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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 <linux/key-type.h>
19#include <net/sock.h>
20#include <net/af_rxrpc.h>
21#include <keys/rxrpc-type.h>
22#include "ar-internal.h"
23
24#define RXKAD_VERSION 2
25#define MAXKRB5TICKETLEN 1024
26#define RXKAD_TKT_TYPE_KERBEROS_V5 256
27#define ANAME_SZ 40 /* size of authentication name */
28#define INST_SZ 40 /* size of principal's instance */
29#define REALM_SZ 40 /* size of principal's auth domain */
30#define SNAME_SZ 40 /* size of service name */
31#define RXKAD_ALIGN 8
32
33struct rxkad_level1_hdr {
34 __be32 data_size; /* true data size (excluding padding) */
35};
36
37struct rxkad_level2_hdr {
38 __be32 data_size; /* true data size (excluding padding) */
39 __be32 checksum; /* decrypted data checksum */
40};
41
42static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
43 struct crypto_sync_skcipher *ci);
44
45/*
46 * this holds a pinned cipher so that keventd doesn't get called by the cipher
47 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
48 * packets
49 */
50static struct crypto_sync_skcipher *rxkad_ci;
51static struct skcipher_request *rxkad_ci_req;
52static DEFINE_MUTEX(rxkad_ci_mutex);
53
54/*
55 * Parse the information from a server key
56 *
57 * The data should be the 8-byte secret key.
58 */
59static int rxkad_preparse_server_key(struct key_preparsed_payload *prep)
60{
61 struct crypto_skcipher *ci;
62
63 if (prep->datalen != 8)
64 return -EINVAL;
65
66 memcpy(&prep->payload.data[2], prep->data, 8);
67
68 ci = crypto_alloc_skcipher("pcbc(des)", 0, CRYPTO_ALG_ASYNC);
69 if (IS_ERR(ci)) {
70 _leave(" = %ld", PTR_ERR(ci));
71 return PTR_ERR(ci);
72 }
73
74 if (crypto_skcipher_setkey(ci, prep->data, 8) < 0)
75 BUG();
76
77 prep->payload.data[0] = ci;
78 _leave(" = 0");
79 return 0;
80}
81
82static void rxkad_free_preparse_server_key(struct key_preparsed_payload *prep)
83{
84
85 if (prep->payload.data[0])
86 crypto_free_skcipher(prep->payload.data[0]);
87}
88
89static void rxkad_destroy_server_key(struct key *key)
90{
91 if (key->payload.data[0]) {
92 crypto_free_skcipher(key->payload.data[0]);
93 key->payload.data[0] = NULL;
94 }
95}
96
97/*
98 * initialise connection security
99 */
100static int rxkad_init_connection_security(struct rxrpc_connection *conn,
101 struct rxrpc_key_token *token)
102{
103 struct crypto_sync_skcipher *ci;
104 int ret;
105
106 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
107
108 conn->security_ix = token->security_index;
109
110 ci = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
111 if (IS_ERR(ci)) {
112 _debug("no cipher");
113 ret = PTR_ERR(ci);
114 goto error;
115 }
116
117 if (crypto_sync_skcipher_setkey(ci, token->kad->session_key,
118 sizeof(token->kad->session_key)) < 0)
119 BUG();
120
121 switch (conn->security_level) {
122 case RXRPC_SECURITY_PLAIN:
123 case RXRPC_SECURITY_AUTH:
124 case RXRPC_SECURITY_ENCRYPT:
125 break;
126 default:
127 ret = -EKEYREJECTED;
128 goto error;
129 }
130
131 ret = rxkad_prime_packet_security(conn, ci);
132 if (ret < 0)
133 goto error_ci;
134
135 conn->rxkad.cipher = ci;
136 return 0;
137
138error_ci:
139 crypto_free_sync_skcipher(ci);
140error:
141 _leave(" = %d", ret);
142 return ret;
143}
144
145/*
146 * Work out how much data we can put in a packet.
147 */
148static struct rxrpc_txbuf *rxkad_alloc_txbuf(struct rxrpc_call *call, size_t remain, gfp_t gfp)
149{
150 struct rxrpc_txbuf *txb;
151 size_t shdr, space;
152
153 remain = min(remain, 65535 - sizeof(struct rxrpc_wire_header));
154
155 switch (call->conn->security_level) {
156 default:
157 space = min_t(size_t, remain, RXRPC_JUMBO_DATALEN);
158 return rxrpc_alloc_data_txbuf(call, space, 1, gfp);
159 case RXRPC_SECURITY_AUTH:
160 shdr = sizeof(struct rxkad_level1_hdr);
161 break;
162 case RXRPC_SECURITY_ENCRYPT:
163 shdr = sizeof(struct rxkad_level2_hdr);
164 break;
165 }
166
167 space = min_t(size_t, round_down(RXRPC_JUMBO_DATALEN, RXKAD_ALIGN), remain + shdr);
168 space = round_up(space, RXKAD_ALIGN);
169
170 txb = rxrpc_alloc_data_txbuf(call, space, RXKAD_ALIGN, gfp);
171 if (!txb)
172 return NULL;
173
174 txb->offset += shdr;
175 txb->space -= shdr;
176 return txb;
177}
178
179/*
180 * prime the encryption state with the invariant parts of a connection's
181 * description
182 */
183static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
184 struct crypto_sync_skcipher *ci)
185{
186 struct skcipher_request *req;
187 struct rxrpc_key_token *token;
188 struct scatterlist sg;
189 struct rxrpc_crypt iv;
190 __be32 *tmpbuf;
191 size_t tmpsize = 4 * sizeof(__be32);
192
193 _enter("");
194
195 if (!conn->key)
196 return 0;
197
198 tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
199 if (!tmpbuf)
200 return -ENOMEM;
201
202 req = skcipher_request_alloc(&ci->base, GFP_NOFS);
203 if (!req) {
204 kfree(tmpbuf);
205 return -ENOMEM;
206 }
207
208 token = conn->key->payload.data[0];
209 memcpy(&iv, token->kad->session_key, sizeof(iv));
210
211 tmpbuf[0] = htonl(conn->proto.epoch);
212 tmpbuf[1] = htonl(conn->proto.cid);
213 tmpbuf[2] = 0;
214 tmpbuf[3] = htonl(conn->security_ix);
215
216 sg_init_one(&sg, tmpbuf, tmpsize);
217 skcipher_request_set_sync_tfm(req, ci);
218 skcipher_request_set_callback(req, 0, NULL, NULL);
219 skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
220 crypto_skcipher_encrypt(req);
221 skcipher_request_free(req);
222
223 memcpy(&conn->rxkad.csum_iv, tmpbuf + 2, sizeof(conn->rxkad.csum_iv));
224 kfree(tmpbuf);
225 _leave(" = 0");
226 return 0;
227}
228
229/*
230 * Allocate and prepare the crypto request on a call. For any particular call,
231 * this is called serially for the packets, so no lock should be necessary.
232 */
233static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
234{
235 struct crypto_skcipher *tfm = &call->conn->rxkad.cipher->base;
236
237 return skcipher_request_alloc(tfm, GFP_NOFS);
238}
239
240/*
241 * Clean up the crypto on a call.
242 */
243static void rxkad_free_call_crypto(struct rxrpc_call *call)
244{
245}
246
247/*
248 * partially encrypt a packet (level 1 security)
249 */
250static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
251 struct rxrpc_txbuf *txb,
252 struct skcipher_request *req)
253{
254 struct rxrpc_wire_header *whdr = txb->kvec[0].iov_base;
255 struct rxkad_level1_hdr *hdr = (void *)(whdr + 1);
256 struct rxrpc_crypt iv;
257 struct scatterlist sg;
258 size_t pad;
259 u16 check;
260
261 _enter("");
262
263 check = txb->seq ^ call->call_id;
264 hdr->data_size = htonl((u32)check << 16 | txb->len);
265
266 txb->len += sizeof(struct rxkad_level1_hdr);
267 pad = txb->len;
268 pad = RXKAD_ALIGN - pad;
269 pad &= RXKAD_ALIGN - 1;
270 if (pad) {
271 memset(txb->kvec[0].iov_base + txb->offset, 0, pad);
272 txb->len += pad;
273 }
274
275 /* start the encryption afresh */
276 memset(&iv, 0, sizeof(iv));
277
278 sg_init_one(&sg, hdr, 8);
279 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
280 skcipher_request_set_callback(req, 0, NULL, NULL);
281 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
282 crypto_skcipher_encrypt(req);
283 skcipher_request_zero(req);
284
285 _leave(" = 0");
286 return 0;
287}
288
289/*
290 * wholly encrypt a packet (level 2 security)
291 */
292static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
293 struct rxrpc_txbuf *txb,
294 struct skcipher_request *req)
295{
296 const struct rxrpc_key_token *token;
297 struct rxrpc_wire_header *whdr = txb->kvec[0].iov_base;
298 struct rxkad_level2_hdr *rxkhdr = (void *)(whdr + 1);
299 struct rxrpc_crypt iv;
300 struct scatterlist sg;
301 size_t pad;
302 u16 check;
303 int ret;
304
305 _enter("");
306
307 check = txb->seq ^ call->call_id;
308
309 rxkhdr->data_size = htonl(txb->len | (u32)check << 16);
310 rxkhdr->checksum = 0;
311
312 txb->len += sizeof(struct rxkad_level2_hdr);
313 pad = txb->len;
314 pad = RXKAD_ALIGN - pad;
315 pad &= RXKAD_ALIGN - 1;
316 if (pad) {
317 memset(txb->kvec[0].iov_base + txb->offset, 0, pad);
318 txb->len += pad;
319 }
320
321 /* encrypt from the session key */
322 token = call->conn->key->payload.data[0];
323 memcpy(&iv, token->kad->session_key, sizeof(iv));
324
325 sg_init_one(&sg, rxkhdr, txb->len);
326 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
327 skcipher_request_set_callback(req, 0, NULL, NULL);
328 skcipher_request_set_crypt(req, &sg, &sg, txb->len, iv.x);
329 ret = crypto_skcipher_encrypt(req);
330 skcipher_request_zero(req);
331 return ret;
332}
333
334/*
335 * checksum an RxRPC packet header
336 */
337static int rxkad_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
338{
339 struct skcipher_request *req;
340 struct rxrpc_crypt iv;
341 struct scatterlist sg;
342 union {
343 __be32 buf[2];
344 } crypto __aligned(8);
345 u32 x, y;
346 int ret;
347
348 _enter("{%d{%x}},{#%u},%u,",
349 call->debug_id, key_serial(call->conn->key),
350 txb->seq, txb->len);
351
352 if (!call->conn->rxkad.cipher)
353 return 0;
354
355 ret = key_validate(call->conn->key);
356 if (ret < 0)
357 return ret;
358
359 req = rxkad_get_call_crypto(call);
360 if (!req)
361 return -ENOMEM;
362
363 /* continue encrypting from where we left off */
364 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
365
366 /* calculate the security checksum */
367 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
368 x |= txb->seq & 0x3fffffff;
369 crypto.buf[0] = htonl(call->call_id);
370 crypto.buf[1] = htonl(x);
371
372 sg_init_one(&sg, crypto.buf, 8);
373 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
374 skcipher_request_set_callback(req, 0, NULL, NULL);
375 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
376 crypto_skcipher_encrypt(req);
377 skcipher_request_zero(req);
378
379 y = ntohl(crypto.buf[1]);
380 y = (y >> 16) & 0xffff;
381 if (y == 0)
382 y = 1; /* zero checksums are not permitted */
383 txb->cksum = htons(y);
384
385 switch (call->conn->security_level) {
386 case RXRPC_SECURITY_PLAIN:
387 ret = 0;
388 break;
389 case RXRPC_SECURITY_AUTH:
390 ret = rxkad_secure_packet_auth(call, txb, req);
391 break;
392 case RXRPC_SECURITY_ENCRYPT:
393 ret = rxkad_secure_packet_encrypt(call, txb, req);
394 break;
395 default:
396 ret = -EPERM;
397 break;
398 }
399
400 skcipher_request_free(req);
401 _leave(" = %d [set %x]", ret, y);
402 return ret;
403}
404
405/*
406 * decrypt partial encryption on a packet (level 1 security)
407 */
408static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
409 rxrpc_seq_t seq,
410 struct skcipher_request *req)
411{
412 struct rxkad_level1_hdr sechdr;
413 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
414 struct rxrpc_crypt iv;
415 struct scatterlist sg[16];
416 u32 data_size, buf;
417 u16 check;
418 int ret;
419
420 _enter("");
421
422 if (sp->len < 8)
423 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
424 rxkad_abort_1_short_header);
425
426 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
427 * directly into the target buffer.
428 */
429 sg_init_table(sg, ARRAY_SIZE(sg));
430 ret = skb_to_sgvec(skb, sg, sp->offset, 8);
431 if (unlikely(ret < 0))
432 return ret;
433
434 /* start the decryption afresh */
435 memset(&iv, 0, sizeof(iv));
436
437 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
438 skcipher_request_set_callback(req, 0, NULL, NULL);
439 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
440 crypto_skcipher_decrypt(req);
441 skcipher_request_zero(req);
442
443 /* Extract the decrypted packet length */
444 if (skb_copy_bits(skb, sp->offset, &sechdr, sizeof(sechdr)) < 0)
445 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
446 rxkad_abort_1_short_encdata);
447 sp->offset += sizeof(sechdr);
448 sp->len -= sizeof(sechdr);
449
450 buf = ntohl(sechdr.data_size);
451 data_size = buf & 0xffff;
452
453 check = buf >> 16;
454 check ^= seq ^ call->call_id;
455 check &= 0xffff;
456 if (check != 0)
457 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
458 rxkad_abort_1_short_check);
459 if (data_size > sp->len)
460 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
461 rxkad_abort_1_short_data);
462 sp->len = data_size;
463
464 _leave(" = 0 [dlen=%x]", data_size);
465 return 0;
466}
467
468/*
469 * wholly decrypt a packet (level 2 security)
470 */
471static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
472 rxrpc_seq_t seq,
473 struct skcipher_request *req)
474{
475 const struct rxrpc_key_token *token;
476 struct rxkad_level2_hdr sechdr;
477 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
478 struct rxrpc_crypt iv;
479 struct scatterlist _sg[4], *sg;
480 u32 data_size, buf;
481 u16 check;
482 int nsg, ret;
483
484 _enter(",{%d}", sp->len);
485
486 if (sp->len < 8)
487 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
488 rxkad_abort_2_short_header);
489
490 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
491 * directly into the target buffer.
492 */
493 sg = _sg;
494 nsg = skb_shinfo(skb)->nr_frags + 1;
495 if (nsg <= 4) {
496 nsg = 4;
497 } else {
498 sg = kmalloc_array(nsg, sizeof(*sg), GFP_NOIO);
499 if (!sg)
500 return -ENOMEM;
501 }
502
503 sg_init_table(sg, nsg);
504 ret = skb_to_sgvec(skb, sg, sp->offset, sp->len);
505 if (unlikely(ret < 0)) {
506 if (sg != _sg)
507 kfree(sg);
508 return ret;
509 }
510
511 /* decrypt from the session key */
512 token = call->conn->key->payload.data[0];
513 memcpy(&iv, token->kad->session_key, sizeof(iv));
514
515 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
516 skcipher_request_set_callback(req, 0, NULL, NULL);
517 skcipher_request_set_crypt(req, sg, sg, sp->len, iv.x);
518 crypto_skcipher_decrypt(req);
519 skcipher_request_zero(req);
520 if (sg != _sg)
521 kfree(sg);
522
523 /* Extract the decrypted packet length */
524 if (skb_copy_bits(skb, sp->offset, &sechdr, sizeof(sechdr)) < 0)
525 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
526 rxkad_abort_2_short_len);
527 sp->offset += sizeof(sechdr);
528 sp->len -= sizeof(sechdr);
529
530 buf = ntohl(sechdr.data_size);
531 data_size = buf & 0xffff;
532
533 check = buf >> 16;
534 check ^= seq ^ call->call_id;
535 check &= 0xffff;
536 if (check != 0)
537 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
538 rxkad_abort_2_short_check);
539
540 if (data_size > sp->len)
541 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
542 rxkad_abort_2_short_data);
543
544 sp->len = data_size;
545 _leave(" = 0 [dlen=%x]", data_size);
546 return 0;
547}
548
549/*
550 * Verify the security on a received packet and the subpackets therein.
551 */
552static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb)
553{
554 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
555 struct skcipher_request *req;
556 struct rxrpc_crypt iv;
557 struct scatterlist sg;
558 union {
559 __be32 buf[2];
560 } crypto __aligned(8);
561 rxrpc_seq_t seq = sp->hdr.seq;
562 int ret;
563 u16 cksum;
564 u32 x, y;
565
566 _enter("{%d{%x}},{#%u}",
567 call->debug_id, key_serial(call->conn->key), seq);
568
569 if (!call->conn->rxkad.cipher)
570 return 0;
571
572 req = rxkad_get_call_crypto(call);
573 if (!req)
574 return -ENOMEM;
575
576 /* continue encrypting from where we left off */
577 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
578
579 /* validate the security checksum */
580 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
581 x |= seq & 0x3fffffff;
582 crypto.buf[0] = htonl(call->call_id);
583 crypto.buf[1] = htonl(x);
584
585 sg_init_one(&sg, crypto.buf, 8);
586 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
587 skcipher_request_set_callback(req, 0, NULL, NULL);
588 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
589 crypto_skcipher_encrypt(req);
590 skcipher_request_zero(req);
591
592 y = ntohl(crypto.buf[1]);
593 cksum = (y >> 16) & 0xffff;
594 if (cksum == 0)
595 cksum = 1; /* zero checksums are not permitted */
596
597 if (cksum != sp->hdr.cksum) {
598 ret = rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
599 rxkad_abort_bad_checksum);
600 goto out;
601 }
602
603 switch (call->conn->security_level) {
604 case RXRPC_SECURITY_PLAIN:
605 ret = 0;
606 break;
607 case RXRPC_SECURITY_AUTH:
608 ret = rxkad_verify_packet_1(call, skb, seq, req);
609 break;
610 case RXRPC_SECURITY_ENCRYPT:
611 ret = rxkad_verify_packet_2(call, skb, seq, req);
612 break;
613 default:
614 ret = -ENOANO;
615 break;
616 }
617
618out:
619 skcipher_request_free(req);
620 return ret;
621}
622
623/*
624 * issue a challenge
625 */
626static int rxkad_issue_challenge(struct rxrpc_connection *conn)
627{
628 struct rxkad_challenge challenge;
629 struct rxrpc_wire_header whdr;
630 struct msghdr msg;
631 struct kvec iov[2];
632 size_t len;
633 u32 serial;
634 int ret;
635
636 _enter("{%d}", conn->debug_id);
637
638 get_random_bytes(&conn->rxkad.nonce, sizeof(conn->rxkad.nonce));
639
640 challenge.version = htonl(2);
641 challenge.nonce = htonl(conn->rxkad.nonce);
642 challenge.min_level = htonl(0);
643 challenge.__padding = 0;
644
645 msg.msg_name = &conn->peer->srx.transport;
646 msg.msg_namelen = conn->peer->srx.transport_len;
647 msg.msg_control = NULL;
648 msg.msg_controllen = 0;
649 msg.msg_flags = 0;
650
651 whdr.epoch = htonl(conn->proto.epoch);
652 whdr.cid = htonl(conn->proto.cid);
653 whdr.callNumber = 0;
654 whdr.seq = 0;
655 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
656 whdr.flags = conn->out_clientflag;
657 whdr.userStatus = 0;
658 whdr.securityIndex = conn->security_ix;
659 whdr._rsvd = 0;
660 whdr.serviceId = htons(conn->service_id);
661
662 iov[0].iov_base = &whdr;
663 iov[0].iov_len = sizeof(whdr);
664 iov[1].iov_base = &challenge;
665 iov[1].iov_len = sizeof(challenge);
666
667 len = iov[0].iov_len + iov[1].iov_len;
668
669 serial = rxrpc_get_next_serial(conn);
670 whdr.serial = htonl(serial);
671
672 ret = kernel_sendmsg(conn->local->socket, &msg, iov, 2, len);
673 if (ret < 0) {
674 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
675 rxrpc_tx_point_rxkad_challenge);
676 return -EAGAIN;
677 }
678
679 conn->peer->last_tx_at = ktime_get_seconds();
680 trace_rxrpc_tx_packet(conn->debug_id, &whdr,
681 rxrpc_tx_point_rxkad_challenge);
682 _leave(" = 0");
683 return 0;
684}
685
686/*
687 * send a Kerberos security response
688 */
689static int rxkad_send_response(struct rxrpc_connection *conn,
690 struct rxrpc_host_header *hdr,
691 struct rxkad_response *resp,
692 const struct rxkad_key *s2)
693{
694 struct rxrpc_wire_header whdr;
695 struct msghdr msg;
696 struct kvec iov[3];
697 size_t len;
698 u32 serial;
699 int ret;
700
701 _enter("");
702
703 msg.msg_name = &conn->peer->srx.transport;
704 msg.msg_namelen = conn->peer->srx.transport_len;
705 msg.msg_control = NULL;
706 msg.msg_controllen = 0;
707 msg.msg_flags = 0;
708
709 memset(&whdr, 0, sizeof(whdr));
710 whdr.epoch = htonl(hdr->epoch);
711 whdr.cid = htonl(hdr->cid);
712 whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
713 whdr.flags = conn->out_clientflag;
714 whdr.securityIndex = hdr->securityIndex;
715 whdr.serviceId = htons(hdr->serviceId);
716
717 iov[0].iov_base = &whdr;
718 iov[0].iov_len = sizeof(whdr);
719 iov[1].iov_base = resp;
720 iov[1].iov_len = sizeof(*resp);
721 iov[2].iov_base = (void *)s2->ticket;
722 iov[2].iov_len = s2->ticket_len;
723
724 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
725
726 serial = rxrpc_get_next_serial(conn);
727 whdr.serial = htonl(serial);
728
729 rxrpc_local_dont_fragment(conn->local, false);
730 ret = kernel_sendmsg(conn->local->socket, &msg, iov, 3, len);
731 if (ret < 0) {
732 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
733 rxrpc_tx_point_rxkad_response);
734 return -EAGAIN;
735 }
736
737 conn->peer->last_tx_at = ktime_get_seconds();
738 _leave(" = 0");
739 return 0;
740}
741
742/*
743 * calculate the response checksum
744 */
745static void rxkad_calc_response_checksum(struct rxkad_response *response)
746{
747 u32 csum = 1000003;
748 int loop;
749 u8 *p = (u8 *) response;
750
751 for (loop = sizeof(*response); loop > 0; loop--)
752 csum = csum * 0x10204081 + *p++;
753
754 response->encrypted.checksum = htonl(csum);
755}
756
757/*
758 * encrypt the response packet
759 */
760static int rxkad_encrypt_response(struct rxrpc_connection *conn,
761 struct rxkad_response *resp,
762 const struct rxkad_key *s2)
763{
764 struct skcipher_request *req;
765 struct rxrpc_crypt iv;
766 struct scatterlist sg[1];
767
768 req = skcipher_request_alloc(&conn->rxkad.cipher->base, GFP_NOFS);
769 if (!req)
770 return -ENOMEM;
771
772 /* continue encrypting from where we left off */
773 memcpy(&iv, s2->session_key, sizeof(iv));
774
775 sg_init_table(sg, 1);
776 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
777 skcipher_request_set_sync_tfm(req, conn->rxkad.cipher);
778 skcipher_request_set_callback(req, 0, NULL, NULL);
779 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
780 crypto_skcipher_encrypt(req);
781 skcipher_request_free(req);
782 return 0;
783}
784
785/*
786 * respond to a challenge packet
787 */
788static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
789 struct sk_buff *skb)
790{
791 const struct rxrpc_key_token *token;
792 struct rxkad_challenge challenge;
793 struct rxkad_response *resp;
794 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
795 u32 version, nonce, min_level;
796 int ret = -EPROTO;
797
798 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
799
800 if (!conn->key)
801 return rxrpc_abort_conn(conn, skb, RX_PROTOCOL_ERROR, -EPROTO,
802 rxkad_abort_chall_no_key);
803
804 ret = key_validate(conn->key);
805 if (ret < 0)
806 return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, ret,
807 rxkad_abort_chall_key_expired);
808
809 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
810 &challenge, sizeof(challenge)) < 0)
811 return rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
812 rxkad_abort_chall_short);
813
814 version = ntohl(challenge.version);
815 nonce = ntohl(challenge.nonce);
816 min_level = ntohl(challenge.min_level);
817
818 trace_rxrpc_rx_challenge(conn, sp->hdr.serial, version, nonce, min_level);
819
820 if (version != RXKAD_VERSION)
821 return rxrpc_abort_conn(conn, skb, RXKADINCONSISTENCY, -EPROTO,
822 rxkad_abort_chall_version);
823
824 if (conn->security_level < min_level)
825 return rxrpc_abort_conn(conn, skb, RXKADLEVELFAIL, -EACCES,
826 rxkad_abort_chall_level);
827
828 token = conn->key->payload.data[0];
829
830 /* build the response packet */
831 resp = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
832 if (!resp)
833 return -ENOMEM;
834
835 resp->version = htonl(RXKAD_VERSION);
836 resp->encrypted.epoch = htonl(conn->proto.epoch);
837 resp->encrypted.cid = htonl(conn->proto.cid);
838 resp->encrypted.securityIndex = htonl(conn->security_ix);
839 resp->encrypted.inc_nonce = htonl(nonce + 1);
840 resp->encrypted.level = htonl(conn->security_level);
841 resp->kvno = htonl(token->kad->kvno);
842 resp->ticket_len = htonl(token->kad->ticket_len);
843 resp->encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
844 resp->encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
845 resp->encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
846 resp->encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
847
848 /* calculate the response checksum and then do the encryption */
849 rxkad_calc_response_checksum(resp);
850 ret = rxkad_encrypt_response(conn, resp, token->kad);
851 if (ret == 0)
852 ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
853 kfree(resp);
854 return ret;
855}
856
857/*
858 * decrypt the kerberos IV ticket in the response
859 */
860static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
861 struct key *server_key,
862 struct sk_buff *skb,
863 void *ticket, size_t ticket_len,
864 struct rxrpc_crypt *_session_key,
865 time64_t *_expiry)
866{
867 struct skcipher_request *req;
868 struct rxrpc_crypt iv, key;
869 struct scatterlist sg[1];
870 struct in_addr addr;
871 unsigned int life;
872 time64_t issue, now;
873 bool little_endian;
874 u8 *p, *q, *name, *end;
875
876 _enter("{%d},{%x}", conn->debug_id, key_serial(server_key));
877
878 *_expiry = 0;
879
880 ASSERT(server_key->payload.data[0] != NULL);
881 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
882
883 memcpy(&iv, &server_key->payload.data[2], sizeof(iv));
884
885 req = skcipher_request_alloc(server_key->payload.data[0], GFP_NOFS);
886 if (!req)
887 return -ENOMEM;
888
889 sg_init_one(&sg[0], ticket, ticket_len);
890 skcipher_request_set_callback(req, 0, NULL, NULL);
891 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
892 crypto_skcipher_decrypt(req);
893 skcipher_request_free(req);
894
895 p = ticket;
896 end = p + ticket_len;
897
898#define Z(field, fieldl) \
899 ({ \
900 u8 *__str = p; \
901 q = memchr(p, 0, end - p); \
902 if (!q || q - p > field##_SZ) \
903 return rxrpc_abort_conn( \
904 conn, skb, RXKADBADTICKET, -EPROTO, \
905 rxkad_abort_resp_tkt_##fieldl); \
906 for (; p < q; p++) \
907 if (!isprint(*p)) \
908 return rxrpc_abort_conn( \
909 conn, skb, RXKADBADTICKET, -EPROTO, \
910 rxkad_abort_resp_tkt_##fieldl); \
911 p++; \
912 __str; \
913 })
914
915 /* extract the ticket flags */
916 _debug("KIV FLAGS: %x", *p);
917 little_endian = *p & 1;
918 p++;
919
920 /* extract the authentication name */
921 name = Z(ANAME, aname);
922 _debug("KIV ANAME: %s", name);
923
924 /* extract the principal's instance */
925 name = Z(INST, inst);
926 _debug("KIV INST : %s", name);
927
928 /* extract the principal's authentication domain */
929 name = Z(REALM, realm);
930 _debug("KIV REALM: %s", name);
931
932 if (end - p < 4 + 8 + 4 + 2)
933 return rxrpc_abort_conn(conn, skb, RXKADBADTICKET, -EPROTO,
934 rxkad_abort_resp_tkt_short);
935
936 /* get the IPv4 address of the entity that requested the ticket */
937 memcpy(&addr, p, sizeof(addr));
938 p += 4;
939 _debug("KIV ADDR : %pI4", &addr);
940
941 /* get the session key from the ticket */
942 memcpy(&key, p, sizeof(key));
943 p += 8;
944 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
945 memcpy(_session_key, &key, sizeof(key));
946
947 /* get the ticket's lifetime */
948 life = *p++ * 5 * 60;
949 _debug("KIV LIFE : %u", life);
950
951 /* get the issue time of the ticket */
952 if (little_endian) {
953 __le32 stamp;
954 memcpy(&stamp, p, 4);
955 issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
956 } else {
957 __be32 stamp;
958 memcpy(&stamp, p, 4);
959 issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
960 }
961 p += 4;
962 now = ktime_get_real_seconds();
963 _debug("KIV ISSUE: %llx [%llx]", issue, now);
964
965 /* check the ticket is in date */
966 if (issue > now)
967 return rxrpc_abort_conn(conn, skb, RXKADNOAUTH, -EKEYREJECTED,
968 rxkad_abort_resp_tkt_future);
969 if (issue < now - life)
970 return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, -EKEYEXPIRED,
971 rxkad_abort_resp_tkt_expired);
972
973 *_expiry = issue + life;
974
975 /* get the service name */
976 name = Z(SNAME, sname);
977 _debug("KIV SNAME: %s", name);
978
979 /* get the service instance name */
980 name = Z(INST, sinst);
981 _debug("KIV SINST: %s", name);
982 return 0;
983}
984
985/*
986 * decrypt the response packet
987 */
988static void rxkad_decrypt_response(struct rxrpc_connection *conn,
989 struct rxkad_response *resp,
990 const struct rxrpc_crypt *session_key)
991{
992 struct skcipher_request *req = rxkad_ci_req;
993 struct scatterlist sg[1];
994 struct rxrpc_crypt iv;
995
996 _enter(",,%08x%08x",
997 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
998
999 mutex_lock(&rxkad_ci_mutex);
1000 if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
1001 sizeof(*session_key)) < 0)
1002 BUG();
1003
1004 memcpy(&iv, session_key, sizeof(iv));
1005
1006 sg_init_table(sg, 1);
1007 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1008 skcipher_request_set_sync_tfm(req, rxkad_ci);
1009 skcipher_request_set_callback(req, 0, NULL, NULL);
1010 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1011 crypto_skcipher_decrypt(req);
1012 skcipher_request_zero(req);
1013
1014 mutex_unlock(&rxkad_ci_mutex);
1015
1016 _leave("");
1017}
1018
1019/*
1020 * verify a response
1021 */
1022static int rxkad_verify_response(struct rxrpc_connection *conn,
1023 struct sk_buff *skb)
1024{
1025 struct rxkad_response *response;
1026 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1027 struct rxrpc_crypt session_key;
1028 struct key *server_key;
1029 time64_t expiry;
1030 void *ticket;
1031 u32 version, kvno, ticket_len, level;
1032 __be32 csum;
1033 int ret, i;
1034
1035 _enter("{%d}", conn->debug_id);
1036
1037 server_key = rxrpc_look_up_server_security(conn, skb, 0, 0);
1038 if (IS_ERR(server_key)) {
1039 ret = PTR_ERR(server_key);
1040 switch (ret) {
1041 case -ENOKEY:
1042 return rxrpc_abort_conn(conn, skb, RXKADUNKNOWNKEY, ret,
1043 rxkad_abort_resp_nokey);
1044 case -EKEYEXPIRED:
1045 return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, ret,
1046 rxkad_abort_resp_key_expired);
1047 default:
1048 return rxrpc_abort_conn(conn, skb, RXKADNOAUTH, ret,
1049 rxkad_abort_resp_key_rejected);
1050 }
1051 }
1052
1053 ret = -ENOMEM;
1054 response = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
1055 if (!response)
1056 goto temporary_error;
1057
1058 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1059 response, sizeof(*response)) < 0) {
1060 rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
1061 rxkad_abort_resp_short);
1062 goto protocol_error;
1063 }
1064
1065 version = ntohl(response->version);
1066 ticket_len = ntohl(response->ticket_len);
1067 kvno = ntohl(response->kvno);
1068
1069 trace_rxrpc_rx_response(conn, sp->hdr.serial, version, kvno, ticket_len);
1070
1071 if (version != RXKAD_VERSION) {
1072 rxrpc_abort_conn(conn, skb, RXKADINCONSISTENCY, -EPROTO,
1073 rxkad_abort_resp_version);
1074 goto protocol_error;
1075 }
1076
1077 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN) {
1078 rxrpc_abort_conn(conn, skb, RXKADTICKETLEN, -EPROTO,
1079 rxkad_abort_resp_tkt_len);
1080 goto protocol_error;
1081 }
1082
1083 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5) {
1084 rxrpc_abort_conn(conn, skb, RXKADUNKNOWNKEY, -EPROTO,
1085 rxkad_abort_resp_unknown_tkt);
1086 goto protocol_error;
1087 }
1088
1089 /* extract the kerberos ticket and decrypt and decode it */
1090 ret = -ENOMEM;
1091 ticket = kmalloc(ticket_len, GFP_NOFS);
1092 if (!ticket)
1093 goto temporary_error_free_resp;
1094
1095 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header) + sizeof(*response),
1096 ticket, ticket_len) < 0) {
1097 rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
1098 rxkad_abort_resp_short_tkt);
1099 goto protocol_error;
1100 }
1101
1102 ret = rxkad_decrypt_ticket(conn, server_key, skb, ticket, ticket_len,
1103 &session_key, &expiry);
1104 if (ret < 0)
1105 goto temporary_error_free_ticket;
1106
1107 /* use the session key from inside the ticket to decrypt the
1108 * response */
1109 rxkad_decrypt_response(conn, response, &session_key);
1110
1111 if (ntohl(response->encrypted.epoch) != conn->proto.epoch ||
1112 ntohl(response->encrypted.cid) != conn->proto.cid ||
1113 ntohl(response->encrypted.securityIndex) != conn->security_ix) {
1114 rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1115 rxkad_abort_resp_bad_param);
1116 goto protocol_error_free;
1117 }
1118
1119 csum = response->encrypted.checksum;
1120 response->encrypted.checksum = 0;
1121 rxkad_calc_response_checksum(response);
1122 if (response->encrypted.checksum != csum) {
1123 rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1124 rxkad_abort_resp_bad_checksum);
1125 goto protocol_error_free;
1126 }
1127
1128 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1129 u32 call_id = ntohl(response->encrypted.call_id[i]);
1130 u32 counter = READ_ONCE(conn->channels[i].call_counter);
1131
1132 if (call_id > INT_MAX) {
1133 rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1134 rxkad_abort_resp_bad_callid);
1135 goto protocol_error_free;
1136 }
1137
1138 if (call_id < counter) {
1139 rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1140 rxkad_abort_resp_call_ctr);
1141 goto protocol_error_free;
1142 }
1143
1144 if (call_id > counter) {
1145 if (conn->channels[i].call) {
1146 rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1147 rxkad_abort_resp_call_state);
1148 goto protocol_error_free;
1149 }
1150 conn->channels[i].call_counter = call_id;
1151 }
1152 }
1153
1154 if (ntohl(response->encrypted.inc_nonce) != conn->rxkad.nonce + 1) {
1155 rxrpc_abort_conn(conn, skb, RXKADOUTOFSEQUENCE, -EPROTO,
1156 rxkad_abort_resp_ooseq);
1157 goto protocol_error_free;
1158 }
1159
1160 level = ntohl(response->encrypted.level);
1161 if (level > RXRPC_SECURITY_ENCRYPT) {
1162 rxrpc_abort_conn(conn, skb, RXKADLEVELFAIL, -EPROTO,
1163 rxkad_abort_resp_level);
1164 goto protocol_error_free;
1165 }
1166 conn->security_level = level;
1167
1168 /* create a key to hold the security data and expiration time - after
1169 * this the connection security can be handled in exactly the same way
1170 * as for a client connection */
1171 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1172 if (ret < 0)
1173 goto temporary_error_free_ticket;
1174
1175 kfree(ticket);
1176 kfree(response);
1177 _leave(" = 0");
1178 return 0;
1179
1180protocol_error_free:
1181 kfree(ticket);
1182protocol_error:
1183 kfree(response);
1184 key_put(server_key);
1185 return -EPROTO;
1186
1187temporary_error_free_ticket:
1188 kfree(ticket);
1189temporary_error_free_resp:
1190 kfree(response);
1191temporary_error:
1192 /* Ignore the response packet if we got a temporary error such as
1193 * ENOMEM. We just want to send the challenge again. Note that we
1194 * also come out this way if the ticket decryption fails.
1195 */
1196 key_put(server_key);
1197 return ret;
1198}
1199
1200/*
1201 * clear the connection security
1202 */
1203static void rxkad_clear(struct rxrpc_connection *conn)
1204{
1205 _enter("");
1206
1207 if (conn->rxkad.cipher)
1208 crypto_free_sync_skcipher(conn->rxkad.cipher);
1209}
1210
1211/*
1212 * Initialise the rxkad security service.
1213 */
1214static int rxkad_init(void)
1215{
1216 struct crypto_sync_skcipher *tfm;
1217 struct skcipher_request *req;
1218
1219 /* pin the cipher we need so that the crypto layer doesn't invoke
1220 * keventd to go get it */
1221 tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
1222 if (IS_ERR(tfm))
1223 return PTR_ERR(tfm);
1224
1225 req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
1226 if (!req)
1227 goto nomem_tfm;
1228
1229 rxkad_ci_req = req;
1230 rxkad_ci = tfm;
1231 return 0;
1232
1233nomem_tfm:
1234 crypto_free_sync_skcipher(tfm);
1235 return -ENOMEM;
1236}
1237
1238/*
1239 * Clean up the rxkad security service.
1240 */
1241static void rxkad_exit(void)
1242{
1243 crypto_free_sync_skcipher(rxkad_ci);
1244 skcipher_request_free(rxkad_ci_req);
1245}
1246
1247/*
1248 * RxRPC Kerberos-based security
1249 */
1250const struct rxrpc_security rxkad = {
1251 .name = "rxkad",
1252 .security_index = RXRPC_SECURITY_RXKAD,
1253 .no_key_abort = RXKADUNKNOWNKEY,
1254 .init = rxkad_init,
1255 .exit = rxkad_exit,
1256 .preparse_server_key = rxkad_preparse_server_key,
1257 .free_preparse_server_key = rxkad_free_preparse_server_key,
1258 .destroy_server_key = rxkad_destroy_server_key,
1259 .init_connection_security = rxkad_init_connection_security,
1260 .alloc_txbuf = rxkad_alloc_txbuf,
1261 .secure_packet = rxkad_secure_packet,
1262 .verify_packet = rxkad_verify_packet,
1263 .free_call_crypto = rxkad_free_call_crypto,
1264 .issue_challenge = rxkad_issue_challenge,
1265 .respond_to_challenge = rxkad_respond_to_challenge,
1266 .verify_response = rxkad_verify_response,
1267 .clear = rxkad_clear,
1268};
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};