linux/net/tipc/sysctl.c
Tuong Lien 1ef6f7c939 tipc: add automatic session key exchange
With support from the master key option in the previous commit, it
becomes easy to make frequent updates/exchanges of session keys between
authenticated cluster nodes.
Basically, there are two situations where the key exchange will take in
place:

- When a new node joins the cluster (with the master key), it will need
  to get its peer's TX key, so that be able to decrypt further messages
  from that peer.

- When a new session key is generated (by either user manual setting or
  later automatic rekeying feature), the key will be distributed to all
  peer nodes in the cluster.

A key to be exchanged is encapsulated in the data part of a 'MSG_CRYPTO
/KEY_DISTR_MSG' TIPC v2 message, then xmit-ed as usual and encrypted by
using the master key before sending out. Upon receipt of the message it
will be decrypted in the same way as regular messages, then attached as
the sender's RX key in the receiver node.

In this way, the key exchange is reliable by the link layer, as well as
security, integrity and authenticity by the crypto layer.

Also, the forward security will be easily achieved by user changing the
master key actively but this should not be required very frequently.

The key exchange feature is independent on the presence of a master key
Note however that the master key still is needed for new nodes to be
able to join the cluster. It is also optional, and can be turned off/on
via the sysfs: 'net/tipc/key_exchange_enabled' [default 1: enabled].

Backward compatibility is guaranteed because for nodes that do not have
master key support, key exchange using master key ie. tx_key = 0 if any
will be shortly discarded at the message validation step. In other
words, the key exchange feature will be automatically disabled to those
nodes.

v2: fix the "implicit declaration of function 'tipc_crypto_key_flush'"
error in node.c. The function only exists when built with the TIPC
"CONFIG_TIPC_CRYPTO" option.

v3: use 'info->extack' for a message emitted due to netlink operations
instead (- David's comment).

Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-18 13:58:37 -07:00

108 lines
3.5 KiB
C

/*
* net/tipc/sysctl.c: sysctl interface to TIPC subsystem
*
* Copyright (c) 2013, Wind River Systems
* 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.
*/
#include "core.h"
#include "trace.h"
#include "crypto.h"
#include "bcast.h"
#include <linux/sysctl.h>
static struct ctl_table_header *tipc_ctl_hdr;
static struct ctl_table tipc_table[] = {
{
.procname = "tipc_rmem",
.data = &sysctl_tipc_rmem,
.maxlen = sizeof(sysctl_tipc_rmem),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
},
{
.procname = "named_timeout",
.data = &sysctl_tipc_named_timeout,
.maxlen = sizeof(sysctl_tipc_named_timeout),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
{
.procname = "sk_filter",
.data = &sysctl_tipc_sk_filter,
.maxlen = sizeof(sysctl_tipc_sk_filter),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
#ifdef CONFIG_TIPC_CRYPTO
{
.procname = "max_tfms",
.data = &sysctl_tipc_max_tfms,
.maxlen = sizeof(sysctl_tipc_max_tfms),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
},
{
.procname = "key_exchange_enabled",
.data = &sysctl_tipc_key_exchange_enabled,
.maxlen = sizeof(sysctl_tipc_key_exchange_enabled),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#endif
{
.procname = "bc_retruni",
.data = &sysctl_tipc_bc_retruni,
.maxlen = sizeof(sysctl_tipc_bc_retruni),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{}
};
int tipc_register_sysctl(void)
{
tipc_ctl_hdr = register_net_sysctl(&init_net, "net/tipc", tipc_table);
if (tipc_ctl_hdr == NULL)
return -ENOMEM;
return 0;
}
void tipc_unregister_sysctl(void)
{
unregister_net_sysctl_table(tipc_ctl_hdr);
}