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Add linux-next specific files for 20110421
[linux-2.6/next.git] / net / rxrpc / rxkad.c
blob7635107726ce76b66be2e28877bec91f9286ae96
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 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;
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;
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] = conn->epoch;
136 tmpbuf.x[1] = 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 = ntohl(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 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 token = call->conn->key->payload.data;
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 __be32 x;
266 u32 y;
267 int ret;
268
269 sp = rxrpc_skb(skb);
270
271 _enter("{%d{%x}},{#%u},%zu,",
272 call->debug_id, key_serial(call->conn->key), ntohl(sp->hdr.seq),
273 data_size);
274
275 if (!call->conn->cipher)
276 return 0;
277
278 ret = key_validate(call->conn->key);
279 if (ret < 0)
280 return ret;
281
282 /* continue encrypting from where we left off */
283 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
284 desc.tfm = call->conn->cipher;
285 desc.info = iv.x;
286 desc.flags = 0;
287
288 /* calculate the security checksum */
289 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
290 x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
291 tmpbuf.x[0] = sp->hdr.callNumber;
292 tmpbuf.x[1] = x;
293
294 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
295 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
296 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
297
298 y = ntohl(tmpbuf.x[1]);
299 y = (y >> 16) & 0xffff;
300 if (y == 0)
301 y = 1; /* zero checksums are not permitted */
302 sp->hdr.cksum = htons(y);
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, y);
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[16];
336 struct sk_buff *trailer;
337 u32 data_size, buf;
338 u16 check;
339 int nsg;
340
341 _enter("");
342
343 sp = rxrpc_skb(skb);
344
345 /* we want to decrypt the skbuff in-place */
346 nsg = skb_cow_data(skb, 0, &trailer);
347 if (nsg < 0 || nsg > 16)
348 goto nomem;
349
350 sg_init_table(sg, nsg);
351 skb_to_sgvec(skb, sg, 0, 8);
352
353 /* start the decryption afresh */
354 memset(&iv, 0, sizeof(iv));
355 desc.tfm = call->conn->cipher;
356 desc.info = iv.x;
357 desc.flags = 0;
358
359 crypto_blkcipher_decrypt_iv(&desc, sg, sg, 8);
360
361 /* remove the decrypted packet length */
362 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
363 goto datalen_error;
364 if (!skb_pull(skb, sizeof(sechdr)))
365 BUG();
366
367 buf = ntohl(sechdr.data_size);
368 data_size = buf & 0xffff;
369
370 check = buf >> 16;
371 check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
372 check &= 0xffff;
373 if (check != 0) {
374 *_abort_code = RXKADSEALEDINCON;
375 goto protocol_error;
376 }
377
378 /* shorten the packet to remove the padding */
379 if (data_size > skb->len)
380 goto datalen_error;
381 else if (data_size < skb->len)
382 skb->len = data_size;
383
384 _leave(" = 0 [dlen=%x]", data_size);
385 return 0;
386
387 datalen_error:
388 *_abort_code = RXKADDATALEN;
389 protocol_error:
390 _leave(" = -EPROTO");
391 return -EPROTO;
392
393 nomem:
394 _leave(" = -ENOMEM");
395 return -ENOMEM;
396 }
397
398 /*
399 * wholly decrypt a packet (level 2 security)
400 */
401 static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
402 struct sk_buff *skb,
403 u32 *_abort_code)
404 {
405 const struct rxrpc_key_token *token;
406 struct rxkad_level2_hdr sechdr;
407 struct rxrpc_skb_priv *sp;
408 struct blkcipher_desc desc;
409 struct rxrpc_crypt iv;
410 struct scatterlist _sg[4], *sg;
411 struct sk_buff *trailer;
412 u32 data_size, buf;
413 u16 check;
414 int nsg;
415
416 _enter(",{%d}", skb->len);
417
418 sp = rxrpc_skb(skb);
419
420 /* we want to decrypt the skbuff in-place */
421 nsg = skb_cow_data(skb, 0, &trailer);
422 if (nsg < 0)
423 goto nomem;
424
425 sg = _sg;
426 if (unlikely(nsg > 4)) {
427 sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
428 if (!sg)
429 goto nomem;
430 }
431
432 sg_init_table(sg, nsg);
433 skb_to_sgvec(skb, sg, 0, skb->len);
434
435 /* decrypt from the session key */
436 token = call->conn->key->payload.data;
437 memcpy(&iv, token->kad->session_key, sizeof(iv));
438 desc.tfm = call->conn->cipher;
439 desc.info = iv.x;
440 desc.flags = 0;
441
442 crypto_blkcipher_decrypt_iv(&desc, sg, sg, skb->len);
443 if (sg != _sg)
444 kfree(sg);
445
446 /* remove the decrypted packet length */
447 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
448 goto datalen_error;
449 if (!skb_pull(skb, sizeof(sechdr)))
450 BUG();
451
452 buf = ntohl(sechdr.data_size);
453 data_size = buf & 0xffff;
454
455 check = buf >> 16;
456 check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
457 check &= 0xffff;
458 if (check != 0) {
459 *_abort_code = RXKADSEALEDINCON;
460 goto protocol_error;
461 }
462
463 /* shorten the packet to remove the padding */
464 if (data_size > skb->len)
465 goto datalen_error;
466 else if (data_size < skb->len)
467 skb->len = data_size;
468
469 _leave(" = 0 [dlen=%x]", data_size);
470 return 0;
471
472 datalen_error:
473 *_abort_code = RXKADDATALEN;
474 protocol_error:
475 _leave(" = -EPROTO");
476 return -EPROTO;
477
478 nomem:
479 _leave(" = -ENOMEM");
480 return -ENOMEM;
481 }
482
483 /*
484 * verify the security on a received packet
485 */
486 static int rxkad_verify_packet(const struct rxrpc_call *call,
487 struct sk_buff *skb,
488 u32 *_abort_code)
489 {
490 struct blkcipher_desc desc;
491 struct rxrpc_skb_priv *sp;
492 struct rxrpc_crypt iv;
493 struct scatterlist sg[2];
494 struct {
495 __be32 x[2];
496 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
497 __be32 x;
498 __be16 cksum;
499 u32 y;
500 int ret;
501
502 sp = rxrpc_skb(skb);
503
504 _enter("{%d{%x}},{#%u}",
505 call->debug_id, key_serial(call->conn->key),
506 ntohl(sp->hdr.seq));
507
508 if (!call->conn->cipher)
509 return 0;
510
511 if (sp->hdr.securityIndex != RXRPC_SECURITY_RXKAD) {
512 *_abort_code = RXKADINCONSISTENCY;
513 _leave(" = -EPROTO [not rxkad]");
514 return -EPROTO;
515 }
516
517 /* continue encrypting from where we left off */
518 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
519 desc.tfm = call->conn->cipher;
520 desc.info = iv.x;
521 desc.flags = 0;
522
523 /* validate the security checksum */
524 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
525 x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
526 tmpbuf.x[0] = call->call_id;
527 tmpbuf.x[1] = x;
528
529 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
530 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
531 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
532
533 y = ntohl(tmpbuf.x[1]);
534 y = (y >> 16) & 0xffff;
535 if (y == 0)
536 y = 1; /* zero checksums are not permitted */
537
538 cksum = htons(y);
539 if (sp->hdr.cksum != cksum) {
540 *_abort_code = RXKADSEALEDINCON;
541 _leave(" = -EPROTO [csum failed]");
542 return -EPROTO;
543 }
544
545 switch (call->conn->security_level) {
546 case RXRPC_SECURITY_PLAIN:
547 ret = 0;
548 break;
549 case RXRPC_SECURITY_AUTH:
550 ret = rxkad_verify_packet_auth(call, skb, _abort_code);
551 break;
552 case RXRPC_SECURITY_ENCRYPT:
553 ret = rxkad_verify_packet_encrypt(call, skb, _abort_code);
554 break;
555 default:
556 ret = -ENOANO;
557 break;
558 }
559
560 _leave(" = %d", ret);
561 return ret;
562 }
563
564 /*
565 * issue a challenge
566 */
567 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
568 {
569 struct rxkad_challenge challenge;
570 struct rxrpc_header hdr;
571 struct msghdr msg;
572 struct kvec iov[2];
573 size_t len;
574 int ret;
575
576 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
577
578 ret = key_validate(conn->key);
579 if (ret < 0)
580 return ret;
581
582 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
583
584 challenge.version = htonl(2);
585 challenge.nonce = htonl(conn->security_nonce);
586 challenge.min_level = htonl(0);
587 challenge.__padding = 0;
588
589 msg.msg_name = &conn->trans->peer->srx.transport.sin;
590 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
591 msg.msg_control = NULL;
592 msg.msg_controllen = 0;
593 msg.msg_flags = 0;
594
595 hdr.epoch = conn->epoch;
596 hdr.cid = conn->cid;
597 hdr.callNumber = 0;
598 hdr.seq = 0;
599 hdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
600 hdr.flags = conn->out_clientflag;
601 hdr.userStatus = 0;
602 hdr.securityIndex = conn->security_ix;
603 hdr._rsvd = 0;
604 hdr.serviceId = conn->service_id;
605
606 iov[0].iov_base = &hdr;
607 iov[0].iov_len = sizeof(hdr);
608 iov[1].iov_base = &challenge;
609 iov[1].iov_len = sizeof(challenge);
610
611 len = iov[0].iov_len + iov[1].iov_len;
612
613 hdr.serial = htonl(atomic_inc_return(&conn->serial));
614 _proto("Tx CHALLENGE %%%u", ntohl(hdr.serial));
615
616 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len);
617 if (ret < 0) {
618 _debug("sendmsg failed: %d", ret);
619 return -EAGAIN;
620 }
621
622 _leave(" = 0");
623 return 0;
624 }
625
626 /*
627 * send a Kerberos security response
628 */
629 static int rxkad_send_response(struct rxrpc_connection *conn,
630 struct rxrpc_header *hdr,
631 struct rxkad_response *resp,
632 const struct rxkad_key *s2)
633 {
634 struct msghdr msg;
635 struct kvec iov[3];
636 size_t len;
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 hdr->epoch = conn->epoch;
648 hdr->seq = 0;
649 hdr->type = RXRPC_PACKET_TYPE_RESPONSE;
650 hdr->flags = conn->out_clientflag;
651 hdr->userStatus = 0;
652 hdr->_rsvd = 0;
653
654 iov[0].iov_base = hdr;
655 iov[0].iov_len = sizeof(*hdr);
656 iov[1].iov_base = resp;
657 iov[1].iov_len = sizeof(*resp);
658 iov[2].iov_base = (void *) s2->ticket;
659 iov[2].iov_len = s2->ticket_len;
660
661 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
662
663 hdr->serial = htonl(atomic_inc_return(&conn->serial));
664 _proto("Tx RESPONSE %%%u", ntohl(hdr->serial));
665
666 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 3, len);
667 if (ret < 0) {
668 _debug("sendmsg failed: %d", ret);
669 return -EAGAIN;
670 }
671
672 _leave(" = 0");
673 return 0;
674 }
675
676 /*
677 * calculate the response checksum
678 */
679 static void rxkad_calc_response_checksum(struct rxkad_response *response)
680 {
681 u32 csum = 1000003;
682 int loop;
683 u8 *p = (u8 *) response;
684
685 for (loop = sizeof(*response); loop > 0; loop--)
686 csum = csum * 0x10204081 + *p++;
687
688 response->encrypted.checksum = htonl(csum);
689 }
690
691 /*
692 * load a scatterlist with a potentially split-page buffer
693 */
694 static void rxkad_sg_set_buf2(struct scatterlist sg[2],
695 void *buf, size_t buflen)
696 {
697 int nsg = 1;
698
699 sg_init_table(sg, 2);
700
701 sg_set_buf(&sg[0], buf, buflen);
702 if (sg[0].offset + buflen > PAGE_SIZE) {
703 /* the buffer was split over two pages */
704 sg[0].length = PAGE_SIZE - sg[0].offset;
705 sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
706 nsg++;
707 }
708
709 sg_mark_end(&sg[nsg - 1]);
710
711 ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
712 }
713
714 /*
715 * encrypt the response packet
716 */
717 static void rxkad_encrypt_response(struct rxrpc_connection *conn,
718 struct rxkad_response *resp,
719 const struct rxkad_key *s2)
720 {
721 struct blkcipher_desc desc;
722 struct rxrpc_crypt iv;
723 struct scatterlist sg[2];
724
725 /* continue encrypting from where we left off */
726 memcpy(&iv, s2->session_key, sizeof(iv));
727 desc.tfm = conn->cipher;
728 desc.info = iv.x;
729 desc.flags = 0;
730
731 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
732 crypto_blkcipher_encrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
733 }
734
735 /*
736 * respond to a challenge packet
737 */
738 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
739 struct sk_buff *skb,
740 u32 *_abort_code)
741 {
742 const struct rxrpc_key_token *token;
743 struct rxkad_challenge challenge;
744 struct rxkad_response resp
745 __attribute__((aligned(8))); /* must be aligned for crypto */
746 struct rxrpc_skb_priv *sp;
747 u32 version, nonce, min_level, abort_code;
748 int ret;
749
750 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
751
752 if (!conn->key) {
753 _leave(" = -EPROTO [no key]");
754 return -EPROTO;
755 }
756
757 ret = key_validate(conn->key);
758 if (ret < 0) {
759 *_abort_code = RXKADEXPIRED;
760 return ret;
761 }
762
763 abort_code = RXKADPACKETSHORT;
764 sp = rxrpc_skb(skb);
765 if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0)
766 goto protocol_error;
767
768 version = ntohl(challenge.version);
769 nonce = ntohl(challenge.nonce);
770 min_level = ntohl(challenge.min_level);
771
772 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
773 ntohl(sp->hdr.serial), version, nonce, min_level);
774
775 abort_code = RXKADINCONSISTENCY;
776 if (version != RXKAD_VERSION)
777 goto protocol_error;
778
779 abort_code = RXKADLEVELFAIL;
780 if (conn->security_level < min_level)
781 goto protocol_error;
782
783 token = conn->key->payload.data;
784
785 /* build the response packet */
786 memset(&resp, 0, sizeof(resp));
787
788 resp.version = RXKAD_VERSION;
789 resp.encrypted.epoch = conn->epoch;
790 resp.encrypted.cid = conn->cid;
791 resp.encrypted.securityIndex = htonl(conn->security_ix);
792 resp.encrypted.call_id[0] =
793 (conn->channels[0] ? conn->channels[0]->call_id : 0);
794 resp.encrypted.call_id[1] =
795 (conn->channels[1] ? conn->channels[1]->call_id : 0);
796 resp.encrypted.call_id[2] =
797 (conn->channels[2] ? conn->channels[2]->call_id : 0);
798 resp.encrypted.call_id[3] =
799 (conn->channels[3] ? conn->channels[3]->call_id : 0);
800 resp.encrypted.inc_nonce = htonl(nonce + 1);
801 resp.encrypted.level = htonl(conn->security_level);
802 resp.kvno = htonl(token->kad->kvno);
803 resp.ticket_len = htonl(token->kad->ticket_len);
804
805 /* calculate the response checksum and then do the encryption */
806 rxkad_calc_response_checksum(&resp);
807 rxkad_encrypt_response(conn, &resp, token->kad);
808 return rxkad_send_response(conn, &sp->hdr, &resp, token->kad);
809
810 protocol_error:
811 *_abort_code = abort_code;
812 _leave(" = -EPROTO [%d]", abort_code);
813 return -EPROTO;
814 }
815
816 /*
817 * decrypt the kerberos IV ticket in the response
818 */
819 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
820 void *ticket, size_t ticket_len,
821 struct rxrpc_crypt *_session_key,
822 time_t *_expiry,
823 u32 *_abort_code)
824 {
825 struct blkcipher_desc desc;
826 struct rxrpc_crypt iv, key;
827 struct scatterlist sg[1];
828 struct in_addr addr;
829 unsigned life;
830 time_t issue, now;
831 bool little_endian;
832 int ret;
833 u8 *p, *q, *name, *end;
834
835 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
836
837 *_expiry = 0;
838
839 ret = key_validate(conn->server_key);
840 if (ret < 0) {
841 switch (ret) {
842 case -EKEYEXPIRED:
843 *_abort_code = RXKADEXPIRED;
844 goto error;
845 default:
846 *_abort_code = RXKADNOAUTH;
847 goto error;
848 }
849 }
850
851 ASSERT(conn->server_key->payload.data != NULL);
852 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
853
854 memcpy(&iv, &conn->server_key->type_data, sizeof(iv));
855
856 desc.tfm = conn->server_key->payload.data;
857 desc.info = iv.x;
858 desc.flags = 0;
859
860 sg_init_one(&sg[0], ticket, ticket_len);
861 crypto_blkcipher_decrypt_iv(&desc, sg, sg, ticket_len);
862
863 p = ticket;
864 end = p + ticket_len;
865
866 #define Z(size) \
867 ({ \
868 u8 *__str = p; \
869 q = memchr(p, 0, end - p); \
870 if (!q || q - p > (size)) \
871 goto bad_ticket; \
872 for (; p < q; p++) \
873 if (!isprint(*p)) \
874 goto bad_ticket; \
875 p++; \
876 __str; \
877 })
878
879 /* extract the ticket flags */
880 _debug("KIV FLAGS: %x", *p);
881 little_endian = *p & 1;
882 p++;
883
884 /* extract the authentication name */
885 name = Z(ANAME_SZ);
886 _debug("KIV ANAME: %s", name);
887
888 /* extract the principal's instance */
889 name = Z(INST_SZ);
890 _debug("KIV INST : %s", name);
891
892 /* extract the principal's authentication domain */
893 name = Z(REALM_SZ);
894 _debug("KIV REALM: %s", name);
895
896 if (end - p < 4 + 8 + 4 + 2)
897 goto bad_ticket;
898
899 /* get the IPv4 address of the entity that requested the ticket */
900 memcpy(&addr, p, sizeof(addr));
901 p += 4;
902 _debug("KIV ADDR : %pI4", &addr);
903
904 /* get the session key from the ticket */
905 memcpy(&key, p, sizeof(key));
906 p += 8;
907 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
908 memcpy(_session_key, &key, sizeof(key));
909
910 /* get the ticket's lifetime */
911 life = *p++ * 5 * 60;
912 _debug("KIV LIFE : %u", life);
913
914 /* get the issue time of the ticket */
915 if (little_endian) {
916 __le32 stamp;
917 memcpy(&stamp, p, 4);
918 issue = le32_to_cpu(stamp);
919 } else {
920 __be32 stamp;
921 memcpy(&stamp, p, 4);
922 issue = be32_to_cpu(stamp);
923 }
924 p += 4;
925 now = get_seconds();
926 _debug("KIV ISSUE: %lx [%lx]", issue, now);
927
928 /* check the ticket is in date */
929 if (issue > now) {
930 *_abort_code = RXKADNOAUTH;
931 ret = -EKEYREJECTED;
932 goto error;
933 }
934
935 if (issue < now - life) {
936 *_abort_code = RXKADEXPIRED;
937 ret = -EKEYEXPIRED;
938 goto error;
939 }
940
941 *_expiry = issue + life;
942
943 /* get the service name */
944 name = Z(SNAME_SZ);
945 _debug("KIV SNAME: %s", name);
946
947 /* get the service instance name */
948 name = Z(INST_SZ);
949 _debug("KIV SINST: %s", name);
950
951 ret = 0;
952 error:
953 _leave(" = %d", ret);
954 return ret;
955
956 bad_ticket:
957 *_abort_code = RXKADBADTICKET;
958 ret = -EBADMSG;
959 goto error;
960 }
961
962 /*
963 * decrypt the response packet
964 */
965 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
966 struct rxkad_response *resp,
967 const struct rxrpc_crypt *session_key)
968 {
969 struct blkcipher_desc desc;
970 struct scatterlist sg[2];
971 struct rxrpc_crypt iv;
972
973 _enter(",,%08x%08x",
974 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
975
976 ASSERT(rxkad_ci != NULL);
977
978 mutex_lock(&rxkad_ci_mutex);
979 if (crypto_blkcipher_setkey(rxkad_ci, session_key->x,
980 sizeof(*session_key)) < 0)
981 BUG();
982
983 memcpy(&iv, session_key, sizeof(iv));
984 desc.tfm = rxkad_ci;
985 desc.info = iv.x;
986 desc.flags = 0;
987
988 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
989 crypto_blkcipher_decrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
990 mutex_unlock(&rxkad_ci_mutex);
991
992 _leave("");
993 }
994
995 /*
996 * verify a response
997 */
998 static int rxkad_verify_response(struct rxrpc_connection *conn,
999 struct sk_buff *skb,
1000 u32 *_abort_code)
1001 {
1002 struct rxkad_response response
1003 __attribute__((aligned(8))); /* must be aligned for crypto */
1004 struct rxrpc_skb_priv *sp;
1005 struct rxrpc_crypt session_key;
1006 time_t expiry;
1007 void *ticket;
1008 u32 abort_code, version, kvno, ticket_len, level;
1009 __be32 csum;
1010 int ret;
1011
1012 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1013
1014 abort_code = RXKADPACKETSHORT;
1015 if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0)
1016 goto protocol_error;
1017 if (!pskb_pull(skb, sizeof(response)))
1018 BUG();
1019
1020 version = ntohl(response.version);
1021 ticket_len = ntohl(response.ticket_len);
1022 kvno = ntohl(response.kvno);
1023 sp = rxrpc_skb(skb);
1024 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1025 ntohl(sp->hdr.serial), version, kvno, ticket_len);
1026
1027 abort_code = RXKADINCONSISTENCY;
1028 if (version != RXKAD_VERSION)
1029 goto protocol_error;
1030
1031 abort_code = RXKADTICKETLEN;
1032 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1033 goto protocol_error;
1034
1035 abort_code = RXKADUNKNOWNKEY;
1036 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1037 goto protocol_error;
1038
1039 /* extract the kerberos ticket and decrypt and decode it */
1040 ticket = kmalloc(ticket_len, GFP_NOFS);
1041 if (!ticket)
1042 return -ENOMEM;
1043
1044 abort_code = RXKADPACKETSHORT;
1045 if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
1046 goto protocol_error_free;
1047
1048 ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
1049 &expiry, &abort_code);
1050 if (ret < 0) {
1051 *_abort_code = abort_code;
1052 kfree(ticket);
1053 return ret;
1054 }
1055
1056 /* use the session key from inside the ticket to decrypt the
1057 * response */
1058 rxkad_decrypt_response(conn, &response, &session_key);
1059
1060 abort_code = RXKADSEALEDINCON;
1061 if (response.encrypted.epoch != conn->epoch)
1062 goto protocol_error_free;
1063 if (response.encrypted.cid != conn->cid)
1064 goto protocol_error_free;
1065 if (ntohl(response.encrypted.securityIndex) != conn->security_ix)
1066 goto protocol_error_free;
1067 csum = response.encrypted.checksum;
1068 response.encrypted.checksum = 0;
1069 rxkad_calc_response_checksum(&response);
1070 if (response.encrypted.checksum != csum)
1071 goto protocol_error_free;
1072
1073 if (ntohl(response.encrypted.call_id[0]) > INT_MAX ||
1074 ntohl(response.encrypted.call_id[1]) > INT_MAX ||
1075 ntohl(response.encrypted.call_id[2]) > INT_MAX ||
1076 ntohl(response.encrypted.call_id[3]) > INT_MAX)
1077 goto protocol_error_free;
1078
1079 abort_code = RXKADOUTOFSEQUENCE;
1080 if (response.encrypted.inc_nonce != htonl(conn->security_nonce + 1))
1081 goto protocol_error_free;
1082
1083 abort_code = RXKADLEVELFAIL;
1084 level = ntohl(response.encrypted.level);
1085 if (level > RXRPC_SECURITY_ENCRYPT)
1086 goto protocol_error_free;
1087 conn->security_level = level;
1088
1089 /* create a key to hold the security data and expiration time - after
1090 * this the connection security can be handled in exactly the same way
1091 * as for a client connection */
1092 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1093 if (ret < 0) {
1094 kfree(ticket);
1095 return ret;
1096 }
1097
1098 kfree(ticket);
1099 _leave(" = 0");
1100 return 0;
1101
1102 protocol_error_free:
1103 kfree(ticket);
1104 protocol_error:
1105 *_abort_code = abort_code;
1106 _leave(" = -EPROTO [%d]", abort_code);
1107 return -EPROTO;
1108 }
1109
1110 /*
1111 * clear the connection security
1112 */
1113 static void rxkad_clear(struct rxrpc_connection *conn)
1114 {
1115 _enter("");
1116
1117 if (conn->cipher)
1118 crypto_free_blkcipher(conn->cipher);
1119 }
1120
1121 /*
1122 * RxRPC Kerberos-based security
1123 */
1124 static struct rxrpc_security rxkad = {
1125 .owner = THIS_MODULE,
1126 .name = "rxkad",
1127 .security_index = RXRPC_SECURITY_RXKAD,
1128 .init_connection_security = rxkad_init_connection_security,
1129 .prime_packet_security = rxkad_prime_packet_security,
1130 .secure_packet = rxkad_secure_packet,
1131 .verify_packet = rxkad_verify_packet,
1132 .issue_challenge = rxkad_issue_challenge,
1133 .respond_to_challenge = rxkad_respond_to_challenge,
1134 .verify_response = rxkad_verify_response,
1135 .clear = rxkad_clear,
1136 };
1137
1138 static __init int rxkad_init(void)
1139 {
1140 _enter("");
1141
1142 /* pin the cipher we need so that the crypto layer doesn't invoke
1143 * keventd to go get it */
1144 rxkad_ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
1145 if (IS_ERR(rxkad_ci))
1146 return PTR_ERR(rxkad_ci);
1147
1148 return rxrpc_register_security(&rxkad);
1149 }
1150
1151 module_init(rxkad_init);
1152
1153 static __exit void rxkad_exit(void)
1154 {
1155 _enter("");
1156
1157 rxrpc_unregister_security(&rxkad);
1158 crypto_free_blkcipher(rxkad_ci);
1159 }
1160
1161 module_exit(rxkad_exit);
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