net/tipc/crypto.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003  * net/tipc/crypto.h: Include file for TIPC crypto
0004  *
0005  * Copyright (c) 2019, Ericsson AB
0006  * All rights reserved.
0007  *
0008  * Redistribution and use in source and binary forms, with or without
0009  * modification, are permitted provided that the following conditions are met:
0010  *
0011  * 1. Redistributions of source code must retain the above copyright
0012  *    notice, this list of conditions and the following disclaimer.
0013  * 2. Redistributions in binary form must reproduce the above copyright
0014  *    notice, this list of conditions and the following disclaimer in the
0015  *    documentation and/or other materials provided with the distribution.
0016  * 3. Neither the names of the copyright holders nor the names of its
0017  *    contributors may be used to endorse or promote products derived from
0018  *    this software without specific prior written permission.
0019  *
0020  * Alternatively, this software may be distributed under the terms of the
0021  * GNU General Public License ("GPL") version 2 as published by the Free
0022  * Software Foundation.
0023  *
0024  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0025  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0026  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0027  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0028  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0029  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0030  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0031  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0032  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0033  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0034  * POSSIBILITY OF SUCH DAMAGE.
0035  */
0036 #ifdef CONFIG_TIPC_CRYPTO
0037 #ifndef _TIPC_CRYPTO_H
0038 #define _TIPC_CRYPTO_H
0039
0040 #include "core.h"
0041 #include "node.h"
0042 #include "msg.h"
0043 #include "bearer.h"
0044
0045 #define TIPC_EVERSION           7
0046
0047 /* AEAD aes(gcm) */
0048 #define TIPC_AES_GCM_KEY_SIZE_128   16
0049 #define TIPC_AES_GCM_KEY_SIZE_192   24
0050 #define TIPC_AES_GCM_KEY_SIZE_256   32
0051
0052 #define TIPC_AES_GCM_SALT_SIZE      4
0053 #define TIPC_AES_GCM_IV_SIZE        12
0054 #define TIPC_AES_GCM_TAG_SIZE       16
0055
0056 /*
0057  * TIPC crypto modes:
0058  * - CLUSTER_KEY:
0059  *  One single key is used for both TX & RX in all nodes in the cluster.
0060  * - PER_NODE_KEY:
0061  *  Each nodes in the cluster has one TX key, for RX a node needs to know
0062  *  its peers' TX key for the decryption of messages from those nodes.
0063  */
0064 enum {
0065     CLUSTER_KEY = 1,
0066     PER_NODE_KEY = (1 << 1),
0067 };
0068
0069 extern int sysctl_tipc_max_tfms __read_mostly;
0070 extern int sysctl_tipc_key_exchange_enabled __read_mostly;
0071
0072 /*
0073  * TIPC encryption message format:
0074  *
0075  *     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
0076  *     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
0077  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0078  * w0:|Ver=7| User  |D|TX |RX |K|M|N|             Rsvd                |
0079  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0080  * w1:|                             Seqno                             |
0081  * w2:|                           (8 octets)                          |
0082  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0083  * w3:\                            Prevnode                           \
0084  *    /                        (4 or 16 octets)                       /
0085  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0086  *    \                                                               \
0087  *    /       Encrypted complete TIPC V2 header and user data         /
0088  *    \                                                               \
0089  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0090  *    |                                                               |
0091  *    |                             AuthTag                           |
0092  *    |                           (16 octets)                         |
0093  *    |                                                               |
0094  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0095  *
0096  * Word0:
0097  *  Ver : = 7 i.e. TIPC encryption message version
0098  *  User    : = 7 (for LINK_PROTOCOL); = 13 (for LINK_CONFIG) or = 0
0099  *  D   : The destined bit i.e. the message's destination node is
0100  *            "known" or not at the message encryption
0101  *  TX  : TX key used for the message encryption
0102  *  RX  : Currently RX active key corresponding to the destination
0103  *            node's TX key (when the "D" bit is set)
0104  *  K   : Keep-alive bit (for RPS, LINK_PROTOCOL/STATE_MSG only)
0105  *  M       : Bit indicates if sender has master key
0106  *  N   : Bit indicates if sender has no RX keys corresponding to the
0107  *            receiver's TX (when the "D" bit is set)
0108  *  Rsvd    : Reserved bit, field
0109  * Word1-2:
0110  *  Seqno   : The 64-bit sequence number of the encrypted message, also
0111  *        part of the nonce used for the message encryption/decryption
0112  * Word3-:
0113  *  Prevnode: The source node address, or ID in case LINK_CONFIG only
0114  *  AuthTag : The authentication tag for the message integrity checking
0115  *        generated by the message encryption
0116  */
0117 struct tipc_ehdr {
0118     union {
0119         struct {
0120 #if defined(__LITTLE_ENDIAN_BITFIELD)
0121             __u8    destined:1,
0122                 user:4,
0123                 version:3;
0124             __u8    reserved_1:1,
0125                 rx_nokey:1,
0126                 master_key:1,
0127                 keepalive:1,
0128                 rx_key_active:2,
0129                 tx_key:2;
0130 #elif defined(__BIG_ENDIAN_BITFIELD)
0131             __u8    version:3,
0132                 user:4,
0133                 destined:1;
0134             __u8    tx_key:2,
0135                 rx_key_active:2,
0136                 keepalive:1,
0137                 master_key:1,
0138                 rx_nokey:1,
0139                 reserved_1:1;
0140 #else
0141 #error  "Please fix <asm/byteorder.h>"
0142 #endif
0143             __be16  reserved_2;
0144         } __packed;
0145         __be32 w0;
0146     };
0147     __be64 seqno;
0148     union {
0149         __be32 addr;
0150         __u8 id[NODE_ID_LEN]; /* For a LINK_CONFIG message only! */
0151     };
0152 #define EHDR_SIZE   (offsetof(struct tipc_ehdr, addr) + sizeof(__be32))
0153 #define EHDR_CFG_SIZE   (sizeof(struct tipc_ehdr))
0154 #define EHDR_MIN_SIZE   (EHDR_SIZE)
0155 #define EHDR_MAX_SIZE   (EHDR_CFG_SIZE)
0156 #define EMSG_OVERHEAD   (EHDR_SIZE + TIPC_AES_GCM_TAG_SIZE)
0157 } __packed;
0158
0159 int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
0160               struct tipc_node *node);
0161 void tipc_crypto_stop(struct tipc_crypto **crypto);
0162 void tipc_crypto_timeout(struct tipc_crypto *rx);
0163 int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
0164              struct tipc_bearer *b, struct tipc_media_addr *dst,
0165              struct tipc_node *__dnode);
0166 int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
0167             struct sk_buff **skb, struct tipc_bearer *b);
0168 int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
0169              u8 mode, bool master_key);
0170 void tipc_crypto_key_flush(struct tipc_crypto *c);
0171 int tipc_crypto_key_distr(struct tipc_crypto *tx, u8 key,
0172               struct tipc_node *dest);
0173 void tipc_crypto_msg_rcv(struct net *net, struct sk_buff *skb);
0174 void tipc_crypto_rekeying_sched(struct tipc_crypto *tx, bool changed,
0175                 u32 new_intv);
0176 int tipc_aead_key_validate(struct tipc_aead_key *ukey, struct genl_info *info);
0177 bool tipc_ehdr_validate(struct sk_buff *skb);
0178
0179 static inline u32 msg_key_gen(struct tipc_msg *m)
0180 {
0181     return msg_bits(m, 4, 16, 0xffff);
0182 }
0183
0184 static inline void msg_set_key_gen(struct tipc_msg *m, u32 gen)
0185 {
0186     msg_set_bits(m, 4, 16, 0xffff, gen);
0187 }
0188
0189 static inline u32 msg_key_mode(struct tipc_msg *m)
0190 {
0191     return msg_bits(m, 4, 0, 0xf);
0192 }
0193
0194 static inline void msg_set_key_mode(struct tipc_msg *m, u32 mode)
0195 {
0196     msg_set_bits(m, 4, 0, 0xf, mode);
0197 }
0198
0199 #endif /* _TIPC_CRYPTO_H */
0200 #endif