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be2net: Fix memset() arg ordering.
[linux-2.6/mini2440.git] / net / rxrpc / rxkad.c
blob713ac593e2e96d5a21b43958ff3ebb67816a8a3c
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 #include <keys/rxrpc-type.h>
22 #define rxrpc_debug rxkad_debug
23 #include "ar-internal.h"
24
25 #define RXKAD_VERSION 2
26 #define MAXKRB5TICKETLEN 1024
27 #define RXKAD_TKT_TYPE_KERBEROS_V5 256
28 #define ANAME_SZ 40 /* size of authentication name */
29 #define INST_SZ 40 /* size of principal's instance */
30 #define REALM_SZ 40 /* size of principal's auth domain */
31 #define SNAME_SZ 40 /* size of service name */
32
33 unsigned rxrpc_debug;
34 module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO);
35 MODULE_PARM_DESC(debug, "rxkad debugging mask");
36
37 struct rxkad_level1_hdr {
38 __be32 data_size; /* true data size (excluding padding) */
39 };
40
41 struct rxkad_level2_hdr {
42 __be32 data_size; /* true data size (excluding padding) */
43 __be32 checksum; /* decrypted data checksum */
44 };
45
46 MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos 4)");
47 MODULE_AUTHOR("Red Hat, Inc.");
48 MODULE_LICENSE("GPL");
49
50 /*
51 * this holds a pinned cipher so that keventd doesn't get called by the cipher
52 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
53 * packets
54 */
55 static struct crypto_blkcipher *rxkad_ci;
56 static DEFINE_MUTEX(rxkad_ci_mutex);
57
58 /*
59 * initialise connection security
60 */
61 static int rxkad_init_connection_security(struct rxrpc_connection *conn)
62 {
63 struct crypto_blkcipher *ci;
64 struct rxrpc_key_token *token;
65 int ret;
66
67 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
68
69 token = conn->key->payload.data;
70 conn->security_ix = token->security_index;
71
72 ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
73 if (IS_ERR(ci)) {
74 _debug("no cipher");
75 ret = PTR_ERR(ci);
76 goto error;
77 }
78
79 if (crypto_blkcipher_setkey(ci, token->kad->session_key,
80 sizeof(token->kad->session_key)) < 0)
81 BUG();
82
83 switch (conn->security_level) {
84 case RXRPC_SECURITY_PLAIN:
85 break;
86 case RXRPC_SECURITY_AUTH:
87 conn->size_align = 8;
88 conn->security_size = sizeof(struct rxkad_level1_hdr);
89 conn->header_size += sizeof(struct rxkad_level1_hdr);
90 break;
91 case RXRPC_SECURITY_ENCRYPT:
92 conn->size_align = 8;
93 conn->security_size = sizeof(struct rxkad_level2_hdr);
94 conn->header_size += sizeof(struct rxkad_level2_hdr);
95 break;
96 default:
97 ret = -EKEYREJECTED;
98 goto error;
99 }
100
101 conn->cipher = ci;
102 ret = 0;
103 error:
104 _leave(" = %d", ret);
105 return ret;
106 }
107
108 /*
109 * prime the encryption state with the invariant parts of a connection's
110 * description
111 */
112 static void rxkad_prime_packet_security(struct rxrpc_connection *conn)
113 {
114 struct rxrpc_key_token *token;
115 struct blkcipher_desc desc;
116 struct scatterlist sg[2];
117 struct rxrpc_crypt iv;
118 struct {
119 __be32 x[4];
120 } tmpbuf __attribute__((aligned(16))); /* must all be in same page */
121
122 _enter("");
123
124 if (!conn->key)
125 return;
126
127 token = conn->key->payload.data;
128 memcpy(&iv, token->kad->session_key, sizeof(iv));
129
130 desc.tfm = conn->cipher;
131 desc.info = iv.x;
132 desc.flags = 0;
133
134 tmpbuf.x[0] = conn->epoch;
135 tmpbuf.x[1] = conn->cid;
136 tmpbuf.x[2] = 0;
137 tmpbuf.x[3] = htonl(conn->security_ix);
138
139 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
140 sg_init_one(&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 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
184 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
185 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
186
187 memcpy(sechdr, &tmpbuf, sizeof(tmpbuf));
188
189 _leave(" = 0");
190 return 0;
191 }
192
193 /*
194 * wholly encrypt a packet (level 2 security)
195 */
196 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
197 struct sk_buff *skb,
198 u32 data_size,
199 void *sechdr)
200 {
201 const struct rxrpc_key_token *token;
202 struct rxkad_level2_hdr rxkhdr
203 __attribute__((aligned(8))); /* must be all on one page */
204 struct rxrpc_skb_priv *sp;
205 struct blkcipher_desc desc;
206 struct rxrpc_crypt iv;
207 struct scatterlist sg[16];
208 struct sk_buff *trailer;
209 unsigned len;
210 u16 check;
211 int nsg;
212
213 sp = rxrpc_skb(skb);
214
215 _enter("");
216
217 check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
218
219 rxkhdr.data_size = htonl(data_size | (u32) check << 16);
220 rxkhdr.checksum = 0;
221
222 /* encrypt from the session key */
223 token = call->conn->key->payload.data;
224 memcpy(&iv, token->kad->session_key, sizeof(iv));
225 desc.tfm = call->conn->cipher;
226 desc.info = iv.x;
227 desc.flags = 0;
228
229 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
230 sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
231 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr));
232
233 /* we want to encrypt the skbuff in-place */
234 nsg = skb_cow_data(skb, 0, &trailer);
235 if (nsg < 0 || nsg > 16)
236 return -ENOMEM;
237
238 len = data_size + call->conn->size_align - 1;
239 len &= ~(call->conn->size_align - 1);
240
241 sg_init_table(sg, nsg);
242 skb_to_sgvec(skb, sg, 0, len);
243 crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
244
245 _leave(" = 0");
246 return 0;
247 }
248
249 /*
250 * checksum an RxRPC packet header
251 */
252 static int rxkad_secure_packet(const struct rxrpc_call *call,
253 struct sk_buff *skb,
254 size_t data_size,
255 void *sechdr)
256 {
257 struct rxrpc_skb_priv *sp;
258 struct blkcipher_desc desc;
259 struct rxrpc_crypt iv;
260 struct scatterlist sg[2];
261 struct {
262 __be32 x[2];
263 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
264 __be32 x;
265 u32 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), 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 & cpu_to_be32(0x3fffffff);
290 tmpbuf.x[0] = sp->hdr.callNumber;
291 tmpbuf.x[1] = 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 = htons(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 ^= ntohl(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;
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 ^= ntohl(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 __be32 x;
497 __be16 cksum;
498 u32 y;
499 int ret;
500
501 sp = rxrpc_skb(skb);
502
503 _enter("{%d{%x}},{#%u}",
504 call->debug_id, key_serial(call->conn->key),
505 ntohl(sp->hdr.seq));
506
507 if (!call->conn->cipher)
508 return 0;
509
510 if (sp->hdr.securityIndex != RXRPC_SECURITY_RXKAD) {
511 *_abort_code = RXKADINCONSISTENCY;
512 _leave(" = -EPROTO [not rxkad]");
513 return -EPROTO;
514 }
515
516 /* continue encrypting from where we left off */
517 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
518 desc.tfm = call->conn->cipher;
519 desc.info = iv.x;
520 desc.flags = 0;
521
522 /* validate the security checksum */
523 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
524 x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
525 tmpbuf.x[0] = call->call_id;
526 tmpbuf.x[1] = x;
527
528 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
529 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
530 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
531
532 y = ntohl(tmpbuf.x[1]);
533 y = (y >> 16) & 0xffff;
534 if (y == 0)
535 y = 1; /* zero checksums are not permitted */
536
537 cksum = htons(y);
538 if (sp->hdr.cksum != cksum) {
539 *_abort_code = RXKADSEALEDINCON;
540 _leave(" = -EPROTO [csum failed]");
541 return -EPROTO;
542 }
543
544 switch (call->conn->security_level) {
545 case RXRPC_SECURITY_PLAIN:
546 ret = 0;
547 break;
548 case RXRPC_SECURITY_AUTH:
549 ret = rxkad_verify_packet_auth(call, skb, _abort_code);
550 break;
551 case RXRPC_SECURITY_ENCRYPT:
552 ret = rxkad_verify_packet_encrypt(call, skb, _abort_code);
553 break;
554 default:
555 ret = -ENOANO;
556 break;
557 }
558
559 _leave(" = %d", ret);
560 return ret;
561 }
562
563 /*
564 * issue a challenge
565 */
566 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
567 {
568 struct rxkad_challenge challenge;
569 struct rxrpc_header hdr;
570 struct msghdr msg;
571 struct kvec iov[2];
572 size_t len;
573 int ret;
574
575 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
576
577 ret = key_validate(conn->key);
578 if (ret < 0)
579 return ret;
580
581 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
582
583 challenge.version = htonl(2);
584 challenge.nonce = htonl(conn->security_nonce);
585 challenge.min_level = htonl(0);
586 challenge.__padding = 0;
587
588 msg.msg_name = &conn->trans->peer->srx.transport.sin;
589 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
590 msg.msg_control = NULL;
591 msg.msg_controllen = 0;
592 msg.msg_flags = 0;
593
594 hdr.epoch = conn->epoch;
595 hdr.cid = conn->cid;
596 hdr.callNumber = 0;
597 hdr.seq = 0;
598 hdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
599 hdr.flags = conn->out_clientflag;
600 hdr.userStatus = 0;
601 hdr.securityIndex = conn->security_ix;
602 hdr._rsvd = 0;
603 hdr.serviceId = conn->service_id;
604
605 iov[0].iov_base = &hdr;
606 iov[0].iov_len = sizeof(hdr);
607 iov[1].iov_base = &challenge;
608 iov[1].iov_len = sizeof(challenge);
609
610 len = iov[0].iov_len + iov[1].iov_len;
611
612 hdr.serial = htonl(atomic_inc_return(&conn->serial));
613 _proto("Tx CHALLENGE %%%u", ntohl(hdr.serial));
614
615 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len);
616 if (ret < 0) {
617 _debug("sendmsg failed: %d", ret);
618 return -EAGAIN;
619 }
620
621 _leave(" = 0");
622 return 0;
623 }
624
625 /*
626 * send a Kerberos security response
627 */
628 static int rxkad_send_response(struct rxrpc_connection *conn,
629 struct rxrpc_header *hdr,
630 struct rxkad_response *resp,
631 const struct rxkad_key *s2)
632 {
633 struct msghdr msg;
634 struct kvec iov[3];
635 size_t len;
636 int ret;
637
638 _enter("");
639
640 msg.msg_name = &conn->trans->peer->srx.transport.sin;
641 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
642 msg.msg_control = NULL;
643 msg.msg_controllen = 0;
644 msg.msg_flags = 0;
645
646 hdr->epoch = conn->epoch;
647 hdr->seq = 0;
648 hdr->type = RXRPC_PACKET_TYPE_RESPONSE;
649 hdr->flags = conn->out_clientflag;
650 hdr->userStatus = 0;
651 hdr->_rsvd = 0;
652
653 iov[0].iov_base = hdr;
654 iov[0].iov_len = sizeof(*hdr);
655 iov[1].iov_base = resp;
656 iov[1].iov_len = sizeof(*resp);
657 iov[2].iov_base = (void *) s2->ticket;
658 iov[2].iov_len = s2->ticket_len;
659
660 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
661
662 hdr->serial = htonl(atomic_inc_return(&conn->serial));
663 _proto("Tx RESPONSE %%%u", ntohl(hdr->serial));
664
665 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 3, len);
666 if (ret < 0) {
667 _debug("sendmsg failed: %d", ret);
668 return -EAGAIN;
669 }
670
671 _leave(" = 0");
672 return 0;
673 }
674
675 /*
676 * calculate the response checksum
677 */
678 static void rxkad_calc_response_checksum(struct rxkad_response *response)
679 {
680 u32 csum = 1000003;
681 int loop;
682 u8 *p = (u8 *) response;
683
684 for (loop = sizeof(*response); loop > 0; loop--)
685 csum = csum * 0x10204081 + *p++;
686
687 response->encrypted.checksum = htonl(csum);
688 }
689
690 /*
691 * load a scatterlist with a potentially split-page buffer
692 */
693 static void rxkad_sg_set_buf2(struct scatterlist sg[2],
694 void *buf, size_t buflen)
695 {
696 int nsg = 1;
697
698 sg_init_table(sg, 2);
699
700 sg_set_buf(&sg[0], buf, buflen);
701 if (sg[0].offset + buflen > PAGE_SIZE) {
702 /* the buffer was split over two pages */
703 sg[0].length = PAGE_SIZE - sg[0].offset;
704 sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
705 nsg++;
706 }
707
708 sg_mark_end(&sg[nsg - 1]);
709
710 ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
711 }
712
713 /*
714 * encrypt the response packet
715 */
716 static void rxkad_encrypt_response(struct rxrpc_connection *conn,
717 struct rxkad_response *resp,
718 const struct rxkad_key *s2)
719 {
720 struct blkcipher_desc desc;
721 struct rxrpc_crypt iv;
722 struct scatterlist sg[2];
723
724 /* continue encrypting from where we left off */
725 memcpy(&iv, s2->session_key, sizeof(iv));
726 desc.tfm = conn->cipher;
727 desc.info = iv.x;
728 desc.flags = 0;
729
730 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
731 crypto_blkcipher_encrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
732 }
733
734 /*
735 * respond to a challenge packet
736 */
737 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
738 struct sk_buff *skb,
739 u32 *_abort_code)
740 {
741 const struct rxrpc_key_token *token;
742 struct rxkad_challenge challenge;
743 struct rxkad_response resp
744 __attribute__((aligned(8))); /* must be aligned for crypto */
745 struct rxrpc_skb_priv *sp;
746 u32 version, nonce, min_level, abort_code;
747 int ret;
748
749 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
750
751 if (!conn->key) {
752 _leave(" = -EPROTO [no key]");
753 return -EPROTO;
754 }
755
756 ret = key_validate(conn->key);
757 if (ret < 0) {
758 *_abort_code = RXKADEXPIRED;
759 return ret;
760 }
761
762 abort_code = RXKADPACKETSHORT;
763 sp = rxrpc_skb(skb);
764 if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0)
765 goto protocol_error;
766
767 version = ntohl(challenge.version);
768 nonce = ntohl(challenge.nonce);
769 min_level = ntohl(challenge.min_level);
770
771 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
772 ntohl(sp->hdr.serial), version, nonce, min_level);
773
774 abort_code = RXKADINCONSISTENCY;
775 if (version != RXKAD_VERSION)
776 goto protocol_error;
777
778 abort_code = RXKADLEVELFAIL;
779 if (conn->security_level < min_level)
780 goto protocol_error;
781
782 token = conn->key->payload.data;
783
784 /* build the response packet */
785 memset(&resp, 0, sizeof(resp));
786
787 resp.version = RXKAD_VERSION;
788 resp.encrypted.epoch = conn->epoch;
789 resp.encrypted.cid = conn->cid;
790 resp.encrypted.securityIndex = htonl(conn->security_ix);
791 resp.encrypted.call_id[0] =
792 (conn->channels[0] ? conn->channels[0]->call_id : 0);
793 resp.encrypted.call_id[1] =
794 (conn->channels[1] ? conn->channels[1]->call_id : 0);
795 resp.encrypted.call_id[2] =
796 (conn->channels[2] ? conn->channels[2]->call_id : 0);
797 resp.encrypted.call_id[3] =
798 (conn->channels[3] ? conn->channels[3]->call_id : 0);
799 resp.encrypted.inc_nonce = htonl(nonce + 1);
800 resp.encrypted.level = htonl(conn->security_level);
801 resp.kvno = htonl(token->kad->kvno);
802 resp.ticket_len = htonl(token->kad->ticket_len);
803
804 /* calculate the response checksum and then do the encryption */
805 rxkad_calc_response_checksum(&resp);
806 rxkad_encrypt_response(conn, &resp, token->kad);
807 return rxkad_send_response(conn, &sp->hdr, &resp, token->kad);
808
809 protocol_error:
810 *_abort_code = abort_code;
811 _leave(" = -EPROTO [%d]", abort_code);
812 return -EPROTO;
813 }
814
815 /*
816 * decrypt the kerberos IV ticket in the response
817 */
818 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
819 void *ticket, size_t ticket_len,
820 struct rxrpc_crypt *_session_key,
821 time_t *_expiry,
822 u32 *_abort_code)
823 {
824 struct blkcipher_desc desc;
825 struct rxrpc_crypt iv, key;
826 struct scatterlist sg[1];
827 struct in_addr addr;
828 unsigned life;
829 time_t issue, now;
830 bool little_endian;
831 int ret;
832 u8 *p, *q, *name, *end;
833
834 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
835
836 *_expiry = 0;
837
838 ret = key_validate(conn->server_key);
839 if (ret < 0) {
840 switch (ret) {
841 case -EKEYEXPIRED:
842 *_abort_code = RXKADEXPIRED;
843 goto error;
844 default:
845 *_abort_code = RXKADNOAUTH;
846 goto error;
847 }
848 }
849
850 ASSERT(conn->server_key->payload.data != NULL);
851 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
852
853 memcpy(&iv, &conn->server_key->type_data, sizeof(iv));
854
855 desc.tfm = conn->server_key->payload.data;
856 desc.info = iv.x;
857 desc.flags = 0;
858
859 sg_init_one(&sg[0], ticket, ticket_len);
860 crypto_blkcipher_decrypt_iv(&desc, sg, sg, ticket_len);
861
862 p = ticket;
863 end = p + ticket_len;
864
865 #define Z(size) \
866 ({ \
867 u8 *__str = p; \
868 q = memchr(p, 0, end - p); \
869 if (!q || q - p > (size)) \
870 goto bad_ticket; \
871 for (; p < q; p++) \
872 if (!isprint(*p)) \
873 goto bad_ticket; \
874 p++; \
875 __str; \
876 })
877
878 /* extract the ticket flags */
879 _debug("KIV FLAGS: %x", *p);
880 little_endian = *p & 1;
881 p++;
882
883 /* extract the authentication name */
884 name = Z(ANAME_SZ);
885 _debug("KIV ANAME: %s", name);
886
887 /* extract the principal's instance */
888 name = Z(INST_SZ);
889 _debug("KIV INST : %s", name);
890
891 /* extract the principal's authentication domain */
892 name = Z(REALM_SZ);
893 _debug("KIV REALM: %s", name);
894
895 if (end - p < 4 + 8 + 4 + 2)
896 goto bad_ticket;
897
898 /* get the IPv4 address of the entity that requested the ticket */
899 memcpy(&addr, p, sizeof(addr));
900 p += 4;
901 _debug("KIV ADDR : %pI4", &addr);
902
903 /* get the session key from the ticket */
904 memcpy(&key, p, sizeof(key));
905 p += 8;
906 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
907 memcpy(_session_key, &key, sizeof(key));
908
909 /* get the ticket's lifetime */
910 life = *p++ * 5 * 60;
911 _debug("KIV LIFE : %u", life);
912
913 /* get the issue time of the ticket */
914 if (little_endian) {
915 __le32 stamp;
916 memcpy(&stamp, p, 4);
917 issue = le32_to_cpu(stamp);
918 } else {
919 __be32 stamp;
920 memcpy(&stamp, p, 4);
921 issue = be32_to_cpu(stamp);
922 }
923 p += 4;
924 now = get_seconds();
925 _debug("KIV ISSUE: %lx [%lx]", issue, now);
926
927 /* check the ticket is in date */
928 if (issue > now) {
929 *_abort_code = RXKADNOAUTH;
930 ret = -EKEYREJECTED;
931 goto error;
932 }
933
934 if (issue < now - life) {
935 *_abort_code = RXKADEXPIRED;
936 ret = -EKEYEXPIRED;
937 goto error;
938 }
939
940 *_expiry = issue + life;
941
942 /* get the service name */
943 name = Z(SNAME_SZ);
944 _debug("KIV SNAME: %s", name);
945
946 /* get the service instance name */
947 name = Z(INST_SZ);
948 _debug("KIV SINST: %s", name);
949
950 ret = 0;
951 error:
952 _leave(" = %d", ret);
953 return ret;
954
955 bad_ticket:
956 *_abort_code = RXKADBADTICKET;
957 ret = -EBADMSG;
958 goto error;
959 }
960
961 /*
962 * decrypt the response packet
963 */
964 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
965 struct rxkad_response *resp,
966 const struct rxrpc_crypt *session_key)
967 {
968 struct blkcipher_desc desc;
969 struct scatterlist sg[2];
970 struct rxrpc_crypt iv;
971
972 _enter(",,%08x%08x",
973 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
974
975 ASSERT(rxkad_ci != NULL);
976
977 mutex_lock(&rxkad_ci_mutex);
978 if (crypto_blkcipher_setkey(rxkad_ci, session_key->x,
979 sizeof(*session_key)) < 0)
980 BUG();
981
982 memcpy(&iv, session_key, sizeof(iv));
983 desc.tfm = rxkad_ci;
984 desc.info = iv.x;
985 desc.flags = 0;
986
987 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
988 crypto_blkcipher_decrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
989 mutex_unlock(&rxkad_ci_mutex);
990
991 _leave("");
992 }
993
994 /*
995 * verify a response
996 */
997 static int rxkad_verify_response(struct rxrpc_connection *conn,
998 struct sk_buff *skb,
999 u32 *_abort_code)
1000 {
1001 struct rxkad_response response
1002 __attribute__((aligned(8))); /* must be aligned for crypto */
1003 struct rxrpc_skb_priv *sp;
1004 struct rxrpc_crypt session_key;
1005 time_t expiry;
1006 void *ticket;
1007 u32 abort_code, version, kvno, ticket_len, level;
1008 __be32 csum;
1009 int ret;
1010
1011 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1012
1013 abort_code = RXKADPACKETSHORT;
1014 if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0)
1015 goto protocol_error;
1016 if (!pskb_pull(skb, sizeof(response)))
1017 BUG();
1018
1019 version = ntohl(response.version);
1020 ticket_len = ntohl(response.ticket_len);
1021 kvno = ntohl(response.kvno);
1022 sp = rxrpc_skb(skb);
1023 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1024 ntohl(sp->hdr.serial), version, kvno, ticket_len);
1025
1026 abort_code = RXKADINCONSISTENCY;
1027 if (version != RXKAD_VERSION)
1028 goto protocol_error;
1029
1030 abort_code = RXKADTICKETLEN;
1031 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1032 goto protocol_error;
1033
1034 abort_code = RXKADUNKNOWNKEY;
1035 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1036 goto protocol_error;
1037
1038 /* extract the kerberos ticket and decrypt and decode it */
1039 ticket = kmalloc(ticket_len, GFP_NOFS);
1040 if (!ticket)
1041 return -ENOMEM;
1042
1043 abort_code = RXKADPACKETSHORT;
1044 if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
1045 goto protocol_error_free;
1046
1047 ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
1048 &expiry, &abort_code);
1049 if (ret < 0) {
1050 *_abort_code = abort_code;
1051 kfree(ticket);
1052 return ret;
1053 }
1054
1055 /* use the session key from inside the ticket to decrypt the
1056 * response */
1057 rxkad_decrypt_response(conn, &response, &session_key);
1058
1059 abort_code = RXKADSEALEDINCON;
1060 if (response.encrypted.epoch != conn->epoch)
1061 goto protocol_error_free;
1062 if (response.encrypted.cid != conn->cid)
1063 goto protocol_error_free;
1064 if (ntohl(response.encrypted.securityIndex) != conn->security_ix)
1065 goto protocol_error_free;
1066 csum = response.encrypted.checksum;
1067 response.encrypted.checksum = 0;
1068 rxkad_calc_response_checksum(&response);
1069 if (response.encrypted.checksum != csum)
1070 goto protocol_error_free;
1071
1072 if (ntohl(response.encrypted.call_id[0]) > INT_MAX ||
1073 ntohl(response.encrypted.call_id[1]) > INT_MAX ||
1074 ntohl(response.encrypted.call_id[2]) > INT_MAX ||
1075 ntohl(response.encrypted.call_id[3]) > INT_MAX)
1076 goto protocol_error_free;
1077
1078 abort_code = RXKADOUTOFSEQUENCE;
1079 if (response.encrypted.inc_nonce != htonl(conn->security_nonce + 1))
1080 goto protocol_error_free;
1081
1082 abort_code = RXKADLEVELFAIL;
1083 level = ntohl(response.encrypted.level);
1084 if (level > RXRPC_SECURITY_ENCRYPT)
1085 goto protocol_error_free;
1086 conn->security_level = level;
1087
1088 /* create a key to hold the security data and expiration time - after
1089 * this the connection security can be handled in exactly the same way
1090 * as for a client connection */
1091 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1092 if (ret < 0) {
1093 kfree(ticket);
1094 return ret;
1095 }
1096
1097 kfree(ticket);
1098 _leave(" = 0");
1099 return 0;
1100
1101 protocol_error_free:
1102 kfree(ticket);
1103 protocol_error:
1104 *_abort_code = abort_code;
1105 _leave(" = -EPROTO [%d]", abort_code);
1106 return -EPROTO;
1107 }
1108
1109 /*
1110 * clear the connection security
1111 */
1112 static void rxkad_clear(struct rxrpc_connection *conn)
1113 {
1114 _enter("");
1115
1116 if (conn->cipher)
1117 crypto_free_blkcipher(conn->cipher);
1118 }
1119
1120 /*
1121 * RxRPC Kerberos-based security
1122 */
1123 static struct rxrpc_security rxkad = {
1124 .owner = THIS_MODULE,
1125 .name = "rxkad",
1126 .security_index = RXRPC_SECURITY_RXKAD,
1127 .init_connection_security = rxkad_init_connection_security,
1128 .prime_packet_security = rxkad_prime_packet_security,
1129 .secure_packet = rxkad_secure_packet,
1130 .verify_packet = rxkad_verify_packet,
1131 .issue_challenge = rxkad_issue_challenge,
1132 .respond_to_challenge = rxkad_respond_to_challenge,
1133 .verify_response = rxkad_verify_response,
1134 .clear = rxkad_clear,
1135 };
1136
1137 static __init int rxkad_init(void)
1138 {
1139 _enter("");
1140
1141 /* pin the cipher we need so that the crypto layer doesn't invoke
1142 * keventd to go get it */
1143 rxkad_ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
1144 if (IS_ERR(rxkad_ci))
1145 return PTR_ERR(rxkad_ci);
1146
1147 return rxrpc_register_security(&rxkad);
1148 }
1149
1150 module_init(rxkad_init);
1151
1152 static __exit void rxkad_exit(void)
1153 {
1154 _enter("");
1155
1156 rxrpc_unregister_security(&rxkad);
1157 crypto_free_blkcipher(rxkad_ci);
1158 }
1159
1160 module_exit(rxkad_exit);
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