linux-stable.git/net/ipv4/netfilter, branch v4.4.121

netfilter: on sockopt() acquire sock lock only in the required scope

2018-02-25T10:03:37+00:00

commit 3f34cfae1238848fd53f25e5c8fd59da57901f4b upstream.

Syzbot reported several deadlocks in the netfilter area caused by
rtnl lock and socket lock being acquired with a different order on
different code paths, leading to backtraces like the following one:

======================================================
WARNING: possible circular locking dependency detected
4.15.0-rc9+ #212 Not tainted
------------------------------------------------------
syzkaller041579/3682 is trying to acquire lock:
  (sk_lock-AF_INET6){+.+.}, at: [<000000008775e4dd>] lock_sock
include/net/sock.h:1463 [inline]
  (sk_lock-AF_INET6){+.+.}, at: [<000000008775e4dd>]
do_ipv6_setsockopt.isra.8+0x3c5/0x39d0 net/ipv6/ipv6_sockglue.c:167

but task is already holding lock:
  (rtnl_mutex){+.+.}, at: [<000000004342eaa9>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (rtnl_mutex){+.+.}:
        __mutex_lock_common kernel/locking/mutex.c:756 [inline]
        __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
        mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
        rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
        register_netdevice_notifier+0xad/0x860 net/core/dev.c:1607
        tee_tg_check+0x1a0/0x280 net/netfilter/xt_TEE.c:106
        xt_check_target+0x22c/0x7d0 net/netfilter/x_tables.c:845
        check_target net/ipv6/netfilter/ip6_tables.c:538 [inline]
        find_check_entry.isra.7+0x935/0xcf0
net/ipv6/netfilter/ip6_tables.c:580
        translate_table+0xf52/0x1690 net/ipv6/netfilter/ip6_tables.c:749
        do_replace net/ipv6/netfilter/ip6_tables.c:1165 [inline]
        do_ip6t_set_ctl+0x370/0x5f0 net/ipv6/netfilter/ip6_tables.c:1691
        nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
        nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115
        ipv6_setsockopt+0x115/0x150 net/ipv6/ipv6_sockglue.c:928
        udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1422
        sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2978
        SYSC_setsockopt net/socket.c:1849 [inline]
        SyS_setsockopt+0x189/0x360 net/socket.c:1828
        entry_SYSCALL_64_fastpath+0x29/0xa0

-> #0 (sk_lock-AF_INET6){+.+.}:
        lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914
        lock_sock_nested+0xc2/0x110 net/core/sock.c:2780
        lock_sock include/net/sock.h:1463 [inline]
        do_ipv6_setsockopt.isra.8+0x3c5/0x39d0 net/ipv6/ipv6_sockglue.c:167
        ipv6_setsockopt+0xd7/0x150 net/ipv6/ipv6_sockglue.c:922
        udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1422
        sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2978
        SYSC_setsockopt net/socket.c:1849 [inline]
        SyS_setsockopt+0x189/0x360 net/socket.c:1828
        entry_SYSCALL_64_fastpath+0x29/0xa0

other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(rtnl_mutex);
                                lock(sk_lock-AF_INET6);
                                lock(rtnl_mutex);
   lock(sk_lock-AF_INET6);

  *** DEADLOCK ***

1 lock held by syzkaller041579/3682:
  #0:  (rtnl_mutex){+.+.}, at: [<000000004342eaa9>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74

The problem, as Florian noted, is that nf_setsockopt() is always
called with the socket held, even if the lock itself is required only
for very tight scopes and only for some operation.

This patch addresses the issues moving the lock_sock() call only
where really needed, namely in ipv*_getorigdst(), so that nf_setsockopt()
does not need anymore to acquire both locks.

Fixes: 22265a5c3c10 ("netfilter: xt_TEE: resolve oif using netdevice notifiers")
Reported-by: syzbot+a4c2dc980ac1af699b36@syzkaller.appspotmail.com
Suggested-by: Florian Westphal 
Signed-off-by: Paolo Abeni 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: ipt_CLUSTERIP: fix out-of-bounds accesses in clusterip_tg_check()

2018-02-25T10:03:37+00:00

commit 1a38956cce5eabd7b74f94bab70265e4df83165e upstream.

Commit 136e92bbec0a switched local_nodes from an array to a bitmask
but did not add proper bounds checks. As the result
clusterip_config_init_nodelist() can both over-read
ipt_clusterip_tgt_info.local_nodes and over-write
clusterip_config.local_nodes.

Add bounds checks for both.

Fixes: 136e92bbec0a ("[NETFILTER] CLUSTERIP: use a bitmap to store node responsibility data")
Signed-off-by: Dmitry Vyukov 
Reported-by: syzbot 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: fix IS_ERR_VALUE usage

2018-01-31T11:06:10+00:00

commit 92b4423e3a0bc5d43ecde4bcad871f8b5ba04efd upstream.

This is a forward-port of the original patch from Andrzej Hajda,
he said:

"IS_ERR_VALUE should be used only with unsigned long type.
Otherwise it can work incorrectly. To achieve this function
xt_percpu_counter_alloc is modified to return unsigned long,
and its result is assigned to temporary variable to perform
error checking, before assigning to .pcnt field.

The patch follows conclusion from discussion on LKML [1][2].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2120927
[2]: http://permalink.gmane.org/gmane.linux.kernel/2150581"

Original patch from Andrzej is here:

http://patchwork.ozlabs.org/patch/582970/

This patch has clashed with input validation fixes for x_tables.

Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman 
Acked-by: Michal Kubecek

netfilter: use fwmark_reflect in nf_send_reset

2018-01-31T11:06:10+00:00

commit cc31d43b4154ad5a7d8aa5543255a93b7e89edc2 upstream.

Otherwise, RST packets generated by ipt_REJECT always have mark 0 when
the routing is checked later in the same code path.

Fixes: e110861f8609 ("net: add a sysctl to reflect the fwmark on replies")
Cc: Lorenzo Colitti 
Signed-off-by: Pau Espin Pedrol 
Signed-off-by: Pablo Neira Ayuso 
Acked-by: Michal Kubecek 
Signed-off-by: Greg Kroah-Hartman

netfilter: arp_tables: fix invoking 32bit "iptable -P INPUT ACCEPT" failed in 64bit kernel

2018-01-31T11:06:10+00:00

commit 17a49cd549d9dc8707dc9262210166455c612dde upstream.

Since 09d9686047db ("netfilter: x_tables: do compat validation via
translate_table"), it used compatr structure to assign newinfo
structure.  In translate_compat_table of ip_tables.c and ip6_tables.c,
it used compatr->hook_entry to replace info->hook_entry and
compatr->underflow to replace info->underflow, but not do the same
replacement in arp_tables.c.

It caused invoking 32-bit "arptbale -P INPUT ACCEPT" failed in 64bit
kernel.
--------------------------------------
root@qemux86-64:~# arptables -P INPUT ACCEPT
root@qemux86-64:~# arptables -P INPUT ACCEPT
ERROR: Policy for `INPUT' offset 448 != underflow 0
arptables: Incompatible with this kernel
--------------------------------------

Fixes: 09d9686047db ("netfilter: x_tables: do compat validation via translate_table")
Signed-off-by: Hongxu Jia 
Acked-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Acked-by: Michal Kubecek 
Signed-off-by: Greg Kroah-Hartman

netfilter: x_tables: speed up jump target validation

2018-01-31T11:06:10+00:00

commit f4dc77713f8016d2e8a3295e1c9c53a21f296def upstream.

The dummy ruleset I used to test the original validation change was broken,
most rules were unreachable and were not tested by mark_source_chains().

In some cases rulesets that used to load in a few seconds now require
several minutes.

sample ruleset that shows the behaviour:

echo "*filter"
for i in $(seq 0 100000);do
        printf ":chain_%06x - [0:0]\n" $i
done
for i in $(seq 0 100000);do
   printf -- "-A INPUT -j chain_%06x\n" $i
   printf -- "-A INPUT -j chain_%06x\n" $i
   printf -- "-A INPUT -j chain_%06x\n" $i
done
echo COMMIT

[ pipe result into iptables-restore ]

This ruleset will be about 74mbyte in size, with ~500k searches
though all 500k[1] rule entries. iptables-restore will take forever
(gave up after 10 minutes)

Instead of always searching the entire blob for a match, fill an
array with the start offsets of every single ipt_entry struct,
then do a binary search to check if the jump target is present or not.

After this change ruleset restore times get again close to what one
gets when reverting 36472341017529e (~3 seconds on my workstation).

[1] every user-defined rule gets an implicit RETURN, so we get
300k jumps + 100k userchains + 100k returns -> 500k rule entries

Fixes: 36472341017529e ("netfilter: x_tables: validate targets of jumps")
Reported-by: Jeff Wu 
Tested-by: Jeff Wu 
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Acked-by: Michal Kubecek 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_nat_snmp: Fix panic when snmp_trap_helper fails to register

2017-12-25T13:22:13+00:00

[ Upstream commit 75c689dca98851d65ef5a27e5ce26b625b68751c ]

In the commit 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp
helper"), the snmp_helper is replaced by nf_nat_snmp_hook. So the
snmp_helper is never registered. But it still tries to unregister the
snmp_helper, it could cause the panic.

Now remove the useless snmp_helper and the unregister call in the
error handler.

Fixes: 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp helper")
Signed-off-by: Gao Feng 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

netfilter: don't track fragmented packets

2017-12-16T09:33:53+00:00

[ Upstream commit 7b4fdf77a450ec0fdcb2f677b080ddbf2c186544 ]

Andrey reports syzkaller splat caused by

NF_CT_ASSERT(!ip_is_fragment(ip_hdr(skb)));

in ipv4 nat.  But this assertion (and the comment) are wrong, this function
does see fragments when IP_NODEFRAG setsockopt is used.

As conntrack doesn't track packets without complete l4 header, only the
first fragment is tracked.

Because applying nat to first packet but not the rest makes no sense this
also turns off tracking of all fragments.

Reported-by: Andrey Konovalov 
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

netfilter: invoke synchronize_rcu after set the _hook_ to NULL

2017-10-08T08:14:19+00:00

[ Upstream commit 3b7dabf029478bb80507a6c4500ca94132a2bc0b ]

Otherwise, another CPU may access the invalid pointer. For example:
    CPU0                CPU1
     -              rcu_read_lock();
     -              pfunc = _hook_;
  _hook_ = NULL;          -
  mod unload              -
     -                 pfunc(); // invalid, panic
     -             rcu_read_unlock();

So we must call synchronize_rcu() to wait the rcu reader to finish.

Also note, in nf_nat_snmp_basic_fini, synchronize_rcu() will be invoked
by later nf_conntrack_helper_unregister, but I'm inclined to add a
explicit synchronize_rcu after set the nf_nat_snmp_hook to NULL. Depend
on such obscure assumptions is not a good idea.

Last, in nfnetlink_cttimeout, we use kfree_rcu to free the time object,
so in cttimeout_exit, invoking rcu_barrier() is not necessary at all,
remove it too.

Signed-off-by: Liping Zhang 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

netfilter: x_tables: introduce and use xt_copy_counters_from_user

2016-06-24T17:18:24+00:00

commit d7591f0c41ce3e67600a982bab6989ef0f07b3ce upstream.

The three variants use same copy&pasted code, condense this into a
helper and use that.

Make sure info.name is 0-terminated.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman