1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Kerberos-based RxRPC security
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
20 #include <net/af_rxrpc.h>
21 #include <keys/rxrpc-type.h>
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 struct rxkad_level1_hdr {
34 __be32 data_size; /* true data size (excluding padding) */
37 struct rxkad_level2_hdr {
38 __be32 data_size; /* true data size (excluding padding) */
39 __be32 checksum; /* decrypted data checksum */
42 static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
43 struct crypto_sync_skcipher *ci);
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
50 static struct crypto_sync_skcipher *rxkad_ci;
51 static struct skcipher_request *rxkad_ci_req;
52 static DEFINE_MUTEX(rxkad_ci_mutex);
55 * Parse the information from a server key
57 * The data should be the 8-byte secret key.
59 static int rxkad_preparse_server_key(struct key_preparsed_payload *prep)
61 struct crypto_skcipher *ci;
63 if (prep->datalen != 8)
66 memcpy(&prep->payload.data[2], prep->data, 8);
68 ci = crypto_alloc_skcipher("pcbc(des)", 0, CRYPTO_ALG_ASYNC);
70 _leave(" = %ld", PTR_ERR(ci));
74 if (crypto_skcipher_setkey(ci, prep->data, 8) < 0)
77 prep->payload.data[0] = ci;
82 static void rxkad_free_preparse_server_key(struct key_preparsed_payload *prep)
85 if (prep->payload.data[0])
86 crypto_free_skcipher(prep->payload.data[0]);
89 static void rxkad_destroy_server_key(struct key *key)
91 if (key->payload.data[0]) {
92 crypto_free_skcipher(key->payload.data[0]);
93 key->payload.data[0] = NULL;
98 * initialise connection security
100 static int rxkad_init_connection_security(struct rxrpc_connection *conn,
101 struct rxrpc_key_token *token)
103 struct crypto_sync_skcipher *ci;
106 _enter("{%d},{%x}", conn->debug_id, key_serial(conn->params.key));
108 conn->security_ix = token->security_index;
110 ci = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
117 if (crypto_sync_skcipher_setkey(ci, token->kad->session_key,
118 sizeof(token->kad->session_key)) < 0)
121 switch (conn->params.security_level) {
122 case RXRPC_SECURITY_PLAIN:
123 case RXRPC_SECURITY_AUTH:
124 case RXRPC_SECURITY_ENCRYPT:
131 ret = rxkad_prime_packet_security(conn, ci);
135 conn->rxkad.cipher = ci;
139 crypto_free_sync_skcipher(ci);
141 _leave(" = %d", ret);
146 * Work out how much data we can put in a packet.
148 static int rxkad_how_much_data(struct rxrpc_call *call, size_t remain,
149 size_t *_buf_size, size_t *_data_size, size_t *_offset)
151 size_t shdr, buf_size, chunk;
153 switch (call->conn->params.security_level) {
155 buf_size = chunk = min_t(size_t, remain, RXRPC_JUMBO_DATALEN);
158 case RXRPC_SECURITY_AUTH:
159 shdr = sizeof(struct rxkad_level1_hdr);
161 case RXRPC_SECURITY_ENCRYPT:
162 shdr = sizeof(struct rxkad_level2_hdr);
166 buf_size = round_down(RXRPC_JUMBO_DATALEN, RXKAD_ALIGN);
168 chunk = buf_size - shdr;
170 buf_size = round_up(shdr + remain, RXKAD_ALIGN);
173 *_buf_size = buf_size;
180 * prime the encryption state with the invariant parts of a connection's
183 static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
184 struct crypto_sync_skcipher *ci)
186 struct skcipher_request *req;
187 struct rxrpc_key_token *token;
188 struct scatterlist sg;
189 struct rxrpc_crypt iv;
191 size_t tmpsize = 4 * sizeof(__be32);
195 if (!conn->params.key)
198 tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
202 req = skcipher_request_alloc(&ci->base, GFP_NOFS);
208 token = conn->params.key->payload.data[0];
209 memcpy(&iv, token->kad->session_key, sizeof(iv));
211 tmpbuf[0] = htonl(conn->proto.epoch);
212 tmpbuf[1] = htonl(conn->proto.cid);
214 tmpbuf[3] = htonl(conn->security_ix);
216 sg_init_one(&sg, tmpbuf, tmpsize);
217 skcipher_request_set_sync_tfm(req, ci);
218 skcipher_request_set_callback(req, 0, NULL, NULL);
219 skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
220 crypto_skcipher_encrypt(req);
221 skcipher_request_free(req);
223 memcpy(&conn->rxkad.csum_iv, tmpbuf + 2, sizeof(conn->rxkad.csum_iv));
230 * Allocate and prepare the crypto request on a call. For any particular call,
231 * this is called serially for the packets, so no lock should be necessary.
233 static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
235 struct crypto_skcipher *tfm = &call->conn->rxkad.cipher->base;
236 struct skcipher_request *cipher_req = call->cipher_req;
239 cipher_req = skcipher_request_alloc(tfm, GFP_NOFS);
242 call->cipher_req = cipher_req;
249 * Clean up the crypto on a call.
251 static void rxkad_free_call_crypto(struct rxrpc_call *call)
253 if (call->cipher_req)
254 skcipher_request_free(call->cipher_req);
255 call->cipher_req = NULL;
259 * partially encrypt a packet (level 1 security)
261 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
262 struct sk_buff *skb, u32 data_size,
263 struct skcipher_request *req)
265 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
266 struct rxkad_level1_hdr hdr;
267 struct rxrpc_crypt iv;
268 struct scatterlist sg;
274 check = sp->hdr.seq ^ call->call_id;
275 data_size |= (u32)check << 16;
277 hdr.data_size = htonl(data_size);
278 memcpy(skb->head, &hdr, sizeof(hdr));
280 pad = sizeof(struct rxkad_level1_hdr) + data_size;
281 pad = RXKAD_ALIGN - pad;
282 pad &= RXKAD_ALIGN - 1;
284 skb_put_zero(skb, pad);
286 /* start the encryption afresh */
287 memset(&iv, 0, sizeof(iv));
289 sg_init_one(&sg, skb->head, 8);
290 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
291 skcipher_request_set_callback(req, 0, NULL, NULL);
292 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
293 crypto_skcipher_encrypt(req);
294 skcipher_request_zero(req);
301 * wholly encrypt a packet (level 2 security)
303 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
306 struct skcipher_request *req)
308 const struct rxrpc_key_token *token;
309 struct rxkad_level2_hdr rxkhdr;
310 struct rxrpc_skb_priv *sp;
311 struct rxrpc_crypt iv;
312 struct scatterlist sg[16];
322 check = sp->hdr.seq ^ call->call_id;
324 rxkhdr.data_size = htonl(data_size | (u32)check << 16);
326 memcpy(skb->head, &rxkhdr, sizeof(rxkhdr));
328 pad = sizeof(struct rxkad_level2_hdr) + data_size;
329 pad = RXKAD_ALIGN - pad;
330 pad &= RXKAD_ALIGN - 1;
332 skb_put_zero(skb, pad);
334 /* encrypt from the session key */
335 token = call->conn->params.key->payload.data[0];
336 memcpy(&iv, token->kad->session_key, sizeof(iv));
338 sg_init_one(&sg[0], skb->head, sizeof(rxkhdr));
339 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
340 skcipher_request_set_callback(req, 0, NULL, NULL);
341 skcipher_request_set_crypt(req, &sg[0], &sg[0], sizeof(rxkhdr), iv.x);
342 crypto_skcipher_encrypt(req);
344 /* we want to encrypt the skbuff in-place */
346 if (skb_shinfo(skb)->nr_frags > 16)
349 len = round_up(data_size, RXKAD_ALIGN);
351 sg_init_table(sg, ARRAY_SIZE(sg));
352 err = skb_to_sgvec(skb, sg, 8, len);
353 if (unlikely(err < 0))
355 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
356 crypto_skcipher_encrypt(req);
362 skcipher_request_zero(req);
367 * checksum an RxRPC packet header
369 static int rxkad_secure_packet(struct rxrpc_call *call,
373 struct rxrpc_skb_priv *sp;
374 struct skcipher_request *req;
375 struct rxrpc_crypt iv;
376 struct scatterlist sg;
382 _enter("{%d{%x}},{#%u},%zu,",
383 call->debug_id, key_serial(call->conn->params.key),
384 sp->hdr.seq, data_size);
386 if (!call->conn->rxkad.cipher)
389 ret = key_validate(call->conn->params.key);
393 req = rxkad_get_call_crypto(call);
397 /* continue encrypting from where we left off */
398 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
400 /* calculate the security checksum */
401 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
402 x |= sp->hdr.seq & 0x3fffffff;
403 call->crypto_buf[0] = htonl(call->call_id);
404 call->crypto_buf[1] = htonl(x);
406 sg_init_one(&sg, call->crypto_buf, 8);
407 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
408 skcipher_request_set_callback(req, 0, NULL, NULL);
409 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
410 crypto_skcipher_encrypt(req);
411 skcipher_request_zero(req);
413 y = ntohl(call->crypto_buf[1]);
414 y = (y >> 16) & 0xffff;
416 y = 1; /* zero checksums are not permitted */
419 switch (call->conn->params.security_level) {
420 case RXRPC_SECURITY_PLAIN:
423 case RXRPC_SECURITY_AUTH:
424 ret = rxkad_secure_packet_auth(call, skb, data_size, req);
426 case RXRPC_SECURITY_ENCRYPT:
427 ret = rxkad_secure_packet_encrypt(call, skb, data_size, req);
434 _leave(" = %d [set %hx]", ret, y);
439 * decrypt partial encryption on a packet (level 1 security)
441 static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
442 unsigned int offset, unsigned int len,
444 struct skcipher_request *req)
446 struct rxkad_level1_hdr sechdr;
447 struct rxrpc_crypt iv;
448 struct scatterlist sg[16];
457 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_hdr", "V1H",
462 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
463 * directly into the target buffer.
465 sg_init_table(sg, ARRAY_SIZE(sg));
466 ret = skb_to_sgvec(skb, sg, offset, 8);
467 if (unlikely(ret < 0))
470 /* start the decryption afresh */
471 memset(&iv, 0, sizeof(iv));
473 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
474 skcipher_request_set_callback(req, 0, NULL, NULL);
475 skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
476 crypto_skcipher_decrypt(req);
477 skcipher_request_zero(req);
479 /* Extract the decrypted packet length */
480 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
481 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_len", "XV1",
485 len -= sizeof(sechdr);
487 buf = ntohl(sechdr.data_size);
488 data_size = buf & 0xffff;
491 check ^= seq ^ call->call_id;
494 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_check", "V1C",
499 if (data_size > len) {
500 aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_datalen", "V1L",
505 _leave(" = 0 [dlen=%x]", data_size);
510 rxrpc_send_abort_packet(call);
515 * wholly decrypt a packet (level 2 security)
517 static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
518 unsigned int offset, unsigned int len,
520 struct skcipher_request *req)
522 const struct rxrpc_key_token *token;
523 struct rxkad_level2_hdr sechdr;
524 struct rxrpc_crypt iv;
525 struct scatterlist _sg[4], *sg;
531 _enter(",{%d}", skb->len);
534 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_hdr", "V2H",
539 /* Decrypt the skbuff in-place. TODO: We really want to decrypt
540 * directly into the target buffer.
543 nsg = skb_shinfo(skb)->nr_frags;
547 sg = kmalloc_array(nsg, sizeof(*sg), GFP_NOIO);
552 sg_init_table(sg, nsg);
553 ret = skb_to_sgvec(skb, sg, offset, len);
554 if (unlikely(ret < 0)) {
560 /* decrypt from the session key */
561 token = call->conn->params.key->payload.data[0];
562 memcpy(&iv, token->kad->session_key, sizeof(iv));
564 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
565 skcipher_request_set_callback(req, 0, NULL, NULL);
566 skcipher_request_set_crypt(req, sg, sg, len, iv.x);
567 crypto_skcipher_decrypt(req);
568 skcipher_request_zero(req);
572 /* Extract the decrypted packet length */
573 if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
574 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_len", "XV2",
578 len -= sizeof(sechdr);
580 buf = ntohl(sechdr.data_size);
581 data_size = buf & 0xffff;
584 check ^= seq ^ call->call_id;
587 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_check", "V2C",
592 if (data_size > len) {
593 aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_datalen", "V2L",
598 _leave(" = 0 [dlen=%x]", data_size);
603 rxrpc_send_abort_packet(call);
607 _leave(" = -ENOMEM");
612 * Verify the security on a received packet or subpacket (if part of a
615 static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
616 unsigned int offset, unsigned int len,
617 rxrpc_seq_t seq, u16 expected_cksum)
619 struct skcipher_request *req;
620 struct rxrpc_crypt iv;
621 struct scatterlist sg;
626 _enter("{%d{%x}},{#%u}",
627 call->debug_id, key_serial(call->conn->params.key), seq);
629 if (!call->conn->rxkad.cipher)
632 req = rxkad_get_call_crypto(call);
636 /* continue encrypting from where we left off */
637 memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
639 /* validate the security checksum */
640 x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
641 x |= seq & 0x3fffffff;
642 call->crypto_buf[0] = htonl(call->call_id);
643 call->crypto_buf[1] = htonl(x);
645 sg_init_one(&sg, call->crypto_buf, 8);
646 skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
647 skcipher_request_set_callback(req, 0, NULL, NULL);
648 skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
649 crypto_skcipher_encrypt(req);
650 skcipher_request_zero(req);
652 y = ntohl(call->crypto_buf[1]);
653 cksum = (y >> 16) & 0xffff;
655 cksum = 1; /* zero checksums are not permitted */
657 if (cksum != expected_cksum) {
658 aborted = rxrpc_abort_eproto(call, skb, "rxkad_csum", "VCK",
663 switch (call->conn->params.security_level) {
664 case RXRPC_SECURITY_PLAIN:
666 case RXRPC_SECURITY_AUTH:
667 return rxkad_verify_packet_1(call, skb, offset, len, seq, req);
668 case RXRPC_SECURITY_ENCRYPT:
669 return rxkad_verify_packet_2(call, skb, offset, len, seq, req);
676 rxrpc_send_abort_packet(call);
681 * Locate the data contained in a packet that was partially encrypted.
683 static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb,
684 unsigned int *_offset, unsigned int *_len)
686 struct rxkad_level1_hdr sechdr;
688 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
690 *_offset += sizeof(sechdr);
691 *_len = ntohl(sechdr.data_size) & 0xffff;
695 * Locate the data contained in a packet that was completely encrypted.
697 static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb,
698 unsigned int *_offset, unsigned int *_len)
700 struct rxkad_level2_hdr sechdr;
702 if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
704 *_offset += sizeof(sechdr);
705 *_len = ntohl(sechdr.data_size) & 0xffff;
709 * Locate the data contained in an already decrypted packet.
711 static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
712 unsigned int *_offset, unsigned int *_len)
714 switch (call->conn->params.security_level) {
715 case RXRPC_SECURITY_AUTH:
716 rxkad_locate_data_1(call, skb, _offset, _len);
718 case RXRPC_SECURITY_ENCRYPT:
719 rxkad_locate_data_2(call, skb, _offset, _len);
729 static int rxkad_issue_challenge(struct rxrpc_connection *conn)
731 struct rxkad_challenge challenge;
732 struct rxrpc_wire_header whdr;
739 _enter("{%d}", conn->debug_id);
741 get_random_bytes(&conn->rxkad.nonce, sizeof(conn->rxkad.nonce));
743 challenge.version = htonl(2);
744 challenge.nonce = htonl(conn->rxkad.nonce);
745 challenge.min_level = htonl(0);
746 challenge.__padding = 0;
748 msg.msg_name = &conn->params.peer->srx.transport;
749 msg.msg_namelen = conn->params.peer->srx.transport_len;
750 msg.msg_control = NULL;
751 msg.msg_controllen = 0;
754 whdr.epoch = htonl(conn->proto.epoch);
755 whdr.cid = htonl(conn->proto.cid);
758 whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
759 whdr.flags = conn->out_clientflag;
761 whdr.securityIndex = conn->security_ix;
763 whdr.serviceId = htons(conn->service_id);
765 iov[0].iov_base = &whdr;
766 iov[0].iov_len = sizeof(whdr);
767 iov[1].iov_base = &challenge;
768 iov[1].iov_len = sizeof(challenge);
770 len = iov[0].iov_len + iov[1].iov_len;
772 serial = atomic_inc_return(&conn->serial);
773 whdr.serial = htonl(serial);
774 _proto("Tx CHALLENGE %%%u", serial);
776 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
778 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
779 rxrpc_tx_point_rxkad_challenge);
783 conn->params.peer->last_tx_at = ktime_get_seconds();
784 trace_rxrpc_tx_packet(conn->debug_id, &whdr,
785 rxrpc_tx_point_rxkad_challenge);
791 * send a Kerberos security response
793 static int rxkad_send_response(struct rxrpc_connection *conn,
794 struct rxrpc_host_header *hdr,
795 struct rxkad_response *resp,
796 const struct rxkad_key *s2)
798 struct rxrpc_wire_header whdr;
807 msg.msg_name = &conn->params.peer->srx.transport;
808 msg.msg_namelen = conn->params.peer->srx.transport_len;
809 msg.msg_control = NULL;
810 msg.msg_controllen = 0;
813 memset(&whdr, 0, sizeof(whdr));
814 whdr.epoch = htonl(hdr->epoch);
815 whdr.cid = htonl(hdr->cid);
816 whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
817 whdr.flags = conn->out_clientflag;
818 whdr.securityIndex = hdr->securityIndex;
819 whdr.serviceId = htons(hdr->serviceId);
821 iov[0].iov_base = &whdr;
822 iov[0].iov_len = sizeof(whdr);
823 iov[1].iov_base = resp;
824 iov[1].iov_len = sizeof(*resp);
825 iov[2].iov_base = (void *)s2->ticket;
826 iov[2].iov_len = s2->ticket_len;
828 len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
830 serial = atomic_inc_return(&conn->serial);
831 whdr.serial = htonl(serial);
832 _proto("Tx RESPONSE %%%u", serial);
834 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 3, len);
836 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
837 rxrpc_tx_point_rxkad_response);
841 conn->params.peer->last_tx_at = ktime_get_seconds();
847 * calculate the response checksum
849 static void rxkad_calc_response_checksum(struct rxkad_response *response)
853 u8 *p = (u8 *) response;
855 for (loop = sizeof(*response); loop > 0; loop--)
856 csum = csum * 0x10204081 + *p++;
858 response->encrypted.checksum = htonl(csum);
862 * encrypt the response packet
864 static int rxkad_encrypt_response(struct rxrpc_connection *conn,
865 struct rxkad_response *resp,
866 const struct rxkad_key *s2)
868 struct skcipher_request *req;
869 struct rxrpc_crypt iv;
870 struct scatterlist sg[1];
872 req = skcipher_request_alloc(&conn->rxkad.cipher->base, GFP_NOFS);
876 /* continue encrypting from where we left off */
877 memcpy(&iv, s2->session_key, sizeof(iv));
879 sg_init_table(sg, 1);
880 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
881 skcipher_request_set_sync_tfm(req, conn->rxkad.cipher);
882 skcipher_request_set_callback(req, 0, NULL, NULL);
883 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
884 crypto_skcipher_encrypt(req);
885 skcipher_request_free(req);
890 * respond to a challenge packet
892 static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
896 const struct rxrpc_key_token *token;
897 struct rxkad_challenge challenge;
898 struct rxkad_response *resp;
899 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
901 u32 version, nonce, min_level, abort_code;
904 _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
906 eproto = tracepoint_string("chall_no_key");
907 abort_code = RX_PROTOCOL_ERROR;
908 if (!conn->params.key)
911 abort_code = RXKADEXPIRED;
912 ret = key_validate(conn->params.key);
916 eproto = tracepoint_string("chall_short");
917 abort_code = RXKADPACKETSHORT;
918 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
919 &challenge, sizeof(challenge)) < 0)
922 version = ntohl(challenge.version);
923 nonce = ntohl(challenge.nonce);
924 min_level = ntohl(challenge.min_level);
926 _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
927 sp->hdr.serial, version, nonce, min_level);
929 eproto = tracepoint_string("chall_ver");
930 abort_code = RXKADINCONSISTENCY;
931 if (version != RXKAD_VERSION)
934 abort_code = RXKADLEVELFAIL;
936 if (conn->params.security_level < min_level)
939 token = conn->params.key->payload.data[0];
941 /* build the response packet */
942 resp = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
946 resp->version = htonl(RXKAD_VERSION);
947 resp->encrypted.epoch = htonl(conn->proto.epoch);
948 resp->encrypted.cid = htonl(conn->proto.cid);
949 resp->encrypted.securityIndex = htonl(conn->security_ix);
950 resp->encrypted.inc_nonce = htonl(nonce + 1);
951 resp->encrypted.level = htonl(conn->params.security_level);
952 resp->kvno = htonl(token->kad->kvno);
953 resp->ticket_len = htonl(token->kad->ticket_len);
954 resp->encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
955 resp->encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
956 resp->encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
957 resp->encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
959 /* calculate the response checksum and then do the encryption */
960 rxkad_calc_response_checksum(resp);
961 ret = rxkad_encrypt_response(conn, resp, token->kad);
963 ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
968 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
971 *_abort_code = abort_code;
976 * decrypt the kerberos IV ticket in the response
978 static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
979 struct key *server_key,
981 void *ticket, size_t ticket_len,
982 struct rxrpc_crypt *_session_key,
986 struct skcipher_request *req;
987 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
988 struct rxrpc_crypt iv, key;
989 struct scatterlist sg[1];
997 u8 *p, *q, *name, *end;
999 _enter("{%d},{%x}", conn->debug_id, key_serial(server_key));
1003 ASSERT(server_key->payload.data[0] != NULL);
1004 ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
1006 memcpy(&iv, &server_key->payload.data[2], sizeof(iv));
1009 req = skcipher_request_alloc(server_key->payload.data[0], GFP_NOFS);
1011 goto temporary_error;
1013 sg_init_one(&sg[0], ticket, ticket_len);
1014 skcipher_request_set_callback(req, 0, NULL, NULL);
1015 skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
1016 crypto_skcipher_decrypt(req);
1017 skcipher_request_free(req);
1020 end = p + ticket_len;
1025 eproto = tracepoint_string("rxkad_bad_"#field); \
1026 q = memchr(p, 0, end - p); \
1027 if (!q || q - p > (field##_SZ)) \
1029 for (; p < q; p++) \
1036 /* extract the ticket flags */
1037 _debug("KIV FLAGS: %x", *p);
1038 little_endian = *p & 1;
1041 /* extract the authentication name */
1043 _debug("KIV ANAME: %s", name);
1045 /* extract the principal's instance */
1047 _debug("KIV INST : %s", name);
1049 /* extract the principal's authentication domain */
1051 _debug("KIV REALM: %s", name);
1053 eproto = tracepoint_string("rxkad_bad_len");
1054 if (end - p < 4 + 8 + 4 + 2)
1057 /* get the IPv4 address of the entity that requested the ticket */
1058 memcpy(&addr, p, sizeof(addr));
1060 _debug("KIV ADDR : %pI4", &addr);
1062 /* get the session key from the ticket */
1063 memcpy(&key, p, sizeof(key));
1065 _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
1066 memcpy(_session_key, &key, sizeof(key));
1068 /* get the ticket's lifetime */
1069 life = *p++ * 5 * 60;
1070 _debug("KIV LIFE : %u", life);
1072 /* get the issue time of the ticket */
1073 if (little_endian) {
1075 memcpy(&stamp, p, 4);
1076 issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
1079 memcpy(&stamp, p, 4);
1080 issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
1083 now = ktime_get_real_seconds();
1084 _debug("KIV ISSUE: %llx [%llx]", issue, now);
1086 /* check the ticket is in date */
1088 abort_code = RXKADNOAUTH;
1089 ret = -EKEYREJECTED;
1093 if (issue < now - life) {
1094 abort_code = RXKADEXPIRED;
1099 *_expiry = issue + life;
1101 /* get the service name */
1103 _debug("KIV SNAME: %s", name);
1105 /* get the service instance name */
1107 _debug("KIV SINST: %s", name);
1111 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1112 abort_code = RXKADBADTICKET;
1115 *_abort_code = abort_code;
1122 * decrypt the response packet
1124 static void rxkad_decrypt_response(struct rxrpc_connection *conn,
1125 struct rxkad_response *resp,
1126 const struct rxrpc_crypt *session_key)
1128 struct skcipher_request *req = rxkad_ci_req;
1129 struct scatterlist sg[1];
1130 struct rxrpc_crypt iv;
1132 _enter(",,%08x%08x",
1133 ntohl(session_key->n[0]), ntohl(session_key->n[1]));
1135 mutex_lock(&rxkad_ci_mutex);
1136 if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
1137 sizeof(*session_key)) < 0)
1140 memcpy(&iv, session_key, sizeof(iv));
1142 sg_init_table(sg, 1);
1143 sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
1144 skcipher_request_set_sync_tfm(req, rxkad_ci);
1145 skcipher_request_set_callback(req, 0, NULL, NULL);
1146 skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
1147 crypto_skcipher_decrypt(req);
1148 skcipher_request_zero(req);
1150 mutex_unlock(&rxkad_ci_mutex);
1158 static int rxkad_verify_response(struct rxrpc_connection *conn,
1159 struct sk_buff *skb,
1162 struct rxkad_response *response;
1163 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1164 struct rxrpc_crypt session_key;
1165 struct key *server_key;
1169 u32 abort_code, version, kvno, ticket_len, level;
1173 _enter("{%d}", conn->debug_id);
1175 server_key = rxrpc_look_up_server_security(conn, skb, 0, 0);
1176 if (IS_ERR(server_key)) {
1177 switch (PTR_ERR(server_key)) {
1179 abort_code = RXKADUNKNOWNKEY;
1182 abort_code = RXKADEXPIRED;
1185 abort_code = RXKADNOAUTH;
1188 trace_rxrpc_abort(0, "SVK",
1189 sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1190 abort_code, PTR_ERR(server_key));
1191 *_abort_code = abort_code;
1196 response = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
1198 goto temporary_error;
1200 eproto = tracepoint_string("rxkad_rsp_short");
1201 abort_code = RXKADPACKETSHORT;
1202 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1203 response, sizeof(*response)) < 0)
1204 goto protocol_error;
1206 version = ntohl(response->version);
1207 ticket_len = ntohl(response->ticket_len);
1208 kvno = ntohl(response->kvno);
1209 _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
1210 sp->hdr.serial, version, kvno, ticket_len);
1212 eproto = tracepoint_string("rxkad_rsp_ver");
1213 abort_code = RXKADINCONSISTENCY;
1214 if (version != RXKAD_VERSION)
1215 goto protocol_error;
1217 eproto = tracepoint_string("rxkad_rsp_tktlen");
1218 abort_code = RXKADTICKETLEN;
1219 if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
1220 goto protocol_error;
1222 eproto = tracepoint_string("rxkad_rsp_unkkey");
1223 abort_code = RXKADUNKNOWNKEY;
1224 if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
1225 goto protocol_error;
1227 /* extract the kerberos ticket and decrypt and decode it */
1229 ticket = kmalloc(ticket_len, GFP_NOFS);
1231 goto temporary_error_free_resp;
1233 eproto = tracepoint_string("rxkad_tkt_short");
1234 abort_code = RXKADPACKETSHORT;
1235 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header) + sizeof(*response),
1236 ticket, ticket_len) < 0)
1237 goto protocol_error_free;
1239 ret = rxkad_decrypt_ticket(conn, server_key, skb, ticket, ticket_len,
1240 &session_key, &expiry, _abort_code);
1242 goto temporary_error_free_ticket;
1244 /* use the session key from inside the ticket to decrypt the
1246 rxkad_decrypt_response(conn, response, &session_key);
1248 eproto = tracepoint_string("rxkad_rsp_param");
1249 abort_code = RXKADSEALEDINCON;
1250 if (ntohl(response->encrypted.epoch) != conn->proto.epoch)
1251 goto protocol_error_free;
1252 if (ntohl(response->encrypted.cid) != conn->proto.cid)
1253 goto protocol_error_free;
1254 if (ntohl(response->encrypted.securityIndex) != conn->security_ix)
1255 goto protocol_error_free;
1256 csum = response->encrypted.checksum;
1257 response->encrypted.checksum = 0;
1258 rxkad_calc_response_checksum(response);
1259 eproto = tracepoint_string("rxkad_rsp_csum");
1260 if (response->encrypted.checksum != csum)
1261 goto protocol_error_free;
1263 spin_lock(&conn->bundle->channel_lock);
1264 for (i = 0; i < RXRPC_MAXCALLS; i++) {
1265 struct rxrpc_call *call;
1266 u32 call_id = ntohl(response->encrypted.call_id[i]);
1268 eproto = tracepoint_string("rxkad_rsp_callid");
1269 if (call_id > INT_MAX)
1270 goto protocol_error_unlock;
1272 eproto = tracepoint_string("rxkad_rsp_callctr");
1273 if (call_id < conn->channels[i].call_counter)
1274 goto protocol_error_unlock;
1276 eproto = tracepoint_string("rxkad_rsp_callst");
1277 if (call_id > conn->channels[i].call_counter) {
1278 call = rcu_dereference_protected(
1279 conn->channels[i].call,
1280 lockdep_is_held(&conn->bundle->channel_lock));
1281 if (call && call->state < RXRPC_CALL_COMPLETE)
1282 goto protocol_error_unlock;
1283 conn->channels[i].call_counter = call_id;
1286 spin_unlock(&conn->bundle->channel_lock);
1288 eproto = tracepoint_string("rxkad_rsp_seq");
1289 abort_code = RXKADOUTOFSEQUENCE;
1290 if (ntohl(response->encrypted.inc_nonce) != conn->rxkad.nonce + 1)
1291 goto protocol_error_free;
1293 eproto = tracepoint_string("rxkad_rsp_level");
1294 abort_code = RXKADLEVELFAIL;
1295 level = ntohl(response->encrypted.level);
1296 if (level > RXRPC_SECURITY_ENCRYPT)
1297 goto protocol_error_free;
1298 conn->params.security_level = level;
1300 /* create a key to hold the security data and expiration time - after
1301 * this the connection security can be handled in exactly the same way
1302 * as for a client connection */
1303 ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
1305 goto temporary_error_free_ticket;
1312 protocol_error_unlock:
1313 spin_unlock(&conn->bundle->channel_lock);
1314 protocol_error_free:
1318 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
1319 key_put(server_key);
1320 *_abort_code = abort_code;
1323 temporary_error_free_ticket:
1325 temporary_error_free_resp:
1328 /* Ignore the response packet if we got a temporary error such as
1329 * ENOMEM. We just want to send the challenge again. Note that we
1330 * also come out this way if the ticket decryption fails.
1332 key_put(server_key);
1337 * clear the connection security
1339 static void rxkad_clear(struct rxrpc_connection *conn)
1343 if (conn->rxkad.cipher)
1344 crypto_free_sync_skcipher(conn->rxkad.cipher);
1348 * Initialise the rxkad security service.
1350 static int rxkad_init(void)
1352 struct crypto_sync_skcipher *tfm;
1353 struct skcipher_request *req;
1355 /* pin the cipher we need so that the crypto layer doesn't invoke
1356 * keventd to go get it */
1357 tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
1359 return PTR_ERR(tfm);
1361 req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
1370 crypto_free_sync_skcipher(tfm);
1375 * Clean up the rxkad security service.
1377 static void rxkad_exit(void)
1379 crypto_free_sync_skcipher(rxkad_ci);
1380 skcipher_request_free(rxkad_ci_req);
1384 * RxRPC Kerberos-based security
1386 const struct rxrpc_security rxkad = {
1388 .security_index = RXRPC_SECURITY_RXKAD,
1389 .no_key_abort = RXKADUNKNOWNKEY,
1392 .preparse_server_key = rxkad_preparse_server_key,
1393 .free_preparse_server_key = rxkad_free_preparse_server_key,
1394 .destroy_server_key = rxkad_destroy_server_key,
1395 .init_connection_security = rxkad_init_connection_security,
1396 .how_much_data = rxkad_how_much_data,
1397 .secure_packet = rxkad_secure_packet,
1398 .verify_packet = rxkad_verify_packet,
1399 .free_call_crypto = rxkad_free_call_crypto,
1400 .locate_data = rxkad_locate_data,
1401 .issue_challenge = rxkad_issue_challenge,
1402 .respond_to_challenge = rxkad_respond_to_challenge,
1403 .verify_response = rxkad_verify_response,
1404 .clear = rxkad_clear,