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
33 struct rxkad_level1_hdr {
34 __be32 data_size; /* true data size (excluding padding) */
35 };
36
37 struct rxkad_level2_hdr {
38 __be32 data_size; /* true data size (excluding padding) */
39 __be32 checksum; /* decrypted data checksum */
40 };
41
42 static 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 */
50 static struct crypto_sync_skcipher *rxkad_ci;
51 static struct skcipher_request *rxkad_ci_req;
52 static 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 */
rxkad_preparse_server_key(struct key_preparsed_payload * prep)59 static 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
rxkad_free_preparse_server_key(struct key_preparsed_payload * prep)82 static 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
rxkad_destroy_server_key(struct key * key)89 static 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 */
rxkad_init_connection_security(struct rxrpc_connection * conn,struct rxrpc_key_token * token)100 static 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->params.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->params.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
138 error_ci:
139 crypto_free_sync_skcipher(ci);
140 error:
141 _leave(" = %d", ret);
142 return ret;
143 }
144
145 /*
146 * Work out how much data we can put in a packet.
147 */
rxkad_how_much_data(struct rxrpc_call * call,size_t remain,size_t * _buf_size,size_t * _data_size,size_t * _offset)148 static 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->params.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
172 out:
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 */
rxkad_prime_packet_security(struct rxrpc_connection * conn,struct crypto_sync_skcipher * ci)183 static 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->params.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->params.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 */
rxkad_get_call_crypto(struct rxrpc_call * call)233 static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
234 {
235 struct crypto_skcipher *tfm = &call->conn->rxkad.cipher->base;
236 struct skcipher_request *cipher_req = call->cipher_req;
237
238 if (!cipher_req) {
239 cipher_req = skcipher_request_alloc(tfm, GFP_NOFS);
240 if (!cipher_req)
241 return NULL;
242 call->cipher_req = cipher_req;
243 }
244
245 return cipher_req;
246 }
247
248 /*
249 * Clean up the crypto on a call.
250 */
rxkad_free_call_crypto(struct rxrpc_call * call)251 static void rxkad_free_call_crypto(struct rxrpc_call *call)
252 {
253 if (call->cipher_req)
254 skcipher_request_free(call->cipher_req);
255 call->cipher_req = NULL;
256 }
257
258 /*
259 * partially encrypt a packet (level 1 security)
260 */
rxkad_secure_packet_auth(const struct rxrpc_call * call,struct sk_buff * skb,u32 data_size,struct skcipher_request * req)261 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
262 struct sk_buff *skb, u32 data_size,
263 struct skcipher_request *req)
264 {
265 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
266 struct rxkad_level1_hdr hdr;
267 struct rxrpc_crypt iv;
268 struct scatterlist sg;
269 size_t pad;
270 u16 check;
271
272 _enter("");
273
274 check = sp->hdr.seq ^ call->call_id;
275 data_size |= (u32)check << 16;
276
277 hdr.data_size = htonl(data_size);
278 memcpy(skb->head, &hdr, sizeof(hdr));
279
280 pad = sizeof(struct rxkad_level1_hdr) + data_size;
281 pad = RXKAD_ALIGN - pad;
282 pad &= RXKAD_ALIGN - 1;
283 if (pad)
284 skb_put_zero(skb, pad);
285
286 /* start the encryption afresh */
287 memset(&iv, 0, sizeof(iv));
288
289 sg_init_one(&sg, skb->head, 8);
290 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
291 skcipher_request_set_callback(req, 0, NULL, NULL);
292 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
293 crypto_skcipher_encrypt(req);
294 skcipher_request_zero(req);
295
296 _leave(" = 0");
297 return 0;
298 }
299
300 /*
301 * wholly encrypt a packet (level 2 security)
302 */
rxkad_secure_packet_encrypt(const struct rxrpc_call * call,struct sk_buff * skb,u32 data_size,struct skcipher_request * req)303 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
304 struct sk_buff *skb,
305 u32 data_size,
306 struct skcipher_request *req)
307 {
308 const struct rxrpc_key_token *token;
309 struct rxkad_level2_hdr rxkhdr;
310 struct rxrpc_skb_priv *sp;
311 struct rxrpc_crypt iv;
312 struct scatterlist sg[16];
313 unsigned int len;
314 size_t pad;
315 u16 check;
316 int err;
317
318 sp = rxrpc_skb(skb);
319
320 _enter("");
321
322 check = sp->hdr.seq ^ call->call_id;
323
324 rxkhdr.data_size = htonl(data_size | (u32)check << 16);
325 rxkhdr.checksum = 0;
326 memcpy(skb->head, &rxkhdr, sizeof(rxkhdr));
327
328 pad = sizeof(struct rxkad_level2_hdr) + data_size;
329 pad = RXKAD_ALIGN - pad;
330 pad &= RXKAD_ALIGN - 1;
331 if (pad)
332 skb_put_zero(skb, pad);
333
334 /* encrypt from the session key */
335 token = call->conn->params.key->payload.data[0];
336 memcpy(&iv, token->kad->session_key, sizeof(iv));
337
338 sg_init_one(&sg[0], skb->head, sizeof(rxkhdr));
339 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
340 skcipher_request_set_callback(req, 0, NULL, NULL);
341 skcipher_request_set_crypt(req, &sg[0], &sg[0], sizeof(rxkhdr), iv.x);
342 crypto_skcipher_encrypt(req);
343
344 /* we want to encrypt the skbuff in-place */
345 err = -EMSGSIZE;
346 if (skb_shinfo(skb)->nr_frags > 16)
347 goto out;
348
349 len = round_up(data_size, RXKAD_ALIGN);
350
351 sg_init_table(sg, ARRAY_SIZE(sg));
352 err = skb_to_sgvec(skb, sg, 8, len);
353 if (unlikely(err < 0))
354 goto out;
355 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
356 crypto_skcipher_encrypt(req);
357
358 _leave(" = 0");
359 err = 0;
360
361 out:
362 skcipher_request_zero(req);
363 return err;
364 }
365
366 /*
367 * checksum an RxRPC packet header
368 */
rxkad_secure_packet(struct rxrpc_call * call,struct sk_buff * skb,size_t data_size)369 static int rxkad_secure_packet(struct rxrpc_call *call,
370 struct sk_buff *skb,
371 size_t data_size)
372 {
373 struct rxrpc_skb_priv *sp;
374 struct skcipher_request *req;
375 struct rxrpc_crypt iv;
376 struct scatterlist sg;
377 u32 x, y;
378 int ret;
379
380 sp = rxrpc_skb(skb);
381
382 _enter("{%d{%x}},{#%u},%zu,",
383 call->debug_id, key_serial(call->conn->params.key),
384 sp->hdr.seq, data_size);
385
386 if (!call->conn->rxkad.cipher)
387 return 0;
388
389 ret = key_validate(call->conn->params.key);
390 if (ret < 0)
391 return ret;
392
393 req = rxkad_get_call_crypto(call);
394 if (!req)
395 return -ENOMEM;
396
397 /* continue encrypting from where we left off */
398 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
399
400 /* calculate the security checksum */
401 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
402 x |= sp->hdr.seq & 0x3fffffff;
403 call->crypto_buf[0] = htonl(call->call_id);
404 call->crypto_buf[1] = htonl(x);
405
406 sg_init_one(&sg, call->crypto_buf, 8);
407 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
408 skcipher_request_set_callback(req, 0, NULL, NULL);
409 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
410 crypto_skcipher_encrypt(req);
411 skcipher_request_zero(req);
412
413 y = ntohl(call->crypto_buf[1]);
414 y = (y >> 16) & 0xffff;
415 if (y == 0)
416 y = 1; /* zero checksums are not permitted */
417 sp->hdr.cksum = y;
418
419 switch (call->conn->params.security_level) {
420 case RXRPC_SECURITY_PLAIN:
421 ret = 0;
422 break;
423 case RXRPC_SECURITY_AUTH:
424 ret = rxkad_secure_packet_auth(call, skb, data_size, req);
425 break;
426 case RXRPC_SECURITY_ENCRYPT:
427 ret = rxkad_secure_packet_encrypt(call, skb, data_size, req);
428 break;
429 default:
430 ret = -EPERM;
431 break;
432 }
433
434 _leave(" = %d [set %hx]", ret, y);
435 return ret;
436 }
437
438 /*
439 * decrypt partial encryption on a packet (level 1 security)
440 */
rxkad_verify_packet_1(struct rxrpc_call * call,struct sk_buff * skb,unsigned int offset,unsigned int len,rxrpc_seq_t seq,struct skcipher_request * req)441 static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
442 unsigned int offset, unsigned int len,
443 rxrpc_seq_t seq,
444 struct skcipher_request *req)
445 {
446 struct rxkad_level1_hdr sechdr;
447 struct rxrpc_crypt iv;
448 struct scatterlist sg[16];
449 bool aborted;
450 u32 data_size, buf;
451 u16 check;
452 int ret;
453
454 _enter("");
455
456 if (len < 8) {
457 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_hdr", "V1H",
458 RXKADSEALEDINCON);
459 goto protocol_error;
460 }
461
462 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
463 * directly into the target buffer.
464 */
465 sg_init_table(sg, ARRAY_SIZE(sg));
466 ret = skb_to_sgvec(skb, sg, offset, 8);
467 if (unlikely(ret < 0))
468 return ret;
469
470 /* start the decryption afresh */
471 memset(&iv, 0, sizeof(iv));
472
473 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
474 skcipher_request_set_callback(req, 0, NULL, NULL);
475 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
476 crypto_skcipher_decrypt(req);
477 skcipher_request_zero(req);
478
479 /* Extract the decrypted packet length */
480 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
481 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_len", "XV1",
482 RXKADDATALEN);
483 goto protocol_error;
484 }
485 len -= sizeof(sechdr);
486
487 buf = ntohl(sechdr.data_size);
488 data_size = buf & 0xffff;
489
490 check = buf >> 16;
491 check ^= seq ^ call->call_id;
492 check &= 0xffff;
493 if (check != 0) {
494 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_check", "V1C",
495 RXKADSEALEDINCON);
496 goto protocol_error;
497 }
498
499 if (data_size > len) {
500 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_datalen", "V1L",
501 RXKADDATALEN);
502 goto protocol_error;
503 }
504
505 _leave(" = 0 [dlen=%x]", data_size);
506 return 0;
507
508 protocol_error:
509 if (aborted)
510 rxrpc_send_abort_packet(call);
511 return -EPROTO;
512 }
513
514 /*
515 * wholly decrypt a packet (level 2 security)
516 */
rxkad_verify_packet_2(struct rxrpc_call * call,struct sk_buff * skb,unsigned int offset,unsigned int len,rxrpc_seq_t seq,struct skcipher_request * req)517 static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
518 unsigned int offset, unsigned int len,
519 rxrpc_seq_t seq,
520 struct skcipher_request *req)
521 {
522 const struct rxrpc_key_token *token;
523 struct rxkad_level2_hdr sechdr;
524 struct rxrpc_crypt iv;
525 struct scatterlist _sg[4], *sg;
526 bool aborted;
527 u32 data_size, buf;
528 u16 check;
529 int nsg, ret;
530
531 _enter(",{%d}", skb->len);
532
533 if (len < 8) {
534 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_hdr", "V2H",
535 RXKADSEALEDINCON);
536 goto protocol_error;
537 }
538
539 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
540 * directly into the target buffer.
541 */
542 sg = _sg;
543 nsg = skb_shinfo(skb)->nr_frags;
544 if (nsg <= 4) {
545 nsg = 4;
546 } else {
547 sg = kmalloc_array(nsg, sizeof(*sg), GFP_NOIO);
548 if (!sg)
549 goto nomem;
550 }
551
552 sg_init_table(sg, nsg);
553 ret = skb_to_sgvec(skb, sg, offset, len);
554 if (unlikely(ret < 0)) {
555 if (sg != _sg)
556 kfree(sg);
557 return ret;
558 }
559
560 /* decrypt from the session key */
561 token = call->conn->params.key->payload.data[0];
562 memcpy(&iv, token->kad->session_key, sizeof(iv));
563
564 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
565 skcipher_request_set_callback(req, 0, NULL, NULL);
566 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
567 crypto_skcipher_decrypt(req);
568 skcipher_request_zero(req);
569 if (sg != _sg)
570 kfree(sg);
571
572 /* Extract the decrypted packet length */
573 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
574 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_len", "XV2",
575 RXKADDATALEN);
576 goto protocol_error;
577 }
578 len -= sizeof(sechdr);
579
580 buf = ntohl(sechdr.data_size);
581 data_size = buf & 0xffff;
582
583 check = buf >> 16;
584 check ^= seq ^ call->call_id;
585 check &= 0xffff;
586 if (check != 0) {
587 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_check", "V2C",
588 RXKADSEALEDINCON);
589 goto protocol_error;
590 }
591
592 if (data_size > len) {
593 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_datalen", "V2L",
594 RXKADDATALEN);
595 goto protocol_error;
596 }
597
598 _leave(" = 0 [dlen=%x]", data_size);
599 return 0;
600
601 protocol_error:
602 if (aborted)
603 rxrpc_send_abort_packet(call);
604 return -EPROTO;
605
606 nomem:
607 _leave(" = -ENOMEM");
608 return -ENOMEM;
609 }
610
611 /*
612 * Verify the security on a received packet or subpacket (if part of a
613 * jumbo packet).
614 */
rxkad_verify_packet(struct rxrpc_call * call,struct sk_buff * skb,unsigned int offset,unsigned int len,rxrpc_seq_t seq,u16 expected_cksum)615 static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
616 unsigned int offset, unsigned int len,
617 rxrpc_seq_t seq, u16 expected_cksum)
618 {
619 struct skcipher_request *req;
620 struct rxrpc_crypt iv;
621 struct scatterlist sg;
622 bool aborted;
623 u16 cksum;
624 u32 x, y;
625
626 _enter("{%d{%x}},{#%u}",
627 call->debug_id, key_serial(call->conn->params.key), seq);
628
629 if (!call->conn->rxkad.cipher)
630 return 0;
631
632 req = rxkad_get_call_crypto(call);
633 if (!req)
634 return -ENOMEM;
635
636 /* continue encrypting from where we left off */
637 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
638
639 /* validate the security checksum */
640 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
641 x |= seq & 0x3fffffff;
642 call->crypto_buf[0] = htonl(call->call_id);
643 call->crypto_buf[1] = htonl(x);
644
645 sg_init_one(&sg, call->crypto_buf, 8);
646 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
647 skcipher_request_set_callback(req, 0, NULL, NULL);
648 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
649 crypto_skcipher_encrypt(req);
650 skcipher_request_zero(req);
651
652 y = ntohl(call->crypto_buf[1]);
653 cksum = (y >> 16) & 0xffff;
654 if (cksum == 0)
655 cksum = 1; /* zero checksums are not permitted */
656
657 if (cksum != expected_cksum) {
658 aborted = rxrpc_abort_eproto(call, skb, "rxkad_csum", "VCK",
659 RXKADSEALEDINCON);
660 goto protocol_error;
661 }
662
663 switch (call->conn->params.security_level) {
664 case RXRPC_SECURITY_PLAIN:
665 return 0;
666 case RXRPC_SECURITY_AUTH:
667 return rxkad_verify_packet_1(call, skb, offset, len, seq, req);
668 case RXRPC_SECURITY_ENCRYPT:
669 return rxkad_verify_packet_2(call, skb, offset, len, seq, req);
670 default:
671 return -ENOANO;
672 }
673
674 protocol_error:
675 if (aborted)
676 rxrpc_send_abort_packet(call);
677 return -EPROTO;
678 }
679
680 /*
681 * Locate the data contained in a packet that was partially encrypted.
682 */
rxkad_locate_data_1(struct rxrpc_call * call,struct sk_buff * skb,unsigned int * _offset,unsigned int * _len)683 static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb,
684 unsigned int *_offset, unsigned int *_len)
685 {
686 struct rxkad_level1_hdr sechdr;
687
688 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
689 BUG();
690 *_offset += sizeof(sechdr);
691 *_len = ntohl(sechdr.data_size) & 0xffff;
692 }
693
694 /*
695 * Locate the data contained in a packet that was completely encrypted.
696 */
rxkad_locate_data_2(struct rxrpc_call * call,struct sk_buff * skb,unsigned int * _offset,unsigned int * _len)697 static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb,
698 unsigned int *_offset, unsigned int *_len)
699 {
700 struct rxkad_level2_hdr sechdr;
701
702 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
703 BUG();
704 *_offset += sizeof(sechdr);
705 *_len = ntohl(sechdr.data_size) & 0xffff;
706 }
707
708 /*
709 * Locate the data contained in an already decrypted packet.
710 */
rxkad_locate_data(struct rxrpc_call * call,struct sk_buff * skb,unsigned int * _offset,unsigned int * _len)711 static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
712 unsigned int *_offset, unsigned int *_len)
713 {
714 switch (call->conn->params.security_level) {
715 case RXRPC_SECURITY_AUTH:
716 rxkad_locate_data_1(call, skb, _offset, _len);
717 return;
718 case RXRPC_SECURITY_ENCRYPT:
719 rxkad_locate_data_2(call, skb, _offset, _len);
720 return;
721 default:
722 return;
723 }
724 }
725
726 /*
727 * issue a challenge
728 */
rxkad_issue_challenge(struct rxrpc_connection * conn)729 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
730 {
731 struct rxkad_challenge challenge;
732 struct rxrpc_wire_header whdr;
733 struct msghdr msg;
734 struct kvec iov[2];
735 size_t len;
736 u32 serial;
737 int ret;
738
739 _enter("{%d}", conn->debug_id);
740
741 get_random_bytes(&conn->rxkad.nonce, sizeof(conn->rxkad.nonce));
742
743 challenge.version = htonl(2);
744 challenge.nonce = htonl(conn->rxkad.nonce);
745 challenge.min_level = htonl(0);
746 challenge.__padding = 0;
747
748 msg.msg_name = &conn->params.peer->srx.transport;
749 msg.msg_namelen = conn->params.peer->srx.transport_len;
750 msg.msg_control = NULL;
751 msg.msg_controllen = 0;
752 msg.msg_flags = 0;
753
754 whdr.epoch = htonl(conn->proto.epoch);
755 whdr.cid = htonl(conn->proto.cid);
756 whdr.callNumber = 0;
757 whdr.seq = 0;
758 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
759 whdr.flags = conn->out_clientflag;
760 whdr.userStatus = 0;
761 whdr.securityIndex = conn->security_ix;
762 whdr._rsvd = 0;
763 whdr.serviceId = htons(conn->service_id);
764
765 iov[0].iov_base = &whdr;
766 iov[0].iov_len = sizeof(whdr);
767 iov[1].iov_base = &challenge;
768 iov[1].iov_len = sizeof(challenge);
769
770 len = iov[0].iov_len + iov[1].iov_len;
771
772 serial = atomic_inc_return(&conn->serial);
773 whdr.serial = htonl(serial);
774 _proto("Tx CHALLENGE %%%u", serial);
775
776 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
777 if (ret < 0) {
778 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
779 rxrpc_tx_point_rxkad_challenge);
780 return -EAGAIN;
781 }
782
783 conn->params.peer->last_tx_at = ktime_get_seconds();
784 trace_rxrpc_tx_packet(conn->debug_id, &whdr,
785 rxrpc_tx_point_rxkad_challenge);
786 _leave(" = 0");
787 return 0;
788 }
789
790 /*
791 * send a Kerberos security response
792 */
rxkad_send_response(struct rxrpc_connection * conn,struct rxrpc_host_header * hdr,struct rxkad_response * resp,const struct rxkad_key * s2)793 static int rxkad_send_response(struct rxrpc_connection *conn,
794 struct rxrpc_host_header *hdr,
795 struct rxkad_response *resp,
796 const struct rxkad_key *s2)
797 {
798 struct rxrpc_wire_header whdr;
799 struct msghdr msg;
800 struct kvec iov[3];
801 size_t len;
802 u32 serial;
803 int ret;
804
805 _enter("");
806
807 msg.msg_name = &conn->params.peer->srx.transport;
808 msg.msg_namelen = conn->params.peer->srx.transport_len;
809 msg.msg_control = NULL;
810 msg.msg_controllen = 0;
811 msg.msg_flags = 0;
812
813 memset(&whdr, 0, sizeof(whdr));
814 whdr.epoch = htonl(hdr->epoch);
815 whdr.cid = htonl(hdr->cid);
816 whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
817 whdr.flags = conn->out_clientflag;
818 whdr.securityIndex = hdr->securityIndex;
819 whdr.serviceId = htons(hdr->serviceId);
820
821 iov[0].iov_base = &whdr;
822 iov[0].iov_len = sizeof(whdr);
823 iov[1].iov_base = resp;
824 iov[1].iov_len = sizeof(*resp);
825 iov[2].iov_base = (void *)s2->ticket;
826 iov[2].iov_len = s2->ticket_len;
827
828 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
829
830 serial = atomic_inc_return(&conn->serial);
831 whdr.serial = htonl(serial);
832 _proto("Tx RESPONSE %%%u", serial);
833
834 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 3, len);
835 if (ret < 0) {
836 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
837 rxrpc_tx_point_rxkad_response);
838 return -EAGAIN;
839 }
840
841 conn->params.peer->last_tx_at = ktime_get_seconds();
842 _leave(" = 0");
843 return 0;
844 }
845
846 /*
847 * calculate the response checksum
848 */
rxkad_calc_response_checksum(struct rxkad_response * response)849 static void rxkad_calc_response_checksum(struct rxkad_response *response)
850 {
851 u32 csum = 1000003;
852 int loop;
853 u8 *p = (u8 *) response;
854
855 for (loop = sizeof(*response); loop > 0; loop--)
856 csum = csum * 0x10204081 + *p++;
857
858 response->encrypted.checksum = htonl(csum);
859 }
860
861 /*
862 * encrypt the response packet
863 */
rxkad_encrypt_response(struct rxrpc_connection * conn,struct rxkad_response * resp,const struct rxkad_key * s2)864 static int rxkad_encrypt_response(struct rxrpc_connection *conn,
865 struct rxkad_response *resp,
866 const struct rxkad_key *s2)
867 {
868 struct skcipher_request *req;
869 struct rxrpc_crypt iv;
870 struct scatterlist sg[1];
871
872 req = skcipher_request_alloc(&conn->rxkad.cipher->base, GFP_NOFS);
873 if (!req)
874 return -ENOMEM;
875
876 /* continue encrypting from where we left off */
877 memcpy(&iv, s2->session_key, sizeof(iv));
878
879 sg_init_table(sg, 1);
880 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
881 skcipher_request_set_sync_tfm(req, conn->rxkad.cipher);
882 skcipher_request_set_callback(req, 0, NULL, NULL);
883 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
884 crypto_skcipher_encrypt(req);
885 skcipher_request_free(req);
886 return 0;
887 }
888
889 /*
890 * respond to a challenge packet
891 */
rxkad_respond_to_challenge(struct rxrpc_connection * conn,struct sk_buff * skb,u32 * _abort_code)892 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
893 struct sk_buff *skb,
894 u32 *_abort_code)
895 {
896 const struct rxrpc_key_token *token;
897 struct rxkad_challenge challenge;
898 struct rxkad_response *resp;
899 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
900 const char *eproto;
901 u32 version, nonce, min_level, abort_code;
902 int ret;
903
904 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
905
906 eproto = tracepoint_string("chall_no_key");
907 abort_code = RX_PROTOCOL_ERROR;
908 if (!conn->params.key)
909 goto protocol_error;
910
911 abort_code = RXKADEXPIRED;
912 ret = key_validate(conn->params.key);
913 if (ret < 0)
914 goto other_error;
915
916 eproto = tracepoint_string("chall_short");
917 abort_code = RXKADPACKETSHORT;
918 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
919 &challenge, sizeof(challenge)) < 0)
920 goto protocol_error;
921
922 version = ntohl(challenge.version);
923 nonce = ntohl(challenge.nonce);
924 min_level = ntohl(challenge.min_level);
925
926 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
927 sp->hdr.serial, version, nonce, min_level);
928
929 eproto = tracepoint_string("chall_ver");
930 abort_code = RXKADINCONSISTENCY;
931 if (version != RXKAD_VERSION)
932 goto protocol_error;
933
934 abort_code = RXKADLEVELFAIL;
935 ret = -EACCES;
936 if (conn->params.security_level < min_level)
937 goto other_error;
938
939 token = conn->params.key->payload.data[0];
940
941 /* build the response packet */
942 resp = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
943 if (!resp)
944 return -ENOMEM;
945
946 resp->version = htonl(RXKAD_VERSION);
947 resp->encrypted.epoch = htonl(conn->proto.epoch);
948 resp->encrypted.cid = htonl(conn->proto.cid);
949 resp->encrypted.securityIndex = htonl(conn->security_ix);
950 resp->encrypted.inc_nonce = htonl(nonce + 1);
951 resp->encrypted.level = htonl(conn->params.security_level);
952 resp->kvno = htonl(token->kad->kvno);
953 resp->ticket_len = htonl(token->kad->ticket_len);
954 resp->encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
955 resp->encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
956 resp->encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
957 resp->encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
958
959 /* calculate the response checksum and then do the encryption */
960 rxkad_calc_response_checksum(resp);
961 ret = rxkad_encrypt_response(conn, resp, token->kad);
962 if (ret == 0)
963 ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
964 kfree(resp);
965 return ret;
966
967 protocol_error:
968 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
969 ret = -EPROTO;
970 other_error:
971 *_abort_code = abort_code;
972 return ret;
973 }
974
975 /*
976 * decrypt the kerberos IV ticket in the response
977 */
rxkad_decrypt_ticket(struct rxrpc_connection * conn,struct key * server_key,struct sk_buff * skb,void * ticket,size_t ticket_len,struct rxrpc_crypt * _session_key,time64_t * _expiry,u32 * _abort_code)978 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
979 struct key *server_key,
980 struct sk_buff *skb,
981 void *ticket, size_t ticket_len,
982 struct rxrpc_crypt *_session_key,
983 time64_t *_expiry,
984 u32 *_abort_code)
985 {
986 struct skcipher_request *req;
987 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
988 struct rxrpc_crypt iv, key;
989 struct scatterlist sg[1];
990 struct in_addr addr;
991 unsigned int life;
992 const char *eproto;
993 time64_t issue, now;
994 bool little_endian;
995 int ret;
996 u32 abort_code;
997 u8 *p, *q, *name, *end;
998
999 _enter("{%d},{%x}", conn->debug_id, key_serial(server_key));
1000
1001 *_expiry = 0;
1002
1003 ASSERT(server_key->payload.data[0] != NULL);
1004 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
1005
1006 memcpy(&iv, &server_key->payload.data[2], sizeof(iv));
1007
1008 ret = -ENOMEM;
1009 req = skcipher_request_alloc(server_key->payload.data[0], GFP_NOFS);
1010 if (!req)
1011 goto temporary_error;
1012
1013 sg_init_one(&sg[0], ticket, ticket_len);
1014 skcipher_request_set_callback(req, 0, NULL, NULL);
1015 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
1016 crypto_skcipher_decrypt(req);
1017 skcipher_request_free(req);
1018
1019 p = ticket;
1020 end = p + ticket_len;
1021
1022 #define Z(field) \
1023 ({ \
1024 u8 *__str = p; \
1025 eproto = tracepoint_string("rxkad_bad_"#field); \
1026 q = memchr(p, 0, end - p); \
1027 if (!q || q - p > (field##_SZ)) \
1028 goto bad_ticket; \
1029 for (; p < q; p++) \
1030 if (!isprint(*p)) \
1031 goto bad_ticket; \
1032 p++; \
1033 __str; \
1034 })
1035
1036 /* extract the ticket flags */
1037 _debug("KIV FLAGS: %x", *p);
1038 little_endian = *p & 1;
1039 p++;
1040
1041 /* extract the authentication name */
1042 name = Z(ANAME);
1043 _debug("KIV ANAME: %s", name);
1044
1045 /* extract the principal's instance */
1046 name = Z(INST);
1047 _debug("KIV INST : %s", name);
1048
1049 /* extract the principal's authentication domain */
1050 name = Z(REALM);
1051 _debug("KIV REALM: %s", name);
1052
1053 eproto = tracepoint_string("rxkad_bad_len");
1054 if (end - p < 4 + 8 + 4 + 2)
1055 goto bad_ticket;
1056
1057 /* get the IPv4 address of the entity that requested the ticket */
1058 memcpy(&addr, p, sizeof(addr));
1059 p += 4;
1060 _debug("KIV ADDR : %pI4", &addr);
1061
1062 /* get the session key from the ticket */
1063 memcpy(&key, p, sizeof(key));
1064 p += 8;
1065 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
1066 memcpy(_session_key, &key, sizeof(key));
1067
1068 /* get the ticket's lifetime */
1069 life = *p++ * 5 * 60;
1070 _debug("KIV LIFE : %u", life);
1071
1072 /* get the issue time of the ticket */
1073 if (little_endian) {
1074 __le32 stamp;
1075 memcpy(&stamp, p, 4);
1076 issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
1077 } else {
1078 __be32 stamp;
1079 memcpy(&stamp, p, 4);
1080 issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
1081 }
1082 p += 4;
1083 now = ktime_get_real_seconds();
1084 _debug("KIV ISSUE: %llx [%llx]", issue, now);
1085
1086 /* check the ticket is in date */
1087 if (issue > now) {
1088 abort_code = RXKADNOAUTH;
1089 ret = -EKEYREJECTED;
1090 goto other_error;
1091 }
1092
1093 if (issue < now - life) {
1094 abort_code = RXKADEXPIRED;
1095 ret = -EKEYEXPIRED;
1096 goto other_error;
1097 }
1098
1099 *_expiry = issue + life;
1100
1101 /* get the service name */
1102 name = Z(SNAME);
1103 _debug("KIV SNAME: %s", name);
1104
1105 /* get the service instance name */
1106 name = Z(INST);
1107 _debug("KIV SINST: %s", name);
1108 return 0;
1109
1110 bad_ticket:
1111 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1112 abort_code = RXKADBADTICKET;
1113 ret = -EPROTO;
1114 other_error:
1115 *_abort_code = abort_code;
1116 return ret;
1117 temporary_error:
1118 return ret;
1119 }
1120
1121 /*
1122 * decrypt the response packet
1123 */
rxkad_decrypt_response(struct rxrpc_connection * conn,struct rxkad_response * resp,const struct rxrpc_crypt * session_key)1124 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
1125 struct rxkad_response *resp,
1126 const struct rxrpc_crypt *session_key)
1127 {
1128 struct skcipher_request *req = rxkad_ci_req;
1129 struct scatterlist sg[1];
1130 struct rxrpc_crypt iv;
1131
1132 _enter(",,%08x%08x",
1133 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
1134
1135 mutex_lock(&rxkad_ci_mutex);
1136 if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
1137 sizeof(*session_key)) < 0)
1138 BUG();
1139
1140 memcpy(&iv, session_key, sizeof(iv));
1141
1142 sg_init_table(sg, 1);
1143 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1144 skcipher_request_set_sync_tfm(req, rxkad_ci);
1145 skcipher_request_set_callback(req, 0, NULL, NULL);
1146 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1147 crypto_skcipher_decrypt(req);
1148 skcipher_request_zero(req);
1149
1150 mutex_unlock(&rxkad_ci_mutex);
1151
1152 _leave("");
1153 }
1154
1155 /*
1156 * verify a response
1157 */
rxkad_verify_response(struct rxrpc_connection * conn,struct sk_buff * skb,u32 * _abort_code)1158 static int rxkad_verify_response(struct rxrpc_connection *conn,
1159 struct sk_buff *skb,
1160 u32 *_abort_code)
1161 {
1162 struct rxkad_response *response;
1163 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1164 struct rxrpc_crypt session_key;
1165 struct key *server_key;
1166 const char *eproto;
1167 time64_t expiry;
1168 void *ticket;
1169 u32 abort_code, version, kvno, ticket_len, level;
1170 __be32 csum;
1171 int ret, i;
1172
1173 _enter("{%d}", conn->debug_id);
1174
1175 server_key = rxrpc_look_up_server_security(conn, skb, 0, 0);
1176 if (IS_ERR(server_key)) {
1177 switch (PTR_ERR(server_key)) {
1178 case -ENOKEY:
1179 abort_code = RXKADUNKNOWNKEY;
1180 break;
1181 case -EKEYEXPIRED:
1182 abort_code = RXKADEXPIRED;
1183 break;
1184 default:
1185 abort_code = RXKADNOAUTH;
1186 break;
1187 }
1188 trace_rxrpc_abort(0, "SVK",
1189 sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1190 abort_code, PTR_ERR(server_key));
1191 *_abort_code = abort_code;
1192 return -EPROTO;
1193 }
1194
1195 ret = -ENOMEM;
1196 response = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
1197 if (!response)
1198 goto temporary_error;
1199
1200 eproto = tracepoint_string("rxkad_rsp_short");
1201 abort_code = RXKADPACKETSHORT;
1202 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1203 response, sizeof(*response)) < 0)
1204 goto protocol_error;
1205
1206 version = ntohl(response->version);
1207 ticket_len = ntohl(response->ticket_len);
1208 kvno = ntohl(response->kvno);
1209 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1210 sp->hdr.serial, version, kvno, ticket_len);
1211
1212 eproto = tracepoint_string("rxkad_rsp_ver");
1213 abort_code = RXKADINCONSISTENCY;
1214 if (version != RXKAD_VERSION)
1215 goto protocol_error;
1216
1217 eproto = tracepoint_string("rxkad_rsp_tktlen");
1218 abort_code = RXKADTICKETLEN;
1219 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1220 goto protocol_error;
1221
1222 eproto = tracepoint_string("rxkad_rsp_unkkey");
1223 abort_code = RXKADUNKNOWNKEY;
1224 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1225 goto protocol_error;
1226
1227 /* extract the kerberos ticket and decrypt and decode it */
1228 ret = -ENOMEM;
1229 ticket = kmalloc(ticket_len, GFP_NOFS);
1230 if (!ticket)
1231 goto temporary_error_free_resp;
1232
1233 eproto = tracepoint_string("rxkad_tkt_short");
1234 abort_code = RXKADPACKETSHORT;
1235 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header) + sizeof(*response),
1236 ticket, ticket_len) < 0)
1237 goto protocol_error_free;
1238
1239 ret = rxkad_decrypt_ticket(conn, server_key, skb, ticket, ticket_len,
1240 &session_key, &expiry, _abort_code);
1241 if (ret < 0)
1242 goto temporary_error_free_ticket;
1243
1244 /* use the session key from inside the ticket to decrypt the
1245 * response */
1246 rxkad_decrypt_response(conn, response, &session_key);
1247
1248 eproto = tracepoint_string("rxkad_rsp_param");
1249 abort_code = RXKADSEALEDINCON;
1250 if (ntohl(response->encrypted.epoch) != conn->proto.epoch)
1251 goto protocol_error_free;
1252 if (ntohl(response->encrypted.cid) != conn->proto.cid)
1253 goto protocol_error_free;
1254 if (ntohl(response->encrypted.securityIndex) != conn->security_ix)
1255 goto protocol_error_free;
1256 csum = response->encrypted.checksum;
1257 response->encrypted.checksum = 0;
1258 rxkad_calc_response_checksum(response);
1259 eproto = tracepoint_string("rxkad_rsp_csum");
1260 if (response->encrypted.checksum != csum)
1261 goto protocol_error_free;
1262
1263 spin_lock(&conn->bundle->channel_lock);
1264 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1265 struct rxrpc_call *call;
1266 u32 call_id = ntohl(response->encrypted.call_id[i]);
1267
1268 eproto = tracepoint_string("rxkad_rsp_callid");
1269 if (call_id > INT_MAX)
1270 goto protocol_error_unlock;
1271
1272 eproto = tracepoint_string("rxkad_rsp_callctr");
1273 if (call_id < conn->channels[i].call_counter)
1274 goto protocol_error_unlock;
1275
1276 eproto = tracepoint_string("rxkad_rsp_callst");
1277 if (call_id > conn->channels[i].call_counter) {
1278 call = rcu_dereference_protected(
1279 conn->channels[i].call,
1280 lockdep_is_held(&conn->bundle->channel_lock));
1281 if (call && call->state < RXRPC_CALL_COMPLETE)
1282 goto protocol_error_unlock;
1283 conn->channels[i].call_counter = call_id;
1284 }
1285 }
1286 spin_unlock(&conn->bundle->channel_lock);
1287
1288 eproto = tracepoint_string("rxkad_rsp_seq");
1289 abort_code = RXKADOUTOFSEQUENCE;
1290 if (ntohl(response->encrypted.inc_nonce) != conn->rxkad.nonce + 1)
1291 goto protocol_error_free;
1292
1293 eproto = tracepoint_string("rxkad_rsp_level");
1294 abort_code = RXKADLEVELFAIL;
1295 level = ntohl(response->encrypted.level);
1296 if (level > RXRPC_SECURITY_ENCRYPT)
1297 goto protocol_error_free;
1298 conn->params.security_level = level;
1299
1300 /* create a key to hold the security data and expiration time - after
1301 * this the connection security can be handled in exactly the same way
1302 * as for a client connection */
1303 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1304 if (ret < 0)
1305 goto temporary_error_free_ticket;
1306
1307 kfree(ticket);
1308 kfree(response);
1309 _leave(" = 0");
1310 return 0;
1311
1312 protocol_error_unlock:
1313 spin_unlock(&conn->bundle->channel_lock);
1314 protocol_error_free:
1315 kfree(ticket);
1316 protocol_error:
1317 kfree(response);
1318 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1319 key_put(server_key);
1320 *_abort_code = abort_code;
1321 return -EPROTO;
1322
1323 temporary_error_free_ticket:
1324 kfree(ticket);
1325 temporary_error_free_resp:
1326 kfree(response);
1327 temporary_error:
1328 /* Ignore the response packet if we got a temporary error such as
1329 * ENOMEM. We just want to send the challenge again. Note that we
1330 * also come out this way if the ticket decryption fails.
1331 */
1332 key_put(server_key);
1333 return ret;
1334 }
1335
1336 /*
1337 * clear the connection security
1338 */
rxkad_clear(struct rxrpc_connection * conn)1339 static void rxkad_clear(struct rxrpc_connection *conn)
1340 {
1341 _enter("");
1342
1343 if (conn->rxkad.cipher)
1344 crypto_free_sync_skcipher(conn->rxkad.cipher);
1345 }
1346
1347 /*
1348 * Initialise the rxkad security service.
1349 */
rxkad_init(void)1350 static int rxkad_init(void)
1351 {
1352 struct crypto_sync_skcipher *tfm;
1353 struct skcipher_request *req;
1354
1355 /* pin the cipher we need so that the crypto layer doesn't invoke
1356 * keventd to go get it */
1357 tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
1358 if (IS_ERR(tfm))
1359 return PTR_ERR(tfm);
1360
1361 req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
1362 if (!req)
1363 goto nomem_tfm;
1364
1365 rxkad_ci_req = req;
1366 rxkad_ci = tfm;
1367 return 0;
1368
1369 nomem_tfm:
1370 crypto_free_sync_skcipher(tfm);
1371 return -ENOMEM;
1372 }
1373
1374 /*
1375 * Clean up the rxkad security service.
1376 */
rxkad_exit(void)1377 static void rxkad_exit(void)
1378 {
1379 crypto_free_sync_skcipher(rxkad_ci);
1380 skcipher_request_free(rxkad_ci_req);
1381 }
1382
1383 /*
1384 * RxRPC Kerberos-based security
1385 */
1386 const struct rxrpc_security rxkad = {
1387 .name = "rxkad",
1388 .security_index = RXRPC_SECURITY_RXKAD,
1389 .no_key_abort = RXKADUNKNOWNKEY,
1390 .init = rxkad_init,
1391 .exit = rxkad_exit,
1392 .preparse_server_key = rxkad_preparse_server_key,
1393 .free_preparse_server_key = rxkad_free_preparse_server_key,
1394 .destroy_server_key = rxkad_destroy_server_key,
1395 .init_connection_security = rxkad_init_connection_security,
1396 .how_much_data = rxkad_how_much_data,
1397 .secure_packet = rxkad_secure_packet,
1398 .verify_packet = rxkad_verify_packet,
1399 .free_call_crypto = rxkad_free_call_crypto,
1400 .locate_data = rxkad_locate_data,
1401 .issue_challenge = rxkad_issue_challenge,
1402 .respond_to_challenge = rxkad_respond_to_challenge,
1403 .verify_response = rxkad_verify_response,
1404 .clear = rxkad_clear,
1405 };
1406