1 /* Kerberos-based RxRPC security
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/module.h>
13 #include <linux/net.h>
14 #include <linux/skbuff.h>
15 #include <linux/udp.h>
16 #include <linux/crypto.h>
17 #include <linux/scatterlist.h>
18 #include <linux/ctype.h>
20 #include <net/af_rxrpc.h>
21 #define rxrpc_debug rxkad_debug
22 #include "ar-internal.h"
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 */
33 module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO);
34 MODULE_PARM_DESC(rxrpc_debug, "rxkad debugging mask");
36 struct rxkad_level1_hdr {
37 __be32 data_size; /* true data size (excluding padding) */
40 struct rxkad_level2_hdr {
41 __be32 data_size; /* true data size (excluding padding) */
42 __be32 checksum; /* decrypted data checksum */
45 MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos)");
46 MODULE_AUTHOR("Red Hat, Inc.");
47 MODULE_LICENSE("GPL");
50 * this holds a pinned cipher so that keventd doesn't get called by the cipher
51 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
54 static struct crypto_blkcipher *rxkad_ci;
55 static DEFINE_MUTEX(rxkad_ci_mutex);
58 * initialise connection security
60 static int rxkad_init_connection_security(struct rxrpc_connection *conn)
62 struct rxrpc_key_payload *payload;
63 struct crypto_blkcipher *ci;
66 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
68 payload = conn->key->payload.data;
69 conn->security_ix = payload->k.security_index;
71 ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
78 if (crypto_blkcipher_setkey(ci, payload->k.session_key,
79 sizeof(payload->k.session_key)) < 0)
82 switch (conn->security_level) {
83 case RXRPC_SECURITY_PLAIN:
85 case RXRPC_SECURITY_AUTH:
87 conn->security_size = sizeof(struct rxkad_level1_hdr);
88 conn->header_size += sizeof(struct rxkad_level1_hdr);
90 case RXRPC_SECURITY_ENCRYPT:
92 conn->security_size = sizeof(struct rxkad_level2_hdr);
93 conn->header_size += sizeof(struct rxkad_level2_hdr);
103 _leave(" = %d", ret);
108 * prime the encryption state with the invariant parts of a connection's
111 static void rxkad_prime_packet_security(struct rxrpc_connection *conn)
113 struct rxrpc_key_payload *payload;
114 struct blkcipher_desc desc;
115 struct scatterlist sg[2];
116 struct rxrpc_crypt iv;
119 } tmpbuf __attribute__((aligned(16))); /* must all be in same page */
126 payload = conn->key->payload.data;
127 memcpy(&iv, payload->k.session_key, sizeof(iv));
129 desc.tfm = conn->cipher;
133 tmpbuf.x[0] = conn->epoch;
134 tmpbuf.x[1] = conn->cid;
136 tmpbuf.x[3] = htonl(conn->security_ix);
138 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
139 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
140 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
142 memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
143 ASSERTCMP(conn->csum_iv.n[0], ==, tmpbuf.x[2]);
149 * partially encrypt a packet (level 1 security)
151 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
156 struct rxrpc_skb_priv *sp;
157 struct blkcipher_desc desc;
158 struct rxrpc_crypt iv;
159 struct scatterlist sg[2];
161 struct rxkad_level1_hdr hdr;
162 __be32 first; /* first four bytes of data and padding */
163 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
170 check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
171 data_size |= (u32) check << 16;
173 tmpbuf.hdr.data_size = htonl(data_size);
174 memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first));
176 /* start the encryption afresh */
177 memset(&iv, 0, sizeof(iv));
178 desc.tfm = call->conn->cipher;
182 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
183 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
184 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
186 memcpy(sechdr, &tmpbuf, sizeof(tmpbuf));
193 * wholly encrypt a packet (level 2 security)
195 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
200 const struct rxrpc_key_payload *payload;
201 struct rxkad_level2_hdr rxkhdr
202 __attribute__((aligned(8))); /* must be all on one page */
203 struct rxrpc_skb_priv *sp;
204 struct blkcipher_desc desc;
205 struct rxrpc_crypt iv;
206 struct scatterlist sg[16];
207 struct sk_buff *trailer;
216 check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
218 rxkhdr.data_size = htonl(data_size | (u32) check << 16);
221 /* encrypt from the session key */
222 payload = call->conn->key->payload.data;
223 memcpy(&iv, payload->k.session_key, sizeof(iv));
224 desc.tfm = call->conn->cipher;
228 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
229 sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
230 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr));
232 /* we want to encrypt the skbuff in-place */
233 nsg = skb_cow_data(skb, 0, &trailer);
234 if (nsg < 0 || nsg > 16)
237 len = data_size + call->conn->size_align - 1;
238 len &= ~(call->conn->size_align - 1);
240 sg_init_table(sg, skb_to_sgvec(skb, sg, 0, len));
241 crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
248 * checksum an RxRPC packet header
250 static int rxkad_secure_packet(const struct rxrpc_call *call,
255 struct rxrpc_skb_priv *sp;
256 struct blkcipher_desc desc;
257 struct rxrpc_crypt iv;
258 struct scatterlist sg[2];
261 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
267 _enter("{%d{%x}},{#%u},%zu,",
268 call->debug_id, key_serial(call->conn->key), ntohl(sp->hdr.seq),
271 if (!call->conn->cipher)
274 ret = key_validate(call->conn->key);
278 /* continue encrypting from where we left off */
279 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
280 desc.tfm = call->conn->cipher;
284 /* calculate the security checksum */
285 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
286 x |= sp->hdr.seq & __constant_cpu_to_be32(0x3fffffff);
287 tmpbuf.x[0] = sp->hdr.callNumber;
290 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
291 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
292 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
294 x = ntohl(tmpbuf.x[1]);
295 x = (x >> 16) & 0xffff;
297 x = 1; /* zero checksums are not permitted */
298 sp->hdr.cksum = htons(x);
300 switch (call->conn->security_level) {
301 case RXRPC_SECURITY_PLAIN:
304 case RXRPC_SECURITY_AUTH:
305 ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
307 case RXRPC_SECURITY_ENCRYPT:
308 ret = rxkad_secure_packet_encrypt(call, skb, data_size,
316 _leave(" = %d [set %hx]", ret, x);
321 * decrypt partial encryption on a packet (level 1 security)
323 static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
327 struct rxkad_level1_hdr sechdr;
328 struct rxrpc_skb_priv *sp;
329 struct blkcipher_desc desc;
330 struct rxrpc_crypt iv;
331 struct scatterlist sg[16];
332 struct sk_buff *trailer;
341 /* we want to decrypt the skbuff in-place */
342 nsg = skb_cow_data(skb, 0, &trailer);
343 if (nsg < 0 || nsg > 16)
346 sg_init_table(sg, nsg);
347 sg_mark_end(sg, skb_to_sgvec(skb, sg, 0, 8));
349 /* start the decryption afresh */
350 memset(&iv, 0, sizeof(iv));
351 desc.tfm = call->conn->cipher;
355 crypto_blkcipher_decrypt_iv(&desc, sg, sg, 8);
357 /* remove the decrypted packet length */
358 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
360 if (!skb_pull(skb, sizeof(sechdr)))
363 buf = ntohl(sechdr.data_size);
364 data_size = buf & 0xffff;
367 check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
370 *_abort_code = RXKADSEALEDINCON;
374 /* shorten the packet to remove the padding */
375 if (data_size > skb->len)
377 else if (data_size < skb->len)
378 skb->len = data_size;
380 _leave(" = 0 [dlen=%x]", data_size);
384 *_abort_code = RXKADDATALEN;
386 _leave(" = -EPROTO");
390 _leave(" = -ENOMEM");
395 * wholly decrypt a packet (level 2 security)
397 static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
401 const struct rxrpc_key_payload *payload;
402 struct rxkad_level2_hdr sechdr;
403 struct rxrpc_skb_priv *sp;
404 struct blkcipher_desc desc;
405 struct rxrpc_crypt iv;
406 struct scatterlist _sg[4], *sg;
407 struct sk_buff *trailer;
412 _enter(",{%d}", skb->len);
416 /* we want to decrypt the skbuff in-place */
417 nsg = skb_cow_data(skb, 0, &trailer);
422 if (unlikely(nsg > 4)) {
423 sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
428 sg_init_table(sg, nsg);
429 sg_mark_end(sg, skb_to_sgvec(skb, sg, 0, skb->len));
431 /* decrypt from the session key */
432 payload = call->conn->key->payload.data;
433 memcpy(&iv, payload->k.session_key, sizeof(iv));
434 desc.tfm = call->conn->cipher;
438 crypto_blkcipher_decrypt_iv(&desc, sg, sg, skb->len);
442 /* remove the decrypted packet length */
443 if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
445 if (!skb_pull(skb, sizeof(sechdr)))
448 buf = ntohl(sechdr.data_size);
449 data_size = buf & 0xffff;
452 check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
455 *_abort_code = RXKADSEALEDINCON;
459 /* shorten the packet to remove the padding */
460 if (data_size > skb->len)
462 else if (data_size < skb->len)
463 skb->len = data_size;
465 _leave(" = 0 [dlen=%x]", data_size);
469 *_abort_code = RXKADDATALEN;
471 _leave(" = -EPROTO");
475 _leave(" = -ENOMEM");
480 * verify the security on a received packet
482 static int rxkad_verify_packet(const struct rxrpc_call *call,
486 struct blkcipher_desc desc;
487 struct rxrpc_skb_priv *sp;
488 struct rxrpc_crypt iv;
489 struct scatterlist sg[2];
492 } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
499 _enter("{%d{%x}},{#%u}",
500 call->debug_id, key_serial(call->conn->key),
503 if (!call->conn->cipher)
506 if (sp->hdr.securityIndex != 2) {
507 *_abort_code = RXKADINCONSISTENCY;
508 _leave(" = -EPROTO [not rxkad]");
512 /* continue encrypting from where we left off */
513 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
514 desc.tfm = call->conn->cipher;
518 /* validate the security checksum */
519 x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
520 x |= sp->hdr.seq & __constant_cpu_to_be32(0x3fffffff);
521 tmpbuf.x[0] = call->call_id;
524 sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
525 sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
526 crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
528 x = ntohl(tmpbuf.x[1]);
529 x = (x >> 16) & 0xffff;
531 x = 1; /* zero checksums are not permitted */
534 if (sp->hdr.cksum != cksum) {
535 *_abort_code = RXKADSEALEDINCON;
536 _leave(" = -EPROTO [csum failed]");
540 switch (call->conn->security_level) {
541 case RXRPC_SECURITY_PLAIN:
544 case RXRPC_SECURITY_AUTH:
545 ret = rxkad_verify_packet_auth(call, skb, _abort_code);
547 case RXRPC_SECURITY_ENCRYPT:
548 ret = rxkad_verify_packet_encrypt(call, skb, _abort_code);
555 _leave(" = %d", ret);
562 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
564 struct rxkad_challenge challenge;
565 struct rxrpc_header hdr;
571 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
573 ret = key_validate(conn->key);
577 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
579 challenge.version = htonl(2);
580 challenge.nonce = htonl(conn->security_nonce);
581 challenge.min_level = htonl(0);
582 challenge.__padding = 0;
584 msg.msg_name = &conn->trans->peer->srx.transport.sin;
585 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
586 msg.msg_control = NULL;
587 msg.msg_controllen = 0;
590 hdr.epoch = conn->epoch;
594 hdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
595 hdr.flags = conn->out_clientflag;
597 hdr.securityIndex = conn->security_ix;
599 hdr.serviceId = conn->service_id;
601 iov[0].iov_base = &hdr;
602 iov[0].iov_len = sizeof(hdr);
603 iov[1].iov_base = &challenge;
604 iov[1].iov_len = sizeof(challenge);
606 len = iov[0].iov_len + iov[1].iov_len;
608 hdr.serial = htonl(atomic_inc_return(&conn->serial));
609 _proto("Tx CHALLENGE %%%u", ntohl(hdr.serial));
611 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len);
613 _debug("sendmsg failed: %d", ret);
622 * send a Kerberos security response
624 static int rxkad_send_response(struct rxrpc_connection *conn,
625 struct rxrpc_header *hdr,
626 struct rxkad_response *resp,
627 const struct rxkad_key *s2)
636 msg.msg_name = &conn->trans->peer->srx.transport.sin;
637 msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
638 msg.msg_control = NULL;
639 msg.msg_controllen = 0;
642 hdr->epoch = conn->epoch;
644 hdr->type = RXRPC_PACKET_TYPE_RESPONSE;
645 hdr->flags = conn->out_clientflag;
649 iov[0].iov_base = hdr;
650 iov[0].iov_len = sizeof(*hdr);
651 iov[1].iov_base = resp;
652 iov[1].iov_len = sizeof(*resp);
653 iov[2].iov_base = (void *) s2->ticket;
654 iov[2].iov_len = s2->ticket_len;
656 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
658 hdr->serial = htonl(atomic_inc_return(&conn->serial));
659 _proto("Tx RESPONSE %%%u", ntohl(hdr->serial));
661 ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 3, len);
663 _debug("sendmsg failed: %d", ret);
672 * calculate the response checksum
674 static void rxkad_calc_response_checksum(struct rxkad_response *response)
678 u8 *p = (u8 *) response;
680 for (loop = sizeof(*response); loop > 0; loop--)
681 csum = csum * 0x10204081 + *p++;
683 response->encrypted.checksum = htonl(csum);
687 * load a scatterlist with a potentially split-page buffer
689 static void rxkad_sg_set_buf2(struct scatterlist sg[2],
690 void *buf, size_t buflen)
694 sg_init_table(sg, 2);
696 sg_set_buf(&sg[0], buf, buflen);
697 if (sg[0].offset + buflen > PAGE_SIZE) {
698 /* the buffer was split over two pages */
699 sg[0].length = PAGE_SIZE - sg[0].offset;
700 sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
704 sg_mark_end(sg, nsg);
706 ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
710 * encrypt the response packet
712 static void rxkad_encrypt_response(struct rxrpc_connection *conn,
713 struct rxkad_response *resp,
714 const struct rxkad_key *s2)
716 struct blkcipher_desc desc;
717 struct rxrpc_crypt iv;
718 struct scatterlist sg[2];
720 /* continue encrypting from where we left off */
721 memcpy(&iv, s2->session_key, sizeof(iv));
722 desc.tfm = conn->cipher;
726 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
727 crypto_blkcipher_encrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
731 * respond to a challenge packet
733 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
737 const struct rxrpc_key_payload *payload;
738 struct rxkad_challenge challenge;
739 struct rxkad_response resp
740 __attribute__((aligned(8))); /* must be aligned for crypto */
741 struct rxrpc_skb_priv *sp;
742 u32 version, nonce, min_level, abort_code;
745 _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
748 _leave(" = -EPROTO [no key]");
752 ret = key_validate(conn->key);
754 *_abort_code = RXKADEXPIRED;
758 abort_code = RXKADPACKETSHORT;
760 if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0)
763 version = ntohl(challenge.version);
764 nonce = ntohl(challenge.nonce);
765 min_level = ntohl(challenge.min_level);
767 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
768 ntohl(sp->hdr.serial), version, nonce, min_level);
770 abort_code = RXKADINCONSISTENCY;
771 if (version != RXKAD_VERSION)
774 abort_code = RXKADLEVELFAIL;
775 if (conn->security_level < min_level)
778 payload = conn->key->payload.data;
780 /* build the response packet */
781 memset(&resp, 0, sizeof(resp));
783 resp.version = RXKAD_VERSION;
784 resp.encrypted.epoch = conn->epoch;
785 resp.encrypted.cid = conn->cid;
786 resp.encrypted.securityIndex = htonl(conn->security_ix);
787 resp.encrypted.call_id[0] =
788 (conn->channels[0] ? conn->channels[0]->call_id : 0);
789 resp.encrypted.call_id[1] =
790 (conn->channels[1] ? conn->channels[1]->call_id : 0);
791 resp.encrypted.call_id[2] =
792 (conn->channels[2] ? conn->channels[2]->call_id : 0);
793 resp.encrypted.call_id[3] =
794 (conn->channels[3] ? conn->channels[3]->call_id : 0);
795 resp.encrypted.inc_nonce = htonl(nonce + 1);
796 resp.encrypted.level = htonl(conn->security_level);
797 resp.kvno = htonl(payload->k.kvno);
798 resp.ticket_len = htonl(payload->k.ticket_len);
800 /* calculate the response checksum and then do the encryption */
801 rxkad_calc_response_checksum(&resp);
802 rxkad_encrypt_response(conn, &resp, &payload->k);
803 return rxkad_send_response(conn, &sp->hdr, &resp, &payload->k);
806 *_abort_code = abort_code;
807 _leave(" = -EPROTO [%d]", abort_code);
812 * decrypt the kerberos IV ticket in the response
814 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
815 void *ticket, size_t ticket_len,
816 struct rxrpc_crypt *_session_key,
820 struct blkcipher_desc desc;
821 struct rxrpc_crypt iv, key;
822 struct scatterlist sg[1];
828 u8 *p, *q, *name, *end;
830 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
834 ret = key_validate(conn->server_key);
838 *_abort_code = RXKADEXPIRED;
841 *_abort_code = RXKADNOAUTH;
846 ASSERT(conn->server_key->payload.data != NULL);
847 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
849 memcpy(&iv, &conn->server_key->type_data, sizeof(iv));
851 desc.tfm = conn->server_key->payload.data;
855 sg_init_one(&sg[0], ticket, ticket_len);
856 crypto_blkcipher_decrypt_iv(&desc, sg, sg, ticket_len);
859 end = p + ticket_len;
864 q = memchr(p, 0, end - p); \
865 if (!q || q - p > (size)) \
874 /* extract the ticket flags */
875 _debug("KIV FLAGS: %x", *p);
876 little_endian = *p & 1;
879 /* extract the authentication name */
881 _debug("KIV ANAME: %s", name);
883 /* extract the principal's instance */
885 _debug("KIV INST : %s", name);
887 /* extract the principal's authentication domain */
889 _debug("KIV REALM: %s", name);
891 if (end - p < 4 + 8 + 4 + 2)
894 /* get the IPv4 address of the entity that requested the ticket */
895 memcpy(&addr, p, sizeof(addr));
897 _debug("KIV ADDR : "NIPQUAD_FMT, NIPQUAD(addr));
899 /* get the session key from the ticket */
900 memcpy(&key, p, sizeof(key));
902 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
903 memcpy(_session_key, &key, sizeof(key));
905 /* get the ticket's lifetime */
906 life = *p++ * 5 * 60;
907 _debug("KIV LIFE : %u", life);
909 /* get the issue time of the ticket */
912 memcpy(&stamp, p, 4);
913 issue = le32_to_cpu(stamp);
916 memcpy(&stamp, p, 4);
917 issue = be32_to_cpu(stamp);
921 _debug("KIV ISSUE: %lx [%lx]", issue, now);
923 /* check the ticket is in date */
925 *_abort_code = RXKADNOAUTH;
930 if (issue < now - life) {
931 *_abort_code = RXKADEXPIRED;
936 *_expiry = issue + life;
938 /* get the service name */
940 _debug("KIV SNAME: %s", name);
942 /* get the service instance name */
944 _debug("KIV SINST: %s", name);
948 _leave(" = %d", ret);
952 *_abort_code = RXKADBADTICKET;
958 * decrypt the response packet
960 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
961 struct rxkad_response *resp,
962 const struct rxrpc_crypt *session_key)
964 struct blkcipher_desc desc;
965 struct scatterlist sg[2];
966 struct rxrpc_crypt iv;
969 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
971 ASSERT(rxkad_ci != NULL);
973 mutex_lock(&rxkad_ci_mutex);
974 if (crypto_blkcipher_setkey(rxkad_ci, session_key->x,
975 sizeof(*session_key)) < 0)
978 memcpy(&iv, session_key, sizeof(iv));
983 rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
984 crypto_blkcipher_decrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
985 mutex_unlock(&rxkad_ci_mutex);
993 static int rxkad_verify_response(struct rxrpc_connection *conn,
997 struct rxkad_response response
998 __attribute__((aligned(8))); /* must be aligned for crypto */
999 struct rxrpc_skb_priv *sp;
1000 struct rxrpc_crypt session_key;
1003 u32 abort_code, version, kvno, ticket_len, csum, level;
1006 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1008 abort_code = RXKADPACKETSHORT;
1009 if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0)
1010 goto protocol_error;
1011 if (!pskb_pull(skb, sizeof(response)))
1014 version = ntohl(response.version);
1015 ticket_len = ntohl(response.ticket_len);
1016 kvno = ntohl(response.kvno);
1017 sp = rxrpc_skb(skb);
1018 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1019 ntohl(sp->hdr.serial), version, kvno, ticket_len);
1021 abort_code = RXKADINCONSISTENCY;
1022 if (version != RXKAD_VERSION)
1024 abort_code = RXKADTICKETLEN;
1025 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1026 goto protocol_error;
1028 abort_code = RXKADUNKNOWNKEY;
1029 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1030 goto protocol_error;
1032 /* extract the kerberos ticket and decrypt and decode it */
1033 ticket = kmalloc(ticket_len, GFP_NOFS);
1037 abort_code = RXKADPACKETSHORT;
1038 if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
1039 goto protocol_error_free;
1041 ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
1042 &expiry, &abort_code);
1044 *_abort_code = abort_code;
1049 /* use the session key from inside the ticket to decrypt the
1051 rxkad_decrypt_response(conn, &response, &session_key);
1053 abort_code = RXKADSEALEDINCON;
1054 if (response.encrypted.epoch != conn->epoch)
1055 goto protocol_error_free;
1056 if (response.encrypted.cid != conn->cid)
1057 goto protocol_error_free;
1058 if (ntohl(response.encrypted.securityIndex) != conn->security_ix)
1059 goto protocol_error_free;
1060 csum = response.encrypted.checksum;
1061 response.encrypted.checksum = 0;
1062 rxkad_calc_response_checksum(&response);
1063 if (response.encrypted.checksum != csum)
1064 goto protocol_error_free;
1066 if (ntohl(response.encrypted.call_id[0]) > INT_MAX ||
1067 ntohl(response.encrypted.call_id[1]) > INT_MAX ||
1068 ntohl(response.encrypted.call_id[2]) > INT_MAX ||
1069 ntohl(response.encrypted.call_id[3]) > INT_MAX)
1070 goto protocol_error_free;
1072 abort_code = RXKADOUTOFSEQUENCE;
1073 if (response.encrypted.inc_nonce != htonl(conn->security_nonce + 1))
1074 goto protocol_error_free;
1076 abort_code = RXKADLEVELFAIL;
1077 level = ntohl(response.encrypted.level);
1078 if (level > RXRPC_SECURITY_ENCRYPT)
1079 goto protocol_error_free;
1080 conn->security_level = level;
1082 /* create a key to hold the security data and expiration time - after
1083 * this the connection security can be handled in exactly the same way
1084 * as for a client connection */
1085 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1095 protocol_error_free:
1098 *_abort_code = abort_code;
1099 _leave(" = -EPROTO [%d]", abort_code);
1104 * clear the connection security
1106 static void rxkad_clear(struct rxrpc_connection *conn)
1111 crypto_free_blkcipher(conn->cipher);
1115 * RxRPC Kerberos-based security
1117 static struct rxrpc_security rxkad = {
1118 .owner = THIS_MODULE,
1120 .security_index = RXKAD_VERSION,
1121 .init_connection_security = rxkad_init_connection_security,
1122 .prime_packet_security = rxkad_prime_packet_security,
1123 .secure_packet = rxkad_secure_packet,
1124 .verify_packet = rxkad_verify_packet,
1125 .issue_challenge = rxkad_issue_challenge,
1126 .respond_to_challenge = rxkad_respond_to_challenge,
1127 .verify_response = rxkad_verify_response,
1128 .clear = rxkad_clear,
1131 static __init int rxkad_init(void)
1135 /* pin the cipher we need so that the crypto layer doesn't invoke
1136 * keventd to go get it */
1137 rxkad_ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
1138 if (IS_ERR(rxkad_ci))
1139 return PTR_ERR(rxkad_ci);
1141 return rxrpc_register_security(&rxkad);
1144 module_init(rxkad_init);
1146 static __exit void rxkad_exit(void)
1150 rxrpc_unregister_security(&rxkad);
1151 crypto_free_blkcipher(rxkad_ci);
1154 module_exit(rxkad_exit);