linux/net/tipc/crypto.h
Tuong Lien fc1b6d6de2 tipc: introduce TIPC encryption & authentication
This commit offers an option to encrypt and authenticate all messaging,
including the neighbor discovery messages. The currently most advanced
algorithm supported is the AEAD AES-GCM (like IPSec or TLS). All
encryption/decryption is done at the bearer layer, just before leaving
or after entering TIPC.

Supported features:
- Encryption & authentication of all TIPC messages (header + data);
- Two symmetric-key modes: Cluster and Per-node;
- Automatic key switching;
- Key-expired revoking (sequence number wrapped);
- Lock-free encryption/decryption (RCU);
- Asynchronous crypto, Intel AES-NI supported;
- Multiple cipher transforms;
- Logs & statistics;

Two key modes:
- Cluster key mode: One single key is used for both TX & RX in all
nodes in the cluster.
- Per-node key mode: Each nodes in the cluster has one specific TX key.
For RX, a node requires its peers' TX key to be able to decrypt the
messages from those peers.

Key setting from user-space is performed via netlink by a user program
(e.g. the iproute2 'tipc' tool).

Internal key state machine:

                                 Attach    Align(RX)
                                     +-+   +-+
                                     | V   | V
        +---------+      Attach     +---------+
        |  IDLE   |---------------->| PENDING |(user = 0)
        +---------+                 +---------+
           A   A                   Switch|  A
           |   |                         |  |
           |   | Free(switch/revoked)    |  |
     (Free)|   +----------------------+  |  |Timeout
           |              (TX)        |  |  |(RX)
           |                          |  |  |
           |                          |  v  |
        +---------+      Switch     +---------+
        | PASSIVE |<----------------| ACTIVE  |
        +---------+       (RX)      +---------+
        (user = 1)                  (user >= 1)

The number of TFMs is 10 by default and can be changed via the procfs
'net/tipc/max_tfms'. At this moment, as for simplicity, this file is
also used to print the crypto statistics at runtime:

echo 0xfff1 > /proc/sys/net/tipc/max_tfms

The patch defines a new TIPC version (v7) for the encryption message (-
backward compatibility as well). The message is basically encapsulated
as follows:

   +----------------------------------------------------------+
   | TIPCv7 encryption  | Original TIPCv2    | Authentication |
   | header             | packet (encrypted) | Tag            |
   +----------------------------------------------------------+

The throughput is about ~40% for small messages (compared with non-
encryption) and ~9% for large messages. With the support from hardware
crypto i.e. the Intel AES-NI CPU instructions, the throughput increases
upto ~85% for small messages and ~55% for large messages.

By default, the new feature is inactive (i.e. no encryption) until user
sets a key for TIPC. There is however also a new option - "TIPC_CRYPTO"
in the kernel configuration to enable/disable the new code when needed.

MAINTAINERS | add two new files 'crypto.h' & 'crypto.c' in tipc

Acked-by: Ying Xue <ying.xue@windreiver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-08 14:01:59 -08:00

168 lines
6.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/**
* net/tipc/crypto.h: Include file for TIPC crypto
*
* Copyright (c) 2019, Ericsson AB
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef CONFIG_TIPC_CRYPTO
#ifndef _TIPC_CRYPTO_H
#define _TIPC_CRYPTO_H
#include "core.h"
#include "node.h"
#include "msg.h"
#include "bearer.h"
#define TIPC_EVERSION 7
/* AEAD aes(gcm) */
#define TIPC_AES_GCM_KEY_SIZE_128 16
#define TIPC_AES_GCM_KEY_SIZE_192 24
#define TIPC_AES_GCM_KEY_SIZE_256 32
#define TIPC_AES_GCM_SALT_SIZE 4
#define TIPC_AES_GCM_IV_SIZE 12
#define TIPC_AES_GCM_TAG_SIZE 16
/**
* TIPC crypto modes:
* - CLUSTER_KEY:
* One single key is used for both TX & RX in all nodes in the cluster.
* - PER_NODE_KEY:
* Each nodes in the cluster has one TX key, for RX a node needs to know
* its peers' TX key for the decryption of messages from those nodes.
*/
enum {
CLUSTER_KEY = 1,
PER_NODE_KEY = (1 << 1),
};
extern int sysctl_tipc_max_tfms __read_mostly;
/**
* TIPC encryption message format:
*
* 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
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* w0:|Ver=7| User |D|TX |RX |K| Rsvd |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* w1:| Seqno |
* w2:| (8 octets) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* w3:\ Prevnode \
* / (4 or 16 octets) /
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* \ \
* / Encrypted complete TIPC V2 header and user data /
* \ \
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | AuthTag |
* | (16 octets) |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* Word0:
* Ver : = 7 i.e. TIPC encryption message version
* User : = 7 (for LINK_PROTOCOL); = 13 (for LINK_CONFIG) or = 0
* D : The destined bit i.e. the message's destination node is
* "known" or not at the message encryption
* TX : TX key used for the message encryption
* RX : Currently RX active key corresponding to the destination
* node's TX key (when the "D" bit is set)
* K : Keep-alive bit (for RPS, LINK_PROTOCOL/STATE_MSG only)
* Rsvd : Reserved bit, field
* Word1-2:
* Seqno : The 64-bit sequence number of the encrypted message, also
* part of the nonce used for the message encryption/decryption
* Word3-:
* Prevnode: The source node address, or ID in case LINK_CONFIG only
* AuthTag : The authentication tag for the message integrity checking
* generated by the message encryption
*/
struct tipc_ehdr {
union {
struct {
#if defined(__LITTLE_ENDIAN_BITFIELD)
__u8 destined:1,
user:4,
version:3;
__u8 reserved_1:3,
keepalive:1,
rx_key_active:2,
tx_key:2;
#elif defined(__BIG_ENDIAN_BITFIELD)
__u8 version:3,
user:4,
destined:1;
__u8 tx_key:2,
rx_key_active:2,
keepalive:1,
reserved_1:3;
#else
#error "Please fix <asm/byteorder.h>"
#endif
__be16 reserved_2;
} __packed;
__be32 w0;
};
__be64 seqno;
union {
__be32 addr;
__u8 id[NODE_ID_LEN]; /* For a LINK_CONFIG message only! */
};
#define EHDR_SIZE (offsetof(struct tipc_ehdr, addr) + sizeof(__be32))
#define EHDR_CFG_SIZE (sizeof(struct tipc_ehdr))
#define EHDR_MIN_SIZE (EHDR_SIZE)
#define EHDR_MAX_SIZE (EHDR_CFG_SIZE)
#define EMSG_OVERHEAD (EHDR_SIZE + TIPC_AES_GCM_TAG_SIZE)
} __packed;
int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
struct tipc_node *node);
void tipc_crypto_stop(struct tipc_crypto **crypto);
void tipc_crypto_timeout(struct tipc_crypto *rx);
int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
struct tipc_bearer *b, struct tipc_media_addr *dst,
struct tipc_node *__dnode);
int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
struct sk_buff **skb, struct tipc_bearer *b);
int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
u8 mode);
void tipc_crypto_key_flush(struct tipc_crypto *c);
int tipc_aead_key_validate(struct tipc_aead_key *ukey);
bool tipc_ehdr_validate(struct sk_buff *skb);
#endif /* _TIPC_CRYPTO_H */
#endif