principal's authentication domain */ | |
934 | name = Z(REALM_SZ); | |
935 | _debug("KIV REALM: %s", name); | |
936 | ||
937 | if (end - p < 4 + 8 + 4 + 2) | |
938 | goto bad_ticket; | |
939 | ||
940 | /* get the IPv4 address of the entity that requested the ticket */ | |
941 | memcpy(&addr, p, sizeof(addr)); | |
942 | p += 4; | |
21454aaa | 943 | _debug("KIV ADDR : %pI4", &addr); |
17926a79 DH |
944 | |
945 | /* get the session key from the ticket */ | |
946 | memcpy(&key, p, sizeof(key)); | |
947 | p += 8; | |
948 | _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1])); | |
949 | memcpy(_session_key, &key, sizeof(key)); | |
950 | ||
951 | /* get the ticket's lifetime */ | |
952 | life = *p++ * 5 * 60; | |
953 | _debug("KIV LIFE : %u", life); | |
954 | ||
955 | /* get the issue time of the ticket */ | |
956 | if (little_endian) { | |
957 | __le32 stamp; | |
958 | memcpy(&stamp, p, 4); | |
959 | issue = le32_to_cpu(stamp); | |
960 | } else { | |
961 | __be32 stamp; | |
962 | memcpy(&stamp, p, 4); | |
963 | issue = be32_to_cpu(stamp); | |
964 | } | |
965 | p += 4; | |
2c6b47de | 966 | now = get_seconds(); |
17926a79 DH |
967 | _debug("KIV ISSUE: %lx [%lx]", issue, now); |
968 | ||
969 | /* check the ticket is in date */ | |
970 | if (issue > now) { | |
971 | *_abort_code = RXKADNOAUTH; | |
972 | ret = -EKEYREJECTED; | |
973 | goto error; | |
974 | } | |
975 | ||
976 | if (issue < now - life) { | |
977 | *_abort_code = RXKADEXPIRED; | |
978 | ret = -EKEYEXPIRED; | |
979 | goto error; | |
980 | } | |
981 | ||
982 | *_expiry = issue + life; | |
983 | ||
984 | /* get the service name */ | |
985 | name = Z(SNAME_SZ); | |
986 | _debug("KIV SNAME: %s", name); | |
987 | ||
988 | /* get the service instance name */ | |
989 | name = Z(INST_SZ); | |
990 | _debug("KIV SINST: %s", name); | |
991 | ||
992 | ret = 0; | |
993 | error: | |
994 | _leave(" = %d", ret); | |
995 | return ret; | |
996 | ||
997 | bad_ticket: | |
998 | *_abort_code = RXKADBADTICKET; | |
999 | ret = -EBADMSG; | |
1000 | goto error; | |
1001 | } | |
1002 | ||
1003 | /* | |
1004 | * decrypt the response packet | |
1005 | */ | |
1006 | static void rxkad_decrypt_response(struct rxrpc_connection *conn, | |
1007 | struct rxkad_response *resp, | |
1008 | const struct rxrpc_crypt *session_key) | |
1009 | { | |
1afe593b | 1010 | SKCIPHER_REQUEST_ON_STACK(req, rxkad_ci); |
68e3f5dd | 1011 | struct scatterlist sg[2]; |
17926a79 DH |
1012 | struct rxrpc_crypt iv; |
1013 | ||
1014 | _enter(",,%08x%08x", | |
1015 | ntohl(session_key->n[0]), ntohl(session_key->n[1])); | |
1016 | ||
1017 | ASSERT(rxkad_ci != NULL); | |
1018 | ||
1019 | mutex_lock(&rxkad_ci_mutex); | |
1afe593b HX |
1020 | if (crypto_skcipher_setkey(rxkad_ci, session_key->x, |
1021 | sizeof(*session_key)) < 0) | |
17926a79 DH |
1022 | BUG(); |
1023 | ||
1024 | memcpy(&iv, session_key, sizeof(iv)); | |
17926a79 | 1025 | |
68e3f5dd | 1026 | rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted)); |
1afe593b HX |
1027 | |
1028 | skcipher_request_set_tfm(req, rxkad_ci); | |
1029 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
1030 | skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x); | |
1031 | ||
1032 | crypto_skcipher_decrypt(req); | |
1033 | skcipher_request_zero(req); | |
1034 | ||
17926a79 DH |
1035 | mutex_unlock(&rxkad_ci_mutex); |
1036 | ||
1037 | _leave(""); | |
1038 | } | |
1039 | ||
1040 | /* | |
1041 | * verify a response | |
1042 | */ | |
1043 | static int rxkad_verify_response(struct rxrpc_connection *conn, | |
1044 | struct sk_buff *skb, | |
1045 | u32 *_abort_code) | |
1046 | { | |
1047 | struct rxkad_response response | |
1048 | __attribute__((aligned(8))); /* must be aligned for crypto */ | |
1049 | struct rxrpc_skb_priv *sp; | |
1050 | struct rxrpc_crypt session_key; | |
1051 | time_t expiry; | |
1052 | void *ticket; | |
91e916cf AV |
1053 | u32 abort_code, version, kvno, ticket_len, level; |
1054 | __be32 csum; | |
17926a79 DH |
1055 | int ret; |
1056 | ||
1057 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key)); | |
1058 | ||
1059 | abort_code = RXKADPACKETSHORT; | |
1060 | if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0) | |
1061 | goto protocol_error; | |
1062 | if (!pskb_pull(skb, sizeof(response))) | |
1063 | BUG(); | |
1064 | ||
1065 | version = ntohl(response.version); | |
1066 | ticket_len = ntohl(response.ticket_len); | |
1067 | kvno = ntohl(response.kvno); | |
1068 | sp = rxrpc_skb(skb); | |
1069 | _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }", | |
0d12f8a4 | 1070 | sp->hdr.serial, version, kvno, ticket_len); |
17926a79 DH |
1071 | |
1072 | abort_code = RXKADINCONSISTENCY; | |
1073 | if (version != RXKAD_VERSION) | |
4aa9cb32 | 1074 | goto protocol_error; |
17926a79 DH |
1075 | |
1076 | abort_code = RXKADTICKETLEN; | |
1077 | if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN) | |
1078 | goto protocol_error; | |
1079 | ||
1080 | abort_code = RXKADUNKNOWNKEY; | |
1081 | if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5) | |
1082 | goto protocol_error; | |
1083 | ||
1084 | /* extract the kerberos ticket and decrypt and decode it */ | |
1085 | ticket = kmalloc(ticket_len, GFP_NOFS); | |
1086 | if (!ticket) | |
1087 | return -ENOMEM; | |
1088 | ||
1089 | abort_code = RXKADPACKETSHORT; | |
1090 | if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0) | |
1091 | goto protocol_error_free; | |
1092 | ||
1093 | ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key, | |
1094 | &expiry, &abort_code); | |
1095 | if (ret < 0) { | |
1096 | *_abort_code = abort_code; | |
1097 | kfree(ticket); | |
1098 | return ret; | |
1099 | } | |
1100 | ||
1101 | /* use the session key from inside the ticket to decrypt the | |
1102 | * response */ | |
1103 | rxkad_decrypt_response(conn, &response, &session_key); | |
1104 | ||
1105 | abort_code = RXKADSEALEDINCON; | |
0d12f8a4 | 1106 | if (ntohl(response.encrypted.epoch) != conn->epoch) |
17926a79 | 1107 | goto protocol_error_free; |
0d12f8a4 | 1108 | if (ntohl(response.encrypted.cid) != conn->cid) |
17926a79 DH |
1109 | goto protocol_error_free; |
1110 | if (ntohl(response.encrypted.securityIndex) != conn->security_ix) | |
1111 | goto protocol_error_free; | |
1112 | csum = response.encrypted.checksum; | |
1113 | response.encrypted.checksum = 0; | |
1114 | rxkad_calc_response_checksum(&response); | |
1115 | if (response.encrypted.checksum != csum) | |
1116 | goto protocol_error_free; | |
1117 | ||
1118 | if (ntohl(response.encrypted.call_id[0]) > INT_MAX || | |
1119 | ntohl(response.encrypted.call_id[1]) > INT_MAX || | |
1120 | ntohl(response.encrypted.call_id[2]) > INT_MAX || | |
1121 | ntohl(response.encrypted.call_id[3]) > INT_MAX) | |
1122 | goto protocol_error_free; | |
1123 | ||
1124 | abort_code = RXKADOUTOFSEQUENCE; | |
0d12f8a4 | 1125 | if (ntohl(response.encrypted.inc_nonce) != conn->security_nonce + 1) |
17926a79 DH |
1126 | goto protocol_error_free; |
1127 | ||
1128 | abort_code = RXKADLEVELFAIL; | |
1129 | level = ntohl(response.encrypted.level); | |
1130 | if (level > RXRPC_SECURITY_ENCRYPT) | |
1131 | goto protocol_error_free; | |
1132 | conn->security_level = level; | |
1133 | ||
1134 | /* create a key to hold the security data and expiration time - after | |
1135 | * this the connection security can be handled in exactly the same way | |
1136 | * as for a client connection */ | |
1137 | ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno); | |
1138 | if (ret < 0) { | |
1139 | kfree(ticket); | |
1140 | return ret; | |
1141 | } | |
1142 | ||
1143 | kfree(ticket); | |
1144 | _leave(" = 0"); | |
1145 | return 0; | |
1146 | ||
1147 | protocol_error_free: | |
1148 | kfree(ticket); | |
1149 | protocol_error: | |
1150 | *_abort_code = abort_code; | |
1151 | _leave(" = -EPROTO [%d]", abort_code); | |
1152 | return -EPROTO; | |
1153 | } | |
1154 | ||
1155 | /* | |
1156 | * clear the connection security | |
1157 | */ | |
1158 | static void rxkad_clear(struct rxrpc_connection *conn) | |
1159 | { | |
1160 | _enter(""); | |
1161 | ||
1162 | if (conn->cipher) | |
1afe593b | 1163 | crypto_free_skcipher(conn->cipher); |
17926a79 DH |
1164 | } |
1165 | ||
1166 | /* | |
1167 | * RxRPC Kerberos-based security | |
1168 | */ | |
1169 | static struct rxrpc_security rxkad = { | |
1170 | .owner = THIS_MODULE, | |
1171 | .name = "rxkad", | |
8b815477 | 1172 | .security_index = RXRPC_SECURITY_RXKAD, |
17926a79 DH |
1173 | .init_connection_security = rxkad_init_connection_security, |
1174 | .prime_packet_security = rxkad_prime_packet_security, | |
1175 | .secure_packet = rxkad_secure_packet, | |
1176 | .verify_packet = rxkad_verify_packet, | |
1177 | .issue_challenge = rxkad_issue_challenge, | |
1178 | .respond_to_challenge = rxkad_respond_to_challenge, | |
1179 | .verify_response = rxkad_verify_response, | |
1180 | .clear = rxkad_clear, | |
1181 | }; | |
1182 | ||
1183 | static __init int rxkad_init(void) | |
1184 | { | |
1185 | _enter(""); | |
1186 | ||
1187 | /* pin the cipher we need so that the crypto layer doesn't invoke | |
1188 | * keventd to go get it */ | |
1afe593b | 1189 | rxkad_ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC); |
17926a79 DH |
1190 | if (IS_ERR(rxkad_ci)) |
1191 | return PTR_ERR(rxkad_ci); | |
1192 | ||
1193 | return rxrpc_register_security(&rxkad); | |
1194 | } | |
1195 | ||
1196 | module_init(rxkad_init); | |
1197 | ||
1198 | static __exit void rxkad_exit(void) | |
1199 | { | |
1200 | _enter(""); | |
1201 | ||
1202 | rxrpc_unregister_security(&rxkad); | |
1afe593b | 1203 | crypto_free_skcipher(rxkad_ci); |
17926a79 DH |
1204 | } |
1205 | ||
1206 | module_exit(rxkad_exit); |