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eeprom: at24: improve the device_id table readability
[linux/fpc-iii.git] / net / rxrpc / rxkad.c
blobbab56ed649ba034847375de135b7b17357f0e532
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
12 #include <crypto/skcipher.h>
13 #include <linux/module.h>
14 #include <linux/net.h>
15 #include <linux/skbuff.h>
16 #include <linux/udp.h>
17 #include <linux/scatterlist.h>
18 #include <linux/ctype.h>
19 #include <linux/slab.h>
20 #include <net/sock.h>
21 #include <net/af_rxrpc.h>
22 #include <keys/rxrpc-type.h>
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
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
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 */
47 static struct crypto_skcipher *rxkad_ci;
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 {
55 struct crypto_skcipher *ci;
56 struct rxrpc_key_token *token;
57 int ret;
58
59 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
60
61 token = conn->key->payload.data[0];
62 conn->security_ix = token->security_index;
63
64 ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
65 if (IS_ERR(ci)) {
66 _debug("no cipher");
67 ret = PTR_ERR(ci);
68 goto error;
69 }
70
71 if (crypto_skcipher_setkey(ci, token->kad->session_key,
72 sizeof(token->kad->session_key)) < 0)
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 {
106 struct rxrpc_key_token *token;
107 SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
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
119 token = conn->key->payload.data[0];
120 memcpy(&iv, token->kad->session_key, sizeof(iv));
121
122 tmpbuf.x[0] = htonl(conn->epoch);
123 tmpbuf.x[1] = htonl(conn->cid);
124 tmpbuf.x[2] = 0;
125 tmpbuf.x[3] = htonl(conn->security_ix);
126
127 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
128 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
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);
136
137 memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
138 ASSERTCMP((u32 __force)conn->csum_iv.n[0], ==, (u32 __force)tmpbuf.x[2]);
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;
152 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
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
165 check = sp->hdr.seq ^ sp->hdr.callNumber;
166 data_size |= (u32)check << 16;
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));
173
174 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
175 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
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);
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,
194 struct sk_buff *skb,
195 u32 data_size,
196 void *sechdr)
197 {
198 const struct rxrpc_key_token *token;
199 struct rxkad_level2_hdr rxkhdr
200 __attribute__((aligned(8))); /* must be all on one page */
201 struct rxrpc_skb_priv *sp;
202 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
203 struct rxrpc_crypt iv;
204 struct scatterlist sg[16];
205 struct sk_buff *trailer;
206 unsigned int len;
207 u16 check;
208 int nsg;
209 int err;
210
211 sp = rxrpc_skb(skb);
212
213 _enter("");
214
215 check = sp->hdr.seq ^ sp->hdr.callNumber;
216
217 rxkhdr.data_size = htonl(data_size | (u32)check << 16);
218 rxkhdr.checksum = 0;
219
220 /* encrypt from the session key */
221 token = call->conn->key->payload.data[0];
222 memcpy(&iv, token->kad->session_key, sizeof(iv));
223
224 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
225 sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
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);
232
233 /* we want to encrypt the skbuff in-place */
234 nsg = skb_cow_data(skb, 0, &trailer);
235 err = -ENOMEM;
236 if (nsg < 0 || nsg > 16)
237 goto out;
238
239 len = data_size + call->conn->size_align - 1;
240 len &= ~(call->conn->size_align - 1);
241
242 sg_init_table(sg, nsg);
243 skb_to_sgvec(skb, sg, 0, len);
244
245 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
246
247 crypto_skcipher_encrypt(req);
248
249 _leave(" = 0");
250 err = 0;
251
252 out:
253 skcipher_request_zero(req);
254 return err;
255 }
256
257 /*
258 * checksum an RxRPC packet header
259 */
260 static int rxkad_secure_packet(const struct rxrpc_call *call,
261 struct sk_buff *skb,
262 size_t data_size,
263 void *sechdr)
264 {
265 struct rxrpc_skb_priv *sp;
266 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
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 */
272 u32 x, y;
273 int ret;
274
275 sp = rxrpc_skb(skb);
276
277 _enter("{%d{%x}},{#%u},%zu,",
278 call->debug_id, key_serial(call->conn->key), sp->hdr.seq,
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));
290
291 /* calculate the security checksum */
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);
296
297 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
298 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
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);
306
307 y = ntohl(tmpbuf.x[1]);
308 y = (y >> 16) & 0xffff;
309 if (y == 0)
310 y = 1; /* zero checksums are not permitted */
311 sp->hdr.cksum = y;
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
329 _leave(" = %d [set %hx]", ret, y);
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;
342 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
343 struct rxrpc_crypt iv;
344 struct scatterlist sg[16];
345 struct sk_buff *trailer;
346 u32 data_size, buf;
347 u16 check;
348 int nsg;
349
350 _enter("");
351
352 sp = rxrpc_skb(skb);
353
354 /* we want to decrypt the skbuff in-place */
355 nsg = skb_cow_data(skb, 0, &trailer);
356 if (nsg < 0 || nsg > 16)
357 goto nomem;
358
359 sg_init_table(sg, nsg);
360 skb_to_sgvec(skb, sg, 0, 8);
361
362 /* start the decryption afresh */
363 memset(&iv, 0, sizeof(iv));
364
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);
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;
382 check ^= sp->hdr.seq ^ sp->hdr.callNumber;
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 {
416 const struct rxrpc_key_token *token;
417 struct rxkad_level2_hdr sechdr;
418 struct rxrpc_skb_priv *sp;
419 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
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
443 sg_init_table(sg, nsg);
444 skb_to_sgvec(skb, sg, 0, skb->len);
445
446 /* decrypt from the session key */
447 token = call->conn->key->payload.data[0];
448 memcpy(&iv, token->kad->session_key, sizeof(iv));
449
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);
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;
469 check ^= sp->hdr.seq ^ sp->hdr.callNumber;
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 {
503 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
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 */
510 u16 cksum;
511 u32 x, y;
512 int ret;
513
514 sp = rxrpc_skb(skb);
515
516 _enter("{%d{%x}},{#%u}",
517 call->debug_id, key_serial(call->conn->key), sp->hdr.seq);
518
519 if (!call->conn->cipher)
520 return 0;
521
522 if (sp->hdr.securityIndex != RXRPC_SECURITY_RXKAD) {
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));
530
531 /* validate the security checksum */
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);
536
537 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
538 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
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);
546
547 y = ntohl(tmpbuf.x[1]);
548 cksum = (y >> 16) & 0xffff;
549 if (cksum == 0)
550 cksum = 1; /* zero checksums are not permitted */
551
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;
583 struct rxrpc_wire_header whdr;
584 struct msghdr msg;
585 struct kvec iov[2];
586 size_t len;
587 u32 serial;
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
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);
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
627 serial = atomic_inc_return(&conn->serial);
628 whdr.serial = htonl(serial);
629 _proto("Tx CHALLENGE %%%u", serial);
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,
645 struct rxrpc_host_header *hdr,
646 struct rxkad_response *resp,
647 const struct rxkad_key *s2)
648 {
649 struct rxrpc_wire_header whdr;
650 struct msghdr msg;
651 struct kvec iov[3];
652 size_t len;
653 u32 serial;
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
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);
671
672 iov[0].iov_base = &whdr;
673 iov[0].iov_len = sizeof(whdr);
674 iov[1].iov_base = resp;
675 iov[1].iov_len = sizeof(*resp);
676 iov[2].iov_base = (void *)s2->ticket;
677 iov[2].iov_len = s2->ticket_len;
678
679 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
680
681 serial = atomic_inc_return(&conn->serial);
682 whdr.serial = htonl(serial);
683 _proto("Tx RESPONSE %%%u", serial);
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 {
716 int nsg = 1;
717
718 sg_init_table(sg, 2);
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);
725 nsg++;
726 }
727
728 sg_mark_end(&sg[nsg - 1]);
729
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 {
740 SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
741 struct rxrpc_crypt iv;
742 struct scatterlist sg[2];
743
744 /* continue encrypting from where we left off */
745 memcpy(&iv, s2->session_key, sizeof(iv));
746
747 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
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);
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 {
764 const struct rxrpc_key_token *token;
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 }",
795 sp->hdr.serial, version, nonce, min_level);
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
805 token = conn->key->payload.data[0];
806
807 /* build the response packet */
808 memset(&resp, 0, sizeof(resp));
809
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
819 resp.encrypted.call_id[0] =
820 htonl(conn->channels[0] ? conn->channels[0]->call_id : 0);
821 resp.encrypted.call_id[1] =
822 htonl(conn->channels[1] ? conn->channels[1]->call_id : 0);
823 resp.encrypted.call_id[2] =
824 htonl(conn->channels[2] ? conn->channels[2]->call_id : 0);
825 resp.encrypted.call_id[3] =
826 htonl(conn->channels[3] ? conn->channels[3]->call_id : 0);
827
828 /* calculate the response checksum and then do the encryption */
829 rxkad_calc_response_checksum(&resp);
830 rxkad_encrypt_response(conn, &resp, token->kad);
831 return rxkad_send_response(conn, &sp->hdr, &resp, token->kad);
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 {
848 struct skcipher_request *req;
849 struct rxrpc_crypt iv, key;
850 struct scatterlist sg[1];
851 struct in_addr addr;
852 unsigned int life;
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
874 ASSERT(conn->server_key->payload.data[0] != NULL);
875 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
876
877 memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv));
878
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 }
886
887 sg_init_one(&sg[0], ticket, ticket_len);
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);
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;
934 _debug("KIV ADDR : %pI4", &addr);
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;
957 now = get_seconds();
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 {
1001 SKCIPHER_REQUEST_ON_STACK(req, rxkad_ci);
1002 struct scatterlist sg[2];
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);
1011 if (crypto_skcipher_setkey(rxkad_ci, session_key->x,
1012 sizeof(*session_key)) < 0)
1013 BUG();
1014
1015 memcpy(&iv, session_key, sizeof(iv));
1016
1017 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
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
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;
1044 u32 abort_code, version, kvno, ticket_len, level;
1045 __be32 csum;
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 }",
1061 sp->hdr.serial, version, kvno, ticket_len);
1062
1063 abort_code = RXKADINCONSISTENCY;
1064 if (version != RXKAD_VERSION)
1065 goto protocol_error;
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;
1097 if (ntohl(response.encrypted.epoch) != conn->epoch)
1098 goto protocol_error_free;
1099 if (ntohl(response.encrypted.cid) != conn->cid)
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;
1116 if (ntohl(response.encrypted.inc_nonce) != conn->security_nonce + 1)
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)
1154 crypto_free_skcipher(conn->cipher);
1155 }
1156
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);
1165 return PTR_ERR_OR_ZERO(rxkad_ci);
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
1177 /*
1178 * RxRPC Kerberos-based security
1179 */
1180 const struct rxrpc_security rxkad = {
1181 .name = "rxkad",
1182 .security_index = RXRPC_SECURITY_RXKAD,
1183 .init = rxkad_init,
1184 .exit = rxkad_exit,
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 };
Linux with added FPC-III support