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update checkpatch.pl to version 0.05
[pv_ops_mirror.git] / net / rxrpc / rxkad.c
blob5ec705144e10f7500b51755699afc97f3aa0e2a5
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 memset(sg, 0, sizeof(sg));
139 sg_set_buf(&sg[0], &tmpbuf, sizeof(tmpbuf));
140 sg_set_buf(&sg[1], &tmpbuf, sizeof(tmpbuf));
141 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
142
143 memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
144 ASSERTCMP(conn->csum_iv.n[0], ==, tmpbuf.x[2]);
145
146 _leave("");
147 }
148
149 /*
150 * partially encrypt a packet (level 1 security)
151 */
152 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
153 struct sk_buff *skb,
154 u32 data_size,
155 void *sechdr)
156 {
157 struct rxrpc_skb_priv *sp;
158 struct blkcipher_desc desc;
159 struct rxrpc_crypt iv;
160 struct scatterlist sg[2];
161 struct {
162 struct rxkad_level1_hdr hdr;
163 __be32 first; /* first four bytes of data and padding */
164 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
165 u16 check;
166
167 sp = rxrpc_skb(skb);
168
169 _enter("");
170
171 check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
172 data_size |= (u32) check << 16;
173
174 tmpbuf.hdr.data_size = htonl(data_size);
175 memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first));
176
177 /* start the encryption afresh */
178 memset(&iv, 0, sizeof(iv));
179 desc.tfm = call->conn->cipher;
180 desc.info = iv.x;
181 desc.flags = 0;
182
183 memset(sg, 0, sizeof(sg));
184 sg_set_buf(&sg[0], &tmpbuf, sizeof(tmpbuf));
185 sg_set_buf(&sg[1], &tmpbuf, sizeof(tmpbuf));
186 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
187
188 memcpy(sechdr, &tmpbuf, sizeof(tmpbuf));
189
190 _leave(" = 0");
191 return 0;
192 }
193
194 /*
195 * wholly encrypt a packet (level 2 security)
196 */
197 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
198 struct sk_buff *skb,
199 u32 data_size,
200 void *sechdr)
201 {
202 const struct rxrpc_key_payload *payload;
203 struct rxkad_level2_hdr rxkhdr
204 __attribute__((aligned(8))); /* must be all on one page */
205 struct rxrpc_skb_priv *sp;
206 struct blkcipher_desc desc;
207 struct rxrpc_crypt iv;
208 struct scatterlist sg[16];
209 struct sk_buff *trailer;
210 unsigned len;
211 u16 check;
212 int nsg;
213
214 sp = rxrpc_skb(skb);
215
216 _enter("");
217
218 check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
219
220 rxkhdr.data_size = htonl(data_size | (u32) check << 16);
221 rxkhdr.checksum = 0;
222
223 /* encrypt from the session key */
224 payload = call->conn->key->payload.data;
225 memcpy(&iv, payload->k.session_key, sizeof(iv));
226 desc.tfm = call->conn->cipher;
227 desc.info = iv.x;
228 desc.flags = 0;
229
230 memset(sg, 0, sizeof(sg[0]) * 2);
231 sg_set_buf(&sg[0], sechdr, sizeof(rxkhdr));
232 sg_set_buf(&sg[1], &rxkhdr, sizeof(rxkhdr));
233 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr));
234
235 /* we want to encrypt the skbuff in-place */
236 nsg = skb_cow_data(skb, 0, &trailer);
237 if (nsg < 0 || nsg > 16)
238 return -ENOMEM;
239
240 len = data_size + call->conn->size_align - 1;
241 len &= ~(call->conn->size_align - 1);
242
243 skb_to_sgvec(skb, sg, 0, len);
244 crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
245
246 _leave(" = 0");
247 return 0;
248 }
249
250 /*
251 * checksum an RxRPC packet header
252 */
253 static int rxkad_secure_packet(const struct rxrpc_call *call,
254 struct sk_buff *skb,
255 size_t data_size,
256 void *sechdr)
257 {
258 struct rxrpc_skb_priv *sp;
259 struct blkcipher_desc desc;
260 struct rxrpc_crypt iv;
261 struct scatterlist sg[2];
262 struct {
263 __be32 x[2];
264 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
265 __be32 x;
266 int ret;
267
268 sp = rxrpc_skb(skb);
269
270 _enter("{%d{%x}},{#%u},%zu,",
271 call->debug_id, key_serial(call->conn->key), ntohl(sp->hdr.seq),
272 data_size);
273
274 if (!call->conn->cipher)
275 return 0;
276
277 ret = key_validate(call->conn->key);
278 if (ret < 0)
279 return ret;
280
281 /* continue encrypting from where we left off */
282 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
283 desc.tfm = call->conn->cipher;
284 desc.info = iv.x;
285 desc.flags = 0;
286
287 /* calculate the security checksum */
288 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
289 x |= sp->hdr.seq & __constant_cpu_to_be32(0x3fffffff);
290 tmpbuf.x[0] = sp->hdr.callNumber;
291 tmpbuf.x[1] = x;
292
293 memset(&sg, 0, sizeof(sg));
294 sg_set_buf(&sg[0], &tmpbuf, sizeof(tmpbuf));
295 sg_set_buf(&sg[1], &tmpbuf, sizeof(tmpbuf));
296 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
297
298 x = ntohl(tmpbuf.x[1]);
299 x = (x >> 16) & 0xffff;
300 if (x == 0)
301 x = 1; /* zero checksums are not permitted */
302 sp->hdr.cksum = htons(x);
303
304 switch (call->conn->security_level) {
305 case RXRPC_SECURITY_PLAIN:
306 ret = 0;
307 break;
308 case RXRPC_SECURITY_AUTH:
309 ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
310 break;
311 case RXRPC_SECURITY_ENCRYPT:
312 ret = rxkad_secure_packet_encrypt(call, skb, data_size,
313 sechdr);
314 break;
315 default:
316 ret = -EPERM;
317 break;
318 }
319
320 _leave(" = %d [set %hx]", ret, x);
321 return ret;
322 }
323
324 /*
325 * decrypt partial encryption on a packet (level 1 security)
326 */
327 static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
328 struct sk_buff *skb,
329 u32 *_abort_code)
330 {
331 struct rxkad_level1_hdr sechdr;
332 struct rxrpc_skb_priv *sp;
333 struct blkcipher_desc desc;
334 struct rxrpc_crypt iv;
335 struct scatterlist sg[2];
336 struct sk_buff *trailer;
337 u32 data_size, buf;
338 u16 check;
339
340 _enter("");
341
342 sp = rxrpc_skb(skb);
343
344 /* we want to decrypt the skbuff in-place */
345 if (skb_cow_data(skb, 0, &trailer) < 0)
346 goto nomem;
347
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 skb_to_sgvec(skb, sg, 0, skb->len);
430
431 /* decrypt from the session key */
432 payload = call->conn->key->payload.data;
433 memcpy(&iv, payload->k.session_key, sizeof(iv));
434 desc.tfm = call->conn->cipher;
435 desc.info = iv.x;
436 desc.flags = 0;
437
438 crypto_blkcipher_decrypt_iv(&desc, sg, sg, skb->len);
439 if (sg != _sg)
440 kfree(sg);
441
442 /* remove the decrypted packet length */
443 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
444 goto datalen_error;
445 if (!skb_pull(skb, sizeof(sechdr)))
446 BUG();
447
448 buf = ntohl(sechdr.data_size);
449 data_size = buf & 0xffff;
450
451 check = buf >> 16;
452 check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
453 check &= 0xffff;
454 if (check != 0) {
455 *_abort_code = RXKADSEALEDINCON;
456 goto protocol_error;
457 }
458
459 /* shorten the packet to remove the padding */
460 if (data_size > skb->len)
461 goto datalen_error;
462 else if (data_size < skb->len)
463 skb->len = data_size;
464
465 _leave(" = 0 [dlen=%x]", data_size);
466 return 0;
467
468 datalen_error:
469 *_abort_code = RXKADDATALEN;
470 protocol_error:
471 _leave(" = -EPROTO");
472 return -EPROTO;
473
474 nomem:
475 _leave(" = -ENOMEM");
476 return -ENOMEM;
477 }
478
479 /*
480 * verify the security on a received packet
481 */
482 static int rxkad_verify_packet(const struct rxrpc_call *call,
483 struct sk_buff *skb,
484 u32 *_abort_code)
485 {
486 struct blkcipher_desc desc;
487 struct rxrpc_skb_priv *sp;
488 struct rxrpc_crypt iv;
489 struct scatterlist sg[2];
490 struct {
491 __be32 x[2];
492 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
493 __be32 x;
494 __be16 cksum;
495 int ret;
496
497 sp = rxrpc_skb(skb);
498
499 _enter("{%d{%x}},{#%u}",
500 call->debug_id, key_serial(call->conn->key),
501 ntohl(sp->hdr.seq));
502
503 if (!call->conn->cipher)
504 return 0;
505
506 if (sp->hdr.securityIndex != 2) {
507 *_abort_code = RXKADINCONSISTENCY;
508 _leave(" = -EPROTO [not rxkad]");
509 return -EPROTO;
510 }
511
512 /* continue encrypting from where we left off */
513 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
514 desc.tfm = call->conn->cipher;
515 desc.info = iv.x;
516 desc.flags = 0;
517
518 /* validate the security checksum */
519 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
520 x |= sp->hdr.seq & __constant_cpu_to_be32(0x3fffffff);
521 tmpbuf.x[0] = call->call_id;
522 tmpbuf.x[1] = x;
523
524 memset(&sg, 0, sizeof(sg));
525 sg_set_buf(&sg[0], &tmpbuf, sizeof(tmpbuf));
526 sg_set_buf(&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
694 memset(sg, 0, sizeof(sg));
695
696 sg_set_buf(&sg[0], buf, buflen);
697 if (sg[0].offset + buflen > PAGE_SIZE) {
698 /* the buffer was split over two pages */
699 sg[0].length = PAGE_SIZE - sg[0].offset;
700 sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
701 }
702
703 ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
704 }
705
706 /*
707 * encrypt the response packet
708 */
709 static void rxkad_encrypt_response(struct rxrpc_connection *conn,
710 struct rxkad_response *resp,
711 const struct rxkad_key *s2)
712 {
713 struct blkcipher_desc desc;
714 struct rxrpc_crypt iv;
715 struct scatterlist ssg[2], dsg[2];
716
717 /* continue encrypting from where we left off */
718 memcpy(&iv, s2->session_key, sizeof(iv));
719 desc.tfm = conn->cipher;
720 desc.info = iv.x;
721 desc.flags = 0;
722
723 rxkad_sg_set_buf2(ssg, &resp->encrypted, sizeof(resp->encrypted));
724 memcpy(dsg, ssg, sizeof(dsg));
725 crypto_blkcipher_encrypt_iv(&desc, dsg, ssg, sizeof(resp->encrypted));
726 }
727
728 /*
729 * respond to a challenge packet
730 */
731 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
732 struct sk_buff *skb,
733 u32 *_abort_code)
734 {
735 const struct rxrpc_key_payload *payload;
736 struct rxkad_challenge challenge;
737 struct rxkad_response resp
738 __attribute__((aligned(8))); /* must be aligned for crypto */
739 struct rxrpc_skb_priv *sp;
740 u32 version, nonce, min_level, abort_code;
741 int ret;
742
743 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
744
745 if (!conn->key) {
746 _leave(" = -EPROTO [no key]");
747 return -EPROTO;
748 }
749
750 ret = key_validate(conn->key);
751 if (ret < 0) {
752 *_abort_code = RXKADEXPIRED;
753 return ret;
754 }
755
756 abort_code = RXKADPACKETSHORT;
757 sp = rxrpc_skb(skb);
758 if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0)
759 goto protocol_error;
760
761 version = ntohl(challenge.version);
762 nonce = ntohl(challenge.nonce);
763 min_level = ntohl(challenge.min_level);
764
765 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
766 ntohl(sp->hdr.serial), version, nonce, min_level);
767
768 abort_code = RXKADINCONSISTENCY;
769 if (version != RXKAD_VERSION)
770 goto protocol_error;
771
772 abort_code = RXKADLEVELFAIL;
773 if (conn->security_level < min_level)
774 goto protocol_error;
775
776 payload = conn->key->payload.data;
777
778 /* build the response packet */
779 memset(&resp, 0, sizeof(resp));
780
781 resp.version = RXKAD_VERSION;
782 resp.encrypted.epoch = conn->epoch;
783 resp.encrypted.cid = conn->cid;
784 resp.encrypted.securityIndex = htonl(conn->security_ix);
785 resp.encrypted.call_id[0] =
786 (conn->channels[0] ? conn->channels[0]->call_id : 0);
787 resp.encrypted.call_id[1] =
788 (conn->channels[1] ? conn->channels[1]->call_id : 0);
789 resp.encrypted.call_id[2] =
790 (conn->channels[2] ? conn->channels[2]->call_id : 0);
791 resp.encrypted.call_id[3] =
792 (conn->channels[3] ? conn->channels[3]->call_id : 0);
793 resp.encrypted.inc_nonce = htonl(nonce + 1);
794 resp.encrypted.level = htonl(conn->security_level);
795 resp.kvno = htonl(payload->k.kvno);
796 resp.ticket_len = htonl(payload->k.ticket_len);
797
798 /* calculate the response checksum and then do the encryption */
799 rxkad_calc_response_checksum(&resp);
800 rxkad_encrypt_response(conn, &resp, &payload->k);
801 return rxkad_send_response(conn, &sp->hdr, &resp, &payload->k);
802
803 protocol_error:
804 *_abort_code = abort_code;
805 _leave(" = -EPROTO [%d]", abort_code);
806 return -EPROTO;
807 }
808
809 /*
810 * decrypt the kerberos IV ticket in the response
811 */
812 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
813 void *ticket, size_t ticket_len,
814 struct rxrpc_crypt *_session_key,
815 time_t *_expiry,
816 u32 *_abort_code)
817 {
818 struct blkcipher_desc desc;
819 struct rxrpc_crypt iv, key;
820 struct scatterlist ssg[1], dsg[1];
821 struct in_addr addr;
822 unsigned life;
823 time_t issue, now;
824 bool little_endian;
825 int ret;
826 u8 *p, *q, *name, *end;
827
828 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
829
830 *_expiry = 0;
831
832 ret = key_validate(conn->server_key);
833 if (ret < 0) {
834 switch (ret) {
835 case -EKEYEXPIRED:
836 *_abort_code = RXKADEXPIRED;
837 goto error;
838 default:
839 *_abort_code = RXKADNOAUTH;
840 goto error;
841 }
842 }
843
844 ASSERT(conn->server_key->payload.data != NULL);
845 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
846
847 memcpy(&iv, &conn->server_key->type_data, sizeof(iv));
848
849 desc.tfm = conn->server_key->payload.data;
850 desc.info = iv.x;
851 desc.flags = 0;
852
853 sg_init_one(&ssg[0], ticket, ticket_len);
854 memcpy(dsg, ssg, sizeof(dsg));
855 crypto_blkcipher_decrypt_iv(&desc, dsg, ssg, ticket_len);
856
857 p = ticket;
858 end = p + ticket_len;
859
860 #define Z(size) \
861 ({ \
862 u8 *__str = p; \
863 q = memchr(p, 0, end - p); \
864 if (!q || q - p > (size)) \
865 goto bad_ticket; \
866 for (; p < q; p++) \
867 if (!isprint(*p)) \
868 goto bad_ticket; \
869 p++; \
870 __str; \
871 })
872
873 /* extract the ticket flags */
874 _debug("KIV FLAGS: %x", *p);
875 little_endian = *p & 1;
876 p++;
877
878 /* extract the authentication name */
879 name = Z(ANAME_SZ);
880 _debug("KIV ANAME: %s", name);
881
882 /* extract the principal's instance */
883 name = Z(INST_SZ);
884 _debug("KIV INST : %s", name);
885
886 /* extract the principal's authentication domain */
887 name = Z(REALM_SZ);
888 _debug("KIV REALM: %s", name);
889
890 if (end - p < 4 + 8 + 4 + 2)
891 goto bad_ticket;
892
893 /* get the IPv4 address of the entity that requested the ticket */
894 memcpy(&addr, p, sizeof(addr));
895 p += 4;
896 _debug("KIV ADDR : "NIPQUAD_FMT, NIPQUAD(addr));
897
898 /* get the session key from the ticket */
899 memcpy(&key, p, sizeof(key));
900 p += 8;
901 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
902 memcpy(_session_key, &key, sizeof(key));
903
904 /* get the ticket's lifetime */
905 life = *p++ * 5 * 60;
906 _debug("KIV LIFE : %u", life);
907
908 /* get the issue time of the ticket */
909 if (little_endian) {
910 __le32 stamp;
911 memcpy(&stamp, p, 4);
912 issue = le32_to_cpu(stamp);
913 } else {
914 __be32 stamp;
915 memcpy(&stamp, p, 4);
916 issue = be32_to_cpu(stamp);
917 }
918 p += 4;
919 now = xtime.tv_sec;
920 _debug("KIV ISSUE: %lx [%lx]", issue, now);
921
922 /* check the ticket is in date */
923 if (issue > now) {
924 *_abort_code = RXKADNOAUTH;
925 ret = -EKEYREJECTED;
926 goto error;
927 }
928
929 if (issue < now - life) {
930 *_abort_code = RXKADEXPIRED;
931 ret = -EKEYEXPIRED;
932 goto error;
933 }
934
935 *_expiry = issue + life;
936
937 /* get the service name */
938 name = Z(SNAME_SZ);
939 _debug("KIV SNAME: %s", name);
940
941 /* get the service instance name */
942 name = Z(INST_SZ);
943 _debug("KIV SINST: %s", name);
944
945 ret = 0;
946 error:
947 _leave(" = %d", ret);
948 return ret;
949
950 bad_ticket:
951 *_abort_code = RXKADBADTICKET;
952 ret = -EBADMSG;
953 goto error;
954 }
955
956 /*
957 * decrypt the response packet
958 */
959 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
960 struct rxkad_response *resp,
961 const struct rxrpc_crypt *session_key)
962 {
963 struct blkcipher_desc desc;
964 struct scatterlist ssg[2], dsg[2];
965 struct rxrpc_crypt iv;
966
967 _enter(",,%08x%08x",
968 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
969
970 ASSERT(rxkad_ci != NULL);
971
972 mutex_lock(&rxkad_ci_mutex);
973 if (crypto_blkcipher_setkey(rxkad_ci, session_key->x,
974 sizeof(*session_key)) < 0)
975 BUG();
976
977 memcpy(&iv, session_key, sizeof(iv));
978 desc.tfm = rxkad_ci;
979 desc.info = iv.x;
980 desc.flags = 0;
981
982 rxkad_sg_set_buf2(ssg, &resp->encrypted, sizeof(resp->encrypted));
983 memcpy(dsg, ssg, sizeof(dsg));
984 crypto_blkcipher_decrypt_iv(&desc, dsg, ssg, sizeof(resp->encrypted));
985 mutex_unlock(&rxkad_ci_mutex);
986
987 _leave("");
988 }
989
990 /*
991 * verify a response
992 */
993 static int rxkad_verify_response(struct rxrpc_connection *conn,
994 struct sk_buff *skb,
995 u32 *_abort_code)
996 {
997 struct rxkad_response response
998 __attribute__((aligned(8))); /* must be aligned for crypto */
999 struct rxrpc_skb_priv *sp;
1000 struct rxrpc_crypt session_key;
1001 time_t expiry;
1002 void *ticket;
1003 u32 abort_code, version, kvno, ticket_len, csum, level;
1004 int ret;
1005
1006 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1007
1008 abort_code = RXKADPACKETSHORT;
1009 if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0)
1010 goto protocol_error;
1011 if (!pskb_pull(skb, sizeof(response)))
1012 BUG();
1013
1014 version = ntohl(response.version);
1015 ticket_len = ntohl(response.ticket_len);
1016 kvno = ntohl(response.kvno);
1017 sp = rxrpc_skb(skb);
1018 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1019 ntohl(sp->hdr.serial), version, kvno, ticket_len);
1020
1021 abort_code = RXKADINCONSISTENCY;
1022 if (version != RXKAD_VERSION)
1023
1024 abort_code = RXKADTICKETLEN;
1025 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1026 goto protocol_error;
1027
1028 abort_code = RXKADUNKNOWNKEY;
1029 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1030 goto protocol_error;
1031
1032 /* extract the kerberos ticket and decrypt and decode it */
1033 ticket = kmalloc(ticket_len, GFP_NOFS);
1034 if (!ticket)
1035 return -ENOMEM;
1036
1037 abort_code = RXKADPACKETSHORT;
1038 if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
1039 goto protocol_error_free;
1040
1041 ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
1042 &expiry, &abort_code);
1043 if (ret < 0) {
1044 *_abort_code = abort_code;
1045 kfree(ticket);
1046 return ret;
1047 }
1048
1049 /* use the session key from inside the ticket to decrypt the
1050 * response */
1051 rxkad_decrypt_response(conn, &response, &session_key);
1052
1053 abort_code = RXKADSEALEDINCON;
1054 if (response.encrypted.epoch != conn->epoch)
1055 goto protocol_error_free;
1056 if (response.encrypted.cid != conn->cid)
1057 goto protocol_error_free;
1058 if (ntohl(response.encrypted.securityIndex) != conn->security_ix)
1059 goto protocol_error_free;
1060 csum = response.encrypted.checksum;
1061 response.encrypted.checksum = 0;
1062 rxkad_calc_response_checksum(&response);
1063 if (response.encrypted.checksum != csum)
1064 goto protocol_error_free;
1065
1066 if (ntohl(response.encrypted.call_id[0]) > INT_MAX ||
1067 ntohl(response.encrypted.call_id[1]) > INT_MAX ||
1068 ntohl(response.encrypted.call_id[2]) > INT_MAX ||
1069 ntohl(response.encrypted.call_id[3]) > INT_MAX)
1070 goto protocol_error_free;
1071
1072 abort_code = RXKADOUTOFSEQUENCE;
1073 if (response.encrypted.inc_nonce != htonl(conn->security_nonce + 1))
1074 goto protocol_error_free;
1075
1076 abort_code = RXKADLEVELFAIL;
1077 level = ntohl(response.encrypted.level);
1078 if (level > RXRPC_SECURITY_ENCRYPT)
1079 goto protocol_error_free;
1080 conn->security_level = level;
1081
1082 /* create a key to hold the security data and expiration time - after
1083 * this the connection security can be handled in exactly the same way
1084 * as for a client connection */
1085 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1086 if (ret < 0) {
1087 kfree(ticket);
1088 return ret;
1089 }
1090
1091 kfree(ticket);
1092 _leave(" = 0");
1093 return 0;
1094
1095 protocol_error_free:
1096 kfree(ticket);
1097 protocol_error:
1098 *_abort_code = abort_code;
1099 _leave(" = -EPROTO [%d]", abort_code);
1100 return -EPROTO;
1101 }
1102
1103 /*
1104 * clear the connection security
1105 */
1106 static void rxkad_clear(struct rxrpc_connection *conn)
1107 {
1108 _enter("");
1109
1110 if (conn->cipher)
1111 crypto_free_blkcipher(conn->cipher);
1112 }
1113
1114 /*
1115 * RxRPC Kerberos-based security
1116 */
1117 static struct rxrpc_security rxkad = {
1118 .owner = THIS_MODULE,
1119 .name = "rxkad",
1120 .security_index = RXKAD_VERSION,
1121 .init_connection_security = rxkad_init_connection_security,
1122 .prime_packet_security = rxkad_prime_packet_security,
1123 .secure_packet = rxkad_secure_packet,
1124 .verify_packet = rxkad_verify_packet,
1125 .issue_challenge = rxkad_issue_challenge,
1126 .respond_to_challenge = rxkad_respond_to_challenge,
1127 .verify_response = rxkad_verify_response,
1128 .clear = rxkad_clear,
1129 };
1130
1131 static __init int rxkad_init(void)
1132 {
1133 _enter("");
1134
1135 /* pin the cipher we need so that the crypto layer doesn't invoke
1136 * keventd to go get it */
1137 rxkad_ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
1138 if (IS_ERR(rxkad_ci))
1139 return PTR_ERR(rxkad_ci);
1140
1141 return rxrpc_register_security(&rxkad);
1142 }
1143
1144 module_init(rxkad_init);
1145
1146 static __exit void rxkad_exit(void)
1147 {
1148 _enter("");
1149
1150 rxrpc_unregister_security(&rxkad);
1151 crypto_free_blkcipher(rxkad_ci);
1152 }
1153
1154 module_exit(rxkad_exit);
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