projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
rxrpc: Keep the skb private record of the Rx header in host byte order
[deliverable/linux.git] / net / rxrpc / rxkad.c
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 <linux/slab.h>
20 #include <net/sock.h>
21 #include <net/af_rxrpc.h>
22 #include <keys/rxrpc-type.h>
23 #define rxrpc_debug rxkad_debug
24 #include "ar-internal.h"
25
26 #define RXKAD_VERSION 2
27 #define MAXKRB5TICKETLEN 1024
28 #define RXKAD_TKT_TYPE_KERBEROS_V5 256
29 #define ANAME_SZ 40 /* size of authentication name */
30 #define INST_SZ 40 /* size of principal's instance */
31 #define REALM_SZ 40 /* size of principal's auth domain */
32 #define SNAME_SZ 40 /* size of service name */
33
34 unsigned int rxrpc_debug;
35 module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO);
36 MODULE_PARM_DESC(debug, "rxkad debugging mask");
37
38 struct rxkad_level1_hdr {
39 __be32 data_size; /* true data size (excluding padding) */
40 };
41
42 struct rxkad_level2_hdr {
43 __be32 data_size; /* true data size (excluding padding) */
44 __be32 checksum; /* decrypted data checksum */
45 };
46
47 MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos 4)");
48 MODULE_AUTHOR("Red Hat, Inc.");
49 MODULE_LICENSE("GPL");
50
51 /*
52 * this holds a pinned cipher so that keventd doesn't get called by the cipher
53 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
54 * packets
55 */
56 static struct crypto_blkcipher *rxkad_ci;
57 static DEFINE_MUTEX(rxkad_ci_mutex);
58
59 /*
60 * initialise connection security
61 */
62 static int rxkad_init_connection_security(struct rxrpc_connection *conn)
63 {
64 struct crypto_blkcipher *ci;
65 struct rxrpc_key_token *token;
66 int ret;
67
68 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
69
70 token = conn->key->payload.data[0];
71 conn->security_ix = token->security_index;
72
73 ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
74 if (IS_ERR(ci)) {
75 _debug("no cipher");
76 ret = PTR_ERR(ci);
77 goto error;
78 }
79
80 if (crypto_blkcipher_setkey(ci, token->kad->session_key,
81 sizeof(token->kad->session_key)) < 0)
82 BUG();
83
84 switch (conn->security_level) {
85 case RXRPC_SECURITY_PLAIN:
86 break;
87 case RXRPC_SECURITY_AUTH:
88 conn->size_align = 8;
89 conn->security_size = sizeof(struct rxkad_level1_hdr);
90 conn->header_size += sizeof(struct rxkad_level1_hdr);
91 break;
92 case RXRPC_SECURITY_ENCRYPT:
93 conn->size_align = 8;
94 conn->security_size = sizeof(struct rxkad_level2_hdr);
95 conn->header_size += sizeof(struct rxkad_level2_hdr);
96 break;
97 default:
98 ret = -EKEYREJECTED;
99 goto error;
100 }
101
102 conn->cipher = ci;
103 ret = 0;
104 error:
105 _leave(" = %d", ret);
106 return ret;
107 }
108
109 /*
110 * prime the encryption state with the invariant parts of a connection's
111 * description
112 */
113 static void rxkad_prime_packet_security(struct rxrpc_connection *conn)
114 {
115 struct rxrpc_key_token *token;
116 struct blkcipher_desc desc;
117 struct scatterlist sg[2];
118 struct rxrpc_crypt iv;
119 struct {
120 __be32 x[4];
121 } tmpbuf __attribute__((aligned(16))); /* must all be in same page */
122
123 _enter("");
124
125 if (!conn->key)
126 return;
127
128 token = conn->key->payload.data[0];
129 memcpy(&iv, token->kad->session_key, sizeof(iv));
130
131 desc.tfm = conn->cipher;
132 desc.info = iv.x;
133 desc.flags = 0;
134
135 tmpbuf.x[0] = htonl(conn->epoch);
136 tmpbuf.x[1] = htonl(conn->cid);
137 tmpbuf.x[2] = 0;
138 tmpbuf.x[3] = htonl(conn->security_ix);
139
140 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
141 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
142 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
143
144 memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
145 ASSERTCMP(conn->csum_iv.n[0], ==, tmpbuf.x[2]);
146
147 _leave("");
148 }
149
150 /*
151 * partially encrypt a packet (level 1 security)
152 */
153 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
154 struct sk_buff *skb,
155 u32 data_size,
156 void *sechdr)
157 {
158 struct rxrpc_skb_priv *sp;
159 struct blkcipher_desc desc;
160 struct rxrpc_crypt iv;
161 struct scatterlist sg[2];
162 struct {
163 struct rxkad_level1_hdr hdr;
164 __be32 first; /* first four bytes of data and padding */
165 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
166 u16 check;
167
168 sp = rxrpc_skb(skb);
169
170 _enter("");
171
172 check = sp->hdr.seq ^ sp->hdr.callNumber;
173 data_size |= (u32)check << 16;
174
175 tmpbuf.hdr.data_size = htonl(data_size);
176 memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first));
177
178 /* start the encryption afresh */
179 memset(&iv, 0, sizeof(iv));
180 desc.tfm = call->conn->cipher;
181 desc.info = iv.x;
182 desc.flags = 0;
183
184 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
185 sg_init_one(&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_token *token;
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 int len;
211 u16 check;
212 int nsg;
213
214 sp = rxrpc_skb(skb);
215
216 _enter("");
217
218 check = 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 token = call->conn->key->payload.data[0];
225 memcpy(&iv, token->kad->session_key, sizeof(iv));
226 desc.tfm = call->conn->cipher;
227 desc.info = iv.x;
228 desc.flags = 0;
229
230 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
231 sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
232 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr));
233
234 /* we want to encrypt the skbuff in-place */
235 nsg = skb_cow_data(skb, 0, &trailer);
236 if (nsg < 0 || nsg > 16)
237 return -ENOMEM;
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 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 u32 x, y;
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), 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 = call->channel << (32 - RXRPC_CIDSHIFT);
289 x |= sp->hdr.seq & 0x3fffffff;
290 tmpbuf.x[0] = htonl(sp->hdr.callNumber);
291 tmpbuf.x[1] = htonl(x);
292
293 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
294 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
295 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
296
297 y = ntohl(tmpbuf.x[1]);
298 y = (y >> 16) & 0xffff;
299 if (y == 0)
300 y = 1; /* zero checksums are not permitted */
301 sp->hdr.cksum = y;
302
303 switch (call->conn->security_level) {
304 case RXRPC_SECURITY_PLAIN:
305 ret = 0;
306 break;
307 case RXRPC_SECURITY_AUTH:
308 ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
309 break;
310 case RXRPC_SECURITY_ENCRYPT:
311 ret = rxkad_secure_packet_encrypt(call, skb, data_size,
312 sechdr);
313 break;
314 default:
315 ret = -EPERM;
316 break;
317 }
318
319 _leave(" = %d [set %hx]", ret, y);
320 return ret;
321 }
322
323 /*
324 * decrypt partial encryption on a packet (level 1 security)
325 */
326 static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
327 struct sk_buff *skb,
328 u32 *_abort_code)
329 {
330 struct rxkad_level1_hdr sechdr;
331 struct rxrpc_skb_priv *sp;
332 struct blkcipher_desc desc;
333 struct rxrpc_crypt iv;
334 struct scatterlist sg[16];
335 struct sk_buff *trailer;
336 u32 data_size, buf;
337 u16 check;
338 int nsg;
339
340 _enter("");
341
342 sp = rxrpc_skb(skb);
343
344 /* we want to decrypt the skbuff in-place */
345 nsg = skb_cow_data(skb, 0, &trailer);
346 if (nsg < 0 || nsg > 16)
347 goto nomem;
348
349 sg_init_table(sg, nsg);
350 skb_to_sgvec(skb, sg, 0, 8);
351
352 /* start the decryption afresh */
353 memset(&iv, 0, sizeof(iv));
354 desc.tfm = call->conn->cipher;
355 desc.info = iv.x;
356 desc.flags = 0;
357
358 crypto_blkcipher_decrypt_iv(&desc, sg, sg, 8);
359
360 /* remove the decrypted packet length */
361 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
362 goto datalen_error;
363 if (!skb_pull(skb, sizeof(sechdr)))
364 BUG();
365
366 buf = ntohl(sechdr.data_size);
367 data_size = buf & 0xffff;
368
369 check = buf >> 16;
370 check ^= sp->hdr.seq ^ sp->hdr.callNumber;
371 check &= 0xffff;
372 if (check != 0) {
373 *_abort_code = RXKADSEALEDINCON;
374 goto protocol_error;
375 }
376
377 /* shorten the packet to remove the padding */
378 if (data_size > skb->len)
379 goto datalen_error;
380 else if (data_size < skb->len)
381 skb->len = data_size;
382
383 _leave(" = 0 [dlen=%x]", data_size);
384 return 0;
385
386 datalen_error:
387 *_abort_code = RXKADDATALEN;
388 protocol_error:
389 _leave(" = -EPROTO");
390 return -EPROTO;
391
392 nomem:
393 _leave(" = -ENOMEM");
394 return -ENOMEM;
395 }
396
397 /*
398 * wholly decrypt a packet (level 2 security)
399 */
400 static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
401 struct sk_buff *skb,
402 u32 *_abort_code)
403 {
404 const struct rxrpc_key_token *token;
405 struct rxkad_level2_hdr sechdr;
406 struct rxrpc_skb_priv *sp;
407 struct blkcipher_desc desc;
408 struct rxrpc_crypt iv;
409 struct scatterlist _sg[4], *sg;
410 struct sk_buff *trailer;
411 u32 data_size, buf;
412 u16 check;
413 int nsg;
414
415 _enter(",{%d}", skb->len);
416
417 sp = rxrpc_skb(skb);
418
419 /* we want to decrypt the skbuff in-place */
420 nsg = skb_cow_data(skb, 0, &trailer);
421 if (nsg < 0)
422 goto nomem;
423
424 sg = _sg;
425 if (unlikely(nsg > 4)) {
426 sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
427 if (!sg)
428 goto nomem;
429 }
430
431 sg_init_table(sg, nsg);
432 skb_to_sgvec(skb, sg, 0, skb->len);
433
434 /* decrypt from the session key */
435 token = call->conn->key->payload.data[0];
436 memcpy(&iv, token->kad->session_key, sizeof(iv));
437 desc.tfm = call->conn->cipher;
438 desc.info = iv.x;
439 desc.flags = 0;
440
441 crypto_blkcipher_decrypt_iv(&desc, sg, sg, skb->len);
442 if (sg != _sg)
443 kfree(sg);
444
445 /* remove the decrypted packet length */
446 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
447 goto datalen_error;
448 if (!skb_pull(skb, sizeof(sechdr)))
449 BUG();
450
451 buf = ntohl(sechdr.data_size);
452 data_size = buf & 0xffff;
453
454 check = buf >> 16;
455 check ^= sp->hdr.seq ^ sp->hdr.callNumber;
456 check &= 0xffff;
457 if (check != 0) {
458 *_abort_code = RXKADSEALEDINCON;
459 goto protocol_error;
460 }
461
462 /* shorten the packet to remove the padding */
463 if (data_size > skb->len)
464 goto datalen_error;
465 else if (data_size < skb->len)
466 skb->len = data_size;
467
468 _leave(" = 0 [dlen=%x]", data_size);
469 return 0;
470
471 datalen_error:
472 *_abort_code = RXKADDATALEN;
473 protocol_error:
474 _leave(" = -EPROTO");
475 return -EPROTO;
476
477 nomem:
478 _leave(" = -ENOMEM");
479 return -ENOMEM;
480 }
481
482 /*
483 * verify the security on a received packet
484 */
485 static int rxkad_verify_packet(const struct rxrpc_call *call,
486 struct sk_buff *skb,
487 u32 *_abort_code)
488 {
489 struct blkcipher_desc desc;
490 struct rxrpc_skb_priv *sp;
491 struct rxrpc_crypt iv;
492 struct scatterlist sg[2];
493 struct {
494 __be32 x[2];
495 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
496 u16 cksum;
497 u32 x, y;
498 int ret;
499
500 sp = rxrpc_skb(skb);
501
502 _enter("{%d{%x}},{#%u}",
503 call->debug_id, key_serial(call->conn->key), sp->hdr.seq);
504
505 if (!call->conn->cipher)
506 return 0;
507
508 if (sp->hdr.securityIndex != RXRPC_SECURITY_RXKAD) {
509 *_abort_code = RXKADINCONSISTENCY;
510 _leave(" = -EPROTO [not rxkad]");
511 return -EPROTO;
512 }
513
514 /* continue encrypting from where we left off */
515 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
516 desc.tfm = call->conn->cipher;
517 desc.info = iv.x;
518 desc.flags = 0;
519
520 /* validate the security checksum */
521 x = call->channel << (32 - RXRPC_CIDSHIFT);
522 x |= sp->hdr.seq & 0x3fffffff;
523 tmpbuf.x[0] = htonl(call->call_id);
524 tmpbuf.x[1] = htonl(x);
525
526 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
527 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
528 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
529
530 y = ntohl(tmpbuf.x[1]);
531 cksum = (y >> 16) & 0xffff;
532 if (cksum == 0)
533 cksum = 1; /* zero checksums are not permitted */
534
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_wire_header whdr;
567 struct msghdr msg;
568 struct kvec iov[2];
569 size_t len;
570 u32 serial;
571 int ret;
572
573 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
574
575 ret = key_validate(conn->key);
576 if (ret < 0)
577 return ret;
578
579 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
580
581 challenge.version = htonl(2);
582 challenge.nonce = htonl(conn->security_nonce);
583 challenge.min_level = htonl(0);
584 challenge.__padding = 0;
585
586 msg.msg_name = &conn->trans->peer->srx.transport.sin;
587 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
588 msg.msg_control = NULL;
589 msg.msg_controllen = 0;
590 msg.msg_flags = 0;
591
592 whdr.epoch = htonl(conn->epoch);
593 whdr.cid = htonl(conn->cid);
594 whdr.callNumber = 0;
595 whdr.seq = 0;
596 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
597 whdr.flags = conn->out_clientflag;
598 whdr.userStatus = 0;
599 whdr.securityIndex = conn->security_ix;
600 whdr._rsvd = 0;
601 whdr.serviceId = htons(conn->service_id);
602
603 iov[0].iov_base = &whdr;
604 iov[0].iov_len = sizeof(whdr);
605 iov[1].iov_base = &challenge;
606 iov[1].iov_len = sizeof(challenge);
607
608 len = iov[0].iov_len + iov[1].iov_len;
609
610 serial = atomic_inc_return(&conn->serial);
611 whdr.serial = htonl(serial);
612 _proto("Tx CHALLENGE %%%u", serial);
613
614 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len);
615 if (ret < 0) {
616 _debug("sendmsg failed: %d", ret);
617 return -EAGAIN;
618 }
619
620 _leave(" = 0");
621 return 0;
622 }
623
624 /*
625 * send a Kerberos security response
626 */
627 static int rxkad_send_response(struct rxrpc_connection *conn,
628 struct rxrpc_host_header *hdr,
629 struct rxkad_response *resp,
630 const struct rxkad_key *s2)
631 {
632 struct rxrpc_wire_header whdr;
633 struct msghdr msg;
634 struct kvec iov[3];
635 size_t len;
636 u32 serial;
637 int ret;
638
639 _enter("");
640
641 msg.msg_name = &conn->trans->peer->srx.transport.sin;
642 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
643 msg.msg_control = NULL;
644 msg.msg_controllen = 0;
645 msg.msg_flags = 0;
646
647 memset(&whdr, 0, sizeof(whdr));
648 whdr.epoch = htonl(hdr->epoch);
649 whdr.cid = htonl(hdr->cid);
650 whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
651 whdr.flags = conn->out_clientflag;
652 whdr.securityIndex = hdr->securityIndex;
653 whdr.serviceId = htons(hdr->serviceId);
654
655 iov[0].iov_base = &whdr;
656 iov[0].iov_len = sizeof(whdr);
657 iov[1].iov_base = resp;
658 iov[1].iov_len = sizeof(*resp);
659 iov[2].iov_base = (void *)s2->ticket;
660 iov[2].iov_len = s2->ticket_len;
661
662 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
663
664 serial = atomic_inc_return(&conn->serial);
665 whdr.serial = htonl(serial);
666 _proto("Tx RESPONSE %%%u", serial);
667
668 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 3, len);
669 if (ret < 0) {
670 _debug("sendmsg failed: %d", ret);
671 return -EAGAIN;
672 }
673
674 _leave(" = 0");
675 return 0;
676 }
677
678 /*
679 * calculate the response checksum
680 */
681 static void rxkad_calc_response_checksum(struct rxkad_response *response)
682 {
683 u32 csum = 1000003;
684 int loop;
685 u8 *p = (u8 *) response;
686
687 for (loop = sizeof(*response); loop > 0; loop--)
688 csum = csum * 0x10204081 + *p++;
689
690 response->encrypted.checksum = htonl(csum);
691 }
692
693 /*
694 * load a scatterlist with a potentially split-page buffer
695 */
696 static void rxkad_sg_set_buf2(struct scatterlist sg[2],
697 void *buf, size_t buflen)
698 {
699 int nsg = 1;
700
701 sg_init_table(sg, 2);
702
703 sg_set_buf(&sg[0], buf, buflen);
704 if (sg[0].offset + buflen > PAGE_SIZE) {
705 /* the buffer was split over two pages */
706 sg[0].length = PAGE_SIZE - sg[0].offset;
707 sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
708 nsg++;
709 }
710
711 sg_mark_end(&sg[nsg - 1]);
712
713 ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
714 }
715
716 /*
717 * encrypt the response packet
718 */
719 static void rxkad_encrypt_response(struct rxrpc_connection *conn,
720 struct rxkad_response *resp,
721 const struct rxkad_key *s2)
722 {
723 struct blkcipher_desc desc;
724 struct rxrpc_crypt iv;
725 struct scatterlist sg[2];
726
727 /* continue encrypting from where we left off */
728 memcpy(&iv, s2->session_key, sizeof(iv));
729 desc.tfm = conn->cipher;
730 desc.info = iv.x;
731 desc.flags = 0;
732
733 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
734 crypto_blkcipher_encrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
735 }
736
737 /*
738 * respond to a challenge packet
739 */
740 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
741 struct sk_buff *skb,
742 u32 *_abort_code)
743 {
744 const struct rxrpc_key_token *token;
745 struct rxkad_challenge challenge;
746 struct rxkad_response resp
747 __attribute__((aligned(8))); /* must be aligned for crypto */
748 struct rxrpc_skb_priv *sp;
749 u32 version, nonce, min_level, abort_code;
750 int ret;
751
752 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
753
754 if (!conn->key) {
755 _leave(" = -EPROTO [no key]");
756 return -EPROTO;
757 }
758
759 ret = key_validate(conn->key);
760 if (ret < 0) {
761 *_abort_code = RXKADEXPIRED;
762 return ret;
763 }
764
765 abort_code = RXKADPACKETSHORT;
766 sp = rxrpc_skb(skb);
767 if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0)
768 goto protocol_error;
769
770 version = ntohl(challenge.version);
771 nonce = ntohl(challenge.nonce);
772 min_level = ntohl(challenge.min_level);
773
774 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
775 sp->hdr.serial, version, nonce, min_level);
776
777 abort_code = RXKADINCONSISTENCY;
778 if (version != RXKAD_VERSION)
779 goto protocol_error;
780
781 abort_code = RXKADLEVELFAIL;
782 if (conn->security_level < min_level)
783 goto protocol_error;
784
785 token = conn->key->payload.data[0];
786
787 /* build the response packet */
788 memset(&resp, 0, sizeof(resp));
789
790 resp.version = RXKAD_VERSION;
791 resp.encrypted.epoch = htonl(conn->epoch);
792 resp.encrypted.cid = htonl(conn->cid);
793 resp.encrypted.securityIndex = htonl(conn->security_ix);
794 resp.encrypted.call_id[0] =
795 htonl(conn->channels[0] ? conn->channels[0]->call_id : 0);
796 resp.encrypted.call_id[1] =
797 htonl(conn->channels[1] ? conn->channels[1]->call_id : 0);
798 resp.encrypted.call_id[2] =
799 htonl(conn->channels[2] ? conn->channels[2]->call_id : 0);
800 resp.encrypted.call_id[3] =
801 htonl(conn->channels[3] ? conn->channels[3]->call_id : 0);
802 resp.encrypted.inc_nonce = htonl(nonce + 1);
803 resp.encrypted.level = htonl(conn->security_level);
804 resp.kvno = htonl(token->kad->kvno);
805 resp.ticket_len = htonl(token->kad->ticket_len);
806
807 /* calculate the response checksum and then do the encryption */
808 rxkad_calc_response_checksum(&resp);
809 rxkad_encrypt_response(conn, &resp, token->kad);
810 return rxkad_send_response(conn, &sp->hdr, &resp, token->kad);
811
812 protocol_error:
813 *_abort_code = abort_code;
814 _leave(" = -EPROTO [%d]", abort_code);
815 return -EPROTO;
816 }
817
818 /*
819 * decrypt the kerberos IV ticket in the response
820 */
821 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
822 void *ticket, size_t ticket_len,
823 struct rxrpc_crypt *_session_key,
824 time_t *_expiry,
825 u32 *_abort_code)
826 {
827 struct blkcipher_desc desc;
828 struct rxrpc_crypt iv, key;
829 struct scatterlist sg[1];
830 struct in_addr addr;
831 unsigned int life;
832 time_t issue, now;
833 bool little_endian;
834 int ret;
835 u8 *p, *q, *name, *end;
836
837 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
838
839 *_expiry = 0;
840
841 ret = key_validate(conn->server_key);
842 if (ret < 0) {
843 switch (ret) {
844 case -EKEYEXPIRED:
845 *_abort_code = RXKADEXPIRED;
846 goto error;
847 default:
848 *_abort_code = RXKADNOAUTH;
849 goto error;
850 }
851 }
852
853 ASSERT(conn->server_key->payload.data[0] != NULL);
854 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
855
856 memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv));
857
858 desc.tfm = conn->server_key->payload.data[0];
859 desc.info = iv.x;
860 desc.flags = 0;
861
862 sg_init_one(&sg[0], ticket, ticket_len);
863 crypto_blkcipher_decrypt_iv(&desc, sg, sg, ticket_len);
864
865 p = ticket;
866 end = p + ticket_len;
867
868 #define Z(size) \
869 ({ \
870 u8 *__str = p; \
871 q = memchr(p, 0, end - p); \
872 if (!q || q - p > (size)) \
873 goto bad_ticket; \
874 for (; p < q; p++) \
875 if (!isprint(*p)) \
876 goto bad_ticket; \
877 p++; \
878 __str; \
879 })
880
881 /* extract the ticket flags */
882 _debug("KIV FLAGS: %x", *p);
883 little_endian = *p & 1;
884 p++;
885
886 /* extract the authentication name */
887 name = Z(ANAME_SZ);
888 _debug("KIV ANAME: %s", name);
889
890 /* extract the principal's instance */
891 name = Z(INST_SZ);
892 _debug("KIV INST : %s", name);
893
894 /* extract the principal's authentication domain */
895 name = Z(REALM_SZ);
896 _debug("KIV REALM: %s", name);
897
898 if (end - p < 4 + 8 + 4 + 2)
899 goto bad_ticket;
900
901 /* get the IPv4 address of the entity that requested the ticket */
902 memcpy(&addr, p, sizeof(addr));
903 p += 4;
904 _debug("KIV ADDR : %pI4", &addr);
905
906 /* get the session key from the ticket */
907 memcpy(&key, p, sizeof(key));
908 p += 8;
909 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
910 memcpy(_session_key, &key, sizeof(key));
911
912 /* get the ticket's lifetime */
913 life = *p++ * 5 * 60;
914 _debug("KIV LIFE : %u", life);
915
916 /* get the issue time of the ticket */
917 if (little_endian) {
918 __le32 stamp;
919 memcpy(&stamp, p, 4);
920 issue = le32_to_cpu(stamp);
921 } else {
922 __be32 stamp;
923 memcpy(&stamp, p, 4);
924 issue = be32_to_cpu(stamp);
925 }
926 p += 4;
927 now = get_seconds();
928 _debug("KIV ISSUE: %lx [%lx]", issue, now);
929
930 /* check the ticket is in date */
931 if (issue > now) {
932 *_abort_code = RXKADNOAUTH;
933 ret = -EKEYREJECTED;
934 goto error;
935 }
936
937 if (issue < now - life) {
938 *_abort_code = RXKADEXPIRED;
939 ret = -EKEYEXPIRED;
940 goto error;
941 }
942
943 *_expiry = issue + life;
944
945 /* get the service name */
946 name = Z(SNAME_SZ);
947 _debug("KIV SNAME: %s", name);
948
949 /* get the service instance name */
950 name = Z(INST_SZ);
951 _debug("KIV SINST: %s", name);
952
953 ret = 0;
954 error:
955 _leave(" = %d", ret);
956 return ret;
957
958 bad_ticket:
959 *_abort_code = RXKADBADTICKET;
960 ret = -EBADMSG;
961 goto error;
962 }
963
964 /*
965 * decrypt the response packet
966 */
967 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
968 struct rxkad_response *resp,
969 const struct rxrpc_crypt *session_key)
970 {
971 struct blkcipher_desc desc;
972 struct scatterlist sg[2];
973 struct rxrpc_crypt iv;
974
975 _enter(",,%08x%08x",
976 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
977
978 ASSERT(rxkad_ci != NULL);
979
980 mutex_lock(&rxkad_ci_mutex);
981 if (crypto_blkcipher_setkey(rxkad_ci, session_key->x,
982 sizeof(*session_key)) < 0)
983 BUG();
984
985 memcpy(&iv, session_key, sizeof(iv));
986 desc.tfm = rxkad_ci;
987 desc.info = iv.x;
988 desc.flags = 0;
989
990 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
991 crypto_blkcipher_decrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
992 mutex_unlock(&rxkad_ci_mutex);
993
994 _leave("");
995 }
996
997 /*
998 * verify a response
999 */
1000 static int rxkad_verify_response(struct rxrpc_connection *conn,
1001 struct sk_buff *skb,
1002 u32 *_abort_code)
1003 {
1004 struct rxkad_response response
1005 __attribute__((aligned(8))); /* must be aligned for crypto */
1006 struct rxrpc_skb_priv *sp;
1007 struct rxrpc_crypt session_key;
1008 time_t expiry;
1009 void *ticket;
1010 u32 abort_code, version, kvno, ticket_len, level;
1011 __be32 csum;
1012 int ret;
1013
1014 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1015
1016 abort_code = RXKADPACKETSHORT;
1017 if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0)
1018 goto protocol_error;
1019 if (!pskb_pull(skb, sizeof(response)))
1020 BUG();
1021
1022 version = ntohl(response.version);
1023 ticket_len = ntohl(response.ticket_len);
1024 kvno = ntohl(response.kvno);
1025 sp = rxrpc_skb(skb);
1026 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1027 sp->hdr.serial, version, kvno, ticket_len);
1028
1029 abort_code = RXKADINCONSISTENCY;
1030 if (version != RXKAD_VERSION)
1031 goto protocol_error;
1032
1033 abort_code = RXKADTICKETLEN;
1034 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1035 goto protocol_error;
1036
1037 abort_code = RXKADUNKNOWNKEY;
1038 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1039 goto protocol_error;
1040
1041 /* extract the kerberos ticket and decrypt and decode it */
1042 ticket = kmalloc(ticket_len, GFP_NOFS);
1043 if (!ticket)
1044 return -ENOMEM;
1045
1046 abort_code = RXKADPACKETSHORT;
1047 if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
1048 goto protocol_error_free;
1049
1050 ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
1051 &expiry, &abort_code);
1052 if (ret < 0) {
1053 *_abort_code = abort_code;
1054 kfree(ticket);
1055 return ret;
1056 }
1057
1058 /* use the session key from inside the ticket to decrypt the
1059 * response */
1060 rxkad_decrypt_response(conn, &response, &session_key);
1061
1062 abort_code = RXKADSEALEDINCON;
1063 if (ntohl(response.encrypted.epoch) != conn->epoch)
1064 goto protocol_error_free;
1065 if (ntohl(response.encrypted.cid) != conn->cid)
1066 goto protocol_error_free;
1067 if (ntohl(response.encrypted.securityIndex) != conn->security_ix)
1068 goto protocol_error_free;
1069 csum = response.encrypted.checksum;
1070 response.encrypted.checksum = 0;
1071 rxkad_calc_response_checksum(&response);
1072 if (response.encrypted.checksum != csum)
1073 goto protocol_error_free;
1074
1075 if (ntohl(response.encrypted.call_id[0]) > INT_MAX ||
1076 ntohl(response.encrypted.call_id[1]) > INT_MAX ||
1077 ntohl(response.encrypted.call_id[2]) > INT_MAX ||
1078 ntohl(response.encrypted.call_id[3]) > INT_MAX)
1079 goto protocol_error_free;
1080
1081 abort_code = RXKADOUTOFSEQUENCE;
1082 if (ntohl(response.encrypted.inc_nonce) != conn->security_nonce + 1)
1083 goto protocol_error_free;
1084
1085 abort_code = RXKADLEVELFAIL;
1086 level = ntohl(response.encrypted.level);
1087 if (level > RXRPC_SECURITY_ENCRYPT)
1088 goto protocol_error_free;
1089 conn->security_level = level;
1090
1091 /* create a key to hold the security data and expiration time - after
1092 * this the connection security can be handled in exactly the same way
1093 * as for a client connection */
1094 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1095 if (ret < 0) {
1096 kfree(ticket);
1097 return ret;
1098 }
1099
1100 kfree(ticket);
1101 _leave(" = 0");
1102 return 0;
1103
1104 protocol_error_free:
1105 kfree(ticket);
1106 protocol_error:
1107 *_abort_code = abort_code;
1108 _leave(" = -EPROTO [%d]", abort_code);
1109 return -EPROTO;
1110 }
1111
1112 /*
1113 * clear the connection security
1114 */
1115 static void rxkad_clear(struct rxrpc_connection *conn)
1116 {
1117 _enter("");
1118
1119 if (conn->cipher)
1120 crypto_free_blkcipher(conn->cipher);
1121 }
1122
1123 /*
1124 * RxRPC Kerberos-based security
1125 */
1126 static struct rxrpc_security rxkad = {
1127 .owner = THIS_MODULE,
1128 .name = "rxkad",
1129 .security_index = RXRPC_SECURITY_RXKAD,
1130 .init_connection_security = rxkad_init_connection_security,
1131 .prime_packet_security = rxkad_prime_packet_security,
1132 .secure_packet = rxkad_secure_packet,
1133 .verify_packet = rxkad_verify_packet,
1134 .issue_challenge = rxkad_issue_challenge,
1135 .respond_to_challenge = rxkad_respond_to_challenge,
1136 .verify_response = rxkad_verify_response,
1137 .clear = rxkad_clear,
1138 };
1139
1140 static __init int rxkad_init(void)
1141 {
1142 _enter("");
1143
1144 /* pin the cipher we need so that the crypto layer doesn't invoke
1145 * keventd to go get it */
1146 rxkad_ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
1147 if (IS_ERR(rxkad_ci))
1148 return PTR_ERR(rxkad_ci);
1149
1150 return rxrpc_register_security(&rxkad);
1151 }
1152
1153 module_init(rxkad_init);
1154
1155 static __exit void rxkad_exit(void)
1156 {
1157 _enter("");
1158
1159 rxrpc_unregister_security(&rxkad);
1160 crypto_free_blkcipher(rxkad_ci);
1161 }
1162
1163 module_exit(rxkad_exit);
Linux kernel - Deliverables
This page took 0.078822 seconds and 5 git commands to generate.