linux/net/tipc/net.c
Johannes Berg 8cb081746c netlink: make validation more configurable for future strictness
We currently have two levels of strict validation:

 1) liberal (default)
     - undefined (type >= max) & NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted
     - garbage at end of message accepted
 2) strict (opt-in)
     - NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted

Split out parsing strictness into four different options:
 * TRAILING     - check that there's no trailing data after parsing
                  attributes (in message or nested)
 * MAXTYPE      - reject attrs > max known type
 * UNSPEC       - reject attributes with NLA_UNSPEC policy entries
 * STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
 * nla_parse           -> nla_parse_deprecated
 * nla_parse_strict    -> nla_parse_deprecated_strict
 * nlmsg_parse         -> nlmsg_parse_deprecated
 * nlmsg_parse_strict  -> nlmsg_parse_deprecated_strict
 * nla_parse_nested    -> nla_parse_nested_deprecated
 * nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
    @@
    expression TB, MAX, HEAD, LEN, POL, EXT;
    @@
    -nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
    +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression TB, MAX, NLA, POL, EXT;
    @@
    -nla_parse_nested(TB, MAX, NLA, POL, EXT)
    +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

    @@
    expression START, MAX, POL, EXT;
    @@
    -nla_validate_nested(START, MAX, POL, EXT)
    +nla_validate_nested_deprecated(START, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, MAX, POL, EXT;
    @@
    -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
    +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:07:21 -04:00

303 lines
9.2 KiB
C

/*
* net/tipc/net.c: TIPC network routing code
*
* Copyright (c) 1995-2006, 2014, Ericsson AB
* Copyright (c) 2005, 2010-2011, 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 "net.h"
#include "name_distr.h"
#include "subscr.h"
#include "socket.h"
#include "node.h"
#include "bcast.h"
#include "netlink.h"
/*
* The TIPC locking policy is designed to ensure a very fine locking
* granularity, permitting complete parallel access to individual
* port and node/link instances. The code consists of four major
* locking domains, each protected with their own disjunct set of locks.
*
* 1: The bearer level.
* RTNL lock is used to serialize the process of configuring bearer
* on update side, and RCU lock is applied on read side to make
* bearer instance valid on both paths of message transmission and
* reception.
*
* 2: The node and link level.
* All node instances are saved into two tipc_node_list and node_htable
* lists. The two lists are protected by node_list_lock on write side,
* and they are guarded with RCU lock on read side. Especially node
* instance is destroyed only when TIPC module is removed, and we can
* confirm that there has no any user who is accessing the node at the
* moment. Therefore, Except for iterating the two lists within RCU
* protection, it's no needed to hold RCU that we access node instance
* in other places.
*
* In addition, all members in node structure including link instances
* are protected by node spin lock.
*
* 3: The transport level of the protocol.
* This consists of the structures port, (and its user level
* representations, such as user_port and tipc_sock), reference and
* tipc_user (port.c, reg.c, socket.c).
*
* This layer has four different locks:
* - The tipc_port spin_lock. This is protecting each port instance
* from parallel data access and removal. Since we can not place
* this lock in the port itself, it has been placed in the
* corresponding reference table entry, which has the same life
* cycle as the module. This entry is difficult to access from
* outside the TIPC core, however, so a pointer to the lock has
* been added in the port instance, -to be used for unlocking
* only.
* - A read/write lock to protect the reference table itself (teg.c).
* (Nobody is using read-only access to this, so it can just as
* well be changed to a spin_lock)
* - A spin lock to protect the registry of kernel/driver users (reg.c)
* - A global spin_lock (tipc_port_lock), which only task is to ensure
* consistency where more than one port is involved in an operation,
* i.e., whe a port is part of a linked list of ports.
* There are two such lists; 'port_list', which is used for management,
* and 'wait_list', which is used to queue ports during congestion.
*
* 4: The name table (name_table.c, name_distr.c, subscription.c)
* - There is one big read/write-lock (tipc_nametbl_lock) protecting the
* overall name table structure. Nothing must be added/removed to
* this structure without holding write access to it.
* - There is one local spin_lock per sub_sequence, which can be seen
* as a sub-domain to the tipc_nametbl_lock domain. It is used only
* for translation operations, and is needed because a translation
* steps the root of the 'publication' linked list between each lookup.
* This is always used within the scope of a tipc_nametbl_lock(read).
* - A local spin_lock protecting the queue of subscriber events.
*/
struct tipc_net_work {
struct work_struct work;
struct net *net;
u32 addr;
};
static void tipc_net_finalize(struct net *net, u32 addr);
int tipc_net_init(struct net *net, u8 *node_id, u32 addr)
{
if (tipc_own_id(net)) {
pr_info("Cannot configure node identity twice\n");
return -1;
}
pr_info("Started in network mode\n");
if (node_id)
tipc_set_node_id(net, node_id);
if (addr)
tipc_net_finalize(net, addr);
return 0;
}
static void tipc_net_finalize(struct net *net, u32 addr)
{
struct tipc_net *tn = tipc_net(net);
if (cmpxchg(&tn->node_addr, 0, addr))
return;
tipc_set_node_addr(net, addr);
tipc_named_reinit(net);
tipc_sk_reinit(net);
tipc_nametbl_publish(net, TIPC_CFG_SRV, addr, addr,
TIPC_CLUSTER_SCOPE, 0, addr);
}
static void tipc_net_finalize_work(struct work_struct *work)
{
struct tipc_net_work *fwork;
fwork = container_of(work, struct tipc_net_work, work);
tipc_net_finalize(fwork->net, fwork->addr);
kfree(fwork);
}
void tipc_sched_net_finalize(struct net *net, u32 addr)
{
struct tipc_net_work *fwork = kzalloc(sizeof(*fwork), GFP_ATOMIC);
if (!fwork)
return;
INIT_WORK(&fwork->work, tipc_net_finalize_work);
fwork->net = net;
fwork->addr = addr;
schedule_work(&fwork->work);
}
void tipc_net_stop(struct net *net)
{
if (!tipc_own_id(net))
return;
rtnl_lock();
tipc_bearer_stop(net);
tipc_node_stop(net);
rtnl_unlock();
pr_info("Left network mode\n");
}
static int __tipc_nl_add_net(struct net *net, struct tipc_nl_msg *msg)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
u64 *w0 = (u64 *)&tn->node_id[0];
u64 *w1 = (u64 *)&tn->node_id[8];
struct nlattr *attrs;
void *hdr;
hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
NLM_F_MULTI, TIPC_NL_NET_GET);
if (!hdr)
return -EMSGSIZE;
attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_NET);
if (!attrs)
goto msg_full;
if (nla_put_u32(msg->skb, TIPC_NLA_NET_ID, tn->net_id))
goto attr_msg_full;
if (nla_put_u64_64bit(msg->skb, TIPC_NLA_NET_NODEID, *w0, 0))
goto attr_msg_full;
if (nla_put_u64_64bit(msg->skb, TIPC_NLA_NET_NODEID_W1, *w1, 0))
goto attr_msg_full;
nla_nest_end(msg->skb, attrs);
genlmsg_end(msg->skb, hdr);
return 0;
attr_msg_full:
nla_nest_cancel(msg->skb, attrs);
msg_full:
genlmsg_cancel(msg->skb, hdr);
return -EMSGSIZE;
}
int tipc_nl_net_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
int err;
int done = cb->args[0];
struct tipc_nl_msg msg;
if (done)
return 0;
msg.skb = skb;
msg.portid = NETLINK_CB(cb->skb).portid;
msg.seq = cb->nlh->nlmsg_seq;
err = __tipc_nl_add_net(net, &msg);
if (err)
goto out;
done = 1;
out:
cb->args[0] = done;
return skb->len;
}
int __tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info)
{
struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
struct net *net = sock_net(skb->sk);
struct tipc_net *tn = tipc_net(net);
int err;
if (!info->attrs[TIPC_NLA_NET])
return -EINVAL;
err = nla_parse_nested_deprecated(attrs, TIPC_NLA_NET_MAX,
info->attrs[TIPC_NLA_NET],
tipc_nl_net_policy, info->extack);
if (err)
return err;
/* Can't change net id once TIPC has joined a network */
if (tipc_own_addr(net))
return -EPERM;
if (attrs[TIPC_NLA_NET_ID]) {
u32 val;
val = nla_get_u32(attrs[TIPC_NLA_NET_ID]);
if (val < 1 || val > 9999)
return -EINVAL;
tn->net_id = val;
}
if (attrs[TIPC_NLA_NET_ADDR]) {
u32 addr;
addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
if (!addr)
return -EINVAL;
tn->legacy_addr_format = true;
tipc_net_init(net, NULL, addr);
}
if (attrs[TIPC_NLA_NET_NODEID]) {
u8 node_id[NODE_ID_LEN];
u64 *w0 = (u64 *)&node_id[0];
u64 *w1 = (u64 *)&node_id[8];
if (!attrs[TIPC_NLA_NET_NODEID_W1])
return -EINVAL;
*w0 = nla_get_u64(attrs[TIPC_NLA_NET_NODEID]);
*w1 = nla_get_u64(attrs[TIPC_NLA_NET_NODEID_W1]);
tipc_net_init(net, node_id, 0);
}
return 0;
}
int tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info)
{
int err;
rtnl_lock();
err = __tipc_nl_net_set(skb, info);
rtnl_unlock();
return err;
}