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