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Linux 5.7.7
[linux/fpc-iii.git] / net / rxrpc / rxkad.c
blob52a24d4ef5d8a841a6e0f1ad58c14873ae03e666
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Kerberos-based RxRPC security
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <crypto/skcipher.h>
11 #include <linux/module.h>
12 #include <linux/net.h>
13 #include <linux/skbuff.h>
14 #include <linux/udp.h>
15 #include <linux/scatterlist.h>
16 #include <linux/ctype.h>
17 #include <linux/slab.h>
18 #include <net/sock.h>
19 #include <net/af_rxrpc.h>
20 #include <keys/rxrpc-type.h>
21 #include "ar-internal.h"
22
23 #define RXKAD_VERSION 2
24 #define MAXKRB5TICKETLEN 1024
25 #define RXKAD_TKT_TYPE_KERBEROS_V5 256
26 #define ANAME_SZ 40 /* size of authentication name */
27 #define INST_SZ 40 /* size of principal's instance */
28 #define REALM_SZ 40 /* size of principal's auth domain */
29 #define SNAME_SZ 40 /* size of service name */
30
31 struct rxkad_level1_hdr {
32 __be32 data_size; /* true data size (excluding padding) */
33 };
34
35 struct rxkad_level2_hdr {
36 __be32 data_size; /* true data size (excluding padding) */
37 __be32 checksum; /* decrypted data checksum */
38 };
39
40 /*
41 * this holds a pinned cipher so that keventd doesn't get called by the cipher
42 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
43 * packets
44 */
45 static struct crypto_sync_skcipher *rxkad_ci;
46 static struct skcipher_request *rxkad_ci_req;
47 static DEFINE_MUTEX(rxkad_ci_mutex);
48
49 /*
50 * initialise connection security
51 */
52 static int rxkad_init_connection_security(struct rxrpc_connection *conn)
53 {
54 struct crypto_sync_skcipher *ci;
55 struct rxrpc_key_token *token;
56 int ret;
57
58 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->params.key));
59
60 token = conn->params.key->payload.data[0];
61 conn->security_ix = token->security_index;
62
63 ci = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
64 if (IS_ERR(ci)) {
65 _debug("no cipher");
66 ret = PTR_ERR(ci);
67 goto error;
68 }
69
70 if (crypto_sync_skcipher_setkey(ci, token->kad->session_key,
71 sizeof(token->kad->session_key)) < 0)
72 BUG();
73
74 switch (conn->params.security_level) {
75 case RXRPC_SECURITY_PLAIN:
76 break;
77 case RXRPC_SECURITY_AUTH:
78 conn->size_align = 8;
79 conn->security_size = sizeof(struct rxkad_level1_hdr);
80 break;
81 case RXRPC_SECURITY_ENCRYPT:
82 conn->size_align = 8;
83 conn->security_size = sizeof(struct rxkad_level2_hdr);
84 break;
85 default:
86 ret = -EKEYREJECTED;
87 goto error;
88 }
89
90 conn->cipher = ci;
91 ret = 0;
92 error:
93 _leave(" = %d", ret);
94 return ret;
95 }
96
97 /*
98 * prime the encryption state with the invariant parts of a connection's
99 * description
100 */
101 static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
102 {
103 struct skcipher_request *req;
104 struct rxrpc_key_token *token;
105 struct scatterlist sg;
106 struct rxrpc_crypt iv;
107 __be32 *tmpbuf;
108 size_t tmpsize = 4 * sizeof(__be32);
109
110 _enter("");
111
112 if (!conn->params.key)
113 return 0;
114
115 tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
116 if (!tmpbuf)
117 return -ENOMEM;
118
119 req = skcipher_request_alloc(&conn->cipher->base, GFP_NOFS);
120 if (!req) {
121 kfree(tmpbuf);
122 return -ENOMEM;
123 }
124
125 token = conn->params.key->payload.data[0];
126 memcpy(&iv, token->kad->session_key, sizeof(iv));
127
128 tmpbuf[0] = htonl(conn->proto.epoch);
129 tmpbuf[1] = htonl(conn->proto.cid);
130 tmpbuf[2] = 0;
131 tmpbuf[3] = htonl(conn->security_ix);
132
133 sg_init_one(&sg, tmpbuf, tmpsize);
134 skcipher_request_set_sync_tfm(req, conn->cipher);
135 skcipher_request_set_callback(req, 0, NULL, NULL);
136 skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
137 crypto_skcipher_encrypt(req);
138 skcipher_request_free(req);
139
140 memcpy(&conn->csum_iv, tmpbuf + 2, sizeof(conn->csum_iv));
141 kfree(tmpbuf);
142 _leave(" = 0");
143 return 0;
144 }
145
146 /*
147 * Allocate and prepare the crypto request on a call. For any particular call,
148 * this is called serially for the packets, so no lock should be necessary.
149 */
150 static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
151 {
152 struct crypto_skcipher *tfm = &call->conn->cipher->base;
153 struct skcipher_request *cipher_req = call->cipher_req;
154
155 if (!cipher_req) {
156 cipher_req = skcipher_request_alloc(tfm, GFP_NOFS);
157 if (!cipher_req)
158 return NULL;
159 call->cipher_req = cipher_req;
160 }
161
162 return cipher_req;
163 }
164
165 /*
166 * Clean up the crypto on a call.
167 */
168 static void rxkad_free_call_crypto(struct rxrpc_call *call)
169 {
170 if (call->cipher_req)
171 skcipher_request_free(call->cipher_req);
172 call->cipher_req = NULL;
173 }
174
175 /*
176 * partially encrypt a packet (level 1 security)
177 */
178 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
179 struct sk_buff *skb,
180 u32 data_size,
181 void *sechdr,
182 struct skcipher_request *req)
183 {
184 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
185 struct rxkad_level1_hdr hdr;
186 struct rxrpc_crypt iv;
187 struct scatterlist sg;
188 u16 check;
189
190 _enter("");
191
192 check = sp->hdr.seq ^ call->call_id;
193 data_size |= (u32)check << 16;
194
195 hdr.data_size = htonl(data_size);
196 memcpy(sechdr, &hdr, sizeof(hdr));
197
198 /* start the encryption afresh */
199 memset(&iv, 0, sizeof(iv));
200
201 sg_init_one(&sg, sechdr, 8);
202 skcipher_request_set_sync_tfm(req, call->conn->cipher);
203 skcipher_request_set_callback(req, 0, NULL, NULL);
204 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
205 crypto_skcipher_encrypt(req);
206 skcipher_request_zero(req);
207
208 _leave(" = 0");
209 return 0;
210 }
211
212 /*
213 * wholly encrypt a packet (level 2 security)
214 */
215 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
216 struct sk_buff *skb,
217 u32 data_size,
218 void *sechdr,
219 struct skcipher_request *req)
220 {
221 const struct rxrpc_key_token *token;
222 struct rxkad_level2_hdr rxkhdr;
223 struct rxrpc_skb_priv *sp;
224 struct rxrpc_crypt iv;
225 struct scatterlist sg[16];
226 unsigned int len;
227 u16 check;
228 int err;
229
230 sp = rxrpc_skb(skb);
231
232 _enter("");
233
234 check = sp->hdr.seq ^ call->call_id;
235
236 rxkhdr.data_size = htonl(data_size | (u32)check << 16);
237 rxkhdr.checksum = 0;
238 memcpy(sechdr, &rxkhdr, sizeof(rxkhdr));
239
240 /* encrypt from the session key */
241 token = call->conn->params.key->payload.data[0];
242 memcpy(&iv, token->kad->session_key, sizeof(iv));
243
244 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
245 skcipher_request_set_sync_tfm(req, call->conn->cipher);
246 skcipher_request_set_callback(req, 0, NULL, NULL);
247 skcipher_request_set_crypt(req, &sg[0], &sg[0], sizeof(rxkhdr), iv.x);
248 crypto_skcipher_encrypt(req);
249
250 /* we want to encrypt the skbuff in-place */
251 err = -EMSGSIZE;
252 if (skb_shinfo(skb)->nr_frags > 16)
253 goto out;
254
255 len = data_size + call->conn->size_align - 1;
256 len &= ~(call->conn->size_align - 1);
257
258 sg_init_table(sg, ARRAY_SIZE(sg));
259 err = skb_to_sgvec(skb, sg, 0, len);
260 if (unlikely(err < 0))
261 goto out;
262 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
263 crypto_skcipher_encrypt(req);
264
265 _leave(" = 0");
266 err = 0;
267
268 out:
269 skcipher_request_zero(req);
270 return err;
271 }
272
273 /*
274 * checksum an RxRPC packet header
275 */
276 static int rxkad_secure_packet(struct rxrpc_call *call,
277 struct sk_buff *skb,
278 size_t data_size,
279 void *sechdr)
280 {
281 struct rxrpc_skb_priv *sp;
282 struct skcipher_request *req;
283 struct rxrpc_crypt iv;
284 struct scatterlist sg;
285 u32 x, y;
286 int ret;
287
288 sp = rxrpc_skb(skb);
289
290 _enter("{%d{%x}},{#%u},%zu,",
291 call->debug_id, key_serial(call->conn->params.key),
292 sp->hdr.seq, data_size);
293
294 if (!call->conn->cipher)
295 return 0;
296
297 ret = key_validate(call->conn->params.key);
298 if (ret < 0)
299 return ret;
300
301 req = rxkad_get_call_crypto(call);
302 if (!req)
303 return -ENOMEM;
304
305 /* continue encrypting from where we left off */
306 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
307
308 /* calculate the security checksum */
309 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
310 x |= sp->hdr.seq & 0x3fffffff;
311 call->crypto_buf[0] = htonl(call->call_id);
312 call->crypto_buf[1] = htonl(x);
313
314 sg_init_one(&sg, call->crypto_buf, 8);
315 skcipher_request_set_sync_tfm(req, call->conn->cipher);
316 skcipher_request_set_callback(req, 0, NULL, NULL);
317 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
318 crypto_skcipher_encrypt(req);
319 skcipher_request_zero(req);
320
321 y = ntohl(call->crypto_buf[1]);
322 y = (y >> 16) & 0xffff;
323 if (y == 0)
324 y = 1; /* zero checksums are not permitted */
325 sp->hdr.cksum = y;
326
327 switch (call->conn->params.security_level) {
328 case RXRPC_SECURITY_PLAIN:
329 ret = 0;
330 break;
331 case RXRPC_SECURITY_AUTH:
332 ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr,
333 req);
334 break;
335 case RXRPC_SECURITY_ENCRYPT:
336 ret = rxkad_secure_packet_encrypt(call, skb, data_size,
337 sechdr, req);
338 break;
339 default:
340 ret = -EPERM;
341 break;
342 }
343
344 _leave(" = %d [set %hx]", ret, y);
345 return ret;
346 }
347
348 /*
349 * decrypt partial encryption on a packet (level 1 security)
350 */
351 static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
352 unsigned int offset, unsigned int len,
353 rxrpc_seq_t seq,
354 struct skcipher_request *req)
355 {
356 struct rxkad_level1_hdr sechdr;
357 struct rxrpc_crypt iv;
358 struct scatterlist sg[16];
359 bool aborted;
360 u32 data_size, buf;
361 u16 check;
362 int ret;
363
364 _enter("");
365
366 if (len < 8) {
367 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_hdr", "V1H",
368 RXKADSEALEDINCON);
369 goto protocol_error;
370 }
371
372 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
373 * directly into the target buffer.
374 */
375 sg_init_table(sg, ARRAY_SIZE(sg));
376 ret = skb_to_sgvec(skb, sg, offset, 8);
377 if (unlikely(ret < 0))
378 return ret;
379
380 /* start the decryption afresh */
381 memset(&iv, 0, sizeof(iv));
382
383 skcipher_request_set_sync_tfm(req, call->conn->cipher);
384 skcipher_request_set_callback(req, 0, NULL, NULL);
385 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
386 crypto_skcipher_decrypt(req);
387 skcipher_request_zero(req);
388
389 /* Extract the decrypted packet length */
390 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
391 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_len", "XV1",
392 RXKADDATALEN);
393 goto protocol_error;
394 }
395 offset += sizeof(sechdr);
396 len -= sizeof(sechdr);
397
398 buf = ntohl(sechdr.data_size);
399 data_size = buf & 0xffff;
400
401 check = buf >> 16;
402 check ^= seq ^ call->call_id;
403 check &= 0xffff;
404 if (check != 0) {
405 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_check", "V1C",
406 RXKADSEALEDINCON);
407 goto protocol_error;
408 }
409
410 if (data_size > len) {
411 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_datalen", "V1L",
412 RXKADDATALEN);
413 goto protocol_error;
414 }
415
416 _leave(" = 0 [dlen=%x]", data_size);
417 return 0;
418
419 protocol_error:
420 if (aborted)
421 rxrpc_send_abort_packet(call);
422 return -EPROTO;
423 }
424
425 /*
426 * wholly decrypt a packet (level 2 security)
427 */
428 static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
429 unsigned int offset, unsigned int len,
430 rxrpc_seq_t seq,
431 struct skcipher_request *req)
432 {
433 const struct rxrpc_key_token *token;
434 struct rxkad_level2_hdr sechdr;
435 struct rxrpc_crypt iv;
436 struct scatterlist _sg[4], *sg;
437 bool aborted;
438 u32 data_size, buf;
439 u16 check;
440 int nsg, ret;
441
442 _enter(",{%d}", skb->len);
443
444 if (len < 8) {
445 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_hdr", "V2H",
446 RXKADSEALEDINCON);
447 goto protocol_error;
448 }
449
450 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
451 * directly into the target buffer.
452 */
453 sg = _sg;
454 nsg = skb_shinfo(skb)->nr_frags;
455 if (nsg <= 4) {
456 nsg = 4;
457 } else {
458 sg = kmalloc_array(nsg, sizeof(*sg), GFP_NOIO);
459 if (!sg)
460 goto nomem;
461 }
462
463 sg_init_table(sg, nsg);
464 ret = skb_to_sgvec(skb, sg, offset, len);
465 if (unlikely(ret < 0)) {
466 if (sg != _sg)
467 kfree(sg);
468 return ret;
469 }
470
471 /* decrypt from the session key */
472 token = call->conn->params.key->payload.data[0];
473 memcpy(&iv, token->kad->session_key, sizeof(iv));
474
475 skcipher_request_set_sync_tfm(req, call->conn->cipher);
476 skcipher_request_set_callback(req, 0, NULL, NULL);
477 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
478 crypto_skcipher_decrypt(req);
479 skcipher_request_zero(req);
480 if (sg != _sg)
481 kfree(sg);
482
483 /* Extract the decrypted packet length */
484 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
485 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_len", "XV2",
486 RXKADDATALEN);
487 goto protocol_error;
488 }
489 offset += sizeof(sechdr);
490 len -= sizeof(sechdr);
491
492 buf = ntohl(sechdr.data_size);
493 data_size = buf & 0xffff;
494
495 check = buf >> 16;
496 check ^= seq ^ call->call_id;
497 check &= 0xffff;
498 if (check != 0) {
499 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_check", "V2C",
500 RXKADSEALEDINCON);
501 goto protocol_error;
502 }
503
504 if (data_size > len) {
505 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_datalen", "V2L",
506 RXKADDATALEN);
507 goto protocol_error;
508 }
509
510 _leave(" = 0 [dlen=%x]", data_size);
511 return 0;
512
513 protocol_error:
514 if (aborted)
515 rxrpc_send_abort_packet(call);
516 return -EPROTO;
517
518 nomem:
519 _leave(" = -ENOMEM");
520 return -ENOMEM;
521 }
522
523 /*
524 * Verify the security on a received packet or subpacket (if part of a
525 * jumbo packet).
526 */
527 static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
528 unsigned int offset, unsigned int len,
529 rxrpc_seq_t seq, u16 expected_cksum)
530 {
531 struct skcipher_request *req;
532 struct rxrpc_crypt iv;
533 struct scatterlist sg;
534 bool aborted;
535 u16 cksum;
536 u32 x, y;
537
538 _enter("{%d{%x}},{#%u}",
539 call->debug_id, key_serial(call->conn->params.key), seq);
540
541 if (!call->conn->cipher)
542 return 0;
543
544 req = rxkad_get_call_crypto(call);
545 if (!req)
546 return -ENOMEM;
547
548 /* continue encrypting from where we left off */
549 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
550
551 /* validate the security checksum */
552 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
553 x |= seq & 0x3fffffff;
554 call->crypto_buf[0] = htonl(call->call_id);
555 call->crypto_buf[1] = htonl(x);
556
557 sg_init_one(&sg, call->crypto_buf, 8);
558 skcipher_request_set_sync_tfm(req, call->conn->cipher);
559 skcipher_request_set_callback(req, 0, NULL, NULL);
560 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
561 crypto_skcipher_encrypt(req);
562 skcipher_request_zero(req);
563
564 y = ntohl(call->crypto_buf[1]);
565 cksum = (y >> 16) & 0xffff;
566 if (cksum == 0)
567 cksum = 1; /* zero checksums are not permitted */
568
569 if (cksum != expected_cksum) {
570 aborted = rxrpc_abort_eproto(call, skb, "rxkad_csum", "VCK",
571 RXKADSEALEDINCON);
572 goto protocol_error;
573 }
574
575 switch (call->conn->params.security_level) {
576 case RXRPC_SECURITY_PLAIN:
577 return 0;
578 case RXRPC_SECURITY_AUTH:
579 return rxkad_verify_packet_1(call, skb, offset, len, seq, req);
580 case RXRPC_SECURITY_ENCRYPT:
581 return rxkad_verify_packet_2(call, skb, offset, len, seq, req);
582 default:
583 return -ENOANO;
584 }
585
586 protocol_error:
587 if (aborted)
588 rxrpc_send_abort_packet(call);
589 return -EPROTO;
590 }
591
592 /*
593 * Locate the data contained in a packet that was partially encrypted.
594 */
595 static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb,
596 unsigned int *_offset, unsigned int *_len)
597 {
598 struct rxkad_level1_hdr sechdr;
599
600 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
601 BUG();
602 *_offset += sizeof(sechdr);
603 *_len = ntohl(sechdr.data_size) & 0xffff;
604 }
605
606 /*
607 * Locate the data contained in a packet that was completely encrypted.
608 */
609 static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb,
610 unsigned int *_offset, unsigned int *_len)
611 {
612 struct rxkad_level2_hdr sechdr;
613
614 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
615 BUG();
616 *_offset += sizeof(sechdr);
617 *_len = ntohl(sechdr.data_size) & 0xffff;
618 }
619
620 /*
621 * Locate the data contained in an already decrypted packet.
622 */
623 static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
624 unsigned int *_offset, unsigned int *_len)
625 {
626 switch (call->conn->params.security_level) {
627 case RXRPC_SECURITY_AUTH:
628 rxkad_locate_data_1(call, skb, _offset, _len);
629 return;
630 case RXRPC_SECURITY_ENCRYPT:
631 rxkad_locate_data_2(call, skb, _offset, _len);
632 return;
633 default:
634 return;
635 }
636 }
637
638 /*
639 * issue a challenge
640 */
641 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
642 {
643 struct rxkad_challenge challenge;
644 struct rxrpc_wire_header whdr;
645 struct msghdr msg;
646 struct kvec iov[2];
647 size_t len;
648 u32 serial;
649 int ret;
650
651 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
652
653 ret = key_validate(conn->server_key);
654 if (ret < 0)
655 return ret;
656
657 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
658
659 challenge.version = htonl(2);
660 challenge.nonce = htonl(conn->security_nonce);
661 challenge.min_level = htonl(0);
662 challenge.__padding = 0;
663
664 msg.msg_name = &conn->params.peer->srx.transport;
665 msg.msg_namelen = conn->params.peer->srx.transport_len;
666 msg.msg_control = NULL;
667 msg.msg_controllen = 0;
668 msg.msg_flags = 0;
669
670 whdr.epoch = htonl(conn->proto.epoch);
671 whdr.cid = htonl(conn->proto.cid);
672 whdr.callNumber = 0;
673 whdr.seq = 0;
674 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
675 whdr.flags = conn->out_clientflag;
676 whdr.userStatus = 0;
677 whdr.securityIndex = conn->security_ix;
678 whdr._rsvd = 0;
679 whdr.serviceId = htons(conn->service_id);
680
681 iov[0].iov_base = &whdr;
682 iov[0].iov_len = sizeof(whdr);
683 iov[1].iov_base = &challenge;
684 iov[1].iov_len = sizeof(challenge);
685
686 len = iov[0].iov_len + iov[1].iov_len;
687
688 serial = atomic_inc_return(&conn->serial);
689 whdr.serial = htonl(serial);
690 _proto("Tx CHALLENGE %%%u", serial);
691
692 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
693 if (ret < 0) {
694 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
695 rxrpc_tx_point_rxkad_challenge);
696 return -EAGAIN;
697 }
698
699 conn->params.peer->last_tx_at = ktime_get_seconds();
700 trace_rxrpc_tx_packet(conn->debug_id, &whdr,
701 rxrpc_tx_point_rxkad_challenge);
702 _leave(" = 0");
703 return 0;
704 }
705
706 /*
707 * send a Kerberos security response
708 */
709 static int rxkad_send_response(struct rxrpc_connection *conn,
710 struct rxrpc_host_header *hdr,
711 struct rxkad_response *resp,
712 const struct rxkad_key *s2)
713 {
714 struct rxrpc_wire_header whdr;
715 struct msghdr msg;
716 struct kvec iov[3];
717 size_t len;
718 u32 serial;
719 int ret;
720
721 _enter("");
722
723 msg.msg_name = &conn->params.peer->srx.transport;
724 msg.msg_namelen = conn->params.peer->srx.transport_len;
725 msg.msg_control = NULL;
726 msg.msg_controllen = 0;
727 msg.msg_flags = 0;
728
729 memset(&whdr, 0, sizeof(whdr));
730 whdr.epoch = htonl(hdr->epoch);
731 whdr.cid = htonl(hdr->cid);
732 whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
733 whdr.flags = conn->out_clientflag;
734 whdr.securityIndex = hdr->securityIndex;
735 whdr.serviceId = htons(hdr->serviceId);
736
737 iov[0].iov_base = &whdr;
738 iov[0].iov_len = sizeof(whdr);
739 iov[1].iov_base = resp;
740 iov[1].iov_len = sizeof(*resp);
741 iov[2].iov_base = (void *)s2->ticket;
742 iov[2].iov_len = s2->ticket_len;
743
744 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
745
746 serial = atomic_inc_return(&conn->serial);
747 whdr.serial = htonl(serial);
748 _proto("Tx RESPONSE %%%u", serial);
749
750 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 3, len);
751 if (ret < 0) {
752 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
753 rxrpc_tx_point_rxkad_response);
754 return -EAGAIN;
755 }
756
757 conn->params.peer->last_tx_at = ktime_get_seconds();
758 _leave(" = 0");
759 return 0;
760 }
761
762 /*
763 * calculate the response checksum
764 */
765 static void rxkad_calc_response_checksum(struct rxkad_response *response)
766 {
767 u32 csum = 1000003;
768 int loop;
769 u8 *p = (u8 *) response;
770
771 for (loop = sizeof(*response); loop > 0; loop--)
772 csum = csum * 0x10204081 + *p++;
773
774 response->encrypted.checksum = htonl(csum);
775 }
776
777 /*
778 * encrypt the response packet
779 */
780 static int rxkad_encrypt_response(struct rxrpc_connection *conn,
781 struct rxkad_response *resp,
782 const struct rxkad_key *s2)
783 {
784 struct skcipher_request *req;
785 struct rxrpc_crypt iv;
786 struct scatterlist sg[1];
787
788 req = skcipher_request_alloc(&conn->cipher->base, GFP_NOFS);
789 if (!req)
790 return -ENOMEM;
791
792 /* continue encrypting from where we left off */
793 memcpy(&iv, s2->session_key, sizeof(iv));
794
795 sg_init_table(sg, 1);
796 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
797 skcipher_request_set_sync_tfm(req, conn->cipher);
798 skcipher_request_set_callback(req, 0, NULL, NULL);
799 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
800 crypto_skcipher_encrypt(req);
801 skcipher_request_free(req);
802 return 0;
803 }
804
805 /*
806 * respond to a challenge packet
807 */
808 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
809 struct sk_buff *skb,
810 u32 *_abort_code)
811 {
812 const struct rxrpc_key_token *token;
813 struct rxkad_challenge challenge;
814 struct rxkad_response *resp;
815 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
816 const char *eproto;
817 u32 version, nonce, min_level, abort_code;
818 int ret;
819
820 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
821
822 eproto = tracepoint_string("chall_no_key");
823 abort_code = RX_PROTOCOL_ERROR;
824 if (!conn->params.key)
825 goto protocol_error;
826
827 abort_code = RXKADEXPIRED;
828 ret = key_validate(conn->params.key);
829 if (ret < 0)
830 goto other_error;
831
832 eproto = tracepoint_string("chall_short");
833 abort_code = RXKADPACKETSHORT;
834 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
835 &challenge, sizeof(challenge)) < 0)
836 goto protocol_error;
837
838 version = ntohl(challenge.version);
839 nonce = ntohl(challenge.nonce);
840 min_level = ntohl(challenge.min_level);
841
842 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
843 sp->hdr.serial, version, nonce, min_level);
844
845 eproto = tracepoint_string("chall_ver");
846 abort_code = RXKADINCONSISTENCY;
847 if (version != RXKAD_VERSION)
848 goto protocol_error;
849
850 abort_code = RXKADLEVELFAIL;
851 ret = -EACCES;
852 if (conn->params.security_level < min_level)
853 goto other_error;
854
855 token = conn->params.key->payload.data[0];
856
857 /* build the response packet */
858 resp = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
859 if (!resp)
860 return -ENOMEM;
861
862 resp->version = htonl(RXKAD_VERSION);
863 resp->encrypted.epoch = htonl(conn->proto.epoch);
864 resp->encrypted.cid = htonl(conn->proto.cid);
865 resp->encrypted.securityIndex = htonl(conn->security_ix);
866 resp->encrypted.inc_nonce = htonl(nonce + 1);
867 resp->encrypted.level = htonl(conn->params.security_level);
868 resp->kvno = htonl(token->kad->kvno);
869 resp->ticket_len = htonl(token->kad->ticket_len);
870 resp->encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
871 resp->encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
872 resp->encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
873 resp->encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
874
875 /* calculate the response checksum and then do the encryption */
876 rxkad_calc_response_checksum(resp);
877 ret = rxkad_encrypt_response(conn, resp, token->kad);
878 if (ret == 0)
879 ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
880 kfree(resp);
881 return ret;
882
883 protocol_error:
884 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
885 ret = -EPROTO;
886 other_error:
887 *_abort_code = abort_code;
888 return ret;
889 }
890
891 /*
892 * decrypt the kerberos IV ticket in the response
893 */
894 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
895 struct sk_buff *skb,
896 void *ticket, size_t ticket_len,
897 struct rxrpc_crypt *_session_key,
898 time64_t *_expiry,
899 u32 *_abort_code)
900 {
901 struct skcipher_request *req;
902 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
903 struct rxrpc_crypt iv, key;
904 struct scatterlist sg[1];
905 struct in_addr addr;
906 unsigned int life;
907 const char *eproto;
908 time64_t issue, now;
909 bool little_endian;
910 int ret;
911 u32 abort_code;
912 u8 *p, *q, *name, *end;
913
914 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
915
916 *_expiry = 0;
917
918 ret = key_validate(conn->server_key);
919 if (ret < 0) {
920 switch (ret) {
921 case -EKEYEXPIRED:
922 abort_code = RXKADEXPIRED;
923 goto other_error;
924 default:
925 abort_code = RXKADNOAUTH;
926 goto other_error;
927 }
928 }
929
930 ASSERT(conn->server_key->payload.data[0] != NULL);
931 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
932
933 memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv));
934
935 ret = -ENOMEM;
936 req = skcipher_request_alloc(conn->server_key->payload.data[0],
937 GFP_NOFS);
938 if (!req)
939 goto temporary_error;
940
941 sg_init_one(&sg[0], ticket, ticket_len);
942 skcipher_request_set_callback(req, 0, NULL, NULL);
943 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
944 crypto_skcipher_decrypt(req);
945 skcipher_request_free(req);
946
947 p = ticket;
948 end = p + ticket_len;
949
950 #define Z(field) \
951 ({ \
952 u8 *__str = p; \
953 eproto = tracepoint_string("rxkad_bad_"#field); \
954 q = memchr(p, 0, end - p); \
955 if (!q || q - p > (field##_SZ)) \
956 goto bad_ticket; \
957 for (; p < q; p++) \
958 if (!isprint(*p)) \
959 goto bad_ticket; \
960 p++; \
961 __str; \
962 })
963
964 /* extract the ticket flags */
965 _debug("KIV FLAGS: %x", *p);
966 little_endian = *p & 1;
967 p++;
968
969 /* extract the authentication name */
970 name = Z(ANAME);
971 _debug("KIV ANAME: %s", name);
972
973 /* extract the principal's instance */
974 name = Z(INST);
975 _debug("KIV INST : %s", name);
976
977 /* extract the principal's authentication domain */
978 name = Z(REALM);
979 _debug("KIV REALM: %s", name);
980
981 eproto = tracepoint_string("rxkad_bad_len");
982 if (end - p < 4 + 8 + 4 + 2)
983 goto bad_ticket;
984
985 /* get the IPv4 address of the entity that requested the ticket */
986 memcpy(&addr, p, sizeof(addr));
987 p += 4;
988 _debug("KIV ADDR : %pI4", &addr);
989
990 /* get the session key from the ticket */
991 memcpy(&key, p, sizeof(key));
992 p += 8;
993 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
994 memcpy(_session_key, &key, sizeof(key));
995
996 /* get the ticket's lifetime */
997 life = *p++ * 5 * 60;
998 _debug("KIV LIFE : %u", life);
999
1000 /* get the issue time of the ticket */
1001 if (little_endian) {
1002 __le32 stamp;
1003 memcpy(&stamp, p, 4);
1004 issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
1005 } else {
1006 __be32 stamp;
1007 memcpy(&stamp, p, 4);
1008 issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
1009 }
1010 p += 4;
1011 now = ktime_get_real_seconds();
1012 _debug("KIV ISSUE: %llx [%llx]", issue, now);
1013
1014 /* check the ticket is in date */
1015 if (issue > now) {
1016 abort_code = RXKADNOAUTH;
1017 ret = -EKEYREJECTED;
1018 goto other_error;
1019 }
1020
1021 if (issue < now - life) {
1022 abort_code = RXKADEXPIRED;
1023 ret = -EKEYEXPIRED;
1024 goto other_error;
1025 }
1026
1027 *_expiry = issue + life;
1028
1029 /* get the service name */
1030 name = Z(SNAME);
1031 _debug("KIV SNAME: %s", name);
1032
1033 /* get the service instance name */
1034 name = Z(INST);
1035 _debug("KIV SINST: %s", name);
1036 return 0;
1037
1038 bad_ticket:
1039 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1040 abort_code = RXKADBADTICKET;
1041 ret = -EPROTO;
1042 other_error:
1043 *_abort_code = abort_code;
1044 return ret;
1045 temporary_error:
1046 return ret;
1047 }
1048
1049 /*
1050 * decrypt the response packet
1051 */
1052 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
1053 struct rxkad_response *resp,
1054 const struct rxrpc_crypt *session_key)
1055 {
1056 struct skcipher_request *req = rxkad_ci_req;
1057 struct scatterlist sg[1];
1058 struct rxrpc_crypt iv;
1059
1060 _enter(",,%08x%08x",
1061 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
1062
1063 mutex_lock(&rxkad_ci_mutex);
1064 if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
1065 sizeof(*session_key)) < 0)
1066 BUG();
1067
1068 memcpy(&iv, session_key, sizeof(iv));
1069
1070 sg_init_table(sg, 1);
1071 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1072 skcipher_request_set_sync_tfm(req, rxkad_ci);
1073 skcipher_request_set_callback(req, 0, NULL, NULL);
1074 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1075 crypto_skcipher_decrypt(req);
1076 skcipher_request_zero(req);
1077
1078 mutex_unlock(&rxkad_ci_mutex);
1079
1080 _leave("");
1081 }
1082
1083 /*
1084 * verify a response
1085 */
1086 static int rxkad_verify_response(struct rxrpc_connection *conn,
1087 struct sk_buff *skb,
1088 u32 *_abort_code)
1089 {
1090 struct rxkad_response *response;
1091 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1092 struct rxrpc_crypt session_key;
1093 const char *eproto;
1094 time64_t expiry;
1095 void *ticket;
1096 u32 abort_code, version, kvno, ticket_len, level;
1097 __be32 csum;
1098 int ret, i;
1099
1100 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1101
1102 ret = -ENOMEM;
1103 response = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
1104 if (!response)
1105 goto temporary_error;
1106
1107 eproto = tracepoint_string("rxkad_rsp_short");
1108 abort_code = RXKADPACKETSHORT;
1109 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1110 response, sizeof(*response)) < 0)
1111 goto protocol_error;
1112 if (!pskb_pull(skb, sizeof(*response)))
1113 BUG();
1114
1115 version = ntohl(response->version);
1116 ticket_len = ntohl(response->ticket_len);
1117 kvno = ntohl(response->kvno);
1118 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1119 sp->hdr.serial, version, kvno, ticket_len);
1120
1121 eproto = tracepoint_string("rxkad_rsp_ver");
1122 abort_code = RXKADINCONSISTENCY;
1123 if (version != RXKAD_VERSION)
1124 goto protocol_error;
1125
1126 eproto = tracepoint_string("rxkad_rsp_tktlen");
1127 abort_code = RXKADTICKETLEN;
1128 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1129 goto protocol_error;
1130
1131 eproto = tracepoint_string("rxkad_rsp_unkkey");
1132 abort_code = RXKADUNKNOWNKEY;
1133 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1134 goto protocol_error;
1135
1136 /* extract the kerberos ticket and decrypt and decode it */
1137 ret = -ENOMEM;
1138 ticket = kmalloc(ticket_len, GFP_NOFS);
1139 if (!ticket)
1140 goto temporary_error;
1141
1142 eproto = tracepoint_string("rxkad_tkt_short");
1143 abort_code = RXKADPACKETSHORT;
1144 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1145 ticket, ticket_len) < 0)
1146 goto protocol_error_free;
1147
1148 ret = rxkad_decrypt_ticket(conn, skb, ticket, ticket_len, &session_key,
1149 &expiry, _abort_code);
1150 if (ret < 0)
1151 goto temporary_error_free_ticket;
1152
1153 /* use the session key from inside the ticket to decrypt the
1154 * response */
1155 rxkad_decrypt_response(conn, response, &session_key);
1156
1157 eproto = tracepoint_string("rxkad_rsp_param");
1158 abort_code = RXKADSEALEDINCON;
1159 if (ntohl(response->encrypted.epoch) != conn->proto.epoch)
1160 goto protocol_error_free;
1161 if (ntohl(response->encrypted.cid) != conn->proto.cid)
1162 goto protocol_error_free;
1163 if (ntohl(response->encrypted.securityIndex) != conn->security_ix)
1164 goto protocol_error_free;
1165 csum = response->encrypted.checksum;
1166 response->encrypted.checksum = 0;
1167 rxkad_calc_response_checksum(response);
1168 eproto = tracepoint_string("rxkad_rsp_csum");
1169 if (response->encrypted.checksum != csum)
1170 goto protocol_error_free;
1171
1172 spin_lock(&conn->channel_lock);
1173 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1174 struct rxrpc_call *call;
1175 u32 call_id = ntohl(response->encrypted.call_id[i]);
1176
1177 eproto = tracepoint_string("rxkad_rsp_callid");
1178 if (call_id > INT_MAX)
1179 goto protocol_error_unlock;
1180
1181 eproto = tracepoint_string("rxkad_rsp_callctr");
1182 if (call_id < conn->channels[i].call_counter)
1183 goto protocol_error_unlock;
1184
1185 eproto = tracepoint_string("rxkad_rsp_callst");
1186 if (call_id > conn->channels[i].call_counter) {
1187 call = rcu_dereference_protected(
1188 conn->channels[i].call,
1189 lockdep_is_held(&conn->channel_lock));
1190 if (call && call->state < RXRPC_CALL_COMPLETE)
1191 goto protocol_error_unlock;
1192 conn->channels[i].call_counter = call_id;
1193 }
1194 }
1195 spin_unlock(&conn->channel_lock);
1196
1197 eproto = tracepoint_string("rxkad_rsp_seq");
1198 abort_code = RXKADOUTOFSEQUENCE;
1199 if (ntohl(response->encrypted.inc_nonce) != conn->security_nonce + 1)
1200 goto protocol_error_free;
1201
1202 eproto = tracepoint_string("rxkad_rsp_level");
1203 abort_code = RXKADLEVELFAIL;
1204 level = ntohl(response->encrypted.level);
1205 if (level > RXRPC_SECURITY_ENCRYPT)
1206 goto protocol_error_free;
1207 conn->params.security_level = level;
1208
1209 /* create a key to hold the security data and expiration time - after
1210 * this the connection security can be handled in exactly the same way
1211 * as for a client connection */
1212 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1213 if (ret < 0)
1214 goto temporary_error_free_ticket;
1215
1216 kfree(ticket);
1217 kfree(response);
1218 _leave(" = 0");
1219 return 0;
1220
1221 protocol_error_unlock:
1222 spin_unlock(&conn->channel_lock);
1223 protocol_error_free:
1224 kfree(ticket);
1225 protocol_error:
1226 kfree(response);
1227 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1228 *_abort_code = abort_code;
1229 return -EPROTO;
1230
1231 temporary_error_free_ticket:
1232 kfree(ticket);
1233 kfree(response);
1234 temporary_error:
1235 /* Ignore the response packet if we got a temporary error such as
1236 * ENOMEM. We just want to send the challenge again. Note that we
1237 * also come out this way if the ticket decryption fails.
1238 */
1239 return ret;
1240 }
1241
1242 /*
1243 * clear the connection security
1244 */
1245 static void rxkad_clear(struct rxrpc_connection *conn)
1246 {
1247 _enter("");
1248
1249 if (conn->cipher)
1250 crypto_free_sync_skcipher(conn->cipher);
1251 }
1252
1253 /*
1254 * Initialise the rxkad security service.
1255 */
1256 static int rxkad_init(void)
1257 {
1258 struct crypto_sync_skcipher *tfm;
1259 struct skcipher_request *req;
1260
1261 /* pin the cipher we need so that the crypto layer doesn't invoke
1262 * keventd to go get it */
1263 tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
1264 if (IS_ERR(tfm))
1265 return PTR_ERR(tfm);
1266
1267 req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
1268 if (!req)
1269 goto nomem_tfm;
1270
1271 rxkad_ci_req = req;
1272 rxkad_ci = tfm;
1273 return 0;
1274
1275 nomem_tfm:
1276 crypto_free_sync_skcipher(tfm);
1277 return -ENOMEM;
1278 }
1279
1280 /*
1281 * Clean up the rxkad security service.
1282 */
1283 static void rxkad_exit(void)
1284 {
1285 crypto_free_sync_skcipher(rxkad_ci);
1286 skcipher_request_free(rxkad_ci_req);
1287 }
1288
1289 /*
1290 * RxRPC Kerberos-based security
1291 */
1292 const struct rxrpc_security rxkad = {
1293 .name = "rxkad",
1294 .security_index = RXRPC_SECURITY_RXKAD,
1295 .no_key_abort = RXKADUNKNOWNKEY,
1296 .init = rxkad_init,
1297 .exit = rxkad_exit,
1298 .init_connection_security = rxkad_init_connection_security,
1299 .prime_packet_security = rxkad_prime_packet_security,
1300 .secure_packet = rxkad_secure_packet,
1301 .verify_packet = rxkad_verify_packet,
1302 .free_call_crypto = rxkad_free_call_crypto,
1303 .locate_data = rxkad_locate_data,
1304 .issue_challenge = rxkad_issue_challenge,
1305 .respond_to_challenge = rxkad_respond_to_challenge,
1306 .verify_response = rxkad_verify_response,
1307 .clear = rxkad_clear,
1308 };
Linux with added FPC-III support