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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <crypto/skcipher.h>
15 #include <linux/module.h>
16 #include <linux/net.h>
17 #include <linux/skbuff.h>
18 #include <linux/udp.h>
19 #include <linux/scatterlist.h>
20 #include <linux/ctype.h>
21 #include <linux/slab.h>
23 #include <net/af_rxrpc.h>
24 #include <keys/rxrpc-type.h>
25 #include "ar-internal.h"
27 #define RXKAD_VERSION 2
28 #define MAXKRB5TICKETLEN 1024
29 #define RXKAD_TKT_TYPE_KERBEROS_V5 256
30 #define ANAME_SZ 40 /* size of authentication name */
31 #define INST_SZ 40 /* size of principal's instance */
32 #define REALM_SZ 40 /* size of principal's auth domain */
33 #define SNAME_SZ 40 /* size of service name */
35 struct rxkad_level1_hdr {
36 __be32 data_size; /* true data size (excluding padding) */
39 struct rxkad_level2_hdr {
40 __be32 data_size; /* true data size (excluding padding) */
41 __be32 checksum; /* decrypted data checksum */
45 * this holds a pinned cipher so that keventd doesn't get called by the cipher
46 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
49 static struct crypto_skcipher *rxkad_ci;
50 static DEFINE_MUTEX(rxkad_ci_mutex);
53 * initialise connection security
55 static int rxkad_init_connection_security(struct rxrpc_connection *conn)
57 struct crypto_skcipher *ci;
58 struct rxrpc_key_token *token;
61 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->params.key));
63 token = conn->params.key->payload.data[0];
64 conn->security_ix = token->security_index;
66 ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
73 if (crypto_skcipher_setkey(ci, token->kad->session_key,
74 sizeof(token->kad->session_key)) < 0)
77 switch (conn->params.security_level) {
78 case RXRPC_SECURITY_PLAIN:
80 case RXRPC_SECURITY_AUTH:
82 conn->security_size = sizeof(struct rxkad_level1_hdr);
84 case RXRPC_SECURITY_ENCRYPT:
86 conn->security_size = sizeof(struct rxkad_level2_hdr);
101 * prime the encryption state with the invariant parts of a connection's
104 static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
106 struct rxrpc_key_token *token;
107 SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
108 struct scatterlist sg;
109 struct rxrpc_crypt iv;
111 size_t tmpsize = 4 * sizeof(__be32);
115 if (!conn->params.key)
118 tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
122 token = conn->params.key->payload.data[0];
123 memcpy(&iv, token->kad->session_key, sizeof(iv));
125 tmpbuf[0] = htonl(conn->proto.epoch);
126 tmpbuf[1] = htonl(conn->proto.cid);
128 tmpbuf[3] = htonl(conn->security_ix);
130 sg_init_one(&sg, tmpbuf, tmpsize);
131 skcipher_request_set_tfm(req, conn->cipher);
132 skcipher_request_set_callback(req, 0, NULL, NULL);
133 skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
134 crypto_skcipher_encrypt(req);
135 skcipher_request_zero(req);
137 memcpy(&conn->csum_iv, tmpbuf + 2, sizeof(conn->csum_iv));
144 * partially encrypt a packet (level 1 security)
146 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
151 struct rxrpc_skb_priv *sp;
152 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
153 struct rxkad_level1_hdr hdr;
154 struct rxrpc_crypt iv;
155 struct scatterlist sg;
162 check = sp->hdr.seq ^ call->call_id;
163 data_size |= (u32)check << 16;
165 hdr.data_size = htonl(data_size);
166 memcpy(sechdr, &hdr, sizeof(hdr));
168 /* start the encryption afresh */
169 memset(&iv, 0, sizeof(iv));
171 sg_init_one(&sg, sechdr, 8);
172 skcipher_request_set_tfm(req, call->conn->cipher);
173 skcipher_request_set_callback(req, 0, NULL, NULL);
174 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
175 crypto_skcipher_encrypt(req);
176 skcipher_request_zero(req);
183 * wholly encrypt a packet (level 2 security)
185 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
190 const struct rxrpc_key_token *token;
191 struct rxkad_level2_hdr rxkhdr;
192 struct rxrpc_skb_priv *sp;
193 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
194 struct rxrpc_crypt iv;
195 struct scatterlist sg[16];
196 struct sk_buff *trailer;
206 check = sp->hdr.seq ^ call->call_id;
208 rxkhdr.data_size = htonl(data_size | (u32)check << 16);
210 memcpy(sechdr, &rxkhdr, sizeof(rxkhdr));
212 /* encrypt from the session key */
213 token = call->conn->params.key->payload.data[0];
214 memcpy(&iv, token->kad->session_key, sizeof(iv));
216 sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
217 skcipher_request_set_tfm(req, call->conn->cipher);
218 skcipher_request_set_callback(req, 0, NULL, NULL);
219 skcipher_request_set_crypt(req, &sg[0], &sg[0], sizeof(rxkhdr), iv.x);
220 crypto_skcipher_encrypt(req);
222 /* we want to encrypt the skbuff in-place */
223 nsg = skb_cow_data(skb, 0, &trailer);
225 if (nsg < 0 || nsg > 16)
228 len = data_size + call->conn->size_align - 1;
229 len &= ~(call->conn->size_align - 1);
231 sg_init_table(sg, nsg);
232 err = skb_to_sgvec(skb, sg, 0, len);
233 if (unlikely(err < 0))
235 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
236 crypto_skcipher_encrypt(req);
242 skcipher_request_zero(req);
247 * checksum an RxRPC packet header
249 static int rxkad_secure_packet(struct rxrpc_call *call,
254 struct rxrpc_skb_priv *sp;
255 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
256 struct rxrpc_crypt iv;
257 struct scatterlist sg;
263 _enter("{%d{%x}},{#%u},%zu,",
264 call->debug_id, key_serial(call->conn->params.key),
265 sp->hdr.seq, data_size);
267 if (!call->conn->cipher)
270 ret = key_validate(call->conn->params.key);
274 /* continue encrypting from where we left off */
275 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
277 /* calculate the security checksum */
278 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
279 x |= sp->hdr.seq & 0x3fffffff;
280 call->crypto_buf[0] = htonl(call->call_id);
281 call->crypto_buf[1] = htonl(x);
283 sg_init_one(&sg, call->crypto_buf, 8);
284 skcipher_request_set_tfm(req, call->conn->cipher);
285 skcipher_request_set_callback(req, 0, NULL, NULL);
286 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
287 crypto_skcipher_encrypt(req);
288 skcipher_request_zero(req);
290 y = ntohl(call->crypto_buf[1]);
291 y = (y >> 16) & 0xffff;
293 y = 1; /* zero checksums are not permitted */
296 switch (call->conn->params.security_level) {
297 case RXRPC_SECURITY_PLAIN:
300 case RXRPC_SECURITY_AUTH:
301 ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
303 case RXRPC_SECURITY_ENCRYPT:
304 ret = rxkad_secure_packet_encrypt(call, skb, data_size,
312 _leave(" = %d [set %hx]", ret, y);
317 * decrypt partial encryption on a packet (level 1 security)
319 static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
320 unsigned int offset, unsigned int len,
323 struct rxkad_level1_hdr sechdr;
324 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
325 struct rxrpc_crypt iv;
326 struct scatterlist sg[16];
327 struct sk_buff *trailer;
335 rxrpc_abort_call("V1H", call, seq, RXKADSEALEDINCON, EPROTO);
339 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
340 * directly into the target buffer.
342 nsg = skb_cow_data(skb, 0, &trailer);
343 if (nsg < 0 || nsg > 16)
346 sg_init_table(sg, nsg);
347 ret = skb_to_sgvec(skb, sg, offset, 8);
348 if (unlikely(ret < 0))
351 /* start the decryption afresh */
352 memset(&iv, 0, sizeof(iv));
354 skcipher_request_set_tfm(req, call->conn->cipher);
355 skcipher_request_set_callback(req, 0, NULL, NULL);
356 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
357 crypto_skcipher_decrypt(req);
358 skcipher_request_zero(req);
360 /* Extract the decrypted packet length */
361 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
362 rxrpc_abort_call("XV1", call, seq, RXKADDATALEN, EPROTO);
365 offset += sizeof(sechdr);
366 len -= sizeof(sechdr);
368 buf = ntohl(sechdr.data_size);
369 data_size = buf & 0xffff;
372 check ^= seq ^ call->call_id;
375 rxrpc_abort_call("V1C", call, seq, RXKADSEALEDINCON, EPROTO);
379 if (data_size > len) {
380 rxrpc_abort_call("V1L", call, seq, RXKADDATALEN, EPROTO);
384 _leave(" = 0 [dlen=%x]", data_size);
388 rxrpc_send_abort_packet(call);
389 _leave(" = -EPROTO");
393 _leave(" = -ENOMEM");
398 * wholly decrypt a packet (level 2 security)
400 static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
401 unsigned int offset, unsigned int len,
404 const struct rxrpc_key_token *token;
405 struct rxkad_level2_hdr sechdr;
406 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
407 struct rxrpc_crypt iv;
408 struct scatterlist _sg[4], *sg;
409 struct sk_buff *trailer;
414 _enter(",{%d}", skb->len);
417 rxrpc_abort_call("V2H", call, seq, RXKADSEALEDINCON, EPROTO);
421 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
422 * directly into the target buffer.
424 nsg = skb_cow_data(skb, 0, &trailer);
429 if (unlikely(nsg > 4)) {
430 sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
435 sg_init_table(sg, nsg);
436 ret = skb_to_sgvec(skb, sg, offset, len);
437 if (unlikely(ret < 0)) {
443 /* decrypt from the session key */
444 token = call->conn->params.key->payload.data[0];
445 memcpy(&iv, token->kad->session_key, sizeof(iv));
447 skcipher_request_set_tfm(req, call->conn->cipher);
448 skcipher_request_set_callback(req, 0, NULL, NULL);
449 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
450 crypto_skcipher_decrypt(req);
451 skcipher_request_zero(req);
455 /* Extract the decrypted packet length */
456 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
457 rxrpc_abort_call("XV2", call, seq, RXKADDATALEN, EPROTO);
460 offset += sizeof(sechdr);
461 len -= sizeof(sechdr);
463 buf = ntohl(sechdr.data_size);
464 data_size = buf & 0xffff;
467 check ^= seq ^ call->call_id;
470 rxrpc_abort_call("V2C", call, seq, RXKADSEALEDINCON, EPROTO);
474 if (data_size > len) {
475 rxrpc_abort_call("V2L", call, seq, RXKADDATALEN, EPROTO);
479 _leave(" = 0 [dlen=%x]", data_size);
483 rxrpc_send_abort_packet(call);
484 _leave(" = -EPROTO");
488 _leave(" = -ENOMEM");
493 * Verify the security on a received packet or subpacket (if part of a
496 static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
497 unsigned int offset, unsigned int len,
498 rxrpc_seq_t seq, u16 expected_cksum)
500 SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
501 struct rxrpc_crypt iv;
502 struct scatterlist sg;
506 _enter("{%d{%x}},{#%u}",
507 call->debug_id, key_serial(call->conn->params.key), seq);
509 if (!call->conn->cipher)
512 /* continue encrypting from where we left off */
513 memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
515 /* validate the security checksum */
516 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
517 x |= seq & 0x3fffffff;
518 call->crypto_buf[0] = htonl(call->call_id);
519 call->crypto_buf[1] = htonl(x);
521 sg_init_one(&sg, call->crypto_buf, 8);
522 skcipher_request_set_tfm(req, call->conn->cipher);
523 skcipher_request_set_callback(req, 0, NULL, NULL);
524 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
525 crypto_skcipher_encrypt(req);
526 skcipher_request_zero(req);
528 y = ntohl(call->crypto_buf[1]);
529 cksum = (y >> 16) & 0xffff;
531 cksum = 1; /* zero checksums are not permitted */
533 if (cksum != expected_cksum) {
534 rxrpc_abort_call("VCK", call, seq, RXKADSEALEDINCON, EPROTO);
535 rxrpc_send_abort_packet(call);
536 _leave(" = -EPROTO [csum failed]");
540 switch (call->conn->params.security_level) {
541 case RXRPC_SECURITY_PLAIN:
543 case RXRPC_SECURITY_AUTH:
544 return rxkad_verify_packet_1(call, skb, offset, len, seq);
545 case RXRPC_SECURITY_ENCRYPT:
546 return rxkad_verify_packet_2(call, skb, offset, len, seq);
553 * Locate the data contained in a packet that was partially encrypted.
555 static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb,
556 unsigned int *_offset, unsigned int *_len)
558 struct rxkad_level1_hdr sechdr;
560 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
562 *_offset += sizeof(sechdr);
563 *_len = ntohl(sechdr.data_size) & 0xffff;
567 * Locate the data contained in a packet that was completely encrypted.
569 static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb,
570 unsigned int *_offset, unsigned int *_len)
572 struct rxkad_level2_hdr sechdr;
574 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
576 *_offset += sizeof(sechdr);
577 *_len = ntohl(sechdr.data_size) & 0xffff;
581 * Locate the data contained in an already decrypted packet.
583 static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
584 unsigned int *_offset, unsigned int *_len)
586 switch (call->conn->params.security_level) {
587 case RXRPC_SECURITY_AUTH:
588 rxkad_locate_data_1(call, skb, _offset, _len);
590 case RXRPC_SECURITY_ENCRYPT:
591 rxkad_locate_data_2(call, skb, _offset, _len);
601 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
603 struct rxkad_challenge challenge;
604 struct rxrpc_wire_header whdr;
611 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
613 ret = key_validate(conn->params.key);
617 get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
619 challenge.version = htonl(2);
620 challenge.nonce = htonl(conn->security_nonce);
621 challenge.min_level = htonl(0);
622 challenge.__padding = 0;
624 msg.msg_name = &conn->params.peer->srx.transport.sin;
625 msg.msg_namelen = sizeof(conn->params.peer->srx.transport.sin);
626 msg.msg_control = NULL;
627 msg.msg_controllen = 0;
630 whdr.epoch = htonl(conn->proto.epoch);
631 whdr.cid = htonl(conn->proto.cid);
634 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
635 whdr.flags = conn->out_clientflag;
637 whdr.securityIndex = conn->security_ix;
639 whdr.serviceId = htons(conn->params.service_id);
641 iov[0].iov_base = &whdr;
642 iov[0].iov_len = sizeof(whdr);
643 iov[1].iov_base = &challenge;
644 iov[1].iov_len = sizeof(challenge);
646 len = iov[0].iov_len + iov[1].iov_len;
648 serial = atomic_inc_return(&conn->serial);
649 whdr.serial = htonl(serial);
650 _proto("Tx CHALLENGE %%%u", serial);
652 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
654 _debug("sendmsg failed: %d", ret);
663 * send a Kerberos security response
665 static int rxkad_send_response(struct rxrpc_connection *conn,
666 struct rxrpc_host_header *hdr,
667 struct rxkad_response *resp,
668 const struct rxkad_key *s2)
670 struct rxrpc_wire_header whdr;
679 msg.msg_name = &conn->params.peer->srx.transport.sin;
680 msg.msg_namelen = sizeof(conn->params.peer->srx.transport.sin);
681 msg.msg_control = NULL;
682 msg.msg_controllen = 0;
685 memset(&whdr, 0, sizeof(whdr));
686 whdr.epoch = htonl(hdr->epoch);
687 whdr.cid = htonl(hdr->cid);
688 whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
689 whdr.flags = conn->out_clientflag;
690 whdr.securityIndex = hdr->securityIndex;
691 whdr.serviceId = htons(hdr->serviceId);
693 iov[0].iov_base = &whdr;
694 iov[0].iov_len = sizeof(whdr);
695 iov[1].iov_base = resp;
696 iov[1].iov_len = sizeof(*resp);
697 iov[2].iov_base = (void *)s2->ticket;
698 iov[2].iov_len = s2->ticket_len;
700 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
702 serial = atomic_inc_return(&conn->serial);
703 whdr.serial = htonl(serial);
704 _proto("Tx RESPONSE %%%u", serial);
706 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 3, len);
708 _debug("sendmsg failed: %d", ret);
717 * calculate the response checksum
719 static void rxkad_calc_response_checksum(struct rxkad_response *response)
723 u8 *p = (u8 *) response;
725 for (loop = sizeof(*response); loop > 0; loop--)
726 csum = csum * 0x10204081 + *p++;
728 response->encrypted.checksum = htonl(csum);
732 * encrypt the response packet
734 static void rxkad_encrypt_response(struct rxrpc_connection *conn,
735 struct rxkad_response *resp,
736 const struct rxkad_key *s2)
738 SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
739 struct rxrpc_crypt iv;
740 struct scatterlist sg[1];
742 /* continue encrypting from where we left off */
743 memcpy(&iv, s2->session_key, sizeof(iv));
745 sg_init_table(sg, 1);
746 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
747 skcipher_request_set_tfm(req, conn->cipher);
748 skcipher_request_set_callback(req, 0, NULL, NULL);
749 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
750 crypto_skcipher_encrypt(req);
751 skcipher_request_zero(req);
755 * respond to a challenge packet
757 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
761 const struct rxrpc_key_token *token;
762 struct rxkad_challenge challenge;
763 struct rxkad_response resp
764 __attribute__((aligned(8))); /* must be aligned for crypto */
765 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
766 u32 version, nonce, min_level, abort_code;
769 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
771 if (!conn->params.key) {
772 _leave(" = -EPROTO [no key]");
776 ret = key_validate(conn->params.key);
778 *_abort_code = RXKADEXPIRED;
782 abort_code = RXKADPACKETSHORT;
783 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
784 &challenge, sizeof(challenge)) < 0)
787 version = ntohl(challenge.version);
788 nonce = ntohl(challenge.nonce);
789 min_level = ntohl(challenge.min_level);
791 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
792 sp->hdr.serial, version, nonce, min_level);
794 abort_code = RXKADINCONSISTENCY;
795 if (version != RXKAD_VERSION)
798 abort_code = RXKADLEVELFAIL;
799 if (conn->params.security_level < min_level)
802 token = conn->params.key->payload.data[0];
804 /* build the response packet */
805 memset(&resp, 0, sizeof(resp));
807 resp.version = htonl(RXKAD_VERSION);
808 resp.encrypted.epoch = htonl(conn->proto.epoch);
809 resp.encrypted.cid = htonl(conn->proto.cid);
810 resp.encrypted.securityIndex = htonl(conn->security_ix);
811 resp.encrypted.inc_nonce = htonl(nonce + 1);
812 resp.encrypted.level = htonl(conn->params.security_level);
813 resp.kvno = htonl(token->kad->kvno);
814 resp.ticket_len = htonl(token->kad->ticket_len);
816 resp.encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
817 resp.encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
818 resp.encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
819 resp.encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
821 /* calculate the response checksum and then do the encryption */
822 rxkad_calc_response_checksum(&resp);
823 rxkad_encrypt_response(conn, &resp, token->kad);
824 return rxkad_send_response(conn, &sp->hdr, &resp, token->kad);
827 *_abort_code = abort_code;
828 _leave(" = -EPROTO [%d]", abort_code);
833 * decrypt the kerberos IV ticket in the response
835 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
836 void *ticket, size_t ticket_len,
837 struct rxrpc_crypt *_session_key,
841 struct skcipher_request *req;
842 struct rxrpc_crypt iv, key;
843 struct scatterlist sg[1];
849 u8 *p, *q, *name, *end;
851 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
855 ret = key_validate(conn->server_key);
859 *_abort_code = RXKADEXPIRED;
862 *_abort_code = RXKADNOAUTH;
867 ASSERT(conn->server_key->payload.data[0] != NULL);
868 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
870 memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv));
872 req = skcipher_request_alloc(conn->server_key->payload.data[0],
875 *_abort_code = RXKADNOAUTH;
880 sg_init_one(&sg[0], ticket, ticket_len);
881 skcipher_request_set_callback(req, 0, NULL, NULL);
882 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
883 crypto_skcipher_decrypt(req);
884 skcipher_request_free(req);
887 end = p + ticket_len;
892 q = memchr(p, 0, end - p); \
893 if (!q || q - p > (size)) \
902 /* extract the ticket flags */
903 _debug("KIV FLAGS: %x", *p);
904 little_endian = *p & 1;
907 /* extract the authentication name */
909 _debug("KIV ANAME: %s", name);
911 /* extract the principal's instance */
913 _debug("KIV INST : %s", name);
915 /* extract the principal's authentication domain */
917 _debug("KIV REALM: %s", name);
919 if (end - p < 4 + 8 + 4 + 2)
922 /* get the IPv4 address of the entity that requested the ticket */
923 memcpy(&addr, p, sizeof(addr));
925 _debug("KIV ADDR : %pI4", &addr);
927 /* get the session key from the ticket */
928 memcpy(&key, p, sizeof(key));
930 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
931 memcpy(_session_key, &key, sizeof(key));
933 /* get the ticket's lifetime */
934 life = *p++ * 5 * 60;
935 _debug("KIV LIFE : %u", life);
937 /* get the issue time of the ticket */
940 memcpy(&stamp, p, 4);
941 issue = le32_to_cpu(stamp);
944 memcpy(&stamp, p, 4);
945 issue = be32_to_cpu(stamp);
949 _debug("KIV ISSUE: %lx [%lx]", issue, now);
951 /* check the ticket is in date */
953 *_abort_code = RXKADNOAUTH;
958 if (issue < now - life) {
959 *_abort_code = RXKADEXPIRED;
964 *_expiry = issue + life;
966 /* get the service name */
968 _debug("KIV SNAME: %s", name);
970 /* get the service instance name */
972 _debug("KIV SINST: %s", name);
976 _leave(" = %d", ret);
980 *_abort_code = RXKADBADTICKET;
986 * decrypt the response packet
988 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
989 struct rxkad_response *resp,
990 const struct rxrpc_crypt *session_key)
992 SKCIPHER_REQUEST_ON_STACK(req, rxkad_ci);
993 struct scatterlist sg[1];
994 struct rxrpc_crypt iv;
997 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
999 ASSERT(rxkad_ci != NULL);
1001 mutex_lock(&rxkad_ci_mutex);
1002 if (crypto_skcipher_setkey(rxkad_ci, session_key->x,
1003 sizeof(*session_key)) < 0)
1006 memcpy(&iv, session_key, sizeof(iv));
1008 sg_init_table(sg, 1);
1009 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1010 skcipher_request_set_tfm(req, rxkad_ci);
1011 skcipher_request_set_callback(req, 0, NULL, NULL);
1012 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1013 crypto_skcipher_decrypt(req);
1014 skcipher_request_zero(req);
1016 mutex_unlock(&rxkad_ci_mutex);
1024 static int rxkad_verify_response(struct rxrpc_connection *conn,
1025 struct sk_buff *skb,
1028 struct rxkad_response response
1029 __attribute__((aligned(8))); /* must be aligned for crypto */
1030 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1031 struct rxrpc_crypt session_key;
1034 u32 abort_code, version, kvno, ticket_len, level;
1038 _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
1040 abort_code = RXKADPACKETSHORT;
1041 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1042 &response, sizeof(response)) < 0)
1043 goto protocol_error;
1044 if (!pskb_pull(skb, sizeof(response)))
1047 version = ntohl(response.version);
1048 ticket_len = ntohl(response.ticket_len);
1049 kvno = ntohl(response.kvno);
1050 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1051 sp->hdr.serial, version, kvno, ticket_len);
1053 abort_code = RXKADINCONSISTENCY;
1054 if (version != RXKAD_VERSION)
1055 goto protocol_error;
1057 abort_code = RXKADTICKETLEN;
1058 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1059 goto protocol_error;
1061 abort_code = RXKADUNKNOWNKEY;
1062 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1063 goto protocol_error;
1065 /* extract the kerberos ticket and decrypt and decode it */
1066 ticket = kmalloc(ticket_len, GFP_NOFS);
1070 abort_code = RXKADPACKETSHORT;
1071 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1072 ticket, ticket_len) < 0)
1073 goto protocol_error_free;
1075 ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
1076 &expiry, &abort_code);
1078 *_abort_code = abort_code;
1083 /* use the session key from inside the ticket to decrypt the
1085 rxkad_decrypt_response(conn, &response, &session_key);
1087 abort_code = RXKADSEALEDINCON;
1088 if (ntohl(response.encrypted.epoch) != conn->proto.epoch)
1089 goto protocol_error_free;
1090 if (ntohl(response.encrypted.cid) != conn->proto.cid)
1091 goto protocol_error_free;
1092 if (ntohl(response.encrypted.securityIndex) != conn->security_ix)
1093 goto protocol_error_free;
1094 csum = response.encrypted.checksum;
1095 response.encrypted.checksum = 0;
1096 rxkad_calc_response_checksum(&response);
1097 if (response.encrypted.checksum != csum)
1098 goto protocol_error_free;
1100 spin_lock(&conn->channel_lock);
1101 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1102 struct rxrpc_call *call;
1103 u32 call_id = ntohl(response.encrypted.call_id[i]);
1105 if (call_id > INT_MAX)
1106 goto protocol_error_unlock;
1108 if (call_id < conn->channels[i].call_counter)
1109 goto protocol_error_unlock;
1110 if (call_id > conn->channels[i].call_counter) {
1111 call = rcu_dereference_protected(
1112 conn->channels[i].call,
1113 lockdep_is_held(&conn->channel_lock));
1114 if (call && call->state < RXRPC_CALL_COMPLETE)
1115 goto protocol_error_unlock;
1116 conn->channels[i].call_counter = call_id;
1119 spin_unlock(&conn->channel_lock);
1121 abort_code = RXKADOUTOFSEQUENCE;
1122 if (ntohl(response.encrypted.inc_nonce) != conn->security_nonce + 1)
1123 goto protocol_error_free;
1125 abort_code = RXKADLEVELFAIL;
1126 level = ntohl(response.encrypted.level);
1127 if (level > RXRPC_SECURITY_ENCRYPT)
1128 goto protocol_error_free;
1129 conn->params.security_level = level;
1131 /* create a key to hold the security data and expiration time - after
1132 * this the connection security can be handled in exactly the same way
1133 * as for a client connection */
1134 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1144 protocol_error_unlock:
1145 spin_unlock(&conn->channel_lock);
1146 protocol_error_free:
1149 *_abort_code = abort_code;
1150 _leave(" = -EPROTO [%d]", abort_code);
1155 * clear the connection security
1157 static void rxkad_clear(struct rxrpc_connection *conn)
1162 crypto_free_skcipher(conn->cipher);
1166 * Initialise the rxkad security service.
1168 static int rxkad_init(void)
1170 /* pin the cipher we need so that the crypto layer doesn't invoke
1171 * keventd to go get it */
1172 rxkad_ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
1173 return PTR_ERR_OR_ZERO(rxkad_ci);
1177 * Clean up the rxkad security service.
1179 static void rxkad_exit(void)
1182 crypto_free_skcipher(rxkad_ci);
1186 * RxRPC Kerberos-based security
1188 const struct rxrpc_security rxkad = {
1190 .security_index = RXRPC_SECURITY_RXKAD,
1193 .init_connection_security = rxkad_init_connection_security,
1194 .prime_packet_security = rxkad_prime_packet_security,
1195 .secure_packet = rxkad_secure_packet,
1196 .verify_packet = rxkad_verify_packet,
1197 .locate_data = rxkad_locate_data,
1198 .issue_challenge = rxkad_issue_challenge,
1199 .respond_to_challenge = rxkad_respond_to_challenge,
1200 .verify_response = rxkad_verify_response,
1201 .clear = rxkad_clear,