1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * net/tipc/crypto.h: Include file for TIPC crypto
4 *
5 * Copyright (c) 2019, Ericsson AB
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the names of the copyright holders nor the names of its
17 *    contributors may be used to endorse or promote products derived from
18 *    this software without specific prior written permission.
19 *
20 * Alternatively, this software may be distributed under the terms of the
21 * GNU General Public License ("GPL") version 2 as published by the Free
22 * Software Foundation.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 */
36#ifdef CONFIG_TIPC_CRYPTO
37#ifndef _TIPC_CRYPTO_H
38#define _TIPC_CRYPTO_H
39
40#include "core.h"
41#include "node.h"
42#include "msg.h"
43#include "bearer.h"
44
45#define TIPC_EVERSION			7
46
47/* AEAD aes(gcm) */
48#define TIPC_AES_GCM_KEY_SIZE_128	16
49#define TIPC_AES_GCM_KEY_SIZE_192	24
50#define TIPC_AES_GCM_KEY_SIZE_256	32
51
52#define TIPC_AES_GCM_SALT_SIZE		4
53#define TIPC_AES_GCM_IV_SIZE		12
54#define TIPC_AES_GCM_TAG_SIZE		16
55
56/*
57 * TIPC crypto modes:
58 * - CLUSTER_KEY:
59 *	One single key is used for both TX & RX in all nodes in the cluster.
60 * - PER_NODE_KEY:
61 *	Each nodes in the cluster has one TX key, for RX a node needs to know
62 *	its peers' TX key for the decryption of messages from those nodes.
63 */
64enum {
65	CLUSTER_KEY = 1,
66	PER_NODE_KEY = (1 << 1),
67};
68
69extern int sysctl_tipc_max_tfms __read_mostly;
70extern int sysctl_tipc_key_exchange_enabled __read_mostly;
71
72/*
73 * TIPC encryption message format:
74 *
75 *     3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0
76 *     1 0 9 8 7 6 5 4|3 2 1 0 9 8 7 6|5 4 3 2 1 0 9 8|7 6 5 4 3 2 1 0
77 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
78 * w0:|Ver=7| User  |D|TX |RX |K|M|N|             Rsvd                |
79 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
80 * w1:|                             Seqno                             |
81 * w2:|                           (8 octets)                          |
82 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
83 * w3:\                            Prevnode                           \
84 *    /                        (4 or 16 octets)                       /
85 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
86 *    \                                                               \
87 *    /       Encrypted complete TIPC V2 header and user data         /
88 *    \                                                               \
89 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
90 *    |                                                               |
91 *    |                             AuthTag                           |
92 *    |                           (16 octets)                         |
93 *    |                                                               |
94 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
95 *
96 * Word0:
97 *	Ver	: = 7 i.e. TIPC encryption message version
98 *	User	: = 7 (for LINK_PROTOCOL); = 13 (for LINK_CONFIG) or = 0
99 *	D	: The destined bit i.e. the message's destination node is
100 *	          "known" or not at the message encryption
101 *	TX	: TX key used for the message encryption
102 *	RX	: Currently RX active key corresponding to the destination
103 *	          node's TX key (when the "D" bit is set)
104 *	K	: Keep-alive bit (for RPS, LINK_PROTOCOL/STATE_MSG only)
105 *	M       : Bit indicates if sender has master key
106 *	N	: Bit indicates if sender has no RX keys corresponding to the
107 *	          receiver's TX (when the "D" bit is set)
108 *	Rsvd	: Reserved bit, field
109 * Word1-2:
110 *	Seqno	: The 64-bit sequence number of the encrypted message, also
111 *		  part of the nonce used for the message encryption/decryption
112 * Word3-:
113 *	Prevnode: The source node address, or ID in case LINK_CONFIG only
114 *	AuthTag	: The authentication tag for the message integrity checking
115 *		  generated by the message encryption
116 */
117struct tipc_ehdr {
118	union {
119		struct {
120#if defined(__LITTLE_ENDIAN_BITFIELD)
121			__u8	destined:1,
122				user:4,
123				version:3;
124			__u8	reserved_1:1,
125				rx_nokey:1,
126				master_key:1,
127				keepalive:1,
128				rx_key_active:2,
129				tx_key:2;
130#elif defined(__BIG_ENDIAN_BITFIELD)
131			__u8	version:3,
132				user:4,
133				destined:1;
134			__u8	tx_key:2,
135				rx_key_active:2,
136				keepalive:1,
137				master_key:1,
138				rx_nokey:1,
139				reserved_1:1;
140#else
141#error  "Please fix <asm/byteorder.h>"
142#endif
143			__be16	reserved_2;
144		} __packed;
145		__be32 w0;
146	};
147	__be64 seqno;
148	union {
149		__be32 addr;
150		__u8 id[NODE_ID_LEN]; /* For a LINK_CONFIG message only! */
151	};
152#define EHDR_SIZE	(offsetof(struct tipc_ehdr, addr) + sizeof(__be32))
153#define EHDR_CFG_SIZE	(sizeof(struct tipc_ehdr))
154#define EHDR_MIN_SIZE	(EHDR_SIZE)
155#define EHDR_MAX_SIZE	(EHDR_CFG_SIZE)
156#define EMSG_OVERHEAD	(EHDR_SIZE + TIPC_AES_GCM_TAG_SIZE)
157} __packed;
158
159int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
160		      struct tipc_node *node);
161void tipc_crypto_stop(struct tipc_crypto **crypto);
162void tipc_crypto_timeout(struct tipc_crypto *rx);
163int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
164		     struct tipc_bearer *b, struct tipc_media_addr *dst,
165		     struct tipc_node *__dnode);
166int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
167		    struct sk_buff **skb, struct tipc_bearer *b);
168int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
169			 u8 mode, bool master_key);
170void tipc_crypto_key_flush(struct tipc_crypto *c);
171int tipc_crypto_key_distr(struct tipc_crypto *tx, u8 key,
172			  struct tipc_node *dest);
173void tipc_crypto_msg_rcv(struct net *net, struct sk_buff *skb);
174void tipc_crypto_rekeying_sched(struct tipc_crypto *tx, bool changed,
175				u32 new_intv);
176int tipc_aead_key_validate(struct tipc_aead_key *ukey, struct genl_info *info);
177bool tipc_ehdr_validate(struct sk_buff *skb);
178
179static inline u32 msg_key_gen(struct tipc_msg *m)
180{
181	return msg_bits(m, 4, 16, 0xffff);
182}
183
184static inline void msg_set_key_gen(struct tipc_msg *m, u32 gen)
185{
186	msg_set_bits(m, 4, 16, 0xffff, gen);
187}
188
189static inline u32 msg_key_mode(struct tipc_msg *m)
190{
191	return msg_bits(m, 4, 0, 0xf);
192}
193
194static inline void msg_set_key_mode(struct tipc_msg *m, u32 mode)
195{
196	msg_set_bits(m, 4, 0, 0xf, mode);
197}
198
199#endif /* _TIPC_CRYPTO_H */
200#endif
201