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[1];
437 void *data = call->rx_dec_buffer;
438 u32 len = sp->len, data_size, buf;
439 u16 check;
440 int ret;
441
442 _enter("");
443
444 if (len < 8)
445 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
446 rxkad_abort_1_short_header);
447
448 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
449 * directly into the target buffer.
450 */
451 sg_init_one(sg, data, len);
452
453 /* start the decryption afresh */
454 memset(&iv, 0, sizeof(iv));
455
456 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
457 skcipher_request_set_callback(req, 0, NULL, NULL);
458 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
459 ret = crypto_skcipher_decrypt(req);
460 skcipher_request_zero(req);
461 if (ret < 0)
462 return ret;
463
464 /* Extract the decrypted packet length */
465 sechdr = data;
466 call->rx_dec_offset = sizeof(*sechdr);
467 len -= sizeof(*sechdr);
468
469 buf = ntohl(sechdr->data_size);
470 data_size = buf & 0xffff;
471
472 check = buf >> 16;
473 check ^= seq ^ call->call_id;
474 check &= 0xffff;
475 if (check != 0)
476 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
477 rxkad_abort_1_short_check);
478 if (data_size > len)
479 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
480 rxkad_abort_1_short_data);
481 call->rx_dec_len = data_size;
482
483 _leave(" = 0 [dlen=%x]", data_size);
484 return 0;
485 }
486
487 /*
488 * wholly decrypt a packet (level 2 security)
489 */
rxkad_verify_packet_2(struct rxrpc_call * call,struct sk_buff * skb,rxrpc_seq_t seq,struct skcipher_request * req)490 static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
491 rxrpc_seq_t seq,
492 struct skcipher_request *req)
493 {
494 const struct rxrpc_key_token *token;
495 struct rxkad_level2_hdr *sechdr;
496 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
497 struct rxrpc_crypt iv;
498 struct scatterlist sg[1];
499 void *data = call->rx_dec_buffer;
500 u32 len = sp->len, data_size, buf;
501 u16 check;
502 int ret;
503
504 _enter(",{%d}", len);
505
506 if (len < 8)
507 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
508 rxkad_abort_2_short_header);
509
510 /* Don't let the crypto algo see a misaligned length. */
511 len = round_down(len, 8);
512
513 /* Decrypt in place in the call's decryption buffer. TODO: We really
514 * want to decrypt directly into the target buffer.
515 */
516 sg_init_one(sg, data, len);
517
518 /* decrypt from the session key */
519 token = call->conn->key->payload.data[0];
520 memcpy(&iv, token->kad->session_key, sizeof(iv));
521
522 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
523 skcipher_request_set_callback(req, 0, NULL, NULL);
524 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
525 ret = crypto_skcipher_decrypt(req);
526 skcipher_request_zero(req);
527 if (ret < 0) {
528 if (ret == -ENOMEM)
529 return ret;
530 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
531 rxkad_abort_2_crypto_unaligned);
532 }
533
534 /* Extract the decrypted packet length */
535 sechdr = data;
536 call->rx_dec_offset = sizeof(*sechdr);
537 len -= sizeof(*sechdr);
538
539 buf = ntohl(sechdr->data_size);
540 data_size = buf & 0xffff;
541
542 check = buf >> 16;
543 check ^= seq ^ call->call_id;
544 check &= 0xffff;
545 if (check != 0)
546 return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
547 rxkad_abort_2_short_check);
548
549 if (data_size > len)
550 return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
551 rxkad_abort_2_short_data);
552
553 call->rx_dec_len = data_size;
554 _leave(" = 0 [dlen=%x]", data_size);
555 return 0;
556 }
557
558 /*
559 * Verify the security on a received (sub)packet. If the packet needs
560 * modifying (e.g. decrypting), it must be copied.
561 */
rxkad_verify_packet(struct rxrpc_call * call,struct sk_buff * skb)562 static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb)
563 {
564 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
565 struct skcipher_request *req;
566 struct rxrpc_crypt iv;
567 struct scatterlist sg;
568 union {
569 __be32 buf[2];
570 } crypto __aligned(8);
571 rxrpc_seq_t seq = sp->hdr.seq;
572 int ret;
573 u16 cksum;
574 u32 x, y;
575
576 _enter("{%d{%x}},{#%u}",
577 call->debug_id, key_serial(call->conn->key), seq);
578
579 if (!call->conn->rxkad.cipher)
580 return 0;
581
582 req = rxkad_get_call_crypto(call);
583 if (!req)
584 return -ENOMEM;
585
586 /* continue encrypting from where we left off */
587 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
588
589 /* validate the security checksum */
590 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
591 x |= seq & 0x3fffffff;
592 crypto.buf[0] = htonl(call->call_id);
593 crypto.buf[1] = htonl(x);
594
595 sg_init_one(&sg, crypto.buf, 8);
596 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
597 skcipher_request_set_callback(req, 0, NULL, NULL);
598 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
599 ret = crypto_skcipher_encrypt(req);
600 skcipher_request_zero(req);
601 if (ret < 0)
602 goto out;
603
604 y = ntohl(crypto.buf[1]);
605 cksum = (y >> 16) & 0xffff;
606 if (cksum == 0)
607 cksum = 1; /* zero checksums are not permitted */
608
609 if (cksum != sp->hdr.cksum) {
610 ret = rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
611 rxkad_abort_bad_checksum);
612 goto out;
613 }
614
615 switch (call->conn->security_level) {
616 case RXRPC_SECURITY_PLAIN:
617 ret = 0;
618 break;
619 case RXRPC_SECURITY_AUTH:
620 ret = rxkad_verify_packet_1(call, skb, seq, req);
621 break;
622 case RXRPC_SECURITY_ENCRYPT:
623 ret = rxkad_verify_packet_2(call, skb, seq, req);
624 break;
625 default:
626 ret = -ENOANO;
627 break;
628 }
629
630 out:
631 skcipher_request_free(req);
632 return ret;
633 }
634
635 /*
636 * issue a challenge
637 */
rxkad_issue_challenge(struct rxrpc_connection * conn)638 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
639 {
640 struct rxkad_challenge challenge;
641 struct rxrpc_wire_header whdr;
642 struct msghdr msg;
643 struct kvec iov[2];
644 size_t len;
645 u32 serial;
646 int ret;
647
648 _enter("{%d}", conn->debug_id);
649
650 get_random_bytes(&conn->rxkad.nonce, sizeof(conn->rxkad.nonce));
651
652 challenge.version = htonl(2);
653 challenge.nonce = htonl(conn->rxkad.nonce);
654 challenge.min_level = htonl(0);
655 challenge.__padding = 0;
656
657 msg.msg_name = &conn->peer->srx.transport;
658 msg.msg_namelen = conn->peer->srx.transport_len;
659 msg.msg_control = NULL;
660 msg.msg_controllen = 0;
661 msg.msg_flags = 0;
662
663 whdr.epoch = htonl(conn->proto.epoch);
664 whdr.cid = htonl(conn->proto.cid);
665 whdr.callNumber = 0;
666 whdr.seq = 0;
667 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
668 whdr.flags = conn->out_clientflag;
669 whdr.userStatus = 0;
670 whdr.securityIndex = conn->security_ix;
671 whdr._rsvd = 0;
672 whdr.serviceId = htons(conn->service_id);
673
674 iov[0].iov_base = &whdr;
675 iov[0].iov_len = sizeof(whdr);
676 iov[1].iov_base = &challenge;
677 iov[1].iov_len = sizeof(challenge);
678
679 len = iov[0].iov_len + iov[1].iov_len;
680
681 serial = rxrpc_get_next_serial(conn);
682 whdr.serial = htonl(serial);
683
684 trace_rxrpc_tx_challenge(conn, serial, 0, conn->rxkad.nonce);
685
686 ret = kernel_sendmsg(conn->local->socket, &msg, iov, 2, len);
687 if (ret < 0) {
688 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
689 rxrpc_tx_point_rxkad_challenge);
690 return -EAGAIN;
691 }
692
693 rxrpc_peer_mark_tx(conn->peer);
694 trace_rxrpc_tx_packet(conn->debug_id, &whdr,
695 rxrpc_tx_point_rxkad_challenge);
696 _leave(" = 0");
697 return 0;
698 }
699
700 /*
701 * calculate the response checksum
702 */
rxkad_calc_response_checksum(struct rxkad_response * response)703 static void rxkad_calc_response_checksum(struct rxkad_response *response)
704 {
705 u32 csum = 1000003;
706 int loop;
707 u8 *p = (u8 *) response;
708
709 for (loop = sizeof(*response); loop > 0; loop--)
710 csum = csum * 0x10204081 + *p++;
711
712 response->encrypted.checksum = htonl(csum);
713 }
714
715 /*
716 * encrypt the response packet
717 */
rxkad_encrypt_response(struct rxrpc_connection * conn,struct sk_buff * response,const struct rxkad_key * s2)718 static int rxkad_encrypt_response(struct rxrpc_connection *conn,
719 struct sk_buff *response,
720 const struct rxkad_key *s2)
721 {
722 struct skcipher_request *req;
723 struct rxrpc_crypt iv;
724 struct scatterlist sg[1];
725 size_t encsize = sizeof(((struct rxkad_response *)0)->encrypted);
726 int ret;
727
728 sg_init_table(sg, ARRAY_SIZE(sg));
729 ret = skb_to_sgvec(response, sg,
730 sizeof(struct rxrpc_wire_header) +
731 offsetof(struct rxkad_response, encrypted), encsize);
732 if (ret < 0)
733 return ret;
734
735 req = skcipher_request_alloc(&conn->rxkad.cipher->base, GFP_NOFS);
736 if (!req)
737 return -ENOMEM;
738
739 /* continue encrypting from where we left off */
740 memcpy(&iv, s2->session_key, sizeof(iv));
741
742 skcipher_request_set_sync_tfm(req, conn->rxkad.cipher);
743 skcipher_request_set_callback(req, 0, NULL, NULL);
744 skcipher_request_set_crypt(req, sg, sg, encsize, iv.x);
745 ret = crypto_skcipher_encrypt(req);
746 skcipher_request_free(req);
747 return ret;
748 }
749
750 /*
751 * Validate a challenge packet.
752 */
rxkad_validate_challenge(struct rxrpc_connection * conn,struct sk_buff * skb)753 static bool rxkad_validate_challenge(struct rxrpc_connection *conn,
754 struct sk_buff *skb)
755 {
756 struct rxkad_challenge challenge;
757 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
758 u32 version, min_level;
759 int ret;
760
761 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
762
763 if (!conn->key) {
764 rxrpc_abort_conn(conn, skb, RX_PROTOCOL_ERROR, -EPROTO,
765 rxkad_abort_chall_no_key);
766 return false;
767 }
768
769 ret = key_validate(conn->key);
770 if (ret < 0) {
771 rxrpc_abort_conn(conn, skb, RXKADEXPIRED, ret,
772 rxkad_abort_chall_key_expired);
773 return false;
774 }
775
776 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
777 &challenge, sizeof(challenge)) < 0) {
778 rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
779 rxkad_abort_chall_short);
780 return false;
781 }
782
783 version = ntohl(challenge.version);
784 sp->chall.rxkad_nonce = ntohl(challenge.nonce);
785 min_level = ntohl(challenge.min_level);
786
787 trace_rxrpc_rx_challenge(conn, sp->hdr.serial, version,
788 sp->chall.rxkad_nonce, min_level);
789
790 if (version != RXKAD_VERSION) {
791 rxrpc_abort_conn(conn, skb, RXKADINCONSISTENCY, -EPROTO,
792 rxkad_abort_chall_version);
793 return false;
794 }
795
796 if (conn->security_level < min_level) {
797 rxrpc_abort_conn(conn, skb, RXKADLEVELFAIL, -EACCES,
798 rxkad_abort_chall_level);
799 return false;
800 }
801 return true;
802 }
803
804 /*
805 * Insert the header into the response.
806 */
807 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)808 int rxkad_insert_response_header(struct rxrpc_connection *conn,
809 const struct rxrpc_key_token *token,
810 struct sk_buff *challenge,
811 struct sk_buff *response,
812 size_t *offset)
813 {
814 struct rxrpc_skb_priv *csp = rxrpc_skb(challenge);
815 struct {
816 struct rxrpc_wire_header whdr;
817 struct rxkad_response resp;
818 } h;
819 int ret;
820
821 h.whdr.epoch = htonl(conn->proto.epoch);
822 h.whdr.cid = htonl(conn->proto.cid);
823 h.whdr.callNumber = 0;
824 h.whdr.serial = 0;
825 h.whdr.seq = 0;
826 h.whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
827 h.whdr.flags = conn->out_clientflag;
828 h.whdr.userStatus = 0;
829 h.whdr.securityIndex = conn->security_ix;
830 h.whdr.cksum = 0;
831 h.whdr.serviceId = htons(conn->service_id);
832 h.resp.version = htonl(RXKAD_VERSION);
833 h.resp.__pad = 0;
834 h.resp.encrypted.epoch = htonl(conn->proto.epoch);
835 h.resp.encrypted.cid = htonl(conn->proto.cid);
836 h.resp.encrypted.checksum = 0;
837 h.resp.encrypted.securityIndex = htonl(conn->security_ix);
838 h.resp.encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
839 h.resp.encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
840 h.resp.encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
841 h.resp.encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
842 h.resp.encrypted.inc_nonce = htonl(csp->chall.rxkad_nonce + 1);
843 h.resp.encrypted.level = htonl(conn->security_level);
844 h.resp.kvno = htonl(token->kad->kvno);
845 h.resp.ticket_len = htonl(token->kad->ticket_len);
846
847 rxkad_calc_response_checksum(&h.resp);
848
849 ret = skb_store_bits(response, *offset, &h, sizeof(h));
850 *offset += sizeof(h);
851 return ret;
852 }
853
854 /*
855 * respond to a challenge packet
856 */
rxkad_respond_to_challenge(struct rxrpc_connection * conn,struct sk_buff * challenge)857 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
858 struct sk_buff *challenge)
859 {
860 const struct rxrpc_key_token *token;
861 struct rxrpc_skb_priv *csp, *rsp;
862 struct sk_buff *response;
863 size_t len, offset = 0;
864 int ret = -EPROTO;
865
866 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
867
868 ret = key_validate(conn->key);
869 if (ret < 0)
870 return rxrpc_abort_conn(conn, challenge, RXKADEXPIRED, ret,
871 rxkad_abort_chall_key_expired);
872
873 token = conn->key->payload.data[0];
874
875 /* build the response packet */
876 len = sizeof(struct rxrpc_wire_header) +
877 sizeof(struct rxkad_response) +
878 token->kad->ticket_len;
879
880 response = alloc_skb_with_frags(0, len, 0, &ret, GFP_NOFS);
881 if (!response)
882 goto error;
883 rxrpc_new_skb(response, rxrpc_skb_new_response_rxkad);
884 response->len = len;
885 response->data_len = len;
886
887 offset = 0;
888 ret = rxkad_insert_response_header(conn, token, challenge, response,
889 &offset);
890 if (ret < 0)
891 goto error;
892
893 ret = rxkad_encrypt_response(conn, response, token->kad);
894 if (ret < 0)
895 goto error;
896
897 ret = skb_store_bits(response, offset, token->kad->ticket,
898 token->kad->ticket_len);
899 if (ret < 0)
900 goto error;
901
902 csp = rxrpc_skb(challenge);
903 rsp = rxrpc_skb(response);
904 rsp->resp.len = len;
905 rsp->resp.challenge_serial = csp->hdr.serial;
906 rxrpc_post_response(conn, response);
907 response = NULL;
908 ret = 0;
909
910 error:
911 rxrpc_free_skb(response, rxrpc_skb_put_response);
912 return ret;
913 }
914
915 /*
916 * RxKAD does automatic response only as there's nothing to manage that isn't
917 * already in the key.
918 */
rxkad_sendmsg_respond_to_challenge(struct sk_buff * challenge,struct msghdr * msg)919 static int rxkad_sendmsg_respond_to_challenge(struct sk_buff *challenge,
920 struct msghdr *msg)
921 {
922 return -EINVAL;
923 }
924
925 /**
926 * rxkad_kernel_respond_to_challenge - Respond to a challenge with appdata
927 * @challenge: The challenge to respond to
928 *
929 * Allow a kernel application to respond to a CHALLENGE.
930 *
931 * Return: %0 if successful and a negative error code otherwise.
932 */
rxkad_kernel_respond_to_challenge(struct sk_buff * challenge)933 int rxkad_kernel_respond_to_challenge(struct sk_buff *challenge)
934 {
935 struct rxrpc_skb_priv *csp = rxrpc_skb(challenge);
936
937 return rxkad_respond_to_challenge(csp->chall.conn, challenge);
938 }
939 EXPORT_SYMBOL(rxkad_kernel_respond_to_challenge);
940
941 /*
942 * decrypt the kerberos IV ticket in the response
943 */
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)944 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
945 struct key *server_key,
946 struct sk_buff *skb,
947 void *ticket, size_t ticket_len,
948 struct rxrpc_crypt *_session_key,
949 time64_t *_expiry)
950 {
951 struct skcipher_request *req;
952 struct rxrpc_crypt iv, key;
953 struct scatterlist sg[1];
954 struct in_addr addr;
955 unsigned int life;
956 time64_t issue, now;
957 int ret;
958 bool little_endian;
959 u8 *p, *q, *name, *end;
960
961 _enter("{%d},{%x}", conn->debug_id, key_serial(server_key));
962
963 *_expiry = 0;
964
965 ASSERT(server_key->payload.data[0] != NULL);
966
967 memcpy(&iv, &server_key->payload.data[2], sizeof(iv));
968
969 req = skcipher_request_alloc(server_key->payload.data[0], GFP_NOFS);
970 if (!req)
971 return -ENOMEM;
972
973 sg_init_one(&sg[0], ticket, ticket_len);
974 skcipher_request_set_callback(req, 0, NULL, NULL);
975 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
976 ret = crypto_skcipher_decrypt(req);
977 skcipher_request_free(req);
978 if (ret < 0)
979 return rxrpc_abort_conn(conn, skb, RXKADBADTICKET, -EPROTO,
980 rxkad_abort_resp_tkt_short);
981
982 p = ticket;
983 end = p + ticket_len;
984
985 #define Z(field, fieldl) \
986 ({ \
987 u8 *__str = p; \
988 q = memchr(p, 0, end - p); \
989 if (!q || q - p > field##_SZ) \
990 return rxrpc_abort_conn( \
991 conn, skb, RXKADBADTICKET, -EPROTO, \
992 rxkad_abort_resp_tkt_##fieldl); \
993 for (; p < q; p++) \
994 if (!isprint(*p)) \
995 return rxrpc_abort_conn( \
996 conn, skb, RXKADBADTICKET, -EPROTO, \
997 rxkad_abort_resp_tkt_##fieldl); \
998 p++; \
999 __str; \
1000 })
1001
1002 /* extract the ticket flags */
1003 _debug("KIV FLAGS: %x", *p);
1004 little_endian = *p & 1;
1005 p++;
1006
1007 /* extract the authentication name */
1008 name = Z(ANAME, aname);
1009 _debug("KIV ANAME: %s", name);
1010
1011 /* extract the principal's instance */
1012 name = Z(INST, inst);
1013 _debug("KIV INST : %s", name);
1014
1015 /* extract the principal's authentication domain */
1016 name = Z(REALM, realm);
1017 _debug("KIV REALM: %s", name);
1018
1019 if (end - p < 4 + 8 + 4 + 2)
1020 return rxrpc_abort_conn(conn, skb, RXKADBADTICKET, -EPROTO,
1021 rxkad_abort_resp_tkt_short);
1022
1023 /* get the IPv4 address of the entity that requested the ticket */
1024 memcpy(&addr, p, sizeof(addr));
1025 p += 4;
1026 _debug("KIV ADDR : %pI4", &addr);
1027
1028 /* get the session key from the ticket */
1029 memcpy(&key, p, sizeof(key));
1030 p += 8;
1031 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
1032 memcpy(_session_key, &key, sizeof(key));
1033
1034 /* get the ticket's lifetime */
1035 life = *p++ * 5 * 60;
1036 _debug("KIV LIFE : %u", life);
1037
1038 /* get the issue time of the ticket */
1039 if (little_endian) {
1040 __le32 stamp;
1041 memcpy(&stamp, p, 4);
1042 issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
1043 } else {
1044 __be32 stamp;
1045 memcpy(&stamp, p, 4);
1046 issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
1047 }
1048 p += 4;
1049 now = ktime_get_real_seconds();
1050 _debug("KIV ISSUE: %llx [%llx]", issue, now);
1051
1052 /* check the ticket is in date */
1053 if (issue > now)
1054 return rxrpc_abort_conn(conn, skb, RXKADNOAUTH, -EKEYREJECTED,
1055 rxkad_abort_resp_tkt_future);
1056 if (issue < now - life)
1057 return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, -EKEYEXPIRED,
1058 rxkad_abort_resp_tkt_expired);
1059
1060 *_expiry = issue + life;
1061
1062 /* get the service name */
1063 name = Z(SNAME, sname);
1064 _debug("KIV SNAME: %s", name);
1065
1066 /* get the service instance name */
1067 name = Z(INST, sinst);
1068 _debug("KIV SINST: %s", name);
1069 return 0;
1070 }
1071
1072 /*
1073 * decrypt the response packet
1074 */
rxkad_decrypt_response(struct rxrpc_connection * conn,struct rxkad_response * resp,const struct rxrpc_crypt * session_key)1075 static int rxkad_decrypt_response(struct rxrpc_connection *conn,
1076 struct rxkad_response *resp,
1077 const struct rxrpc_crypt *session_key)
1078 {
1079 struct skcipher_request *req = rxkad_ci_req;
1080 struct scatterlist sg[1];
1081 struct rxrpc_crypt iv;
1082 int ret;
1083
1084 _enter(",,%08x%08x",
1085 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
1086
1087 mutex_lock(&rxkad_ci_mutex);
1088 ret = crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
1089 sizeof(*session_key));
1090 if (ret < 0)
1091 goto unlock;
1092
1093 memcpy(&iv, session_key, sizeof(iv));
1094
1095 sg_init_table(sg, 1);
1096 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1097 skcipher_request_set_sync_tfm(req, rxkad_ci);
1098 skcipher_request_set_callback(req, 0, NULL, NULL);
1099 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1100 ret = crypto_skcipher_decrypt(req);
1101 skcipher_request_zero(req);
1102
1103 unlock:
1104 mutex_unlock(&rxkad_ci_mutex);
1105
1106 _leave("");
1107 return ret;
1108 }
1109
1110 /*
1111 * verify a response
1112 */
rxkad_verify_response(struct rxrpc_connection * conn,struct sk_buff * skb,void * buffer,unsigned int len)1113 static int rxkad_verify_response(struct rxrpc_connection *conn,
1114 struct sk_buff *skb,
1115 void *buffer, unsigned int len)
1116 {
1117 struct rxkad_response *response;
1118 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1119 struct rxrpc_crypt session_key;
1120 struct key *server_key;
1121 time64_t expiry;
1122 void *ticket;
1123 u32 version, kvno, ticket_len, level;
1124 __be32 csum;
1125 int ret, i;
1126
1127 _enter("{%d}", conn->debug_id);
1128
1129 server_key = rxrpc_look_up_server_security(conn, skb, 0, 0);
1130 if (IS_ERR(server_key)) {
1131 ret = PTR_ERR(server_key);
1132 switch (ret) {
1133 case -ENOKEY:
1134 return rxrpc_abort_conn(conn, skb, RXKADUNKNOWNKEY, ret,
1135 rxkad_abort_resp_nokey);
1136 case -EKEYEXPIRED:
1137 return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, ret,
1138 rxkad_abort_resp_key_expired);
1139 default:
1140 return rxrpc_abort_conn(conn, skb, RXKADNOAUTH, ret,
1141 rxkad_abort_resp_key_rejected);
1142 }
1143 }
1144
1145 response = buffer;
1146 if (len < sizeof(*response)) {
1147 ret = rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
1148 rxkad_abort_resp_short);
1149 goto error;
1150 }
1151
1152 version = ntohl(response->version);
1153 ticket_len = ntohl(response->ticket_len);
1154 kvno = ntohl(response->kvno);
1155
1156 trace_rxrpc_rx_response(conn, sp->hdr.serial, version, kvno, ticket_len);
1157
1158 buffer += sizeof(*response);
1159 len -= sizeof(*response);
1160
1161 if (version != RXKAD_VERSION) {
1162 ret = rxrpc_abort_conn(conn, skb, RXKADINCONSISTENCY, -EPROTO,
1163 rxkad_abort_resp_version);
1164 goto error;
1165 }
1166
1167 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN) {
1168 ret = rxrpc_abort_conn(conn, skb, RXKADTICKETLEN, -EPROTO,
1169 rxkad_abort_resp_tkt_len);
1170 goto error;
1171 }
1172
1173 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5) {
1174 ret = rxrpc_abort_conn(conn, skb, RXKADUNKNOWNKEY, -EPROTO,
1175 rxkad_abort_resp_unknown_tkt);
1176 goto error;
1177 }
1178
1179 /* extract the kerberos ticket and decrypt and decode it */
1180 ticket = buffer;
1181 if (ticket_len > len) {
1182 ret = rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
1183 rxkad_abort_resp_short_tkt);
1184 goto error;
1185 }
1186
1187 ret = rxkad_decrypt_ticket(conn, server_key, skb, ticket, ticket_len,
1188 &session_key, &expiry);
1189 if (ret < 0)
1190 goto error;
1191
1192 /* use the session key from inside the ticket to decrypt the
1193 * response */
1194 ret = rxkad_decrypt_response(conn, response, &session_key);
1195 if (ret < 0)
1196 goto error;
1197
1198 if (ntohl(response->encrypted.epoch) != conn->proto.epoch ||
1199 ntohl(response->encrypted.cid) != conn->proto.cid ||
1200 ntohl(response->encrypted.securityIndex) != conn->security_ix) {
1201 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1202 rxkad_abort_resp_bad_param);
1203 goto error;
1204 }
1205
1206 csum = response->encrypted.checksum;
1207 response->encrypted.checksum = 0;
1208 rxkad_calc_response_checksum(response);
1209 if (response->encrypted.checksum != csum) {
1210 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1211 rxkad_abort_resp_bad_checksum);
1212 goto error;
1213 }
1214
1215 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1216 u32 call_id = ntohl(response->encrypted.call_id[i]);
1217 u32 counter = READ_ONCE(conn->channels[i].call_counter);
1218
1219 if (call_id > INT_MAX) {
1220 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1221 rxkad_abort_resp_bad_callid);
1222 goto error;
1223 }
1224
1225 if (call_id < counter) {
1226 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1227 rxkad_abort_resp_call_ctr);
1228 goto error;
1229 }
1230
1231 if (call_id > counter) {
1232 if (conn->channels[i].call) {
1233 ret = rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
1234 rxkad_abort_resp_call_state);
1235 goto error;
1236 }
1237 conn->channels[i].call_counter = call_id;
1238 }
1239 }
1240
1241 if (ntohl(response->encrypted.inc_nonce) != conn->rxkad.nonce + 1) {
1242 ret = rxrpc_abort_conn(conn, skb, RXKADOUTOFSEQUENCE, -EPROTO,
1243 rxkad_abort_resp_ooseq);
1244 goto error;
1245 }
1246
1247 level = ntohl(response->encrypted.level);
1248 if (level > RXRPC_SECURITY_ENCRYPT) {
1249 ret = rxrpc_abort_conn(conn, skb, RXKADLEVELFAIL, -EPROTO,
1250 rxkad_abort_resp_level);
1251 goto error;
1252 }
1253 conn->security_level = level;
1254
1255 /* create a key to hold the security data and expiration time - after
1256 * this the connection security can be handled in exactly the same way
1257 * as for a client connection */
1258 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1259
1260 error:
1261 key_put(server_key);
1262 _leave(" = %d", ret);
1263 return ret;
1264 }
1265
1266 /*
1267 * clear the connection security
1268 */
rxkad_clear(struct rxrpc_connection * conn)1269 static void rxkad_clear(struct rxrpc_connection *conn)
1270 {
1271 _enter("");
1272
1273 if (conn->rxkad.cipher)
1274 crypto_free_sync_skcipher(conn->rxkad.cipher);
1275 }
1276
1277 /*
1278 * Initialise the rxkad security service.
1279 */
rxkad_init(void)1280 static int rxkad_init(void)
1281 {
1282 struct crypto_sync_skcipher *tfm;
1283 struct skcipher_request *req;
1284
1285 /* pin the cipher we need so that the crypto layer doesn't invoke
1286 * keventd to go get it */
1287 tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
1288 if (IS_ERR(tfm))
1289 return PTR_ERR(tfm);
1290
1291 req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
1292 if (!req)
1293 goto nomem_tfm;
1294
1295 rxkad_ci_req = req;
1296 rxkad_ci = tfm;
1297 return 0;
1298
1299 nomem_tfm:
1300 crypto_free_sync_skcipher(tfm);
1301 return -ENOMEM;
1302 }
1303
1304 /*
1305 * Clean up the rxkad security service.
1306 */
rxkad_exit(void)1307 static void rxkad_exit(void)
1308 {
1309 crypto_free_sync_skcipher(rxkad_ci);
1310 skcipher_request_free(rxkad_ci_req);
1311 }
1312
1313 /*
1314 * RxRPC Kerberos-based security
1315 */
1316 const struct rxrpc_security rxkad = {
1317 .name = "rxkad",
1318 .security_index = RXRPC_SECURITY_RXKAD,
1319 .no_key_abort = RXKADUNKNOWNKEY,
1320 .init = rxkad_init,
1321 .exit = rxkad_exit,
1322 .preparse_server_key = rxkad_preparse_server_key,
1323 .free_preparse_server_key = rxkad_free_preparse_server_key,
1324 .destroy_server_key = rxkad_destroy_server_key,
1325 .init_connection_security = rxkad_init_connection_security,
1326 .alloc_txbuf = rxkad_alloc_txbuf,
1327 .secure_packet = rxkad_secure_packet,
1328 .verify_packet = rxkad_verify_packet,
1329 .free_call_crypto = rxkad_free_call_crypto,
1330 .issue_challenge = rxkad_issue_challenge,
1331 .validate_challenge = rxkad_validate_challenge,
1332 .sendmsg_respond_to_challenge = rxkad_sendmsg_respond_to_challenge,
1333 .respond_to_challenge = rxkad_respond_to_challenge,
1334 .verify_response = rxkad_verify_response,
1335 .clear = rxkad_clear,
1336 };
1337