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->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
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_alloc_txbuf(struct rxrpc_call * call,size_t remain,gfp_t gfp)148 static struct rxrpc_txbuf *rxkad_alloc_txbuf(struct rxrpc_call *call, size_t remain, gfp_t gfp)
149 {
150 struct rxrpc_txbuf *txb;
151 size_t shdr, alloc, limit, part;
152
153 remain = umin(remain, 65535 - sizeof(struct rxrpc_wire_header));
154
155 switch (call->conn->security_level) {
156 default:
157 alloc = umin(remain, RXRPC_JUMBO_DATALEN);
158 return rxrpc_alloc_data_txbuf(call, alloc, 1, gfp);
159 case RXRPC_SECURITY_AUTH:
160 shdr = sizeof(struct rxkad_level1_hdr);
161 break;
162 case RXRPC_SECURITY_ENCRYPT:
163 shdr = sizeof(struct rxkad_level2_hdr);
164 break;
165 }
166
167 limit = round_down(RXRPC_JUMBO_DATALEN, RXKAD_ALIGN) - shdr;
168 if (remain < limit) {
169 part = remain;
170 alloc = round_up(shdr + part, RXKAD_ALIGN);
171 } else {
172 part = limit;
173 alloc = RXRPC_JUMBO_DATALEN;
174 }
175
176 txb = rxrpc_alloc_data_txbuf(call, alloc, RXKAD_ALIGN, gfp);
177 if (!txb)
178 return NULL;
179
180 txb->crypto_header = 0;
181 txb->sec_header = shdr;
182 txb->offset += shdr;
183 txb->space = part;
184 return txb;
185 }
186
187 /*
188 * prime the encryption state with the invariant parts of a connection's
189 * description
190 */
rxkad_prime_packet_security(struct rxrpc_connection * conn,struct crypto_sync_skcipher * ci)191 static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
192 struct crypto_sync_skcipher *ci)
193 {
194 struct skcipher_request *req;
195 struct rxrpc_key_token *token;
196 struct scatterlist sg;
197 struct rxrpc_crypt iv;
198 __be32 *tmpbuf;
199 size_t tmpsize = 4 * sizeof(__be32);
200 int ret;
201
202 _enter("");
203
204 if (!conn->key)
205 return 0;
206
207 tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
208 if (!tmpbuf)
209 return -ENOMEM;
210
211 req = skcipher_request_alloc(&ci->base, GFP_NOFS);
212 if (!req) {
213 kfree(tmpbuf);
214 return -ENOMEM;
215 }
216
217 token = conn->key->payload.data[0];
218 memcpy(&iv, token->kad->session_key, sizeof(iv));
219
220 tmpbuf[0] = htonl(conn->proto.epoch);
221 tmpbuf[1] = htonl(conn->proto.cid);
222 tmpbuf[2] = 0;
223 tmpbuf[3] = htonl(conn->security_ix);
224
225 sg_init_one(&sg, tmpbuf, tmpsize);
226 skcipher_request_set_sync_tfm(req, ci);
227 skcipher_request_set_callback(req, 0, NULL, NULL);
228 skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
229 ret = crypto_skcipher_encrypt(req);
230 skcipher_request_free(req);
231
232 memcpy(&conn->rxkad.csum_iv, tmpbuf + 2, sizeof(conn->rxkad.csum_iv));
233 kfree(tmpbuf);
234 _leave(" = %d", ret);
235 return ret;
236 }
237
238 /*
239 * Allocate and prepare the crypto request on a call. For any particular call,
240 * this is called serially for the packets, so no lock should be necessary.
241 */
rxkad_get_call_crypto(struct rxrpc_call * call)242 static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
243 {
244 struct crypto_skcipher *tfm = &call->conn->rxkad.cipher->base;
245
246 return skcipher_request_alloc(tfm, GFP_NOFS);
247 }
248
249 /*
250 * Clean up the crypto on a call.
251 */
rxkad_free_call_crypto(struct rxrpc_call * call)252 static void rxkad_free_call_crypto(struct rxrpc_call *call)
253 {
254 }
255
256 /*
257 * partially encrypt a packet (level 1 security)
258 */
rxkad_secure_packet_auth(const struct rxrpc_call * call,struct rxrpc_txbuf * txb,struct skcipher_request * req)259 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
260 struct rxrpc_txbuf *txb,
261 struct skcipher_request *req)
262 {
263 struct rxkad_level1_hdr *hdr = txb->data;
264 struct rxrpc_crypt iv;
265 struct scatterlist sg;
266 size_t pad;
267 u16 check;
268 int ret;
269
270 _enter("");
271
272 check = txb->seq ^ call->call_id;
273 hdr->data_size = htonl((u32)check << 16 | txb->len);
274
275 txb->pkt_len = sizeof(struct rxkad_level1_hdr) + txb->len;
276 pad = txb->pkt_len;
277 pad = RXKAD_ALIGN - pad;
278 pad &= RXKAD_ALIGN - 1;
279 if (pad) {
280 memset(txb->data + txb->offset, 0, pad);
281 txb->pkt_len += pad;
282 }
283
284 /* start the encryption afresh */
285 memset(&iv, 0, sizeof(iv));
286
287 sg_init_one(&sg, hdr, 8);
288 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
289 skcipher_request_set_callback(req, 0, NULL, NULL);
290 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
291 ret = crypto_skcipher_encrypt(req);
292 skcipher_request_zero(req);
293
294 _leave(" = %d", ret);
295 return ret;
296 }
297
298 /*
299 * wholly encrypt a packet (level 2 security)
300 */
rxkad_secure_packet_encrypt(const struct rxrpc_call * call,struct rxrpc_txbuf * txb,struct skcipher_request * req)301 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
302 struct rxrpc_txbuf *txb,
303 struct skcipher_request *req)
304 {
305 const struct rxrpc_key_token *token;
306 struct rxkad_level2_hdr *rxkhdr = txb->data;
307 struct rxrpc_crypt iv;
308 struct scatterlist sg;
309 size_t content, pad;
310 u16 check;
311 int ret;
312
313 _enter("");
314
315 check = txb->seq ^ call->call_id;
316
317 rxkhdr->data_size = htonl(txb->len | (u32)check << 16);
318 rxkhdr->checksum = 0;
319
320 content = sizeof(struct rxkad_level2_hdr) + txb->len;
321 txb->pkt_len = round_up(content, RXKAD_ALIGN);
322 pad = txb->pkt_len - content;
323 if (pad)
324 memset(txb->data + txb->offset, 0, pad);
325
326 /* encrypt from the session key */
327 token = call->conn->key->payload.data[0];
328 memcpy(&iv, token->kad->session_key, sizeof(iv));
329
330 sg_init_one(&sg, rxkhdr, txb->pkt_len);
331 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
332 skcipher_request_set_callback(req, 0, NULL, NULL);
333 skcipher_request_set_crypt(req, &sg, &sg, txb->pkt_len, iv.x);
334 ret = crypto_skcipher_encrypt(req);
335 skcipher_request_zero(req);
336 return ret;
337 }
338
339 /*
340 * checksum an RxRPC packet header
341 */
rxkad_secure_packet(struct rxrpc_call * call,struct rxrpc_txbuf * txb)342 static int rxkad_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
343 {
344 struct skcipher_request *req;
345 struct rxrpc_crypt iv;
346 struct scatterlist sg;
347 union {
348 __be32 buf[2];
349 } crypto __aligned(8);
350 u32 x, y = 0;
351 int ret;
352
353 _enter("{%d{%x}},{#%u},%u,",
354 call->debug_id, key_serial(call->conn->key),
355 txb->seq, txb->len);
356
357 if (!call->conn->rxkad.cipher)
358 return 0;
359
360 ret = key_validate(call->conn->key);
361 if (ret < 0)
362 return ret;
363
364 req = rxkad_get_call_crypto(call);
365 if (!req)
366 return -ENOMEM;
367
368 /* continue encrypting from where we left off */
369 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
370
371 /* calculate the security checksum */
372 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
373 x |= txb->seq & 0x3fffffff;
374 crypto.buf[0] = htonl(call->call_id);
375 crypto.buf[1] = htonl(x);
376
377 sg_init_one(&sg, crypto.buf, 8);
378 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
379 skcipher_request_set_callback(req, 0, NULL, NULL);
380 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
381 ret = crypto_skcipher_encrypt(req);
382 skcipher_request_zero(req);
383 if (ret < 0)
384 goto out;
385
386 y = ntohl(crypto.buf[1]);
387 y = (y >> 16) & 0xffff;
388 if (y == 0)
389 y = 1; /* zero checksums are not permitted */
390 txb->cksum = htons(y);
391
392 switch (call->conn->security_level) {
393 case RXRPC_SECURITY_PLAIN:
394 txb->pkt_len = txb->len;
395 ret = 0;
396 break;
397 case RXRPC_SECURITY_AUTH:
398 ret = rxkad_secure_packet_auth(call, txb, req);
399 if (txb->alloc_size == RXRPC_JUMBO_DATALEN)
400 txb->jumboable = true;
401 break;
402 case RXRPC_SECURITY_ENCRYPT:
403 ret = rxkad_secure_packet_encrypt(call, txb, req);
404 if (txb->alloc_size == RXRPC_JUMBO_DATALEN)
405 txb->jumboable = true;
406 break;
407 default:
408 ret = -EPERM;
409 break;
410 }
411
412 /* Clear excess space in the packet */
413 if (txb->pkt_len < txb->alloc_size) {
414 size_t gap = txb->alloc_size - txb->pkt_len;
415 void *p = txb->data;
416
417 memset(p + txb->pkt_len, 0, gap);
418 }
419
420 out:
421 skcipher_request_free(req);
422 _leave(" = %d [set %x]", ret, y);
423 return ret;
424 }
425
426 /*
427 * decrypt partial encryption on a packet (level 1 security)
428 */
rxkad_verify_packet_1(struct rxrpc_call * call,struct sk_buff * skb,rxrpc_seq_t seq,struct skcipher_request * req)429 static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
430 rxrpc_seq_t seq,
431 struct skcipher_request *req)
432 {
433 struct rxkad_level1_hdr sechdr;
434 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
435 struct rxrpc_crypt iv;
436 struct scatterlist sg[16];
437 u32 data_size, buf;
438 u16 check;
439 int ret;
440
441 _enter("");
442
443 if (sp->len < 8)
444 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
445 rxkad_abort_1_short_header);
446
447 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
448 * directly into the target buffer.
449 */
450 sg_init_table(sg, ARRAY_SIZE(sg));
451 ret = skb_to_sgvec(skb, sg, sp->offset, 8);
452 if (unlikely(ret < 0))
453 return ret;
454
455 /* start the decryption afresh */
456 memset(&iv, 0, sizeof(iv));
457
458 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
459 skcipher_request_set_callback(req, 0, NULL, NULL);
460 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
461 ret = crypto_skcipher_decrypt(req);
462 skcipher_request_zero(req);
463 if (ret < 0)
464 return ret;
465
466 /* Extract the decrypted packet length */
467 if (skb_copy_bits(skb, sp->offset, &sechdr, sizeof(sechdr)) < 0)
468 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
469 rxkad_abort_1_short_encdata);
470 sp->offset += sizeof(sechdr);
471 sp->len -= sizeof(sechdr);
472
473 buf = ntohl(sechdr.data_size);
474 data_size = buf & 0xffff;
475
476 check = buf >> 16;
477 check ^= seq ^ call->call_id;
478 check &= 0xffff;
479 if (check != 0)
480 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
481 rxkad_abort_1_short_check);
482 if (data_size > sp->len)
483 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
484 rxkad_abort_1_short_data);
485 sp->len = data_size;
486
487 _leave(" = 0 [dlen=%x]", data_size);
488 return 0;
489 }
490
491 /*
492 * wholly decrypt a packet (level 2 security)
493 */
rxkad_verify_packet_2(struct rxrpc_call * call,struct sk_buff * skb,rxrpc_seq_t seq,struct skcipher_request * req)494 static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
495 rxrpc_seq_t seq,
496 struct skcipher_request *req)
497 {
498 const struct rxrpc_key_token *token;
499 struct rxkad_level2_hdr sechdr;
500 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
501 struct rxrpc_crypt iv;
502 struct scatterlist _sg[4], *sg;
503 u32 data_size, buf;
504 u16 check;
505 int nsg, ret;
506
507 _enter(",{%d}", sp->len);
508
509 if (sp->len < 8)
510 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
511 rxkad_abort_2_short_header);
512
513 /* Don't let the crypto algo see a misaligned length. */
514 sp->len = round_down(sp->len, 8);
515
516 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
517 * directly into the target buffer.
518 */
519 sg = _sg;
520 nsg = skb_shinfo(skb)->nr_frags + 1;
521 if (nsg <= 4) {
522 nsg = 4;
523 } else {
524 sg = kmalloc_objs(*sg, nsg, GFP_NOIO);
525 if (!sg)
526 return -ENOMEM;
527 }
528
529 sg_init_table(sg, nsg);
530 ret = skb_to_sgvec(skb, sg, sp->offset, sp->len);
531 if (unlikely(ret < 0)) {
532 if (sg != _sg)
533 kfree(sg);
534 return ret;
535 }
536
537 /* decrypt from the session key */
538 token = call->conn->key->payload.data[0];
539 memcpy(&iv, token->kad->session_key, sizeof(iv));
540
541 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
542 skcipher_request_set_callback(req, 0, NULL, NULL);
543 skcipher_request_set_crypt(req, sg, sg, sp->len, iv.x);
544 ret = crypto_skcipher_decrypt(req);
545 skcipher_request_zero(req);
546 if (sg != _sg)
547 kfree(sg);
548 if (ret < 0) {
549 if (ret == -ENOMEM)
550 return ret;
551 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
552 rxkad_abort_2_crypto_unaligned);
553 }
554
555 /* Extract the decrypted packet length */
556 if (skb_copy_bits(skb, sp->offset, &sechdr, sizeof(sechdr)) < 0)
557 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
558 rxkad_abort_2_short_len);
559 sp->offset += sizeof(sechdr);
560 sp->len -= sizeof(sechdr);
561
562 buf = ntohl(sechdr.data_size);
563 data_size = buf & 0xffff;
564
565 check = buf >> 16;
566 check ^= seq ^ call->call_id;
567 check &= 0xffff;
568 if (check != 0)
569 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
570 rxkad_abort_2_short_check);
571
572 if (data_size > sp->len)
573 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
574 rxkad_abort_2_short_data);
575
576 sp->len = data_size;
577 _leave(" = 0 [dlen=%x]", data_size);
578 return 0;
579 }
580
581 /*
582 * Verify the security on a received packet and the subpackets therein.
583 */
rxkad_verify_packet(struct rxrpc_call * call,struct sk_buff * skb)584 static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb)
585 {
586 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
587 struct skcipher_request *req;
588 struct rxrpc_crypt iv;
589 struct scatterlist sg;
590 union {
591 __be32 buf[2];
592 } crypto __aligned(8);
593 rxrpc_seq_t seq = sp->hdr.seq;
594 int ret;
595 u16 cksum;
596 u32 x, y;
597
598 _enter("{%d{%x}},{#%u}",
599 call->debug_id, key_serial(call->conn->key), seq);
600
601 if (!call->conn->rxkad.cipher)
602 return 0;
603
604 req = rxkad_get_call_crypto(call);
605 if (!req)
606 return -ENOMEM;
607
608 /* continue encrypting from where we left off */
609 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
610
611 /* validate the security checksum */
612 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
613 x |= seq & 0x3fffffff;
614 crypto.buf[0] = htonl(call->call_id);
615 crypto.buf[1] = htonl(x);
616
617 sg_init_one(&sg, crypto.buf, 8);
618 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
619 skcipher_request_set_callback(req, 0, NULL, NULL);
620 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
621 ret = crypto_skcipher_encrypt(req);
622 skcipher_request_zero(req);
623 if (ret < 0)
624 goto out;
625
626 y = ntohl(crypto.buf[1]);
627 cksum = (y >> 16) & 0xffff;
628 if (cksum == 0)
629 cksum = 1; /* zero checksums are not permitted */
630
631 if (cksum != sp->hdr.cksum) {
632 ret = rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
633 rxkad_abort_bad_checksum);
634 goto out;
635 }
636
637 switch (call->conn->security_level) {
638 case RXRPC_SECURITY_PLAIN:
639 ret = 0;
640 break;
641 case RXRPC_SECURITY_AUTH:
642 ret = rxkad_verify_packet_1(call, skb, seq, req);
643 break;
644 case RXRPC_SECURITY_ENCRYPT:
645 ret = rxkad_verify_packet_2(call, skb, seq, req);
646 break;
647 default:
648 ret = -ENOANO;
649 break;
650 }
651
652 out:
653 skcipher_request_free(req);
654 return ret;
655 }
656
657 /*
658 * issue a challenge
659 */
rxkad_issue_challenge(struct rxrpc_connection * conn)660 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
661 {
662 struct rxkad_challenge challenge;
663 struct rxrpc_wire_header whdr;
664 struct msghdr msg;
665 struct kvec iov[2];
666 size_t len;
667 u32 serial;
668 int ret;
669
670 _enter("{%d}", conn->debug_id);
671
672 get_random_bytes(&conn->rxkad.nonce, sizeof(conn->rxkad.nonce));
673
674 challenge.version = htonl(2);
675 challenge.nonce = htonl(conn->rxkad.nonce);
676 challenge.min_level = htonl(0);
677 challenge.__padding = 0;
678
679 msg.msg_name = &conn->peer->srx.transport;
680 msg.msg_namelen = conn->peer->srx.transport_len;
681 msg.msg_control = NULL;
682 msg.msg_controllen = 0;
683 msg.msg_flags = 0;
684
685 whdr.epoch = htonl(conn->proto.epoch);
686 whdr.cid = htonl(conn->proto.cid);
687 whdr.callNumber = 0;
688 whdr.seq = 0;
689 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
690 whdr.flags = conn->out_clientflag;
691 whdr.userStatus = 0;
692 whdr.securityIndex = conn->security_ix;
693 whdr._rsvd = 0;
694 whdr.serviceId = htons(conn->service_id);
695
696 iov[0].iov_base = &whdr;
697 iov[0].iov_len = sizeof(whdr);
698 iov[1].iov_base = &challenge;
699 iov[1].iov_len = sizeof(challenge);
700
701 len = iov[0].iov_len + iov[1].iov_len;
702
703 serial = rxrpc_get_next_serial(conn);
704 whdr.serial = htonl(serial);
705
706 trace_rxrpc_tx_challenge(conn, serial, 0, conn->rxkad.nonce);
707
708 ret = kernel_sendmsg(conn->local->socket, &msg, iov, 2, len);
709 if (ret < 0) {
710 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
711 rxrpc_tx_point_rxkad_challenge);
712 return -EAGAIN;
713 }
714
715 rxrpc_peer_mark_tx(conn->peer);
716 trace_rxrpc_tx_packet(conn->debug_id, &whdr,
717 rxrpc_tx_point_rxkad_challenge);
718 _leave(" = 0");
719 return 0;
720 }
721
722 /*
723 * calculate the response checksum
724 */
rxkad_calc_response_checksum(struct rxkad_response * response)725 static void rxkad_calc_response_checksum(struct rxkad_response *response)
726 {
727 u32 csum = 1000003;
728 int loop;
729 u8 *p = (u8 *) response;
730
731 for (loop = sizeof(*response); loop > 0; loop--)
732 csum = csum * 0x10204081 + *p++;
733
734 response->encrypted.checksum = htonl(csum);
735 }
736
737 /*
738 * encrypt the response packet
739 */
rxkad_encrypt_response(struct rxrpc_connection * conn,struct sk_buff * response,const struct rxkad_key * s2)740 static int rxkad_encrypt_response(struct rxrpc_connection *conn,
741 struct sk_buff *response,
742 const struct rxkad_key *s2)
743 {
744 struct skcipher_request *req;
745 struct rxrpc_crypt iv;
746 struct scatterlist sg[1];
747 size_t encsize = sizeof(((struct rxkad_response *)0)->encrypted);
748 int ret;
749
750 sg_init_table(sg, ARRAY_SIZE(sg));
751 ret = skb_to_sgvec(response, sg,
752 sizeof(struct rxrpc_wire_header) +
753 offsetof(struct rxkad_response, encrypted), encsize);
754 if (ret < 0)
755 return ret;
756
757 req = skcipher_request_alloc(&conn->rxkad.cipher->base, GFP_NOFS);
758 if (!req)
759 return -ENOMEM;
760
761 /* continue encrypting from where we left off */
762 memcpy(&iv, s2->session_key, sizeof(iv));
763
764 skcipher_request_set_sync_tfm(req, conn->rxkad.cipher);
765 skcipher_request_set_callback(req, 0, NULL, NULL);
766 skcipher_request_set_crypt(req, sg, sg, encsize, iv.x);
767 ret = crypto_skcipher_encrypt(req);
768 skcipher_request_free(req);
769 return ret;
770 }
771
772 /*
773 * Validate a challenge packet.
774 */
rxkad_validate_challenge(struct rxrpc_connection * conn,struct sk_buff * skb)775 static bool rxkad_validate_challenge(struct rxrpc_connection *conn,
776 struct sk_buff *skb)
777 {
778 struct rxkad_challenge challenge;
779 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
780 u32 version, min_level;
781 int ret;
782
783 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
784
785 if (!conn->key) {
786 rxrpc_abort_conn(conn, skb, RX_PROTOCOL_ERROR, -EPROTO,
787 rxkad_abort_chall_no_key);
788 return false;
789 }
790
791 ret = key_validate(conn->key);
792 if (ret < 0) {
793 rxrpc_abort_conn(conn, skb, RXKADEXPIRED, ret,
794 rxkad_abort_chall_key_expired);
795 return false;
796 }
797
798 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
799 &challenge, sizeof(challenge)) < 0) {
800 rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
801 rxkad_abort_chall_short);
802 return false;
803 }
804
805 version = ntohl(challenge.version);
806 sp->chall.rxkad_nonce = ntohl(challenge.nonce);
807 min_level = ntohl(challenge.min_level);
808
809 trace_rxrpc_rx_challenge(conn, sp->hdr.serial, version,
810 sp->chall.rxkad_nonce, min_level);
811
812 if (version != RXKAD_VERSION) {
813 rxrpc_abort_conn(conn, skb, RXKADINCONSISTENCY, -EPROTO,
814 rxkad_abort_chall_version);
815 return false;
816 }
817
818 if (conn->security_level < min_level) {
819 rxrpc_abort_conn(conn, skb, RXKADLEVELFAIL, -EACCES,
820 rxkad_abort_chall_level);
821 return false;
822 }
823 return true;
824 }
825
826 /*
827 * Insert the header into the response.
828 */
829 static noinline
rxkad_insert_response_header(struct rxrpc_connection * conn,const struct rxrpc_key_token * token,struct sk_buff * challenge,struct sk_buff * response,size_t * offset)830 int rxkad_insert_response_header(struct rxrpc_connection *conn,
831 const struct rxrpc_key_token *token,
832 struct sk_buff *challenge,
833 struct sk_buff *response,
834 size_t *offset)
835 {
836 struct rxrpc_skb_priv *csp = rxrpc_skb(challenge);
837 struct {
838 struct rxrpc_wire_header whdr;
839 struct rxkad_response resp;
840 } h;
841 int ret;
842
843 h.whdr.epoch = htonl(conn->proto.epoch);
844 h.whdr.cid = htonl(conn->proto.cid);
845 h.whdr.callNumber = 0;
846 h.whdr.serial = 0;
847 h.whdr.seq = 0;
848 h.whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
849 h.whdr.flags = conn->out_clientflag;
850 h.whdr.userStatus = 0;
851 h.whdr.securityIndex = conn->security_ix;
852 h.whdr.cksum = 0;
853 h.whdr.serviceId = htons(conn->service_id);
854 h.resp.version = htonl(RXKAD_VERSION);
855 h.resp.__pad = 0;
856 h.resp.encrypted.epoch = htonl(conn->proto.epoch);
857 h.resp.encrypted.cid = htonl(conn->proto.cid);
858 h.resp.encrypted.checksum = 0;
859 h.resp.encrypted.securityIndex = htonl(conn->security_ix);
860 h.resp.encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
861 h.resp.encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
862 h.resp.encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
863 h.resp.encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
864 h.resp.encrypted.inc_nonce = htonl(csp->chall.rxkad_nonce + 1);
865 h.resp.encrypted.level = htonl(conn->security_level);
866 h.resp.kvno = htonl(token->kad->kvno);
867 h.resp.ticket_len = htonl(token->kad->ticket_len);
868
869 rxkad_calc_response_checksum(&h.resp);
870
871 ret = skb_store_bits(response, *offset, &h, sizeof(h));
872 *offset += sizeof(h);
873 return ret;
874 }
875
876 /*
877 * respond to a challenge packet
878 */
rxkad_respond_to_challenge(struct rxrpc_connection * conn,struct sk_buff * challenge)879 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
880 struct sk_buff *challenge)
881 {
882 const struct rxrpc_key_token *token;
883 struct rxrpc_skb_priv *csp, *rsp;
884 struct sk_buff *response;
885 size_t len, offset = 0;
886 int ret = -EPROTO;
887
888 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
889
890 ret = key_validate(conn->key);
891 if (ret < 0)
892 return rxrpc_abort_conn(conn, challenge, RXKADEXPIRED, ret,
893 rxkad_abort_chall_key_expired);
894
895 token = conn->key->payload.data[0];
896
897 /* build the response packet */
898 len = sizeof(struct rxrpc_wire_header) +
899 sizeof(struct rxkad_response) +
900 token->kad->ticket_len;
901
902 response = alloc_skb_with_frags(0, len, 0, &ret, GFP_NOFS);
903 if (!response)
904 goto error;
905 rxrpc_new_skb(response, rxrpc_skb_new_response_rxkad);
906 response->len = len;
907 response->data_len = len;
908
909 offset = 0;
910 ret = rxkad_insert_response_header(conn, token, challenge, response,
911 &offset);
912 if (ret < 0)
913 goto error;
914
915 ret = rxkad_encrypt_response(conn, response, token->kad);
916 if (ret < 0)
917 goto error;
918
919 ret = skb_store_bits(response, offset, token->kad->ticket,
920 token->kad->ticket_len);
921 if (ret < 0)
922 goto error;
923
924 csp = rxrpc_skb(challenge);
925 rsp = rxrpc_skb(response);
926 rsp->resp.len = len;
927 rsp->resp.challenge_serial = csp->hdr.serial;
928 rxrpc_post_response(conn, response);
929 response = NULL;
930 ret = 0;
931
932 error:
933 rxrpc_free_skb(response, rxrpc_skb_put_response);
934 return ret;
935 }
936
937 /*
938 * RxKAD does automatic response only as there's nothing to manage that isn't
939 * already in the key.
940 */
rxkad_sendmsg_respond_to_challenge(struct sk_buff * challenge,struct msghdr * msg)941 static int rxkad_sendmsg_respond_to_challenge(struct sk_buff *challenge,
942 struct msghdr *msg)
943 {
944 return -EINVAL;
945 }
946
947 /**
948 * rxkad_kernel_respond_to_challenge - Respond to a challenge with appdata
949 * @challenge: The challenge to respond to
950 *
951 * Allow a kernel application to respond to a CHALLENGE.
952 *
953 * Return: %0 if successful and a negative error code otherwise.
954 */
rxkad_kernel_respond_to_challenge(struct sk_buff * challenge)955 int rxkad_kernel_respond_to_challenge(struct sk_buff *challenge)
956 {
957 struct rxrpc_skb_priv *csp = rxrpc_skb(challenge);
958
959 return rxkad_respond_to_challenge(csp->chall.conn, challenge);
960 }
961 EXPORT_SYMBOL(rxkad_kernel_respond_to_challenge);
962
963 /*
964 * decrypt the kerberos IV ticket in the response
965 */
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)966 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
967 struct key *server_key,
968 struct sk_buff *skb,
969 void *ticket, size_t ticket_len,
970 struct rxrpc_crypt *_session_key,
971 time64_t *_expiry)
972 {
973 struct skcipher_request *req;
974 struct rxrpc_crypt iv, key;
975 struct scatterlist sg[1];
976 struct in_addr addr;
977 unsigned int life;
978 time64_t issue, now;
979 int ret;
980 bool little_endian;
981 u8 *p, *q, *name, *end;
982
983 _enter("{%d},{%x}", conn->debug_id, key_serial(server_key));
984
985 *_expiry = 0;
986
987 ASSERT(server_key->payload.data[0] != NULL);
988 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
989
990 memcpy(&iv, &server_key->payload.data[2], sizeof(iv));
991
992 req = skcipher_request_alloc(server_key->payload.data[0], GFP_NOFS);
993 if (!req)
994 return -ENOMEM;
995
996 sg_init_one(&sg[0], ticket, ticket_len);
997 skcipher_request_set_callback(req, 0, NULL, NULL);
998 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
999 ret = crypto_skcipher_decrypt(req);
1000 skcipher_request_free(req);
1001 if (ret < 0)
1002 return rxrpc_abort_conn(conn, skb, RXKADBADTICKET, -EPROTO,
1003 rxkad_abort_resp_tkt_short);
1004
1005 p = ticket;
1006 end = p + ticket_len;
1007
1008 #define Z(field, fieldl) \
1009 ({ \
1010 u8 *__str = p; \
1011 q = memchr(p, 0, end - p); \
1012 if (!q || q - p > field##_SZ) \
1013 return rxrpc_abort_conn( \
1014 conn, skb, RXKADBADTICKET, -EPROTO, \
1015 rxkad_abort_resp_tkt_##fieldl); \
1016 for (; p < q; p++) \
1017 if (!isprint(*p)) \
1018 return rxrpc_abort_conn( \
1019 conn, skb, RXKADBADTICKET, -EPROTO, \
1020 rxkad_abort_resp_tkt_##fieldl); \
1021 p++; \
1022 __str; \
1023 })
1024
1025 /* extract the ticket flags */
1026 _debug("KIV FLAGS: %x", *p);
1027 little_endian = *p & 1;
1028 p++;
1029
1030 /* extract the authentication name */
1031 name = Z(ANAME, aname);
1032 _debug("KIV ANAME: %s", name);
1033
1034 /* extract the principal's instance */
1035 name = Z(INST, inst);
1036 _debug("KIV INST : %s", name);
1037
1038 /* extract the principal's authentication domain */
1039 name = Z(REALM, realm);
1040 _debug("KIV REALM: %s", name);
1041
1042 if (end - p < 4 + 8 + 4 + 2)
1043 return rxrpc_abort_conn(conn, skb, RXKADBADTICKET, -EPROTO,
1044 rxkad_abort_resp_tkt_short);
1045
1046 /* get the IPv4 address of the entity that requested the ticket */
1047 memcpy(&addr, p, sizeof(addr));
1048 p += 4;
1049 _debug("KIV ADDR : %pI4", &addr);
1050
1051 /* get the session key from the ticket */
1052 memcpy(&key, p, sizeof(key));
1053 p += 8;
1054 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
1055 memcpy(_session_key, &key, sizeof(key));
1056
1057 /* get the ticket's lifetime */
1058 life = *p++ * 5 * 60;
1059 _debug("KIV LIFE : %u", life);
1060
1061 /* get the issue time of the ticket */
1062 if (little_endian) {
1063 __le32 stamp;
1064 memcpy(&stamp, p, 4);
1065 issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
1066 } else {
1067 __be32 stamp;
1068 memcpy(&stamp, p, 4);
1069 issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
1070 }
1071 p += 4;
1072 now = ktime_get_real_seconds();
1073 _debug("KIV ISSUE: %llx [%llx]", issue, now);
1074
1075 /* check the ticket is in date */
1076 if (issue > now)
1077 return rxrpc_abort_conn(conn, skb, RXKADNOAUTH, -EKEYREJECTED,
1078 rxkad_abort_resp_tkt_future);
1079 if (issue < now - life)
1080 return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, -EKEYEXPIRED,
1081 rxkad_abort_resp_tkt_expired);
1082
1083 *_expiry = issue + life;
1084
1085 /* get the service name */
1086 name = Z(SNAME, sname);
1087 _debug("KIV SNAME: %s", name);
1088
1089 /* get the service instance name */
1090 name = Z(INST, sinst);
1091 _debug("KIV SINST: %s", name);
1092 return 0;
1093 }
1094
1095 /*
1096 * decrypt the response packet
1097 */
rxkad_decrypt_response(struct rxrpc_connection * conn,struct rxkad_response * resp,const struct rxrpc_crypt * session_key)1098 static int rxkad_decrypt_response(struct rxrpc_connection *conn,
1099 struct rxkad_response *resp,
1100 const struct rxrpc_crypt *session_key)
1101 {
1102 struct skcipher_request *req = rxkad_ci_req;
1103 struct scatterlist sg[1];
1104 struct rxrpc_crypt iv;
1105 int ret;
1106
1107 _enter(",,%08x%08x",
1108 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
1109
1110 mutex_lock(&rxkad_ci_mutex);
1111 ret = crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
1112 sizeof(*session_key));
1113 if (ret < 0)
1114 goto unlock;
1115
1116 memcpy(&iv, session_key, sizeof(iv));
1117
1118 sg_init_table(sg, 1);
1119 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1120 skcipher_request_set_sync_tfm(req, rxkad_ci);
1121 skcipher_request_set_callback(req, 0, NULL, NULL);
1122 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1123 ret = crypto_skcipher_decrypt(req);
1124 skcipher_request_zero(req);
1125
1126 unlock:
1127 mutex_unlock(&rxkad_ci_mutex);
1128
1129 _leave("");
1130 return ret;
1131 }
1132
1133 /*
1134 * verify a response
1135 */
rxkad_verify_response(struct rxrpc_connection * conn,struct sk_buff * skb)1136 static int rxkad_verify_response(struct rxrpc_connection *conn,
1137 struct sk_buff *skb)
1138 {
1139 struct rxkad_response *response;
1140 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1141 struct rxrpc_crypt session_key;
1142 struct key *server_key;
1143 time64_t expiry;
1144 void *ticket = NULL;
1145 u32 version, kvno, ticket_len, level;
1146 __be32 csum;
1147 int ret, i;
1148
1149 _enter("{%d}", conn->debug_id);
1150
1151 server_key = rxrpc_look_up_server_security(conn, skb, 0, 0);
1152 if (IS_ERR(server_key)) {
1153 ret = PTR_ERR(server_key);
1154 switch (ret) {
1155 case -ENOKEY:
1156 return rxrpc_abort_conn(conn, skb, RXKADUNKNOWNKEY, ret,
1157 rxkad_abort_resp_nokey);
1158 case -EKEYEXPIRED:
1159 return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, ret,
1160 rxkad_abort_resp_key_expired);
1161 default:
1162 return rxrpc_abort_conn(conn, skb, RXKADNOAUTH, ret,
1163 rxkad_abort_resp_key_rejected);
1164 }
1165 }
1166
1167 ret = -ENOMEM;
1168 response = kzalloc_obj(struct rxkad_response, GFP_NOFS);
1169 if (!response)
1170 goto error;
1171
1172 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1173 response, sizeof(*response)) < 0) {
1174 ret = rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
1175 rxkad_abort_resp_short);
1176 goto error;
1177 }
1178
1179 version = ntohl(response->version);
1180 ticket_len = ntohl(response->ticket_len);
1181 kvno = ntohl(response->kvno);
1182
1183 trace_rxrpc_rx_response(conn, sp->hdr.serial, version, kvno, ticket_len);
1184
1185 if (version != RXKAD_VERSION) {
1186 ret = rxrpc_abort_conn(conn, skb, RXKADINCONSISTENCY, -EPROTO,
1187 rxkad_abort_resp_version);
1188 goto error;
1189 }
1190
1191 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN) {
1192 ret = rxrpc_abort_conn(conn, skb, RXKADTICKETLEN, -EPROTO,
1193 rxkad_abort_resp_tkt_len);
1194 goto error;
1195 }
1196
1197 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5) {
1198 ret = rxrpc_abort_conn(conn, skb, RXKADUNKNOWNKEY, -EPROTO,
1199 rxkad_abort_resp_unknown_tkt);
1200 goto error;
1201 }
1202
1203 /* extract the kerberos ticket and decrypt and decode it */
1204 ret = -ENOMEM;
1205 ticket = kmalloc(ticket_len, GFP_NOFS);
1206 if (!ticket)
1207 goto error;
1208
1209 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header) + sizeof(*response),
1210 ticket, ticket_len) < 0) {
1211 ret = rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
1212 rxkad_abort_resp_short_tkt);
1213 goto error;
1214 }
1215
1216 ret = rxkad_decrypt_ticket(conn, server_key, skb, ticket, ticket_len,
1217 &session_key, &expiry);
1218 if (ret < 0)
1219 goto error;
1220
1221 /* use the session key from inside the ticket to decrypt the
1222 * response */
1223 ret = rxkad_decrypt_response(conn, response, &session_key);
1224 if (ret < 0)
1225 goto error;
1226
1227 if (ntohl(response->encrypted.epoch) != conn->proto.epoch ||
1228 ntohl(response->encrypted.cid) != conn->proto.cid ||
1229 ntohl(response->encrypted.securityIndex) != conn->security_ix) {
1230 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1231 rxkad_abort_resp_bad_param);
1232 goto error;
1233 }
1234
1235 csum = response->encrypted.checksum;
1236 response->encrypted.checksum = 0;
1237 rxkad_calc_response_checksum(response);
1238 if (response->encrypted.checksum != csum) {
1239 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1240 rxkad_abort_resp_bad_checksum);
1241 goto error;
1242 }
1243
1244 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1245 u32 call_id = ntohl(response->encrypted.call_id[i]);
1246 u32 counter = READ_ONCE(conn->channels[i].call_counter);
1247
1248 if (call_id > INT_MAX) {
1249 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1250 rxkad_abort_resp_bad_callid);
1251 goto error;
1252 }
1253
1254 if (call_id < counter) {
1255 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1256 rxkad_abort_resp_call_ctr);
1257 goto error;
1258 }
1259
1260 if (call_id > counter) {
1261 if (conn->channels[i].call) {
1262 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1263 rxkad_abort_resp_call_state);
1264 goto error;
1265 }
1266 conn->channels[i].call_counter = call_id;
1267 }
1268 }
1269
1270 if (ntohl(response->encrypted.inc_nonce) != conn->rxkad.nonce + 1) {
1271 ret = rxrpc_abort_conn(conn, skb, RXKADOUTOFSEQUENCE, -EPROTO,
1272 rxkad_abort_resp_ooseq);
1273 goto error;
1274 }
1275
1276 level = ntohl(response->encrypted.level);
1277 if (level > RXRPC_SECURITY_ENCRYPT) {
1278 ret = rxrpc_abort_conn(conn, skb, RXKADLEVELFAIL, -EPROTO,
1279 rxkad_abort_resp_level);
1280 goto error;
1281 }
1282 conn->security_level = level;
1283
1284 /* create a key to hold the security data and expiration time - after
1285 * this the connection security can be handled in exactly the same way
1286 * as for a client connection */
1287 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1288
1289 error:
1290 kfree(ticket);
1291 kfree(response);
1292 key_put(server_key);
1293 _leave(" = %d", ret);
1294 return ret;
1295 }
1296
1297 /*
1298 * clear the connection security
1299 */
rxkad_clear(struct rxrpc_connection * conn)1300 static void rxkad_clear(struct rxrpc_connection *conn)
1301 {
1302 _enter("");
1303
1304 if (conn->rxkad.cipher)
1305 crypto_free_sync_skcipher(conn->rxkad.cipher);
1306 }
1307
1308 /*
1309 * Initialise the rxkad security service.
1310 */
rxkad_init(void)1311 static int rxkad_init(void)
1312 {
1313 struct crypto_sync_skcipher *tfm;
1314 struct skcipher_request *req;
1315
1316 /* pin the cipher we need so that the crypto layer doesn't invoke
1317 * keventd to go get it */
1318 tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
1319 if (IS_ERR(tfm))
1320 return PTR_ERR(tfm);
1321
1322 req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
1323 if (!req)
1324 goto nomem_tfm;
1325
1326 rxkad_ci_req = req;
1327 rxkad_ci = tfm;
1328 return 0;
1329
1330 nomem_tfm:
1331 crypto_free_sync_skcipher(tfm);
1332 return -ENOMEM;
1333 }
1334
1335 /*
1336 * Clean up the rxkad security service.
1337 */
rxkad_exit(void)1338 static void rxkad_exit(void)
1339 {
1340 crypto_free_sync_skcipher(rxkad_ci);
1341 skcipher_request_free(rxkad_ci_req);
1342 }
1343
1344 /*
1345 * RxRPC Kerberos-based security
1346 */
1347 const struct rxrpc_security rxkad = {
1348 .name = "rxkad",
1349 .security_index = RXRPC_SECURITY_RXKAD,
1350 .no_key_abort = RXKADUNKNOWNKEY,
1351 .init = rxkad_init,
1352 .exit = rxkad_exit,
1353 .preparse_server_key = rxkad_preparse_server_key,
1354 .free_preparse_server_key = rxkad_free_preparse_server_key,
1355 .destroy_server_key = rxkad_destroy_server_key,
1356 .init_connection_security = rxkad_init_connection_security,
1357 .alloc_txbuf = rxkad_alloc_txbuf,
1358 .secure_packet = rxkad_secure_packet,
1359 .verify_packet = rxkad_verify_packet,
1360 .free_call_crypto = rxkad_free_call_crypto,
1361 .issue_challenge = rxkad_issue_challenge,
1362 .validate_challenge = rxkad_validate_challenge,
1363 .sendmsg_respond_to_challenge = rxkad_sendmsg_respond_to_challenge,
1364 .respond_to_challenge = rxkad_respond_to_challenge,
1365 .verify_response = rxkad_verify_response,
1366 .clear = rxkad_clear,
1367 };
1368