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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#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 int 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 int 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 int 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);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Kerberos-based RxRPC security
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <crypto/skcipher.h>
11#include <linux/module.h>
12#include <linux/net.h>
13#include <linux/skbuff.h>
14#include <linux/udp.h>
15#include <linux/scatterlist.h>
16#include <linux/ctype.h>
17#include <linux/slab.h>
18#include <net/sock.h>
19#include <net/af_rxrpc.h>
20#include <keys/rxrpc-type.h>
21#include "ar-internal.h"
22
23#define RXKAD_VERSION 2
24#define MAXKRB5TICKETLEN 1024
25#define RXKAD_TKT_TYPE_KERBEROS_V5 256
26#define ANAME_SZ 40 /* size of authentication name */
27#define INST_SZ 40 /* size of principal's instance */
28#define REALM_SZ 40 /* size of principal's auth domain */
29#define SNAME_SZ 40 /* size of service name */
30
31struct rxkad_level1_hdr {
32 __be32 data_size; /* true data size (excluding padding) */
33};
34
35struct rxkad_level2_hdr {
36 __be32 data_size; /* true data size (excluding padding) */
37 __be32 checksum; /* decrypted data checksum */
38};
39
40/*
41 * this holds a pinned cipher so that keventd doesn't get called by the cipher
42 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
43 * packets
44 */
45static struct crypto_sync_skcipher *rxkad_ci;
46static struct skcipher_request *rxkad_ci_req;
47static DEFINE_MUTEX(rxkad_ci_mutex);
48
49/*
50 * initialise connection security
51 */
52static int rxkad_init_connection_security(struct rxrpc_connection *conn)
53{
54 struct crypto_sync_skcipher *ci;
55 struct rxrpc_key_token *token;
56 int ret;
57
58 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->params.key));
59
60 token = conn->params.key->payload.data[0];
61 conn->security_ix = token->security_index;
62
63 ci = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
64 if (IS_ERR(ci)) {
65 _debug("no cipher");
66 ret = PTR_ERR(ci);
67 goto error;
68 }
69
70 if (crypto_sync_skcipher_setkey(ci, token->kad->session_key,
71 sizeof(token->kad->session_key)) < 0)
72 BUG();
73
74 switch (conn->params.security_level) {
75 case RXRPC_SECURITY_PLAIN:
76 break;
77 case RXRPC_SECURITY_AUTH:
78 conn->size_align = 8;
79 conn->security_size = sizeof(struct rxkad_level1_hdr);
80 break;
81 case RXRPC_SECURITY_ENCRYPT:
82 conn->size_align = 8;
83 conn->security_size = sizeof(struct rxkad_level2_hdr);
84 break;
85 default:
86 ret = -EKEYREJECTED;
87 goto error;
88 }
89
90 conn->cipher = ci;
91 ret = 0;
92error:
93 _leave(" = %d", ret);
94 return ret;
95}
96
97/*
98 * prime the encryption state with the invariant parts of a connection's
99 * description
100 */
101static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
102{
103 struct skcipher_request *req;
104 struct rxrpc_key_token *token;
105 struct scatterlist sg;
106 struct rxrpc_crypt iv;
107 __be32 *tmpbuf;
108 size_t tmpsize = 4 * sizeof(__be32);
109
110 _enter("");
111
112 if (!conn->params.key)
113 return 0;
114
115 tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
116 if (!tmpbuf)
117 return -ENOMEM;
118
119 req = skcipher_request_alloc(&conn->cipher->base, GFP_NOFS);
120 if (!req) {
121 kfree(tmpbuf);
122 return -ENOMEM;
123 }
124
125 token = conn->params.key->payload.data[0];
126 memcpy(&iv, token->kad->session_key, sizeof(iv));
127
128 tmpbuf[0] = htonl(conn->proto.epoch);
129 tmpbuf[1] = htonl(conn->proto.cid);
130 tmpbuf[2] = 0;
131 tmpbuf[3] = htonl(conn->security_ix);
132
133 sg_init_one(&sg, tmpbuf, tmpsize);
134 skcipher_request_set_sync_tfm(req, conn->cipher);
135 skcipher_request_set_callback(req, 0, NULL, NULL);
136 skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
137 crypto_skcipher_encrypt(req);
138 skcipher_request_free(req);
139
140 memcpy(&conn->csum_iv, tmpbuf + 2, sizeof(conn->csum_iv));
141 kfree(tmpbuf);
142 _leave(" = 0");
143 return 0;
144}
145
146/*
147 * Allocate and prepare the crypto request on a call. For any particular call,
148 * this is called serially for the packets, so no lock should be necessary.
149 */
150static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
151{
152 struct crypto_skcipher *tfm = &call->conn->cipher->base;
153 struct skcipher_request *cipher_req = call->cipher_req;
154
155 if (!cipher_req) {
156 cipher_req = skcipher_request_alloc(tfm, GFP_NOFS);
157 if (!cipher_req)
158 return NULL;
159 call->cipher_req = cipher_req;
160 }
161
162 return cipher_req;
163}
164
165/*
166 * Clean up the crypto on a call.
167 */
168static void rxkad_free_call_crypto(struct rxrpc_call *call)
169{
170 if (call->cipher_req)
171 skcipher_request_free(call->cipher_req);
172 call->cipher_req = NULL;
173}
174
175/*
176 * partially encrypt a packet (level 1 security)
177 */
178static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
179 struct sk_buff *skb,
180 u32 data_size,
181 void *sechdr,
182 struct skcipher_request *req)
183{
184 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
185 struct rxkad_level1_hdr hdr;
186 struct rxrpc_crypt iv;
187 struct scatterlist sg;
188 u16 check;
189
190 _enter("");
191
192 check = sp->hdr.seq ^ call->call_id;
193 data_size |= (u32)check << 16;
194
195 hdr.data_size = htonl(data_size);
196 memcpy(sechdr, &hdr, sizeof(hdr));
197
198 /* start the encryption afresh */
199 memset(&iv, 0, sizeof(iv));
200
201 sg_init_one(&sg, sechdr, 8);
202 skcipher_request_set_sync_tfm(req, call->conn->cipher);
203 skcipher_request_set_callback(req, 0, NULL, NULL);
204 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
205 crypto_skcipher_encrypt(req);
206 skcipher_request_zero(req);
207
208 _leave(" = 0");
209 return 0;
210}
211
212/*
213 * wholly encrypt a packet (level 2 security)
214 */
215static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
216 struct sk_buff *skb,
217 u32 data_size,
218 void *sechdr,
219 struct skcipher_request *req)
220{
221 const struct rxrpc_key_token *token;
222 struct rxkad_level2_hdr rxkhdr;
223 struct rxrpc_skb_priv *sp;
224 struct rxrpc_crypt iv;
225 struct scatterlist sg[16];
226 unsigned int len;
227 u16 check;
228 int err;
229
230 sp = rxrpc_skb(skb);
231
232 _enter("");
233
234 check = sp->hdr.seq ^ call->call_id;
235
236 rxkhdr.data_size = htonl(data_size | (u32)check << 16);
237 rxkhdr.checksum = 0;
238 memcpy(sechdr, &rxkhdr, sizeof(rxkhdr));
239
240 /* encrypt from the session key */
241 token = call->conn->params.key->payload.data[0];
242 memcpy(&iv, token->kad->session_key, sizeof(iv));
243
244 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
245 skcipher_request_set_sync_tfm(req, call->conn->cipher);
246 skcipher_request_set_callback(req, 0, NULL, NULL);
247 skcipher_request_set_crypt(req, &sg[0], &sg[0], sizeof(rxkhdr), iv.x);
248 crypto_skcipher_encrypt(req);
249
250 /* we want to encrypt the skbuff in-place */
251 err = -EMSGSIZE;
252 if (skb_shinfo(skb)->nr_frags > 16)
253 goto out;
254
255 len = data_size + call->conn->size_align - 1;
256 len &= ~(call->conn->size_align - 1);
257
258 sg_init_table(sg, ARRAY_SIZE(sg));
259 err = skb_to_sgvec(skb, sg, 0, len);
260 if (unlikely(err < 0))
261 goto out;
262 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
263 crypto_skcipher_encrypt(req);
264
265 _leave(" = 0");
266 err = 0;
267
268out:
269 skcipher_request_zero(req);
270 return err;
271}
272
273/*
274 * checksum an RxRPC packet header
275 */
276static int rxkad_secure_packet(struct rxrpc_call *call,
277 struct sk_buff *skb,
278 size_t data_size,
279 void *sechdr)
280{
281 struct rxrpc_skb_priv *sp;
282 struct skcipher_request *req;
283 struct rxrpc_crypt iv;
284 struct scatterlist sg;
285 u32 x, y;
286 int ret;
287
288 sp = rxrpc_skb(skb);
289
290 _enter("{%d{%x}},{#%u},%zu,",
291 call->debug_id, key_serial(call->conn->params.key),
292 sp->hdr.seq, data_size);
293
294 if (!call->conn->cipher)
295 return 0;
296
297 ret = key_validate(call->conn->params.key);
298 if (ret < 0)
299 return ret;
300
301 req = rxkad_get_call_crypto(call);
302 if (!req)
303 return -ENOMEM;
304
305 /* continue encrypting from where we left off */
306 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
307
308 /* calculate the security checksum */
309 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
310 x |= sp->hdr.seq & 0x3fffffff;
311 call->crypto_buf[0] = htonl(call->call_id);
312 call->crypto_buf[1] = htonl(x);
313
314 sg_init_one(&sg, call->crypto_buf, 8);
315 skcipher_request_set_sync_tfm(req, call->conn->cipher);
316 skcipher_request_set_callback(req, 0, NULL, NULL);
317 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
318 crypto_skcipher_encrypt(req);
319 skcipher_request_zero(req);
320
321 y = ntohl(call->crypto_buf[1]);
322 y = (y >> 16) & 0xffff;
323 if (y == 0)
324 y = 1; /* zero checksums are not permitted */
325 sp->hdr.cksum = y;
326
327 switch (call->conn->params.security_level) {
328 case RXRPC_SECURITY_PLAIN:
329 ret = 0;
330 break;
331 case RXRPC_SECURITY_AUTH:
332 ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr,
333 req);
334 break;
335 case RXRPC_SECURITY_ENCRYPT:
336 ret = rxkad_secure_packet_encrypt(call, skb, data_size,
337 sechdr, req);
338 break;
339 default:
340 ret = -EPERM;
341 break;
342 }
343
344 _leave(" = %d [set %hx]", ret, y);
345 return ret;
346}
347
348/*
349 * decrypt partial encryption on a packet (level 1 security)
350 */
351static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
352 unsigned int offset, unsigned int len,
353 rxrpc_seq_t seq,
354 struct skcipher_request *req)
355{
356 struct rxkad_level1_hdr sechdr;
357 struct rxrpc_crypt iv;
358 struct scatterlist sg[16];
359 bool aborted;
360 u32 data_size, buf;
361 u16 check;
362 int ret;
363
364 _enter("");
365
366 if (len < 8) {
367 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_hdr", "V1H",
368 RXKADSEALEDINCON);
369 goto protocol_error;
370 }
371
372 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
373 * directly into the target buffer.
374 */
375 sg_init_table(sg, ARRAY_SIZE(sg));
376 ret = skb_to_sgvec(skb, sg, offset, 8);
377 if (unlikely(ret < 0))
378 return ret;
379
380 /* start the decryption afresh */
381 memset(&iv, 0, sizeof(iv));
382
383 skcipher_request_set_sync_tfm(req, call->conn->cipher);
384 skcipher_request_set_callback(req, 0, NULL, NULL);
385 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
386 crypto_skcipher_decrypt(req);
387 skcipher_request_zero(req);
388
389 /* Extract the decrypted packet length */
390 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
391 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_len", "XV1",
392 RXKADDATALEN);
393 goto protocol_error;
394 }
395 offset += sizeof(sechdr);
396 len -= sizeof(sechdr);
397
398 buf = ntohl(sechdr.data_size);
399 data_size = buf & 0xffff;
400
401 check = buf >> 16;
402 check ^= seq ^ call->call_id;
403 check &= 0xffff;
404 if (check != 0) {
405 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_check", "V1C",
406 RXKADSEALEDINCON);
407 goto protocol_error;
408 }
409
410 if (data_size > len) {
411 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_datalen", "V1L",
412 RXKADDATALEN);
413 goto protocol_error;
414 }
415
416 _leave(" = 0 [dlen=%x]", data_size);
417 return 0;
418
419protocol_error:
420 if (aborted)
421 rxrpc_send_abort_packet(call);
422 return -EPROTO;
423}
424
425/*
426 * wholly decrypt a packet (level 2 security)
427 */
428static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
429 unsigned int offset, unsigned int len,
430 rxrpc_seq_t seq,
431 struct skcipher_request *req)
432{
433 const struct rxrpc_key_token *token;
434 struct rxkad_level2_hdr sechdr;
435 struct rxrpc_crypt iv;
436 struct scatterlist _sg[4], *sg;
437 bool aborted;
438 u32 data_size, buf;
439 u16 check;
440 int nsg, ret;
441
442 _enter(",{%d}", skb->len);
443
444 if (len < 8) {
445 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_hdr", "V2H",
446 RXKADSEALEDINCON);
447 goto protocol_error;
448 }
449
450 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
451 * directly into the target buffer.
452 */
453 sg = _sg;
454 nsg = skb_shinfo(skb)->nr_frags;
455 if (nsg <= 4) {
456 nsg = 4;
457 } else {
458 sg = kmalloc_array(nsg, sizeof(*sg), GFP_NOIO);
459 if (!sg)
460 goto nomem;
461 }
462
463 sg_init_table(sg, nsg);
464 ret = skb_to_sgvec(skb, sg, offset, len);
465 if (unlikely(ret < 0)) {
466 if (sg != _sg)
467 kfree(sg);
468 return ret;
469 }
470
471 /* decrypt from the session key */
472 token = call->conn->params.key->payload.data[0];
473 memcpy(&iv, token->kad->session_key, sizeof(iv));
474
475 skcipher_request_set_sync_tfm(req, call->conn->cipher);
476 skcipher_request_set_callback(req, 0, NULL, NULL);
477 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
478 crypto_skcipher_decrypt(req);
479 skcipher_request_zero(req);
480 if (sg != _sg)
481 kfree(sg);
482
483 /* Extract the decrypted packet length */
484 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
485 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_len", "XV2",
486 RXKADDATALEN);
487 goto protocol_error;
488 }
489 offset += sizeof(sechdr);
490 len -= sizeof(sechdr);
491
492 buf = ntohl(sechdr.data_size);
493 data_size = buf & 0xffff;
494
495 check = buf >> 16;
496 check ^= seq ^ call->call_id;
497 check &= 0xffff;
498 if (check != 0) {
499 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_check", "V2C",
500 RXKADSEALEDINCON);
501 goto protocol_error;
502 }
503
504 if (data_size > len) {
505 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_datalen", "V2L",
506 RXKADDATALEN);
507 goto protocol_error;
508 }
509
510 _leave(" = 0 [dlen=%x]", data_size);
511 return 0;
512
513protocol_error:
514 if (aborted)
515 rxrpc_send_abort_packet(call);
516 return -EPROTO;
517
518nomem:
519 _leave(" = -ENOMEM");
520 return -ENOMEM;
521}
522
523/*
524 * Verify the security on a received packet or subpacket (if part of a
525 * jumbo packet).
526 */
527static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
528 unsigned int offset, unsigned int len,
529 rxrpc_seq_t seq, u16 expected_cksum)
530{
531 struct skcipher_request *req;
532 struct rxrpc_crypt iv;
533 struct scatterlist sg;
534 bool aborted;
535 u16 cksum;
536 u32 x, y;
537
538 _enter("{%d{%x}},{#%u}",
539 call->debug_id, key_serial(call->conn->params.key), seq);
540
541 if (!call->conn->cipher)
542 return 0;
543
544 req = rxkad_get_call_crypto(call);
545 if (!req)
546 return -ENOMEM;
547
548 /* continue encrypting from where we left off */
549 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
550
551 /* validate the security checksum */
552 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
553 x |= seq & 0x3fffffff;
554 call->crypto_buf[0] = htonl(call->call_id);
555 call->crypto_buf[1] = htonl(x);
556
557 sg_init_one(&sg, call->crypto_buf, 8);
558 skcipher_request_set_sync_tfm(req, call->conn->cipher);
559 skcipher_request_set_callback(req, 0, NULL, NULL);
560 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
561 crypto_skcipher_encrypt(req);
562 skcipher_request_zero(req);
563
564 y = ntohl(call->crypto_buf[1]);
565 cksum = (y >> 16) & 0xffff;
566 if (cksum == 0)
567 cksum = 1; /* zero checksums are not permitted */
568
569 if (cksum != expected_cksum) {
570 aborted = rxrpc_abort_eproto(call, skb, "rxkad_csum", "VCK",
571 RXKADSEALEDINCON);
572 goto protocol_error;
573 }
574
575 switch (call->conn->params.security_level) {
576 case RXRPC_SECURITY_PLAIN:
577 return 0;
578 case RXRPC_SECURITY_AUTH:
579 return rxkad_verify_packet_1(call, skb, offset, len, seq, req);
580 case RXRPC_SECURITY_ENCRYPT:
581 return rxkad_verify_packet_2(call, skb, offset, len, seq, req);
582 default:
583 return -ENOANO;
584 }
585
586protocol_error:
587 if (aborted)
588 rxrpc_send_abort_packet(call);
589 return -EPROTO;
590}
591
592/*
593 * Locate the data contained in a packet that was partially encrypted.
594 */
595static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb,
596 unsigned int *_offset, unsigned int *_len)
597{
598 struct rxkad_level1_hdr sechdr;
599
600 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
601 BUG();
602 *_offset += sizeof(sechdr);
603 *_len = ntohl(sechdr.data_size) & 0xffff;
604}
605
606/*
607 * Locate the data contained in a packet that was completely encrypted.
608 */
609static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb,
610 unsigned int *_offset, unsigned int *_len)
611{
612 struct rxkad_level2_hdr sechdr;
613
614 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
615 BUG();
616 *_offset += sizeof(sechdr);
617 *_len = ntohl(sechdr.data_size) & 0xffff;
618}
619
620/*
621 * Locate the data contained in an already decrypted packet.
622 */
623static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
624 unsigned int *_offset, unsigned int *_len)
625{
626 switch (call->conn->params.security_level) {
627 case RXRPC_SECURITY_AUTH:
628 rxkad_locate_data_1(call, skb, _offset, _len);
629 return;
630 case RXRPC_SECURITY_ENCRYPT:
631 rxkad_locate_data_2(call, skb, _offset, _len);
632 return;
633 default:
634 return;
635 }
636}
637
638/*
639 * issue a challenge
640 */
641static int rxkad_issue_challenge(struct rxrpc_connection *conn)
642{
643 struct rxkad_challenge challenge;
644 struct rxrpc_wire_header whdr;
645 struct msghdr msg;
646 struct kvec iov[2];
647 size_t len;
648 u32 serial;
649 int ret;
650
651 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
652
653 ret = key_validate(conn->params.key);
654 if (ret < 0)
655 return ret;
656
657 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
658
659 challenge.version = htonl(2);
660 challenge.nonce = htonl(conn->security_nonce);
661 challenge.min_level = htonl(0);
662 challenge.__padding = 0;
663
664 msg.msg_name = &conn->params.peer->srx.transport;
665 msg.msg_namelen = conn->params.peer->srx.transport_len;
666 msg.msg_control = NULL;
667 msg.msg_controllen = 0;
668 msg.msg_flags = 0;
669
670 whdr.epoch = htonl(conn->proto.epoch);
671 whdr.cid = htonl(conn->proto.cid);
672 whdr.callNumber = 0;
673 whdr.seq = 0;
674 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
675 whdr.flags = conn->out_clientflag;
676 whdr.userStatus = 0;
677 whdr.securityIndex = conn->security_ix;
678 whdr._rsvd = 0;
679 whdr.serviceId = htons(conn->service_id);
680
681 iov[0].iov_base = &whdr;
682 iov[0].iov_len = sizeof(whdr);
683 iov[1].iov_base = &challenge;
684 iov[1].iov_len = sizeof(challenge);
685
686 len = iov[0].iov_len + iov[1].iov_len;
687
688 serial = atomic_inc_return(&conn->serial);
689 whdr.serial = htonl(serial);
690 _proto("Tx CHALLENGE %%%u", serial);
691
692 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
693 if (ret < 0) {
694 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
695 rxrpc_tx_point_rxkad_challenge);
696 return -EAGAIN;
697 }
698
699 conn->params.peer->last_tx_at = ktime_get_seconds();
700 trace_rxrpc_tx_packet(conn->debug_id, &whdr,
701 rxrpc_tx_point_rxkad_challenge);
702 _leave(" = 0");
703 return 0;
704}
705
706/*
707 * send a Kerberos security response
708 */
709static int rxkad_send_response(struct rxrpc_connection *conn,
710 struct rxrpc_host_header *hdr,
711 struct rxkad_response *resp,
712 const struct rxkad_key *s2)
713{
714 struct rxrpc_wire_header whdr;
715 struct msghdr msg;
716 struct kvec iov[3];
717 size_t len;
718 u32 serial;
719 int ret;
720
721 _enter("");
722
723 msg.msg_name = &conn->params.peer->srx.transport;
724 msg.msg_namelen = conn->params.peer->srx.transport_len;
725 msg.msg_control = NULL;
726 msg.msg_controllen = 0;
727 msg.msg_flags = 0;
728
729 memset(&whdr, 0, sizeof(whdr));
730 whdr.epoch = htonl(hdr->epoch);
731 whdr.cid = htonl(hdr->cid);
732 whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
733 whdr.flags = conn->out_clientflag;
734 whdr.securityIndex = hdr->securityIndex;
735 whdr.serviceId = htons(hdr->serviceId);
736
737 iov[0].iov_base = &whdr;
738 iov[0].iov_len = sizeof(whdr);
739 iov[1].iov_base = resp;
740 iov[1].iov_len = sizeof(*resp);
741 iov[2].iov_base = (void *)s2->ticket;
742 iov[2].iov_len = s2->ticket_len;
743
744 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
745
746 serial = atomic_inc_return(&conn->serial);
747 whdr.serial = htonl(serial);
748 _proto("Tx RESPONSE %%%u", serial);
749
750 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 3, len);
751 if (ret < 0) {
752 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
753 rxrpc_tx_point_rxkad_response);
754 return -EAGAIN;
755 }
756
757 conn->params.peer->last_tx_at = ktime_get_seconds();
758 _leave(" = 0");
759 return 0;
760}
761
762/*
763 * calculate the response checksum
764 */
765static void rxkad_calc_response_checksum(struct rxkad_response *response)
766{
767 u32 csum = 1000003;
768 int loop;
769 u8 *p = (u8 *) response;
770
771 for (loop = sizeof(*response); loop > 0; loop--)
772 csum = csum * 0x10204081 + *p++;
773
774 response->encrypted.checksum = htonl(csum);
775}
776
777/*
778 * encrypt the response packet
779 */
780static int rxkad_encrypt_response(struct rxrpc_connection *conn,
781 struct rxkad_response *resp,
782 const struct rxkad_key *s2)
783{
784 struct skcipher_request *req;
785 struct rxrpc_crypt iv;
786 struct scatterlist sg[1];
787
788 req = skcipher_request_alloc(&conn->cipher->base, GFP_NOFS);
789 if (!req)
790 return -ENOMEM;
791
792 /* continue encrypting from where we left off */
793 memcpy(&iv, s2->session_key, sizeof(iv));
794
795 sg_init_table(sg, 1);
796 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
797 skcipher_request_set_sync_tfm(req, conn->cipher);
798 skcipher_request_set_callback(req, 0, NULL, NULL);
799 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
800 crypto_skcipher_encrypt(req);
801 skcipher_request_free(req);
802 return 0;
803}
804
805/*
806 * respond to a challenge packet
807 */
808static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
809 struct sk_buff *skb,
810 u32 *_abort_code)
811{
812 const struct rxrpc_key_token *token;
813 struct rxkad_challenge challenge;
814 struct rxkad_response *resp;
815 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
816 const char *eproto;
817 u32 version, nonce, min_level, abort_code;
818 int ret;
819
820 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
821
822 eproto = tracepoint_string("chall_no_key");
823 abort_code = RX_PROTOCOL_ERROR;
824 if (!conn->params.key)
825 goto protocol_error;
826
827 abort_code = RXKADEXPIRED;
828 ret = key_validate(conn->params.key);
829 if (ret < 0)
830 goto other_error;
831
832 eproto = tracepoint_string("chall_short");
833 abort_code = RXKADPACKETSHORT;
834 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
835 &challenge, sizeof(challenge)) < 0)
836 goto protocol_error;
837
838 version = ntohl(challenge.version);
839 nonce = ntohl(challenge.nonce);
840 min_level = ntohl(challenge.min_level);
841
842 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
843 sp->hdr.serial, version, nonce, min_level);
844
845 eproto = tracepoint_string("chall_ver");
846 abort_code = RXKADINCONSISTENCY;
847 if (version != RXKAD_VERSION)
848 goto protocol_error;
849
850 abort_code = RXKADLEVELFAIL;
851 ret = -EACCES;
852 if (conn->params.security_level < min_level)
853 goto other_error;
854
855 token = conn->params.key->payload.data[0];
856
857 /* build the response packet */
858 resp = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
859 if (!resp)
860 return -ENOMEM;
861
862 resp->version = htonl(RXKAD_VERSION);
863 resp->encrypted.epoch = htonl(conn->proto.epoch);
864 resp->encrypted.cid = htonl(conn->proto.cid);
865 resp->encrypted.securityIndex = htonl(conn->security_ix);
866 resp->encrypted.inc_nonce = htonl(nonce + 1);
867 resp->encrypted.level = htonl(conn->params.security_level);
868 resp->kvno = htonl(token->kad->kvno);
869 resp->ticket_len = htonl(token->kad->ticket_len);
870 resp->encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
871 resp->encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
872 resp->encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
873 resp->encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
874
875 /* calculate the response checksum and then do the encryption */
876 rxkad_calc_response_checksum(resp);
877 ret = rxkad_encrypt_response(conn, resp, token->kad);
878 if (ret == 0)
879 ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
880 kfree(resp);
881 return ret;
882
883protocol_error:
884 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
885 ret = -EPROTO;
886other_error:
887 *_abort_code = abort_code;
888 return ret;
889}
890
891/*
892 * decrypt the kerberos IV ticket in the response
893 */
894static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
895 struct sk_buff *skb,
896 void *ticket, size_t ticket_len,
897 struct rxrpc_crypt *_session_key,
898 time64_t *_expiry,
899 u32 *_abort_code)
900{
901 struct skcipher_request *req;
902 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
903 struct rxrpc_crypt iv, key;
904 struct scatterlist sg[1];
905 struct in_addr addr;
906 unsigned int life;
907 const char *eproto;
908 time64_t issue, now;
909 bool little_endian;
910 int ret;
911 u32 abort_code;
912 u8 *p, *q, *name, *end;
913
914 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
915
916 *_expiry = 0;
917
918 ret = key_validate(conn->server_key);
919 if (ret < 0) {
920 switch (ret) {
921 case -EKEYEXPIRED:
922 abort_code = RXKADEXPIRED;
923 goto other_error;
924 default:
925 abort_code = RXKADNOAUTH;
926 goto other_error;
927 }
928 }
929
930 ASSERT(conn->server_key->payload.data[0] != NULL);
931 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
932
933 memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv));
934
935 ret = -ENOMEM;
936 req = skcipher_request_alloc(conn->server_key->payload.data[0],
937 GFP_NOFS);
938 if (!req)
939 goto temporary_error;
940
941 sg_init_one(&sg[0], ticket, ticket_len);
942 skcipher_request_set_callback(req, 0, NULL, NULL);
943 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
944 crypto_skcipher_decrypt(req);
945 skcipher_request_free(req);
946
947 p = ticket;
948 end = p + ticket_len;
949
950#define Z(field) \
951 ({ \
952 u8 *__str = p; \
953 eproto = tracepoint_string("rxkad_bad_"#field); \
954 q = memchr(p, 0, end - p); \
955 if (!q || q - p > (field##_SZ)) \
956 goto bad_ticket; \
957 for (; p < q; p++) \
958 if (!isprint(*p)) \
959 goto bad_ticket; \
960 p++; \
961 __str; \
962 })
963
964 /* extract the ticket flags */
965 _debug("KIV FLAGS: %x", *p);
966 little_endian = *p & 1;
967 p++;
968
969 /* extract the authentication name */
970 name = Z(ANAME);
971 _debug("KIV ANAME: %s", name);
972
973 /* extract the principal's instance */
974 name = Z(INST);
975 _debug("KIV INST : %s", name);
976
977 /* extract the principal's authentication domain */
978 name = Z(REALM);
979 _debug("KIV REALM: %s", name);
980
981 eproto = tracepoint_string("rxkad_bad_len");
982 if (end - p < 4 + 8 + 4 + 2)
983 goto bad_ticket;
984
985 /* get the IPv4 address of the entity that requested the ticket */
986 memcpy(&addr, p, sizeof(addr));
987 p += 4;
988 _debug("KIV ADDR : %pI4", &addr);
989
990 /* get the session key from the ticket */
991 memcpy(&key, p, sizeof(key));
992 p += 8;
993 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
994 memcpy(_session_key, &key, sizeof(key));
995
996 /* get the ticket's lifetime */
997 life = *p++ * 5 * 60;
998 _debug("KIV LIFE : %u", life);
999
1000 /* get the issue time of the ticket */
1001 if (little_endian) {
1002 __le32 stamp;
1003 memcpy(&stamp, p, 4);
1004 issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
1005 } else {
1006 __be32 stamp;
1007 memcpy(&stamp, p, 4);
1008 issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
1009 }
1010 p += 4;
1011 now = ktime_get_real_seconds();
1012 _debug("KIV ISSUE: %llx [%llx]", issue, now);
1013
1014 /* check the ticket is in date */
1015 if (issue > now) {
1016 abort_code = RXKADNOAUTH;
1017 ret = -EKEYREJECTED;
1018 goto other_error;
1019 }
1020
1021 if (issue < now - life) {
1022 abort_code = RXKADEXPIRED;
1023 ret = -EKEYEXPIRED;
1024 goto other_error;
1025 }
1026
1027 *_expiry = issue + life;
1028
1029 /* get the service name */
1030 name = Z(SNAME);
1031 _debug("KIV SNAME: %s", name);
1032
1033 /* get the service instance name */
1034 name = Z(INST);
1035 _debug("KIV SINST: %s", name);
1036 return 0;
1037
1038bad_ticket:
1039 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1040 abort_code = RXKADBADTICKET;
1041 ret = -EPROTO;
1042other_error:
1043 *_abort_code = abort_code;
1044 return ret;
1045temporary_error:
1046 return ret;
1047}
1048
1049/*
1050 * decrypt the response packet
1051 */
1052static void rxkad_decrypt_response(struct rxrpc_connection *conn,
1053 struct rxkad_response *resp,
1054 const struct rxrpc_crypt *session_key)
1055{
1056 struct skcipher_request *req = rxkad_ci_req;
1057 struct scatterlist sg[1];
1058 struct rxrpc_crypt iv;
1059
1060 _enter(",,%08x%08x",
1061 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
1062
1063 mutex_lock(&rxkad_ci_mutex);
1064 if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
1065 sizeof(*session_key)) < 0)
1066 BUG();
1067
1068 memcpy(&iv, session_key, sizeof(iv));
1069
1070 sg_init_table(sg, 1);
1071 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1072 skcipher_request_set_sync_tfm(req, rxkad_ci);
1073 skcipher_request_set_callback(req, 0, NULL, NULL);
1074 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1075 crypto_skcipher_decrypt(req);
1076 skcipher_request_zero(req);
1077
1078 mutex_unlock(&rxkad_ci_mutex);
1079
1080 _leave("");
1081}
1082
1083/*
1084 * verify a response
1085 */
1086static int rxkad_verify_response(struct rxrpc_connection *conn,
1087 struct sk_buff *skb,
1088 u32 *_abort_code)
1089{
1090 struct rxkad_response *response;
1091 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1092 struct rxrpc_crypt session_key;
1093 const char *eproto;
1094 time64_t expiry;
1095 void *ticket;
1096 u32 abort_code, version, kvno, ticket_len, level;
1097 __be32 csum;
1098 int ret, i;
1099
1100 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1101
1102 ret = -ENOMEM;
1103 response = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
1104 if (!response)
1105 goto temporary_error;
1106
1107 eproto = tracepoint_string("rxkad_rsp_short");
1108 abort_code = RXKADPACKETSHORT;
1109 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1110 response, sizeof(*response)) < 0)
1111 goto protocol_error;
1112 if (!pskb_pull(skb, sizeof(*response)))
1113 BUG();
1114
1115 version = ntohl(response->version);
1116 ticket_len = ntohl(response->ticket_len);
1117 kvno = ntohl(response->kvno);
1118 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1119 sp->hdr.serial, version, kvno, ticket_len);
1120
1121 eproto = tracepoint_string("rxkad_rsp_ver");
1122 abort_code = RXKADINCONSISTENCY;
1123 if (version != RXKAD_VERSION)
1124 goto protocol_error;
1125
1126 eproto = tracepoint_string("rxkad_rsp_tktlen");
1127 abort_code = RXKADTICKETLEN;
1128 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1129 goto protocol_error;
1130
1131 eproto = tracepoint_string("rxkad_rsp_unkkey");
1132 abort_code = RXKADUNKNOWNKEY;
1133 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1134 goto protocol_error;
1135
1136 /* extract the kerberos ticket and decrypt and decode it */
1137 ret = -ENOMEM;
1138 ticket = kmalloc(ticket_len, GFP_NOFS);
1139 if (!ticket)
1140 goto temporary_error;
1141
1142 eproto = tracepoint_string("rxkad_tkt_short");
1143 abort_code = RXKADPACKETSHORT;
1144 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1145 ticket, ticket_len) < 0)
1146 goto protocol_error_free;
1147
1148 ret = rxkad_decrypt_ticket(conn, skb, ticket, ticket_len, &session_key,
1149 &expiry, _abort_code);
1150 if (ret < 0)
1151 goto temporary_error_free_resp;
1152
1153 /* use the session key from inside the ticket to decrypt the
1154 * response */
1155 rxkad_decrypt_response(conn, response, &session_key);
1156
1157 eproto = tracepoint_string("rxkad_rsp_param");
1158 abort_code = RXKADSEALEDINCON;
1159 if (ntohl(response->encrypted.epoch) != conn->proto.epoch)
1160 goto protocol_error_free;
1161 if (ntohl(response->encrypted.cid) != conn->proto.cid)
1162 goto protocol_error_free;
1163 if (ntohl(response->encrypted.securityIndex) != conn->security_ix)
1164 goto protocol_error_free;
1165 csum = response->encrypted.checksum;
1166 response->encrypted.checksum = 0;
1167 rxkad_calc_response_checksum(response);
1168 eproto = tracepoint_string("rxkad_rsp_csum");
1169 if (response->encrypted.checksum != csum)
1170 goto protocol_error_free;
1171
1172 spin_lock(&conn->channel_lock);
1173 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1174 struct rxrpc_call *call;
1175 u32 call_id = ntohl(response->encrypted.call_id[i]);
1176
1177 eproto = tracepoint_string("rxkad_rsp_callid");
1178 if (call_id > INT_MAX)
1179 goto protocol_error_unlock;
1180
1181 eproto = tracepoint_string("rxkad_rsp_callctr");
1182 if (call_id < conn->channels[i].call_counter)
1183 goto protocol_error_unlock;
1184
1185 eproto = tracepoint_string("rxkad_rsp_callst");
1186 if (call_id > conn->channels[i].call_counter) {
1187 call = rcu_dereference_protected(
1188 conn->channels[i].call,
1189 lockdep_is_held(&conn->channel_lock));
1190 if (call && call->state < RXRPC_CALL_COMPLETE)
1191 goto protocol_error_unlock;
1192 conn->channels[i].call_counter = call_id;
1193 }
1194 }
1195 spin_unlock(&conn->channel_lock);
1196
1197 eproto = tracepoint_string("rxkad_rsp_seq");
1198 abort_code = RXKADOUTOFSEQUENCE;
1199 if (ntohl(response->encrypted.inc_nonce) != conn->security_nonce + 1)
1200 goto protocol_error_free;
1201
1202 eproto = tracepoint_string("rxkad_rsp_level");
1203 abort_code = RXKADLEVELFAIL;
1204 level = ntohl(response->encrypted.level);
1205 if (level > RXRPC_SECURITY_ENCRYPT)
1206 goto protocol_error_free;
1207 conn->params.security_level = level;
1208
1209 /* create a key to hold the security data and expiration time - after
1210 * this the connection security can be handled in exactly the same way
1211 * as for a client connection */
1212 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1213 if (ret < 0)
1214 goto temporary_error_free_ticket;
1215
1216 kfree(ticket);
1217 kfree(response);
1218 _leave(" = 0");
1219 return 0;
1220
1221protocol_error_unlock:
1222 spin_unlock(&conn->channel_lock);
1223protocol_error_free:
1224 kfree(ticket);
1225protocol_error:
1226 kfree(response);
1227 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1228 *_abort_code = abort_code;
1229 return -EPROTO;
1230
1231temporary_error_free_ticket:
1232 kfree(ticket);
1233temporary_error_free_resp:
1234 kfree(response);
1235temporary_error:
1236 /* Ignore the response packet if we got a temporary error such as
1237 * ENOMEM. We just want to send the challenge again. Note that we
1238 * also come out this way if the ticket decryption fails.
1239 */
1240 return ret;
1241}
1242
1243/*
1244 * clear the connection security
1245 */
1246static void rxkad_clear(struct rxrpc_connection *conn)
1247{
1248 _enter("");
1249
1250 if (conn->cipher)
1251 crypto_free_sync_skcipher(conn->cipher);
1252}
1253
1254/*
1255 * Initialise the rxkad security service.
1256 */
1257static int rxkad_init(void)
1258{
1259 struct crypto_sync_skcipher *tfm;
1260 struct skcipher_request *req;
1261
1262 /* pin the cipher we need so that the crypto layer doesn't invoke
1263 * keventd to go get it */
1264 tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
1265 if (IS_ERR(tfm))
1266 return PTR_ERR(tfm);
1267
1268 req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
1269 if (!req)
1270 goto nomem_tfm;
1271
1272 rxkad_ci_req = req;
1273 rxkad_ci = tfm;
1274 return 0;
1275
1276nomem_tfm:
1277 crypto_free_sync_skcipher(tfm);
1278 return -ENOMEM;
1279}
1280
1281/*
1282 * Clean up the rxkad security service.
1283 */
1284static void rxkad_exit(void)
1285{
1286 crypto_free_sync_skcipher(rxkad_ci);
1287 skcipher_request_free(rxkad_ci_req);
1288}
1289
1290/*
1291 * RxRPC Kerberos-based security
1292 */
1293const struct rxrpc_security rxkad = {
1294 .name = "rxkad",
1295 .security_index = RXRPC_SECURITY_RXKAD,
1296 .init = rxkad_init,
1297 .exit = rxkad_exit,
1298 .init_connection_security = rxkad_init_connection_security,
1299 .prime_packet_security = rxkad_prime_packet_security,
1300 .secure_packet = rxkad_secure_packet,
1301 .verify_packet = rxkad_verify_packet,
1302 .free_call_crypto = rxkad_free_call_crypto,
1303 .locate_data = rxkad_locate_data,
1304 .issue_challenge = rxkad_issue_challenge,
1305 .respond_to_challenge = rxkad_respond_to_challenge,
1306 .verify_response = rxkad_verify_response,
1307 .clear = rxkad_clear,
1308};