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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <crypto/skcipher.h>
15#include <linux/module.h>
16#include <linux/net.h>
17#include <linux/skbuff.h>
18#include <linux/udp.h>
19#include <linux/scatterlist.h>
20#include <linux/ctype.h>
21#include <linux/slab.h>
22#include <net/sock.h>
23#include <net/af_rxrpc.h>
24#include <keys/rxrpc-type.h>
25#include "ar-internal.h"
26
27#define RXKAD_VERSION 2
28#define MAXKRB5TICKETLEN 1024
29#define RXKAD_TKT_TYPE_KERBEROS_V5 256
30#define ANAME_SZ 40 /* size of authentication name */
31#define INST_SZ 40 /* size of principal's instance */
32#define REALM_SZ 40 /* size of principal's auth domain */
33#define SNAME_SZ 40 /* size of service name */
34
35struct rxkad_level1_hdr {
36 __be32 data_size; /* true data size (excluding padding) */
37};
38
39struct rxkad_level2_hdr {
40 __be32 data_size; /* true data size (excluding padding) */
41 __be32 checksum; /* decrypted data checksum */
42};
43
44/*
45 * this holds a pinned cipher so that keventd doesn't get called by the cipher
46 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
47 * packets
48 */
49static struct crypto_skcipher *rxkad_ci;
50static DEFINE_MUTEX(rxkad_ci_mutex);
51
52/*
53 * initialise connection security
54 */
55static int rxkad_init_connection_security(struct rxrpc_connection *conn)
56{
57 struct crypto_skcipher *ci;
58 struct rxrpc_key_token *token;
59 int ret;
60
61 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->params.key));
62
63 token = conn->params.key->payload.data[0];
64 conn->security_ix = token->security_index;
65
66 ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
67 if (IS_ERR(ci)) {
68 _debug("no cipher");
69 ret = PTR_ERR(ci);
70 goto error;
71 }
72
73 if (crypto_skcipher_setkey(ci, token->kad->session_key,
74 sizeof(token->kad->session_key)) < 0)
75 BUG();
76
77 switch (conn->params.security_level) {
78 case RXRPC_SECURITY_PLAIN:
79 break;
80 case RXRPC_SECURITY_AUTH:
81 conn->size_align = 8;
82 conn->security_size = sizeof(struct rxkad_level1_hdr);
83 break;
84 case RXRPC_SECURITY_ENCRYPT:
85 conn->size_align = 8;
86 conn->security_size = sizeof(struct rxkad_level2_hdr);
87 break;
88 default:
89 ret = -EKEYREJECTED;
90 goto error;
91 }
92
93 conn->cipher = ci;
94 ret = 0;
95error:
96 _leave(" = %d", ret);
97 return ret;
98}
99
100/*
101 * prime the encryption state with the invariant parts of a connection's
102 * description
103 */
104static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
105{
106 struct rxrpc_key_token *token;
107 SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
108 struct scatterlist sg;
109 struct rxrpc_crypt iv;
110 __be32 *tmpbuf;
111 size_t tmpsize = 4 * sizeof(__be32);
112
113 _enter("");
114
115 if (!conn->params.key)
116 return 0;
117
118 tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
119 if (!tmpbuf)
120 return -ENOMEM;
121
122 token = conn->params.key->payload.data[0];
123 memcpy(&iv, token->kad->session_key, sizeof(iv));
124
125 tmpbuf[0] = htonl(conn->proto.epoch);
126 tmpbuf[1] = htonl(conn->proto.cid);
127 tmpbuf[2] = 0;
128 tmpbuf[3] = htonl(conn->security_ix);
129
130 sg_init_one(&sg, tmpbuf, tmpsize);
131 skcipher_request_set_tfm(req, conn->cipher);
132 skcipher_request_set_callback(req, 0, NULL, NULL);
133 skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
134 crypto_skcipher_encrypt(req);
135 skcipher_request_zero(req);
136
137 memcpy(&conn->csum_iv, tmpbuf + 2, sizeof(conn->csum_iv));
138 kfree(tmpbuf);
139 _leave(" = 0");
140 return 0;
141}
142
143/*
144 * partially encrypt a packet (level 1 security)
145 */
146static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
147 struct sk_buff *skb,
148 u32 data_size,
149 void *sechdr)
150{
151 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
152 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
153 struct rxkad_level1_hdr hdr;
154 struct rxrpc_crypt iv;
155 struct scatterlist sg;
156 u16 check;
157
158 _enter("");
159
160 check = sp->hdr.seq ^ call->call_id;
161 data_size |= (u32)check << 16;
162
163 hdr.data_size = htonl(data_size);
164 memcpy(sechdr, &hdr, sizeof(hdr));
165
166 /* start the encryption afresh */
167 memset(&iv, 0, sizeof(iv));
168
169 sg_init_one(&sg, sechdr, 8);
170 skcipher_request_set_tfm(req, call->conn->cipher);
171 skcipher_request_set_callback(req, 0, NULL, NULL);
172 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
173 crypto_skcipher_encrypt(req);
174 skcipher_request_zero(req);
175
176 _leave(" = 0");
177 return 0;
178}
179
180/*
181 * wholly encrypt a packet (level 2 security)
182 */
183static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
184 struct sk_buff *skb,
185 u32 data_size,
186 void *sechdr)
187{
188 const struct rxrpc_key_token *token;
189 struct rxkad_level2_hdr rxkhdr;
190 struct rxrpc_skb_priv *sp;
191 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
192 struct rxrpc_crypt iv;
193 struct scatterlist sg[16];
194 struct sk_buff *trailer;
195 unsigned int len;
196 u16 check;
197 int nsg;
198 int err;
199
200 sp = rxrpc_skb(skb);
201
202 _enter("");
203
204 check = sp->hdr.seq ^ call->call_id;
205
206 rxkhdr.data_size = htonl(data_size | (u32)check << 16);
207 rxkhdr.checksum = 0;
208 memcpy(sechdr, &rxkhdr, sizeof(rxkhdr));
209
210 /* encrypt from the session key */
211 token = call->conn->params.key->payload.data[0];
212 memcpy(&iv, token->kad->session_key, sizeof(iv));
213
214 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
215 skcipher_request_set_tfm(req, call->conn->cipher);
216 skcipher_request_set_callback(req, 0, NULL, NULL);
217 skcipher_request_set_crypt(req, &sg[0], &sg[0], sizeof(rxkhdr), iv.x);
218 crypto_skcipher_encrypt(req);
219
220 /* we want to encrypt the skbuff in-place */
221 nsg = skb_cow_data(skb, 0, &trailer);
222 err = -ENOMEM;
223 if (nsg < 0 || nsg > 16)
224 goto out;
225
226 len = data_size + call->conn->size_align - 1;
227 len &= ~(call->conn->size_align - 1);
228
229 sg_init_table(sg, nsg);
230 err = skb_to_sgvec(skb, sg, 0, len);
231 if (unlikely(err < 0))
232 goto out;
233 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
234 crypto_skcipher_encrypt(req);
235
236 _leave(" = 0");
237 err = 0;
238
239out:
240 skcipher_request_zero(req);
241 return err;
242}
243
244/*
245 * checksum an RxRPC packet header
246 */
247static int rxkad_secure_packet(struct rxrpc_call *call,
248 struct sk_buff *skb,
249 size_t data_size,
250 void *sechdr)
251{
252 struct rxrpc_skb_priv *sp;
253 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
254 struct rxrpc_crypt iv;
255 struct scatterlist sg;
256 u32 x, y;
257 int ret;
258
259 sp = rxrpc_skb(skb);
260
261 _enter("{%d{%x}},{#%u},%zu,",
262 call->debug_id, key_serial(call->conn->params.key),
263 sp->hdr.seq, data_size);
264
265 if (!call->conn->cipher)
266 return 0;
267
268 ret = key_validate(call->conn->params.key);
269 if (ret < 0)
270 return ret;
271
272 /* continue encrypting from where we left off */
273 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
274
275 /* calculate the security checksum */
276 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
277 x |= sp->hdr.seq & 0x3fffffff;
278 call->crypto_buf[0] = htonl(call->call_id);
279 call->crypto_buf[1] = htonl(x);
280
281 sg_init_one(&sg, call->crypto_buf, 8);
282 skcipher_request_set_tfm(req, call->conn->cipher);
283 skcipher_request_set_callback(req, 0, NULL, NULL);
284 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
285 crypto_skcipher_encrypt(req);
286 skcipher_request_zero(req);
287
288 y = ntohl(call->crypto_buf[1]);
289 y = (y >> 16) & 0xffff;
290 if (y == 0)
291 y = 1; /* zero checksums are not permitted */
292 sp->hdr.cksum = y;
293
294 switch (call->conn->params.security_level) {
295 case RXRPC_SECURITY_PLAIN:
296 ret = 0;
297 break;
298 case RXRPC_SECURITY_AUTH:
299 ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
300 break;
301 case RXRPC_SECURITY_ENCRYPT:
302 ret = rxkad_secure_packet_encrypt(call, skb, data_size,
303 sechdr);
304 break;
305 default:
306 ret = -EPERM;
307 break;
308 }
309
310 _leave(" = %d [set %hx]", ret, y);
311 return ret;
312}
313
314/*
315 * decrypt partial encryption on a packet (level 1 security)
316 */
317static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
318 unsigned int offset, unsigned int len,
319 rxrpc_seq_t seq)
320{
321 struct rxkad_level1_hdr sechdr;
322 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
323 struct rxrpc_crypt iv;
324 struct scatterlist sg[16];
325 struct sk_buff *trailer;
326 bool aborted;
327 u32 data_size, buf;
328 u16 check;
329 int nsg, ret;
330
331 _enter("");
332
333 if (len < 8) {
334 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_hdr", "V1H",
335 RXKADSEALEDINCON);
336 goto protocol_error;
337 }
338
339 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
340 * directly into the target buffer.
341 */
342 nsg = skb_cow_data(skb, 0, &trailer);
343 if (nsg < 0 || nsg > 16)
344 goto nomem;
345
346 sg_init_table(sg, nsg);
347 ret = skb_to_sgvec(skb, sg, offset, 8);
348 if (unlikely(ret < 0))
349 return ret;
350
351 /* start the decryption afresh */
352 memset(&iv, 0, sizeof(iv));
353
354 skcipher_request_set_tfm(req, call->conn->cipher);
355 skcipher_request_set_callback(req, 0, NULL, NULL);
356 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
357 crypto_skcipher_decrypt(req);
358 skcipher_request_zero(req);
359
360 /* Extract the decrypted packet length */
361 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
362 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_len", "XV1",
363 RXKADDATALEN);
364 goto protocol_error;
365 }
366 offset += sizeof(sechdr);
367 len -= sizeof(sechdr);
368
369 buf = ntohl(sechdr.data_size);
370 data_size = buf & 0xffff;
371
372 check = buf >> 16;
373 check ^= seq ^ call->call_id;
374 check &= 0xffff;
375 if (check != 0) {
376 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_check", "V1C",
377 RXKADSEALEDINCON);
378 goto protocol_error;
379 }
380
381 if (data_size > len) {
382 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_datalen", "V1L",
383 RXKADDATALEN);
384 goto protocol_error;
385 }
386
387 _leave(" = 0 [dlen=%x]", data_size);
388 return 0;
389
390protocol_error:
391 if (aborted)
392 rxrpc_send_abort_packet(call);
393 return -EPROTO;
394
395nomem:
396 _leave(" = -ENOMEM");
397 return -ENOMEM;
398}
399
400/*
401 * wholly decrypt a packet (level 2 security)
402 */
403static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
404 unsigned int offset, unsigned int len,
405 rxrpc_seq_t seq)
406{
407 const struct rxrpc_key_token *token;
408 struct rxkad_level2_hdr sechdr;
409 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
410 struct rxrpc_crypt iv;
411 struct scatterlist _sg[4], *sg;
412 struct sk_buff *trailer;
413 bool aborted;
414 u32 data_size, buf;
415 u16 check;
416 int nsg, ret;
417
418 _enter(",{%d}", skb->len);
419
420 if (len < 8) {
421 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_hdr", "V2H",
422 RXKADSEALEDINCON);
423 goto protocol_error;
424 }
425
426 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
427 * directly into the target buffer.
428 */
429 nsg = skb_cow_data(skb, 0, &trailer);
430 if (nsg < 0)
431 goto nomem;
432
433 sg = _sg;
434 if (unlikely(nsg > 4)) {
435 sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
436 if (!sg)
437 goto nomem;
438 }
439
440 sg_init_table(sg, nsg);
441 ret = skb_to_sgvec(skb, sg, offset, len);
442 if (unlikely(ret < 0)) {
443 if (sg != _sg)
444 kfree(sg);
445 return ret;
446 }
447
448 /* decrypt from the session key */
449 token = call->conn->params.key->payload.data[0];
450 memcpy(&iv, token->kad->session_key, sizeof(iv));
451
452 skcipher_request_set_tfm(req, call->conn->cipher);
453 skcipher_request_set_callback(req, 0, NULL, NULL);
454 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
455 crypto_skcipher_decrypt(req);
456 skcipher_request_zero(req);
457 if (sg != _sg)
458 kfree(sg);
459
460 /* Extract the decrypted packet length */
461 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
462 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_len", "XV2",
463 RXKADDATALEN);
464 goto protocol_error;
465 }
466 offset += sizeof(sechdr);
467 len -= sizeof(sechdr);
468
469 buf = ntohl(sechdr.data_size);
470 data_size = buf & 0xffff;
471
472 check = buf >> 16;
473 check ^= seq ^ call->call_id;
474 check &= 0xffff;
475 if (check != 0) {
476 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_check", "V2C",
477 RXKADSEALEDINCON);
478 goto protocol_error;
479 }
480
481 if (data_size > len) {
482 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_datalen", "V2L",
483 RXKADDATALEN);
484 goto protocol_error;
485 }
486
487 _leave(" = 0 [dlen=%x]", data_size);
488 return 0;
489
490protocol_error:
491 if (aborted)
492 rxrpc_send_abort_packet(call);
493 return -EPROTO;
494
495nomem:
496 _leave(" = -ENOMEM");
497 return -ENOMEM;
498}
499
500/*
501 * Verify the security on a received packet or subpacket (if part of a
502 * jumbo packet).
503 */
504static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
505 unsigned int offset, unsigned int len,
506 rxrpc_seq_t seq, u16 expected_cksum)
507{
508 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
509 struct rxrpc_crypt iv;
510 struct scatterlist sg;
511 bool aborted;
512 u16 cksum;
513 u32 x, y;
514
515 _enter("{%d{%x}},{#%u}",
516 call->debug_id, key_serial(call->conn->params.key), seq);
517
518 if (!call->conn->cipher)
519 return 0;
520
521 /* continue encrypting from where we left off */
522 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
523
524 /* validate the security checksum */
525 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
526 x |= seq & 0x3fffffff;
527 call->crypto_buf[0] = htonl(call->call_id);
528 call->crypto_buf[1] = htonl(x);
529
530 sg_init_one(&sg, call->crypto_buf, 8);
531 skcipher_request_set_tfm(req, call->conn->cipher);
532 skcipher_request_set_callback(req, 0, NULL, NULL);
533 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
534 crypto_skcipher_encrypt(req);
535 skcipher_request_zero(req);
536
537 y = ntohl(call->crypto_buf[1]);
538 cksum = (y >> 16) & 0xffff;
539 if (cksum == 0)
540 cksum = 1; /* zero checksums are not permitted */
541
542 if (cksum != expected_cksum) {
543 aborted = rxrpc_abort_eproto(call, skb, "rxkad_csum", "VCK",
544 RXKADSEALEDINCON);
545 goto protocol_error;
546 }
547
548 switch (call->conn->params.security_level) {
549 case RXRPC_SECURITY_PLAIN:
550 return 0;
551 case RXRPC_SECURITY_AUTH:
552 return rxkad_verify_packet_1(call, skb, offset, len, seq);
553 case RXRPC_SECURITY_ENCRYPT:
554 return rxkad_verify_packet_2(call, skb, offset, len, seq);
555 default:
556 return -ENOANO;
557 }
558
559protocol_error:
560 if (aborted)
561 rxrpc_send_abort_packet(call);
562 return -EPROTO;
563}
564
565/*
566 * Locate the data contained in a packet that was partially encrypted.
567 */
568static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb,
569 unsigned int *_offset, unsigned int *_len)
570{
571 struct rxkad_level1_hdr sechdr;
572
573 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
574 BUG();
575 *_offset += sizeof(sechdr);
576 *_len = ntohl(sechdr.data_size) & 0xffff;
577}
578
579/*
580 * Locate the data contained in a packet that was completely encrypted.
581 */
582static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb,
583 unsigned int *_offset, unsigned int *_len)
584{
585 struct rxkad_level2_hdr sechdr;
586
587 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
588 BUG();
589 *_offset += sizeof(sechdr);
590 *_len = ntohl(sechdr.data_size) & 0xffff;
591}
592
593/*
594 * Locate the data contained in an already decrypted packet.
595 */
596static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
597 unsigned int *_offset, unsigned int *_len)
598{
599 switch (call->conn->params.security_level) {
600 case RXRPC_SECURITY_AUTH:
601 rxkad_locate_data_1(call, skb, _offset, _len);
602 return;
603 case RXRPC_SECURITY_ENCRYPT:
604 rxkad_locate_data_2(call, skb, _offset, _len);
605 return;
606 default:
607 return;
608 }
609}
610
611/*
612 * issue a challenge
613 */
614static int rxkad_issue_challenge(struct rxrpc_connection *conn)
615{
616 struct rxkad_challenge challenge;
617 struct rxrpc_wire_header whdr;
618 struct msghdr msg;
619 struct kvec iov[2];
620 size_t len;
621 u32 serial;
622 int ret;
623
624 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
625
626 ret = key_validate(conn->params.key);
627 if (ret < 0)
628 return ret;
629
630 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
631
632 challenge.version = htonl(2);
633 challenge.nonce = htonl(conn->security_nonce);
634 challenge.min_level = htonl(0);
635 challenge.__padding = 0;
636
637 msg.msg_name = &conn->params.peer->srx.transport;
638 msg.msg_namelen = conn->params.peer->srx.transport_len;
639 msg.msg_control = NULL;
640 msg.msg_controllen = 0;
641 msg.msg_flags = 0;
642
643 whdr.epoch = htonl(conn->proto.epoch);
644 whdr.cid = htonl(conn->proto.cid);
645 whdr.callNumber = 0;
646 whdr.seq = 0;
647 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
648 whdr.flags = conn->out_clientflag;
649 whdr.userStatus = 0;
650 whdr.securityIndex = conn->security_ix;
651 whdr._rsvd = 0;
652 whdr.serviceId = htons(conn->service_id);
653
654 iov[0].iov_base = &whdr;
655 iov[0].iov_len = sizeof(whdr);
656 iov[1].iov_base = &challenge;
657 iov[1].iov_len = sizeof(challenge);
658
659 len = iov[0].iov_len + iov[1].iov_len;
660
661 serial = atomic_inc_return(&conn->serial);
662 whdr.serial = htonl(serial);
663 _proto("Tx CHALLENGE %%%u", serial);
664
665 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
666 if (ret < 0) {
667 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
668 rxrpc_tx_fail_conn_challenge);
669 return -EAGAIN;
670 }
671
672 conn->params.peer->last_tx_at = ktime_get_real();
673 _leave(" = 0");
674 return 0;
675}
676
677/*
678 * send a Kerberos security response
679 */
680static int rxkad_send_response(struct rxrpc_connection *conn,
681 struct rxrpc_host_header *hdr,
682 struct rxkad_response *resp,
683 const struct rxkad_key *s2)
684{
685 struct rxrpc_wire_header whdr;
686 struct msghdr msg;
687 struct kvec iov[3];
688 size_t len;
689 u32 serial;
690 int ret;
691
692 _enter("");
693
694 msg.msg_name = &conn->params.peer->srx.transport;
695 msg.msg_namelen = conn->params.peer->srx.transport_len;
696 msg.msg_control = NULL;
697 msg.msg_controllen = 0;
698 msg.msg_flags = 0;
699
700 memset(&whdr, 0, sizeof(whdr));
701 whdr.epoch = htonl(hdr->epoch);
702 whdr.cid = htonl(hdr->cid);
703 whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
704 whdr.flags = conn->out_clientflag;
705 whdr.securityIndex = hdr->securityIndex;
706 whdr.serviceId = htons(hdr->serviceId);
707
708 iov[0].iov_base = &whdr;
709 iov[0].iov_len = sizeof(whdr);
710 iov[1].iov_base = resp;
711 iov[1].iov_len = sizeof(*resp);
712 iov[2].iov_base = (void *)s2->ticket;
713 iov[2].iov_len = s2->ticket_len;
714
715 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
716
717 serial = atomic_inc_return(&conn->serial);
718 whdr.serial = htonl(serial);
719 _proto("Tx RESPONSE %%%u", serial);
720
721 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 3, len);
722 if (ret < 0) {
723 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
724 rxrpc_tx_fail_conn_response);
725 return -EAGAIN;
726 }
727
728 conn->params.peer->last_tx_at = ktime_get_real();
729 _leave(" = 0");
730 return 0;
731}
732
733/*
734 * calculate the response checksum
735 */
736static void rxkad_calc_response_checksum(struct rxkad_response *response)
737{
738 u32 csum = 1000003;
739 int loop;
740 u8 *p = (u8 *) response;
741
742 for (loop = sizeof(*response); loop > 0; loop--)
743 csum = csum * 0x10204081 + *p++;
744
745 response->encrypted.checksum = htonl(csum);
746}
747
748/*
749 * encrypt the response packet
750 */
751static void rxkad_encrypt_response(struct rxrpc_connection *conn,
752 struct rxkad_response *resp,
753 const struct rxkad_key *s2)
754{
755 SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
756 struct rxrpc_crypt iv;
757 struct scatterlist sg[1];
758
759 /* continue encrypting from where we left off */
760 memcpy(&iv, s2->session_key, sizeof(iv));
761
762 sg_init_table(sg, 1);
763 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
764 skcipher_request_set_tfm(req, conn->cipher);
765 skcipher_request_set_callback(req, 0, NULL, NULL);
766 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
767 crypto_skcipher_encrypt(req);
768 skcipher_request_zero(req);
769}
770
771/*
772 * respond to a challenge packet
773 */
774static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
775 struct sk_buff *skb,
776 u32 *_abort_code)
777{
778 const struct rxrpc_key_token *token;
779 struct rxkad_challenge challenge;
780 struct rxkad_response *resp;
781 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
782 const char *eproto;
783 u32 version, nonce, min_level, abort_code;
784 int ret;
785
786 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
787
788 eproto = tracepoint_string("chall_no_key");
789 abort_code = RX_PROTOCOL_ERROR;
790 if (!conn->params.key)
791 goto protocol_error;
792
793 abort_code = RXKADEXPIRED;
794 ret = key_validate(conn->params.key);
795 if (ret < 0)
796 goto other_error;
797
798 eproto = tracepoint_string("chall_short");
799 abort_code = RXKADPACKETSHORT;
800 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
801 &challenge, sizeof(challenge)) < 0)
802 goto protocol_error;
803
804 version = ntohl(challenge.version);
805 nonce = ntohl(challenge.nonce);
806 min_level = ntohl(challenge.min_level);
807
808 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
809 sp->hdr.serial, version, nonce, min_level);
810
811 eproto = tracepoint_string("chall_ver");
812 abort_code = RXKADINCONSISTENCY;
813 if (version != RXKAD_VERSION)
814 goto protocol_error;
815
816 abort_code = RXKADLEVELFAIL;
817 ret = -EACCES;
818 if (conn->params.security_level < min_level)
819 goto other_error;
820
821 token = conn->params.key->payload.data[0];
822
823 /* build the response packet */
824 resp = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
825 if (!resp)
826 return -ENOMEM;
827
828 resp->version = htonl(RXKAD_VERSION);
829 resp->encrypted.epoch = htonl(conn->proto.epoch);
830 resp->encrypted.cid = htonl(conn->proto.cid);
831 resp->encrypted.securityIndex = htonl(conn->security_ix);
832 resp->encrypted.inc_nonce = htonl(nonce + 1);
833 resp->encrypted.level = htonl(conn->params.security_level);
834 resp->kvno = htonl(token->kad->kvno);
835 resp->ticket_len = htonl(token->kad->ticket_len);
836 resp->encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
837 resp->encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
838 resp->encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
839 resp->encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
840
841 /* calculate the response checksum and then do the encryption */
842 rxkad_calc_response_checksum(resp);
843 rxkad_encrypt_response(conn, resp, token->kad);
844 ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
845 kfree(resp);
846 return ret;
847
848protocol_error:
849 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
850 ret = -EPROTO;
851other_error:
852 *_abort_code = abort_code;
853 return ret;
854}
855
856/*
857 * decrypt the kerberos IV ticket in the response
858 */
859static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
860 struct sk_buff *skb,
861 void *ticket, size_t ticket_len,
862 struct rxrpc_crypt *_session_key,
863 time64_t *_expiry,
864 u32 *_abort_code)
865{
866 struct skcipher_request *req;
867 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
868 struct rxrpc_crypt iv, key;
869 struct scatterlist sg[1];
870 struct in_addr addr;
871 unsigned int life;
872 const char *eproto;
873 time64_t issue, now;
874 bool little_endian;
875 int ret;
876 u32 abort_code;
877 u8 *p, *q, *name, *end;
878
879 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
880
881 *_expiry = 0;
882
883 ret = key_validate(conn->server_key);
884 if (ret < 0) {
885 switch (ret) {
886 case -EKEYEXPIRED:
887 abort_code = RXKADEXPIRED;
888 goto other_error;
889 default:
890 abort_code = RXKADNOAUTH;
891 goto other_error;
892 }
893 }
894
895 ASSERT(conn->server_key->payload.data[0] != NULL);
896 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
897
898 memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv));
899
900 ret = -ENOMEM;
901 req = skcipher_request_alloc(conn->server_key->payload.data[0],
902 GFP_NOFS);
903 if (!req)
904 goto temporary_error;
905
906 sg_init_one(&sg[0], ticket, ticket_len);
907 skcipher_request_set_callback(req, 0, NULL, NULL);
908 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
909 crypto_skcipher_decrypt(req);
910 skcipher_request_free(req);
911
912 p = ticket;
913 end = p + ticket_len;
914
915#define Z(field) \
916 ({ \
917 u8 *__str = p; \
918 eproto = tracepoint_string("rxkad_bad_"#field); \
919 q = memchr(p, 0, end - p); \
920 if (!q || q - p > (field##_SZ)) \
921 goto bad_ticket; \
922 for (; p < q; p++) \
923 if (!isprint(*p)) \
924 goto bad_ticket; \
925 p++; \
926 __str; \
927 })
928
929 /* extract the ticket flags */
930 _debug("KIV FLAGS: %x", *p);
931 little_endian = *p & 1;
932 p++;
933
934 /* extract the authentication name */
935 name = Z(ANAME);
936 _debug("KIV ANAME: %s", name);
937
938 /* extract the principal's instance */
939 name = Z(INST);
940 _debug("KIV INST : %s", name);
941
942 /* extract the principal's authentication domain */
943 name = Z(REALM);
944 _debug("KIV REALM: %s", name);
945
946 eproto = tracepoint_string("rxkad_bad_len");
947 if (end - p < 4 + 8 + 4 + 2)
948 goto bad_ticket;
949
950 /* get the IPv4 address of the entity that requested the ticket */
951 memcpy(&addr, p, sizeof(addr));
952 p += 4;
953 _debug("KIV ADDR : %pI4", &addr);
954
955 /* get the session key from the ticket */
956 memcpy(&key, p, sizeof(key));
957 p += 8;
958 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
959 memcpy(_session_key, &key, sizeof(key));
960
961 /* get the ticket's lifetime */
962 life = *p++ * 5 * 60;
963 _debug("KIV LIFE : %u", life);
964
965 /* get the issue time of the ticket */
966 if (little_endian) {
967 __le32 stamp;
968 memcpy(&stamp, p, 4);
969 issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
970 } else {
971 __be32 stamp;
972 memcpy(&stamp, p, 4);
973 issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
974 }
975 p += 4;
976 now = ktime_get_real_seconds();
977 _debug("KIV ISSUE: %llx [%llx]", issue, now);
978
979 /* check the ticket is in date */
980 if (issue > now) {
981 abort_code = RXKADNOAUTH;
982 ret = -EKEYREJECTED;
983 goto other_error;
984 }
985
986 if (issue < now - life) {
987 abort_code = RXKADEXPIRED;
988 ret = -EKEYEXPIRED;
989 goto other_error;
990 }
991
992 *_expiry = issue + life;
993
994 /* get the service name */
995 name = Z(SNAME);
996 _debug("KIV SNAME: %s", name);
997
998 /* get the service instance name */
999 name = Z(INST);
1000 _debug("KIV SINST: %s", name);
1001 return 0;
1002
1003bad_ticket:
1004 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1005 abort_code = RXKADBADTICKET;
1006 ret = -EPROTO;
1007other_error:
1008 *_abort_code = abort_code;
1009 return ret;
1010temporary_error:
1011 return ret;
1012}
1013
1014/*
1015 * decrypt the response packet
1016 */
1017static void rxkad_decrypt_response(struct rxrpc_connection *conn,
1018 struct rxkad_response *resp,
1019 const struct rxrpc_crypt *session_key)
1020{
1021 SKCIPHER_REQUEST_ON_STACK(req, rxkad_ci);
1022 struct scatterlist sg[1];
1023 struct rxrpc_crypt iv;
1024
1025 _enter(",,%08x%08x",
1026 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
1027
1028 ASSERT(rxkad_ci != NULL);
1029
1030 mutex_lock(&rxkad_ci_mutex);
1031 if (crypto_skcipher_setkey(rxkad_ci, session_key->x,
1032 sizeof(*session_key)) < 0)
1033 BUG();
1034
1035 memcpy(&iv, session_key, sizeof(iv));
1036
1037 sg_init_table(sg, 1);
1038 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1039 skcipher_request_set_tfm(req, rxkad_ci);
1040 skcipher_request_set_callback(req, 0, NULL, NULL);
1041 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1042 crypto_skcipher_decrypt(req);
1043 skcipher_request_zero(req);
1044
1045 mutex_unlock(&rxkad_ci_mutex);
1046
1047 _leave("");
1048}
1049
1050/*
1051 * verify a response
1052 */
1053static int rxkad_verify_response(struct rxrpc_connection *conn,
1054 struct sk_buff *skb,
1055 u32 *_abort_code)
1056{
1057 struct rxkad_response *response;
1058 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1059 struct rxrpc_crypt session_key;
1060 const char *eproto;
1061 time64_t expiry;
1062 void *ticket;
1063 u32 abort_code, version, kvno, ticket_len, level;
1064 __be32 csum;
1065 int ret, i;
1066
1067 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1068
1069 ret = -ENOMEM;
1070 response = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
1071 if (!response)
1072 goto temporary_error;
1073
1074 eproto = tracepoint_string("rxkad_rsp_short");
1075 abort_code = RXKADPACKETSHORT;
1076 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1077 response, sizeof(*response)) < 0)
1078 goto protocol_error;
1079 if (!pskb_pull(skb, sizeof(*response)))
1080 BUG();
1081
1082 version = ntohl(response->version);
1083 ticket_len = ntohl(response->ticket_len);
1084 kvno = ntohl(response->kvno);
1085 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1086 sp->hdr.serial, version, kvno, ticket_len);
1087
1088 eproto = tracepoint_string("rxkad_rsp_ver");
1089 abort_code = RXKADINCONSISTENCY;
1090 if (version != RXKAD_VERSION)
1091 goto protocol_error;
1092
1093 eproto = tracepoint_string("rxkad_rsp_tktlen");
1094 abort_code = RXKADTICKETLEN;
1095 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1096 goto protocol_error;
1097
1098 eproto = tracepoint_string("rxkad_rsp_unkkey");
1099 abort_code = RXKADUNKNOWNKEY;
1100 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1101 goto protocol_error;
1102
1103 /* extract the kerberos ticket and decrypt and decode it */
1104 ret = -ENOMEM;
1105 ticket = kmalloc(ticket_len, GFP_NOFS);
1106 if (!ticket)
1107 goto temporary_error;
1108
1109 eproto = tracepoint_string("rxkad_tkt_short");
1110 abort_code = RXKADPACKETSHORT;
1111 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1112 ticket, ticket_len) < 0)
1113 goto protocol_error_free;
1114
1115 ret = rxkad_decrypt_ticket(conn, skb, ticket, ticket_len, &session_key,
1116 &expiry, _abort_code);
1117 if (ret < 0)
1118 goto temporary_error_free_resp;
1119
1120 /* use the session key from inside the ticket to decrypt the
1121 * response */
1122 rxkad_decrypt_response(conn, response, &session_key);
1123
1124 eproto = tracepoint_string("rxkad_rsp_param");
1125 abort_code = RXKADSEALEDINCON;
1126 if (ntohl(response->encrypted.epoch) != conn->proto.epoch)
1127 goto protocol_error_free;
1128 if (ntohl(response->encrypted.cid) != conn->proto.cid)
1129 goto protocol_error_free;
1130 if (ntohl(response->encrypted.securityIndex) != conn->security_ix)
1131 goto protocol_error_free;
1132 csum = response->encrypted.checksum;
1133 response->encrypted.checksum = 0;
1134 rxkad_calc_response_checksum(response);
1135 eproto = tracepoint_string("rxkad_rsp_csum");
1136 if (response->encrypted.checksum != csum)
1137 goto protocol_error_free;
1138
1139 spin_lock(&conn->channel_lock);
1140 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1141 struct rxrpc_call *call;
1142 u32 call_id = ntohl(response->encrypted.call_id[i]);
1143
1144 eproto = tracepoint_string("rxkad_rsp_callid");
1145 if (call_id > INT_MAX)
1146 goto protocol_error_unlock;
1147
1148 eproto = tracepoint_string("rxkad_rsp_callctr");
1149 if (call_id < conn->channels[i].call_counter)
1150 goto protocol_error_unlock;
1151
1152 eproto = tracepoint_string("rxkad_rsp_callst");
1153 if (call_id > conn->channels[i].call_counter) {
1154 call = rcu_dereference_protected(
1155 conn->channels[i].call,
1156 lockdep_is_held(&conn->channel_lock));
1157 if (call && call->state < RXRPC_CALL_COMPLETE)
1158 goto protocol_error_unlock;
1159 conn->channels[i].call_counter = call_id;
1160 }
1161 }
1162 spin_unlock(&conn->channel_lock);
1163
1164 eproto = tracepoint_string("rxkad_rsp_seq");
1165 abort_code = RXKADOUTOFSEQUENCE;
1166 if (ntohl(response->encrypted.inc_nonce) != conn->security_nonce + 1)
1167 goto protocol_error_free;
1168
1169 eproto = tracepoint_string("rxkad_rsp_level");
1170 abort_code = RXKADLEVELFAIL;
1171 level = ntohl(response->encrypted.level);
1172 if (level > RXRPC_SECURITY_ENCRYPT)
1173 goto protocol_error_free;
1174 conn->params.security_level = level;
1175
1176 /* create a key to hold the security data and expiration time - after
1177 * this the connection security can be handled in exactly the same way
1178 * as for a client connection */
1179 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1180 if (ret < 0)
1181 goto temporary_error_free_ticket;
1182
1183 kfree(ticket);
1184 kfree(response);
1185 _leave(" = 0");
1186 return 0;
1187
1188protocol_error_unlock:
1189 spin_unlock(&conn->channel_lock);
1190protocol_error_free:
1191 kfree(ticket);
1192protocol_error:
1193 kfree(response);
1194 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1195 *_abort_code = abort_code;
1196 return -EPROTO;
1197
1198temporary_error_free_ticket:
1199 kfree(ticket);
1200temporary_error_free_resp:
1201 kfree(response);
1202temporary_error:
1203 /* Ignore the response packet if we got a temporary error such as
1204 * ENOMEM. We just want to send the challenge again. Note that we
1205 * also come out this way if the ticket decryption fails.
1206 */
1207 return ret;
1208}
1209
1210/*
1211 * clear the connection security
1212 */
1213static void rxkad_clear(struct rxrpc_connection *conn)
1214{
1215 _enter("");
1216
1217 if (conn->cipher)
1218 crypto_free_skcipher(conn->cipher);
1219}
1220
1221/*
1222 * Initialise the rxkad security service.
1223 */
1224static int rxkad_init(void)
1225{
1226 /* pin the cipher we need so that the crypto layer doesn't invoke
1227 * keventd to go get it */
1228 rxkad_ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
1229 return PTR_ERR_OR_ZERO(rxkad_ci);
1230}
1231
1232/*
1233 * Clean up the rxkad security service.
1234 */
1235static void rxkad_exit(void)
1236{
1237 if (rxkad_ci)
1238 crypto_free_skcipher(rxkad_ci);
1239}
1240
1241/*
1242 * RxRPC Kerberos-based security
1243 */
1244const struct rxrpc_security rxkad = {
1245 .name = "rxkad",
1246 .security_index = RXRPC_SECURITY_RXKAD,
1247 .init = rxkad_init,
1248 .exit = rxkad_exit,
1249 .init_connection_security = rxkad_init_connection_security,
1250 .prime_packet_security = rxkad_prime_packet_security,
1251 .secure_packet = rxkad_secure_packet,
1252 .verify_packet = rxkad_verify_packet,
1253 .locate_data = rxkad_locate_data,
1254 .issue_challenge = rxkad_issue_challenge,
1255 .respond_to_challenge = rxkad_respond_to_challenge,
1256 .verify_response = rxkad_verify_response,
1257 .clear = rxkad_clear,
1258};
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
34unsigned rxrpc_debug;
35module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO);
36MODULE_PARM_DESC(debug, "rxkad debugging mask");
37
38struct rxkad_level1_hdr {
39 __be32 data_size; /* true data size (excluding padding) */
40};
41
42struct rxkad_level2_hdr {
43 __be32 data_size; /* true data size (excluding padding) */
44 __be32 checksum; /* decrypted data checksum */
45};
46
47MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos 4)");
48MODULE_AUTHOR("Red Hat, Inc.");
49MODULE_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 */
56static struct crypto_blkcipher *rxkad_ci;
57static DEFINE_MUTEX(rxkad_ci_mutex);
58
59/*
60 * initialise connection security
61 */
62static 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;
104error:
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 */
113static 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 */
153static 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 */
197static 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 */
253static 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 */
327static 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
387datalen_error:
388 *_abort_code = RXKADDATALEN;
389protocol_error:
390 _leave(" = -EPROTO");
391 return -EPROTO;
392
393nomem:
394 _leave(" = -ENOMEM");
395 return -ENOMEM;
396}
397
398/*
399 * wholly decrypt a packet (level 2 security)
400 */
401static 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
472datalen_error:
473 *_abort_code = RXKADDATALEN;
474protocol_error:
475 _leave(" = -EPROTO");
476 return -EPROTO;
477
478nomem:
479 _leave(" = -ENOMEM");
480 return -ENOMEM;
481}
482
483/*
484 * verify the security on a received packet
485 */
486static 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 */
567static 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 */
629static 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 */
679static 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 */
694static 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 */
717static 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 */
738static 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
810protocol_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 */
819static 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;
952error:
953 _leave(" = %d", ret);
954 return ret;
955
956bad_ticket:
957 *_abort_code = RXKADBADTICKET;
958 ret = -EBADMSG;
959 goto error;
960}
961
962/*
963 * decrypt the response packet
964 */
965static 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 */
998static 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
1102protocol_error_free:
1103 kfree(ticket);
1104protocol_error:
1105 *_abort_code = abort_code;
1106 _leave(" = -EPROTO [%d]", abort_code);
1107 return -EPROTO;
1108}
1109
1110/*
1111 * clear the connection security
1112 */
1113static 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 */
1124static 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
1138static __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
1151module_init(rxkad_init);
1152
1153static __exit void rxkad_exit(void)
1154{
1155 _enter("");
1156
1157 rxrpc_unregister_security(&rxkad);
1158 crypto_free_blkcipher(rxkad_ci);
1159}
1160
1161module_exit(rxkad_exit);