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m68knommu: remove local gettimeofday code
[wrt350n-kernel.git] / net / rxrpc / rxkad.c
blobf48434adb7c242a5cae2e6cdbd074a43951aac1d
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 <linux/module.h>
13 #include <linux/net.h>
14 #include <linux/skbuff.h>
15 #include <linux/udp.h>
16 #include <linux/crypto.h>
17 #include <linux/scatterlist.h>
18 #include <linux/ctype.h>
19 #include <net/sock.h>
20 #include <net/af_rxrpc.h>
21 #define rxrpc_debug rxkad_debug
22 #include "ar-internal.h"
23
24 #define RXKAD_VERSION 2
25 #define MAXKRB5TICKETLEN 1024
26 #define RXKAD_TKT_TYPE_KERBEROS_V5 256
27 #define ANAME_SZ 40 /* size of authentication name */
28 #define INST_SZ 40 /* size of principal's instance */
29 #define REALM_SZ 40 /* size of principal's auth domain */
30 #define SNAME_SZ 40 /* size of service name */
31
32 unsigned rxrpc_debug;
33 module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO);
34 MODULE_PARM_DESC(rxrpc_debug, "rxkad debugging mask");
35
36 struct rxkad_level1_hdr {
37 __be32 data_size; /* true data size (excluding padding) */
38 };
39
40 struct rxkad_level2_hdr {
41 __be32 data_size; /* true data size (excluding padding) */
42 __be32 checksum; /* decrypted data checksum */
43 };
44
45 MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos)");
46 MODULE_AUTHOR("Red Hat, Inc.");
47 MODULE_LICENSE("GPL");
48
49 /*
50 * this holds a pinned cipher so that keventd doesn't get called by the cipher
51 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
52 * packets
53 */
54 static struct crypto_blkcipher *rxkad_ci;
55 static DEFINE_MUTEX(rxkad_ci_mutex);
56
57 /*
58 * initialise connection security
59 */
60 static int rxkad_init_connection_security(struct rxrpc_connection *conn)
61 {
62 struct rxrpc_key_payload *payload;
63 struct crypto_blkcipher *ci;
64 int ret;
65
66 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
67
68 payload = conn->key->payload.data;
69 conn->security_ix = payload->k.security_index;
70
71 ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
72 if (IS_ERR(ci)) {
73 _debug("no cipher");
74 ret = PTR_ERR(ci);
75 goto error;
76 }
77
78 if (crypto_blkcipher_setkey(ci, payload->k.session_key,
79 sizeof(payload->k.session_key)) < 0)
80 BUG();
81
82 switch (conn->security_level) {
83 case RXRPC_SECURITY_PLAIN:
84 break;
85 case RXRPC_SECURITY_AUTH:
86 conn->size_align = 8;
87 conn->security_size = sizeof(struct rxkad_level1_hdr);
88 conn->header_size += sizeof(struct rxkad_level1_hdr);
89 break;
90 case RXRPC_SECURITY_ENCRYPT:
91 conn->size_align = 8;
92 conn->security_size = sizeof(struct rxkad_level2_hdr);
93 conn->header_size += sizeof(struct rxkad_level2_hdr);
94 break;
95 default:
96 ret = -EKEYREJECTED;
97 goto error;
98 }
99
100 conn->cipher = ci;
101 ret = 0;
102 error:
103 _leave(" = %d", ret);
104 return ret;
105 }
106
107 /*
108 * prime the encryption state with the invariant parts of a connection's
109 * description
110 */
111 static void rxkad_prime_packet_security(struct rxrpc_connection *conn)
112 {
113 struct rxrpc_key_payload *payload;
114 struct blkcipher_desc desc;
115 struct scatterlist sg[2];
116 struct rxrpc_crypt iv;
117 struct {
118 __be32 x[4];
119 } tmpbuf __attribute__((aligned(16))); /* must all be in same page */
120
121 _enter("");
122
123 if (!conn->key)
124 return;
125
126 payload = conn->key->payload.data;
127 memcpy(&iv, payload->k.session_key, sizeof(iv));
128
129 desc.tfm = conn->cipher;
130 desc.info = iv.x;
131 desc.flags = 0;
132
133 tmpbuf.x[0] = conn->epoch;
134 tmpbuf.x[1] = conn->cid;
135 tmpbuf.x[2] = 0;
136 tmpbuf.x[3] = htonl(conn->security_ix);
137
138 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
139 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
140 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
141
142 memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
143 ASSERTCMP(conn->csum_iv.n[0], ==, tmpbuf.x[2]);
144
145 _leave("");
146 }
147
148 /*
149 * partially encrypt a packet (level 1 security)
150 */
151 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
152 struct sk_buff *skb,
153 u32 data_size,
154 void *sechdr)
155 {
156 struct rxrpc_skb_priv *sp;
157 struct blkcipher_desc desc;
158 struct rxrpc_crypt iv;
159 struct scatterlist sg[2];
160 struct {
161 struct rxkad_level1_hdr hdr;
162 __be32 first; /* first four bytes of data and padding */
163 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
164 u16 check;
165
166 sp = rxrpc_skb(skb);
167
168 _enter("");
169
170 check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
171 data_size |= (u32) check << 16;
172
173 tmpbuf.hdr.data_size = htonl(data_size);
174 memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first));
175
176 /* start the encryption afresh */
177 memset(&iv, 0, sizeof(iv));
178 desc.tfm = call->conn->cipher;
179 desc.info = iv.x;
180 desc.flags = 0;
181
182 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
183 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
184 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
185
186 memcpy(sechdr, &tmpbuf, sizeof(tmpbuf));
187
188 _leave(" = 0");
189 return 0;
190 }
191
192 /*
193 * wholly encrypt a packet (level 2 security)
194 */
195 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
196 struct sk_buff *skb,
197 u32 data_size,
198 void *sechdr)
199 {
200 const struct rxrpc_key_payload *payload;
201 struct rxkad_level2_hdr rxkhdr
202 __attribute__((aligned(8))); /* must be all on one page */
203 struct rxrpc_skb_priv *sp;
204 struct blkcipher_desc desc;
205 struct rxrpc_crypt iv;
206 struct scatterlist sg[16];
207 struct sk_buff *trailer;
208 unsigned len;
209 u16 check;
210 int nsg;
211
212 sp = rxrpc_skb(skb);
213
214 _enter("");
215
216 check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
217
218 rxkhdr.data_size = htonl(data_size | (u32) check << 16);
219 rxkhdr.checksum = 0;
220
221 /* encrypt from the session key */
222 payload = call->conn->key->payload.data;
223 memcpy(&iv, payload->k.session_key, sizeof(iv));
224 desc.tfm = call->conn->cipher;
225 desc.info = iv.x;
226 desc.flags = 0;
227
228 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
229 sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
230 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr));
231
232 /* we want to encrypt the skbuff in-place */
233 nsg = skb_cow_data(skb, 0, &trailer);
234 if (nsg < 0 || nsg > 16)
235 return -ENOMEM;
236
237 len = data_size + call->conn->size_align - 1;
238 len &= ~(call->conn->size_align - 1);
239
240 sg_init_table(sg, nsg);
241 skb_to_sgvec(skb, sg, 0, len);
242 crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
243
244 _leave(" = 0");
245 return 0;
246 }
247
248 /*
249 * checksum an RxRPC packet header
250 */
251 static int rxkad_secure_packet(const struct rxrpc_call *call,
252 struct sk_buff *skb,
253 size_t data_size,
254 void *sechdr)
255 {
256 struct rxrpc_skb_priv *sp;
257 struct blkcipher_desc desc;
258 struct rxrpc_crypt iv;
259 struct scatterlist sg[2];
260 struct {
261 __be32 x[2];
262 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
263 __be32 x;
264 int ret;
265
266 sp = rxrpc_skb(skb);
267
268 _enter("{%d{%x}},{#%u},%zu,",
269 call->debug_id, key_serial(call->conn->key), ntohl(sp->hdr.seq),
270 data_size);
271
272 if (!call->conn->cipher)
273 return 0;
274
275 ret = key_validate(call->conn->key);
276 if (ret < 0)
277 return ret;
278
279 /* continue encrypting from where we left off */
280 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
281 desc.tfm = call->conn->cipher;
282 desc.info = iv.x;
283 desc.flags = 0;
284
285 /* calculate the security checksum */
286 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
287 x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
288 tmpbuf.x[0] = sp->hdr.callNumber;
289 tmpbuf.x[1] = x;
290
291 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
292 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
293 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
294
295 x = ntohl(tmpbuf.x[1]);
296 x = (x >> 16) & 0xffff;
297 if (x == 0)
298 x = 1; /* zero checksums are not permitted */
299 sp->hdr.cksum = htons(x);
300
301 switch (call->conn->security_level) {
302 case RXRPC_SECURITY_PLAIN:
303 ret = 0;
304 break;
305 case RXRPC_SECURITY_AUTH:
306 ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
307 break;
308 case RXRPC_SECURITY_ENCRYPT:
309 ret = rxkad_secure_packet_encrypt(call, skb, data_size,
310 sechdr);
311 break;
312 default:
313 ret = -EPERM;
314 break;
315 }
316
317 _leave(" = %d [set %hx]", ret, x);
318 return ret;
319 }
320
321 /*
322 * decrypt partial encryption on a packet (level 1 security)
323 */
324 static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
325 struct sk_buff *skb,
326 u32 *_abort_code)
327 {
328 struct rxkad_level1_hdr sechdr;
329 struct rxrpc_skb_priv *sp;
330 struct blkcipher_desc desc;
331 struct rxrpc_crypt iv;
332 struct scatterlist sg[16];
333 struct sk_buff *trailer;
334 u32 data_size, buf;
335 u16 check;
336 int nsg;
337
338 _enter("");
339
340 sp = rxrpc_skb(skb);
341
342 /* we want to decrypt the skbuff in-place */
343 nsg = skb_cow_data(skb, 0, &trailer);
344 if (nsg < 0 || nsg > 16)
345 goto nomem;
346
347 sg_init_table(sg, nsg);
348 skb_to_sgvec(skb, sg, 0, 8);
349
350 /* start the decryption afresh */
351 memset(&iv, 0, sizeof(iv));
352 desc.tfm = call->conn->cipher;
353 desc.info = iv.x;
354 desc.flags = 0;
355
356 crypto_blkcipher_decrypt_iv(&desc, sg, sg, 8);
357
358 /* remove the decrypted packet length */
359 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
360 goto datalen_error;
361 if (!skb_pull(skb, sizeof(sechdr)))
362 BUG();
363
364 buf = ntohl(sechdr.data_size);
365 data_size = buf & 0xffff;
366
367 check = buf >> 16;
368 check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
369 check &= 0xffff;
370 if (check != 0) {
371 *_abort_code = RXKADSEALEDINCON;
372 goto protocol_error;
373 }
374
375 /* shorten the packet to remove the padding */
376 if (data_size > skb->len)
377 goto datalen_error;
378 else if (data_size < skb->len)
379 skb->len = data_size;
380
381 _leave(" = 0 [dlen=%x]", data_size);
382 return 0;
383
384 datalen_error:
385 *_abort_code = RXKADDATALEN;
386 protocol_error:
387 _leave(" = -EPROTO");
388 return -EPROTO;
389
390 nomem:
391 _leave(" = -ENOMEM");
392 return -ENOMEM;
393 }
394
395 /*
396 * wholly decrypt a packet (level 2 security)
397 */
398 static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
399 struct sk_buff *skb,
400 u32 *_abort_code)
401 {
402 const struct rxrpc_key_payload *payload;
403 struct rxkad_level2_hdr sechdr;
404 struct rxrpc_skb_priv *sp;
405 struct blkcipher_desc desc;
406 struct rxrpc_crypt iv;
407 struct scatterlist _sg[4], *sg;
408 struct sk_buff *trailer;
409 u32 data_size, buf;
410 u16 check;
411 int nsg;
412
413 _enter(",{%d}", skb->len);
414
415 sp = rxrpc_skb(skb);
416
417 /* we want to decrypt the skbuff in-place */
418 nsg = skb_cow_data(skb, 0, &trailer);
419 if (nsg < 0)
420 goto nomem;
421
422 sg = _sg;
423 if (unlikely(nsg > 4)) {
424 sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
425 if (!sg)
426 goto nomem;
427 }
428
429 sg_init_table(sg, nsg);
430 skb_to_sgvec(skb, sg, 0, skb->len);
431
432 /* decrypt from the session key */
433 payload = call->conn->key->payload.data;
434 memcpy(&iv, payload->k.session_key, sizeof(iv));
435 desc.tfm = call->conn->cipher;
436 desc.info = iv.x;
437 desc.flags = 0;
438
439 crypto_blkcipher_decrypt_iv(&desc, sg, sg, skb->len);
440 if (sg != _sg)
441 kfree(sg);
442
443 /* remove the decrypted packet length */
444 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
445 goto datalen_error;
446 if (!skb_pull(skb, sizeof(sechdr)))
447 BUG();
448
449 buf = ntohl(sechdr.data_size);
450 data_size = buf & 0xffff;
451
452 check = buf >> 16;
453 check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
454 check &= 0xffff;
455 if (check != 0) {
456 *_abort_code = RXKADSEALEDINCON;
457 goto protocol_error;
458 }
459
460 /* shorten the packet to remove the padding */
461 if (data_size > skb->len)
462 goto datalen_error;
463 else if (data_size < skb->len)
464 skb->len = data_size;
465
466 _leave(" = 0 [dlen=%x]", data_size);
467 return 0;
468
469 datalen_error:
470 *_abort_code = RXKADDATALEN;
471 protocol_error:
472 _leave(" = -EPROTO");
473 return -EPROTO;
474
475 nomem:
476 _leave(" = -ENOMEM");
477 return -ENOMEM;
478 }
479
480 /*
481 * verify the security on a received packet
482 */
483 static int rxkad_verify_packet(const struct rxrpc_call *call,
484 struct sk_buff *skb,
485 u32 *_abort_code)
486 {
487 struct blkcipher_desc desc;
488 struct rxrpc_skb_priv *sp;
489 struct rxrpc_crypt iv;
490 struct scatterlist sg[2];
491 struct {
492 __be32 x[2];
493 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
494 __be32 x;
495 __be16 cksum;
496 int ret;
497
498 sp = rxrpc_skb(skb);
499
500 _enter("{%d{%x}},{#%u}",
501 call->debug_id, key_serial(call->conn->key),
502 ntohl(sp->hdr.seq));
503
504 if (!call->conn->cipher)
505 return 0;
506
507 if (sp->hdr.securityIndex != 2) {
508 *_abort_code = RXKADINCONSISTENCY;
509 _leave(" = -EPROTO [not rxkad]");
510 return -EPROTO;
511 }
512
513 /* continue encrypting from where we left off */
514 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
515 desc.tfm = call->conn->cipher;
516 desc.info = iv.x;
517 desc.flags = 0;
518
519 /* validate the security checksum */
520 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
521 x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
522 tmpbuf.x[0] = call->call_id;
523 tmpbuf.x[1] = x;
524
525 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
526 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
527 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
528
529 x = ntohl(tmpbuf.x[1]);
530 x = (x >> 16) & 0xffff;
531 if (x == 0)
532 x = 1; /* zero checksums are not permitted */
533
534 cksum = htons(x);
535 if (sp->hdr.cksum != cksum) {
536 *_abort_code = RXKADSEALEDINCON;
537 _leave(" = -EPROTO [csum failed]");
538 return -EPROTO;
539 }
540
541 switch (call->conn->security_level) {
542 case RXRPC_SECURITY_PLAIN:
543 ret = 0;
544 break;
545 case RXRPC_SECURITY_AUTH:
546 ret = rxkad_verify_packet_auth(call, skb, _abort_code);
547 break;
548 case RXRPC_SECURITY_ENCRYPT:
549 ret = rxkad_verify_packet_encrypt(call, skb, _abort_code);
550 break;
551 default:
552 ret = -ENOANO;
553 break;
554 }
555
556 _leave(" = %d", ret);
557 return ret;
558 }
559
560 /*
561 * issue a challenge
562 */
563 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
564 {
565 struct rxkad_challenge challenge;
566 struct rxrpc_header hdr;
567 struct msghdr msg;
568 struct kvec iov[2];
569 size_t len;
570 int ret;
571
572 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
573
574 ret = key_validate(conn->key);
575 if (ret < 0)
576 return ret;
577
578 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
579
580 challenge.version = htonl(2);
581 challenge.nonce = htonl(conn->security_nonce);
582 challenge.min_level = htonl(0);
583 challenge.__padding = 0;
584
585 msg.msg_name = &conn->trans->peer->srx.transport.sin;
586 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
587 msg.msg_control = NULL;
588 msg.msg_controllen = 0;
589 msg.msg_flags = 0;
590
591 hdr.epoch = conn->epoch;
592 hdr.cid = conn->cid;
593 hdr.callNumber = 0;
594 hdr.seq = 0;
595 hdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
596 hdr.flags = conn->out_clientflag;
597 hdr.userStatus = 0;
598 hdr.securityIndex = conn->security_ix;
599 hdr._rsvd = 0;
600 hdr.serviceId = conn->service_id;
601
602 iov[0].iov_base = &hdr;
603 iov[0].iov_len = sizeof(hdr);
604 iov[1].iov_base = &challenge;
605 iov[1].iov_len = sizeof(challenge);
606
607 len = iov[0].iov_len + iov[1].iov_len;
608
609 hdr.serial = htonl(atomic_inc_return(&conn->serial));
610 _proto("Tx CHALLENGE %%%u", ntohl(hdr.serial));
611
612 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len);
613 if (ret < 0) {
614 _debug("sendmsg failed: %d", ret);
615 return -EAGAIN;
616 }
617
618 _leave(" = 0");
619 return 0;
620 }
621
622 /*
623 * send a Kerberos security response
624 */
625 static int rxkad_send_response(struct rxrpc_connection *conn,
626 struct rxrpc_header *hdr,
627 struct rxkad_response *resp,
628 const struct rxkad_key *s2)
629 {
630 struct msghdr msg;
631 struct kvec iov[3];
632 size_t len;
633 int ret;
634
635 _enter("");
636
637 msg.msg_name = &conn->trans->peer->srx.transport.sin;
638 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
639 msg.msg_control = NULL;
640 msg.msg_controllen = 0;
641 msg.msg_flags = 0;
642
643 hdr->epoch = conn->epoch;
644 hdr->seq = 0;
645 hdr->type = RXRPC_PACKET_TYPE_RESPONSE;
646 hdr->flags = conn->out_clientflag;
647 hdr->userStatus = 0;
648 hdr->_rsvd = 0;
649
650 iov[0].iov_base = hdr;
651 iov[0].iov_len = sizeof(*hdr);
652 iov[1].iov_base = resp;
653 iov[1].iov_len = sizeof(*resp);
654 iov[2].iov_base = (void *) s2->ticket;
655 iov[2].iov_len = s2->ticket_len;
656
657 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
658
659 hdr->serial = htonl(atomic_inc_return(&conn->serial));
660 _proto("Tx RESPONSE %%%u", ntohl(hdr->serial));
661
662 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 3, len);
663 if (ret < 0) {
664 _debug("sendmsg failed: %d", ret);
665 return -EAGAIN;
666 }
667
668 _leave(" = 0");
669 return 0;
670 }
671
672 /*
673 * calculate the response checksum
674 */
675 static void rxkad_calc_response_checksum(struct rxkad_response *response)
676 {
677 u32 csum = 1000003;
678 int loop;
679 u8 *p = (u8 *) response;
680
681 for (loop = sizeof(*response); loop > 0; loop--)
682 csum = csum * 0x10204081 + *p++;
683
684 response->encrypted.checksum = htonl(csum);
685 }
686
687 /*
688 * load a scatterlist with a potentially split-page buffer
689 */
690 static void rxkad_sg_set_buf2(struct scatterlist sg[2],
691 void *buf, size_t buflen)
692 {
693 int nsg = 1;
694
695 sg_init_table(sg, 2);
696
697 sg_set_buf(&sg[0], buf, buflen);
698 if (sg[0].offset + buflen > PAGE_SIZE) {
699 /* the buffer was split over two pages */
700 sg[0].length = PAGE_SIZE - sg[0].offset;
701 sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
702 nsg++;
703 }
704
705 sg_mark_end(&sg[nsg - 1]);
706
707 ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
708 }
709
710 /*
711 * encrypt the response packet
712 */
713 static void rxkad_encrypt_response(struct rxrpc_connection *conn,
714 struct rxkad_response *resp,
715 const struct rxkad_key *s2)
716 {
717 struct blkcipher_desc desc;
718 struct rxrpc_crypt iv;
719 struct scatterlist sg[2];
720
721 /* continue encrypting from where we left off */
722 memcpy(&iv, s2->session_key, sizeof(iv));
723 desc.tfm = conn->cipher;
724 desc.info = iv.x;
725 desc.flags = 0;
726
727 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
728 crypto_blkcipher_encrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
729 }
730
731 /*
732 * respond to a challenge packet
733 */
734 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
735 struct sk_buff *skb,
736 u32 *_abort_code)
737 {
738 const struct rxrpc_key_payload *payload;
739 struct rxkad_challenge challenge;
740 struct rxkad_response resp
741 __attribute__((aligned(8))); /* must be aligned for crypto */
742 struct rxrpc_skb_priv *sp;
743 u32 version, nonce, min_level, abort_code;
744 int ret;
745
746 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
747
748 if (!conn->key) {
749 _leave(" = -EPROTO [no key]");
750 return -EPROTO;
751 }
752
753 ret = key_validate(conn->key);
754 if (ret < 0) {
755 *_abort_code = RXKADEXPIRED;
756 return ret;
757 }
758
759 abort_code = RXKADPACKETSHORT;
760 sp = rxrpc_skb(skb);
761 if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0)
762 goto protocol_error;
763
764 version = ntohl(challenge.version);
765 nonce = ntohl(challenge.nonce);
766 min_level = ntohl(challenge.min_level);
767
768 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
769 ntohl(sp->hdr.serial), version, nonce, min_level);
770
771 abort_code = RXKADINCONSISTENCY;
772 if (version != RXKAD_VERSION)
773 goto protocol_error;
774
775 abort_code = RXKADLEVELFAIL;
776 if (conn->security_level < min_level)
777 goto protocol_error;
778
779 payload = conn->key->payload.data;
780
781 /* build the response packet */
782 memset(&resp, 0, sizeof(resp));
783
784 resp.version = RXKAD_VERSION;
785 resp.encrypted.epoch = conn->epoch;
786 resp.encrypted.cid = conn->cid;
787 resp.encrypted.securityIndex = htonl(conn->security_ix);
788 resp.encrypted.call_id[0] =
789 (conn->channels[0] ? conn->channels[0]->call_id : 0);
790 resp.encrypted.call_id[1] =
791 (conn->channels[1] ? conn->channels[1]->call_id : 0);
792 resp.encrypted.call_id[2] =
793 (conn->channels[2] ? conn->channels[2]->call_id : 0);
794 resp.encrypted.call_id[3] =
795 (conn->channels[3] ? conn->channels[3]->call_id : 0);
796 resp.encrypted.inc_nonce = htonl(nonce + 1);
797 resp.encrypted.level = htonl(conn->security_level);
798 resp.kvno = htonl(payload->k.kvno);
799 resp.ticket_len = htonl(payload->k.ticket_len);
800
801 /* calculate the response checksum and then do the encryption */
802 rxkad_calc_response_checksum(&resp);
803 rxkad_encrypt_response(conn, &resp, &payload->k);
804 return rxkad_send_response(conn, &sp->hdr, &resp, &payload->k);
805
806 protocol_error:
807 *_abort_code = abort_code;
808 _leave(" = -EPROTO [%d]", abort_code);
809 return -EPROTO;
810 }
811
812 /*
813 * decrypt the kerberos IV ticket in the response
814 */
815 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
816 void *ticket, size_t ticket_len,
817 struct rxrpc_crypt *_session_key,
818 time_t *_expiry,
819 u32 *_abort_code)
820 {
821 struct blkcipher_desc desc;
822 struct rxrpc_crypt iv, key;
823 struct scatterlist sg[1];
824 struct in_addr addr;
825 unsigned life;
826 time_t issue, now;
827 bool little_endian;
828 int ret;
829 u8 *p, *q, *name, *end;
830
831 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
832
833 *_expiry = 0;
834
835 ret = key_validate(conn->server_key);
836 if (ret < 0) {
837 switch (ret) {
838 case -EKEYEXPIRED:
839 *_abort_code = RXKADEXPIRED;
840 goto error;
841 default:
842 *_abort_code = RXKADNOAUTH;
843 goto error;
844 }
845 }
846
847 ASSERT(conn->server_key->payload.data != NULL);
848 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
849
850 memcpy(&iv, &conn->server_key->type_data, sizeof(iv));
851
852 desc.tfm = conn->server_key->payload.data;
853 desc.info = iv.x;
854 desc.flags = 0;
855
856 sg_init_one(&sg[0], ticket, ticket_len);
857 crypto_blkcipher_decrypt_iv(&desc, sg, sg, ticket_len);
858
859 p = ticket;
860 end = p + ticket_len;
861
862 #define Z(size) \
863 ({ \
864 u8 *__str = p; \
865 q = memchr(p, 0, end - p); \
866 if (!q || q - p > (size)) \
867 goto bad_ticket; \
868 for (; p < q; p++) \
869 if (!isprint(*p)) \
870 goto bad_ticket; \
871 p++; \
872 __str; \
873 })
874
875 /* extract the ticket flags */
876 _debug("KIV FLAGS: %x", *p);
877 little_endian = *p & 1;
878 p++;
879
880 /* extract the authentication name */
881 name = Z(ANAME_SZ);
882 _debug("KIV ANAME: %s", name);
883
884 /* extract the principal's instance */
885 name = Z(INST_SZ);
886 _debug("KIV INST : %s", name);
887
888 /* extract the principal's authentication domain */
889 name = Z(REALM_SZ);
890 _debug("KIV REALM: %s", name);
891
892 if (end - p < 4 + 8 + 4 + 2)
893 goto bad_ticket;
894
895 /* get the IPv4 address of the entity that requested the ticket */
896 memcpy(&addr, p, sizeof(addr));
897 p += 4;
898 _debug("KIV ADDR : "NIPQUAD_FMT, NIPQUAD(addr));
899
900 /* get the session key from the ticket */
901 memcpy(&key, p, sizeof(key));
902 p += 8;
903 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
904 memcpy(_session_key, &key, sizeof(key));
905
906 /* get the ticket's lifetime */
907 life = *p++ * 5 * 60;
908 _debug("KIV LIFE : %u", life);
909
910 /* get the issue time of the ticket */
911 if (little_endian) {
912 __le32 stamp;
913 memcpy(&stamp, p, 4);
914 issue = le32_to_cpu(stamp);
915 } else {
916 __be32 stamp;
917 memcpy(&stamp, p, 4);
918 issue = be32_to_cpu(stamp);
919 }
920 p += 4;
921 now = get_seconds();
922 _debug("KIV ISSUE: %lx [%lx]", issue, now);
923
924 /* check the ticket is in date */
925 if (issue > now) {
926 *_abort_code = RXKADNOAUTH;
927 ret = -EKEYREJECTED;
928 goto error;
929 }
930
931 if (issue < now - life) {
932 *_abort_code = RXKADEXPIRED;
933 ret = -EKEYEXPIRED;
934 goto error;
935 }
936
937 *_expiry = issue + life;
938
939 /* get the service name */
940 name = Z(SNAME_SZ);
941 _debug("KIV SNAME: %s", name);
942
943 /* get the service instance name */
944 name = Z(INST_SZ);
945 _debug("KIV SINST: %s", name);
946
947 ret = 0;
948 error:
949 _leave(" = %d", ret);
950 return ret;
951
952 bad_ticket:
953 *_abort_code = RXKADBADTICKET;
954 ret = -EBADMSG;
955 goto error;
956 }
957
958 /*
959 * decrypt the response packet
960 */
961 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
962 struct rxkad_response *resp,
963 const struct rxrpc_crypt *session_key)
964 {
965 struct blkcipher_desc desc;
966 struct scatterlist sg[2];
967 struct rxrpc_crypt iv;
968
969 _enter(",,%08x%08x",
970 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
971
972 ASSERT(rxkad_ci != NULL);
973
974 mutex_lock(&rxkad_ci_mutex);
975 if (crypto_blkcipher_setkey(rxkad_ci, session_key->x,
976 sizeof(*session_key)) < 0)
977 BUG();
978
979 memcpy(&iv, session_key, sizeof(iv));
980 desc.tfm = rxkad_ci;
981 desc.info = iv.x;
982 desc.flags = 0;
983
984 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
985 crypto_blkcipher_decrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
986 mutex_unlock(&rxkad_ci_mutex);
987
988 _leave("");
989 }
990
991 /*
992 * verify a response
993 */
994 static int rxkad_verify_response(struct rxrpc_connection *conn,
995 struct sk_buff *skb,
996 u32 *_abort_code)
997 {
998 struct rxkad_response response
999 __attribute__((aligned(8))); /* must be aligned for crypto */
1000 struct rxrpc_skb_priv *sp;
1001 struct rxrpc_crypt session_key;
1002 time_t expiry;
1003 void *ticket;
1004 u32 abort_code, version, kvno, ticket_len, csum, level;
1005 int ret;
1006
1007 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1008
1009 abort_code = RXKADPACKETSHORT;
1010 if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0)
1011 goto protocol_error;
1012 if (!pskb_pull(skb, sizeof(response)))
1013 BUG();
1014
1015 version = ntohl(response.version);
1016 ticket_len = ntohl(response.ticket_len);
1017 kvno = ntohl(response.kvno);
1018 sp = rxrpc_skb(skb);
1019 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1020 ntohl(sp->hdr.serial), version, kvno, ticket_len);
1021
1022 abort_code = RXKADINCONSISTENCY;
1023 if (version != RXKAD_VERSION)
1024 goto protocol_error;
1025
1026 abort_code = RXKADTICKETLEN;
1027 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1028 goto protocol_error;
1029
1030 abort_code = RXKADUNKNOWNKEY;
1031 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1032 goto protocol_error;
1033
1034 /* extract the kerberos ticket and decrypt and decode it */
1035 ticket = kmalloc(ticket_len, GFP_NOFS);
1036 if (!ticket)
1037 return -ENOMEM;
1038
1039 abort_code = RXKADPACKETSHORT;
1040 if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
1041 goto protocol_error_free;
1042
1043 ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
1044 &expiry, &abort_code);
1045 if (ret < 0) {
1046 *_abort_code = abort_code;
1047 kfree(ticket);
1048 return ret;
1049 }
1050
1051 /* use the session key from inside the ticket to decrypt the
1052 * response */
1053 rxkad_decrypt_response(conn, &response, &session_key);
1054
1055 abort_code = RXKADSEALEDINCON;
1056 if (response.encrypted.epoch != conn->epoch)
1057 goto protocol_error_free;
1058 if (response.encrypted.cid != conn->cid)
1059 goto protocol_error_free;
1060 if (ntohl(response.encrypted.securityIndex) != conn->security_ix)
1061 goto protocol_error_free;
1062 csum = response.encrypted.checksum;
1063 response.encrypted.checksum = 0;
1064 rxkad_calc_response_checksum(&response);
1065 if (response.encrypted.checksum != csum)
1066 goto protocol_error_free;
1067
1068 if (ntohl(response.encrypted.call_id[0]) > INT_MAX ||
1069 ntohl(response.encrypted.call_id[1]) > INT_MAX ||
1070 ntohl(response.encrypted.call_id[2]) > INT_MAX ||
1071 ntohl(response.encrypted.call_id[3]) > INT_MAX)
1072 goto protocol_error_free;
1073
1074 abort_code = RXKADOUTOFSEQUENCE;
1075 if (response.encrypted.inc_nonce != htonl(conn->security_nonce + 1))
1076 goto protocol_error_free;
1077
1078 abort_code = RXKADLEVELFAIL;
1079 level = ntohl(response.encrypted.level);
1080 if (level > RXRPC_SECURITY_ENCRYPT)
1081 goto protocol_error_free;
1082 conn->security_level = level;
1083
1084 /* create a key to hold the security data and expiration time - after
1085 * this the connection security can be handled in exactly the same way
1086 * as for a client connection */
1087 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1088 if (ret < 0) {
1089 kfree(ticket);
1090 return ret;
1091 }
1092
1093 kfree(ticket);
1094 _leave(" = 0");
1095 return 0;
1096
1097 protocol_error_free:
1098 kfree(ticket);
1099 protocol_error:
1100 *_abort_code = abort_code;
1101 _leave(" = -EPROTO [%d]", abort_code);
1102 return -EPROTO;
1103 }
1104
1105 /*
1106 * clear the connection security
1107 */
1108 static void rxkad_clear(struct rxrpc_connection *conn)
1109 {
1110 _enter("");
1111
1112 if (conn->cipher)
1113 crypto_free_blkcipher(conn->cipher);
1114 }
1115
1116 /*
1117 * RxRPC Kerberos-based security
1118 */
1119 static struct rxrpc_security rxkad = {
1120 .owner = THIS_MODULE,
1121 .name = "rxkad",
1122 .security_index = RXKAD_VERSION,
1123 .init_connection_security = rxkad_init_connection_security,
1124 .prime_packet_security = rxkad_prime_packet_security,
1125 .secure_packet = rxkad_secure_packet,
1126 .verify_packet = rxkad_verify_packet,
1127 .issue_challenge = rxkad_issue_challenge,
1128 .respond_to_challenge = rxkad_respond_to_challenge,
1129 .verify_response = rxkad_verify_response,
1130 .clear = rxkad_clear,
1131 };
1132
1133 static __init int rxkad_init(void)
1134 {
1135 _enter("");
1136
1137 /* pin the cipher we need so that the crypto layer doesn't invoke
1138 * keventd to go get it */
1139 rxkad_ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
1140 if (IS_ERR(rxkad_ci))
1141 return PTR_ERR(rxkad_ci);
1142
1143 return rxrpc_register_security(&rxkad);
1144 }
1145
1146 module_init(rxkad_init);
1147
1148 static __exit void rxkad_exit(void)
1149 {
1150 _enter("");
1151
1152 rxrpc_unregister_security(&rxkad);
1153 crypto_free_blkcipher(rxkad_ci);
1154 }
1155
1156 module_exit(rxkad_exit);
WRT350N Kernel Patches