linux-stable.git/net/ipv6/netfilter, branch v4.20.2 Linux kernel stable tree ipv4: ipv6: netfilter: Adjust the frag mem limit when truesize changes 2018-12-06T04:44:46+00:00 Jiri Wiesner jwiesner@suse.com 2018-12-05T15:55:29+00:00 ebaf39e6032faf77218220707fc3fa22487784e0 The *_frag_reasm() functions are susceptible to miscalculating the byte count of packet fragments in case the truesize of a head buffer changes. The truesize member may be changed by the call to skb_unclone(), leaving the fragment memory limit counter unbalanced even if all fragments are processed. This miscalculation goes unnoticed as long as the network namespace which holds the counter is not destroyed. Should an attempt be made to destroy a network namespace that holds an unbalanced fragment memory limit counter the cleanup of the namespace never finishes. The thread handling the cleanup gets stuck in inet_frags_exit_net() waiting for the percpu counter to reach zero. The thread is usually in running state with a stacktrace similar to: PID: 1073 TASK: ffff880626711440 CPU: 1 COMMAND: "kworker/u48:4" #5 [ffff880621563d48] _raw_spin_lock at ffffffff815f5480 #6 [ffff880621563d48] inet_evict_bucket at ffffffff8158020b #7 [ffff880621563d80] inet_frags_exit_net at ffffffff8158051c #8 [ffff880621563db0] ops_exit_list at ffffffff814f5856 #9 [ffff880621563dd8] cleanup_net at ffffffff814f67c0 #10 [ffff880621563e38] process_one_work at ffffffff81096f14 It is not possible to create new network namespaces, and processes that call unshare() end up being stuck in uninterruptible sleep state waiting to acquire the net_mutex. The bug was observed in the IPv6 netfilter code by Per Sundstrom. I thank him for his analysis of the problem. The parts of this patch that apply to IPv4 and IPv6 fragment reassembly are preemptive measures. Signed-off-by: Jiri Wiesner <jwiesner@suse.com> Reported-by: Per Sundstrom <per.sundstrom@redqube.se> Acked-by: Peter Oskolkov <posk@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
The *_frag_reasm() functions are susceptible to miscalculating the byte
count of packet fragments in case the truesize of a head buffer changes.
The truesize member may be changed by the call to skb_unclone(), leaving
the fragment memory limit counter unbalanced even if all fragments are
processed. This miscalculation goes unnoticed as long as the network
namespace which holds the counter is not destroyed.

Should an attempt be made to destroy a network namespace that holds an
unbalanced fragment memory limit counter the cleanup of the namespace
never finishes. The thread handling the cleanup gets stuck in
inet_frags_exit_net() waiting for the percpu counter to reach zero. The
thread is usually in running state with a stacktrace similar to:

 PID: 1073   TASK: ffff880626711440  CPU: 1   COMMAND: "kworker/u48:4"
  #5 [ffff880621563d48] _raw_spin_lock at ffffffff815f5480
  #6 [ffff880621563d48] inet_evict_bucket at ffffffff8158020b
  #7 [ffff880621563d80] inet_frags_exit_net at ffffffff8158051c
  #8 [ffff880621563db0] ops_exit_list at ffffffff814f5856
  #9 [ffff880621563dd8] cleanup_net at ffffffff814f67c0
 #10 [ffff880621563e38] process_one_work at ffffffff81096f14

It is not possible to create new network namespaces, and processes
that call unshare() end up being stuck in uninterruptible sleep state
waiting to acquire the net_mutex.

The bug was observed in the IPv6 netfilter code by Per Sundstrom.
I thank him for his analysis of the problem. The parts of this patch
that apply to IPv4 and IPv6 fragment reassembly are preemptive measures.

Signed-off-by: Jiri Wiesner <jwiesner@suse.com>
Reported-by: Per Sundstrom <per.sundstrom@redqube.se>
Acked-by: Peter Oskolkov <posk@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netfilter: nat: fix double register in masquerade modules 2018-11-26T23:36:46+00:00 Taehee Yoo ap420073@gmail.com 2018-11-22T10:59:57+00:00 095faf45e64be00bff4da2d6182dface3d69c9b7 There is a reference counter to ensure that masquerade modules register notifiers only once. However, the existing reference counter approach is not safe, test commands are: while : do modprobe ip6t_MASQUERADE & modprobe nft_masq_ipv6 & modprobe -rv ip6t_MASQUERADE & modprobe -rv nft_masq_ipv6 & done numbers below represent the reference counter. -------------------------------------------------------- CPU0 CPU1 CPU2 CPU3 CPU4 [insmod] [insmod] [rmmod] [rmmod] [insmod] -------------------------------------------------------- 0->1 register 1->2 returns 2->1 returns 1->0 0->1 register <-- unregister -------------------------------------------------------- The unregistation of CPU3 should be processed before the registration of CPU4. In order to fix this, use a mutex instead of reference counter. splat looks like: [ 323.869557] watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [modprobe:1381] [ 323.869574] Modules linked in: nf_tables(+) nf_nat_ipv6(-) nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 n] [ 323.869574] irq event stamp: 194074 [ 323.898930] hardirqs last enabled at (194073): [<ffffffff90004a0d>] trace_hardirqs_on_thunk+0x1a/0x1c [ 323.898930] hardirqs last disabled at (194074): [<ffffffff90004a29>] trace_hardirqs_off_thunk+0x1a/0x1c [ 323.898930] softirqs last enabled at (182132): [<ffffffff922006ec>] __do_softirq+0x6ec/0xa3b [ 323.898930] softirqs last disabled at (182109): [<ffffffff90193426>] irq_exit+0x1a6/0x1e0 [ 323.898930] CPU: 0 PID: 1381 Comm: modprobe Not tainted 4.20.0-rc2+ #27 [ 323.898930] RIP: 0010:raw_notifier_chain_register+0xea/0x240 [ 323.898930] Code: 3c 03 0f 8e f2 00 00 00 44 3b 6b 10 7f 4d 49 bc 00 00 00 00 00 fc ff df eb 22 48 8d 7b 10 488 [ 323.898930] RSP: 0018:ffff888101597218 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 [ 323.898930] RAX: 0000000000000000 RBX: ffffffffc04361c0 RCX: 0000000000000000 [ 323.898930] RDX: 1ffffffff26132ae RSI: ffffffffc04aa3c0 RDI: ffffffffc04361d0 [ 323.898930] RBP: ffffffffc04361c8 R08: 0000000000000000 R09: 0000000000000001 [ 323.898930] R10: ffff8881015972b0 R11: fffffbfff26132c4 R12: dffffc0000000000 [ 323.898930] R13: 0000000000000000 R14: 1ffff110202b2e44 R15: ffffffffc04aa3c0 [ 323.898930] FS: 00007f813ed41540(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000 [ 323.898930] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 323.898930] CR2: 0000559bf2c9f120 CR3: 000000010bc80000 CR4: 00000000001006f0 [ 323.898930] Call Trace: [ 323.898930] ? atomic_notifier_chain_register+0x2d0/0x2d0 [ 323.898930] ? down_read+0x150/0x150 [ 323.898930] ? sched_clock_cpu+0x126/0x170 [ 323.898930] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 323.898930] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 323.898930] register_netdevice_notifier+0xbb/0x790 [ 323.898930] ? __dev_close_many+0x2d0/0x2d0 [ 323.898930] ? __mutex_unlock_slowpath+0x17f/0x740 [ 323.898930] ? wait_for_completion+0x710/0x710 [ 323.898930] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 323.898930] ? up_write+0x6c/0x210 [ 323.898930] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 324.127073] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 324.127073] nft_chain_filter_init+0x1e/0xe8a [nf_tables] [ 324.127073] nf_tables_module_init+0x37/0x92 [nf_tables] [ ... ] Fixes: 8dd33cc93ec9 ("netfilter: nf_nat: generalize IPv4 masquerading support for nf_tables") Fixes: be6b635cd674 ("netfilter: nf_nat: generalize IPv6 masquerading support for nf_tables") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
There is a reference counter to ensure that masquerade modules register
notifiers only once. However, the existing reference counter approach is
not safe, test commands are:

   while :
   do
   	   modprobe ip6t_MASQUERADE &
	   modprobe nft_masq_ipv6 &
	   modprobe -rv ip6t_MASQUERADE &
	   modprobe -rv nft_masq_ipv6 &
   done

numbers below represent the reference counter.
--------------------------------------------------------
CPU0        CPU1        CPU2        CPU3        CPU4
[insmod]    [insmod]    [rmmod]     [rmmod]     [insmod]
--------------------------------------------------------
0->1
register    1->2
            returns     2->1
			returns     1->0
                                                0->1
                                                register <--
                                    unregister
--------------------------------------------------------

The unregistation of CPU3 should be processed before the
registration of CPU4.

In order to fix this, use a mutex instead of reference counter.

splat looks like:
[  323.869557] watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [modprobe:1381]
[  323.869574] Modules linked in: nf_tables(+) nf_nat_ipv6(-) nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 n]
[  323.869574] irq event stamp: 194074
[  323.898930] hardirqs last  enabled at (194073): [<ffffffff90004a0d>] trace_hardirqs_on_thunk+0x1a/0x1c
[  323.898930] hardirqs last disabled at (194074): [<ffffffff90004a29>] trace_hardirqs_off_thunk+0x1a/0x1c
[  323.898930] softirqs last  enabled at (182132): [<ffffffff922006ec>] __do_softirq+0x6ec/0xa3b
[  323.898930] softirqs last disabled at (182109): [<ffffffff90193426>] irq_exit+0x1a6/0x1e0
[  323.898930] CPU: 0 PID: 1381 Comm: modprobe Not tainted 4.20.0-rc2+ #27
[  323.898930] RIP: 0010:raw_notifier_chain_register+0xea/0x240
[  323.898930] Code: 3c 03 0f 8e f2 00 00 00 44 3b 6b 10 7f 4d 49 bc 00 00 00 00 00 fc ff df eb 22 48 8d 7b 10 488
[  323.898930] RSP: 0018:ffff888101597218 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
[  323.898930] RAX: 0000000000000000 RBX: ffffffffc04361c0 RCX: 0000000000000000
[  323.898930] RDX: 1ffffffff26132ae RSI: ffffffffc04aa3c0 RDI: ffffffffc04361d0
[  323.898930] RBP: ffffffffc04361c8 R08: 0000000000000000 R09: 0000000000000001
[  323.898930] R10: ffff8881015972b0 R11: fffffbfff26132c4 R12: dffffc0000000000
[  323.898930] R13: 0000000000000000 R14: 1ffff110202b2e44 R15: ffffffffc04aa3c0
[  323.898930] FS:  00007f813ed41540(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000
[  323.898930] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  323.898930] CR2: 0000559bf2c9f120 CR3: 000000010bc80000 CR4: 00000000001006f0
[  323.898930] Call Trace:
[  323.898930]  ? atomic_notifier_chain_register+0x2d0/0x2d0
[  323.898930]  ? down_read+0x150/0x150
[  323.898930]  ? sched_clock_cpu+0x126/0x170
[  323.898930]  ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables]
[  323.898930]  ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables]
[  323.898930]  register_netdevice_notifier+0xbb/0x790
[  323.898930]  ? __dev_close_many+0x2d0/0x2d0
[  323.898930]  ? __mutex_unlock_slowpath+0x17f/0x740
[  323.898930]  ? wait_for_completion+0x710/0x710
[  323.898930]  ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables]
[  323.898930]  ? up_write+0x6c/0x210
[  323.898930]  ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables]
[  324.127073]  ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables]
[  324.127073]  nft_chain_filter_init+0x1e/0xe8a [nf_tables]
[  324.127073]  nf_tables_module_init+0x37/0x92 [nf_tables]
[ ... ]

Fixes: 8dd33cc93ec9 ("netfilter: nf_nat: generalize IPv4 masquerading support for nf_tables")
Fixes: be6b635cd674 ("netfilter: nf_nat: generalize IPv6 masquerading support for nf_tables")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
netfilter: add missing error handling code for register functions 2018-11-26T23:35:19+00:00 Taehee Yoo ap420073@gmail.com 2018-11-22T10:59:46+00:00 584eab291c67894cb17cc87544b9d086228ea70f register_{netdevice/inetaddr/inet6addr}_notifier may return an error value, this patch adds the code to handle these error paths. Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
register_{netdevice/inetaddr/inet6addr}_notifier may return an error
value, this patch adds the code to handle these error paths.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
netfilter: ipv6: fix oops when defragmenting locally generated fragments 2018-10-25T08:18:26+00:00 Florian Westphal fw@strlen.de 2018-10-23T14:47:16+00:00 61792b677415b77c8db04991c22966bb8de7603e Unlike ipv4 and normal ipv6 defrag, netfilter ipv6 defragmentation did not save/restore skb->dst. This causes oops when handling locally generated ipv6 fragments, as output path needs a valid dst. Reported-by: Maciej Żenczykowski <zenczykowski@gmail.com> Fixes: 84379c9afe01 ("netfilter: ipv6: nf_defrag: drop skb dst before queueing") Signed-off-by: Florian Westphal <fw@strlen.de> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
Unlike ipv4 and normal ipv6 defrag, netfilter ipv6 defragmentation did
not save/restore skb->dst.

This causes oops when handling locally generated ipv6 fragments, as
output path needs a valid dst.

Reported-by: Maciej Żenczykowski <zenczykowski@gmail.com>
Fixes: 84379c9afe01 ("netfilter: ipv6: nf_defrag: drop skb dst before queueing")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
netfilter: masquerade: don't flush all conntracks if only one address deleted on device 2018-09-28T12:28:26+00:00 Tan Hu tan.hu@zte.com.cn 2018-09-07T08:33:33+00:00 097f95d319f817e651bd51f8846aced92a55a6a1 We configured iptables as below, which only allowed incoming data on established connections: iptables -t mangle -A PREROUTING -m state --state ESTABLISHED -j ACCEPT iptables -t mangle -P PREROUTING DROP When deleting a secondary address, current masquerade implements would flush all conntracks on this device. All the established connections on primary address also be deleted, then subsequent incoming data on the connections would be dropped wrongly because it was identified as NEW connection. So when an address was delete, it should only flush connections related with the address. Signed-off-by: Tan Hu <tan.hu@zte.com.cn> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
We configured iptables as below, which only allowed incoming data on
established connections:

iptables -t mangle -A PREROUTING -m state --state ESTABLISHED -j ACCEPT
iptables -t mangle -P PREROUTING DROP

When deleting a secondary address, current masquerade implements would
flush all conntracks on this device. All the established connections on
primary address also be deleted, then subsequent incoming data on the
connections would be dropped wrongly because it was identified as NEW
connection.

So when an address was delete, it should only flush connections related
with the address.

Signed-off-by: Tan Hu <tan.hu@zte.com.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
netfilter: xtables: avoid BUG_ON 2018-09-17T14:11:12+00:00 Florian Westphal fw@strlen.de 2018-09-04T14:01:57+00:00 70c0eb1ca016f7b6be6cd2a47efc4c701ce4488f I see no reason for them, label or timer cannot be NULL, and if they were, we'll crash with null deref anyway. For skb_header_pointer failure, just set hotdrop to true and toss such packet. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
I see no reason for them, label or timer cannot be NULL, and if they
were, we'll crash with null deref anyway.

For skb_header_pointer failure, just set hotdrop to true and toss
such packet.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-09-13T05:22:42+00:00 David S. Miller davem@davemloft.net 2018-09-13T05:22:42+00:00 aaf9253025e80cf8f62d7b33670e84e838eec5a3 






net: Add and use skb_mark_not_on_list().
2018-09-10T17:06:54+00:00

David S. Miller
davem@davemloft.net

2018-07-30T03:42:53+00:00

a8305bff685252e80b7c60f4f5e7dd2e63e38218

An SKB is not on a list if skb->next is NULL.

Codify this convention into a helper function and use it
where we are dequeueing an SKB and need to mark it as such.

Signed-off-by: David S. Miller <davem@davemloft.net>





An SKB is not on a list if skb->next is NULL.

Codify this convention into a helper function and use it
where we are dequeueing an SKB and need to mark it as such.

Signed-off-by: David S. Miller <davem@davemloft.net>







ip: frags: fix crash in ip_do_fragment()
2018-09-09T21:50:56+00:00

Taehee Yoo
ap420073@gmail.com

2018-09-09T17:47:05+00:00

5d407b071dc369c26a38398326ee2be53651cfe4

A kernel crash occurrs when defragmented packet is fragmented
in ip_do_fragment().
In defragment routine, skb_orphan() is called and
skb->ip_defrag_offset is set. but skb->sk and
skb->ip_defrag_offset are same union member. so that
frag->sk is not NULL.
Hence crash occurrs in skb->sk check routine in ip_do_fragment() when
defragmented packet is fragmented.

test commands:
   %iptables -t nat -I POSTROUTING -j MASQUERADE
   %hping3 192.168.4.2 -s 1000 -p 2000 -d 60000

splat looks like:
[  261.069429] kernel BUG at net/ipv4/ip_output.c:636!
[  261.075753] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[  261.083854] CPU: 1 PID: 1349 Comm: hping3 Not tainted 4.19.0-rc2+ #3
[  261.100977] RIP: 0010:ip_do_fragment+0x1613/0x2600
[  261.106945] Code: e8 e2 38 e3 fe 4c 8b 44 24 18 48 8b 74 24 08 e9 92 f6 ff ff 80 3c 02 00 0f 85 da 07 00 00 48 8b b5 d0 00 00 00 e9 25 f6 ff ff <0f> 0b 0f 0b 44 8b 54 24 58 4c 8b 4c 24 18 4c 8b 5c 24 60 4c 8b 6c
[  261.127015] RSP: 0018:ffff8801031cf2c0 EFLAGS: 00010202
[  261.134156] RAX: 1ffff1002297537b RBX: ffffed0020639e6e RCX: 0000000000000004
[  261.142156] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880114ba9bd8
[  261.150157] RBP: ffff880114ba8a40 R08: ffffed0022975395 R09: ffffed0022975395
[  261.158157] R10: 0000000000000001 R11: ffffed0022975394 R12: ffff880114ba9ca4
[  261.166159] R13: 0000000000000010 R14: ffff880114ba9bc0 R15: dffffc0000000000
[  261.174169] FS:  00007fbae2199700(0000) GS:ffff88011b400000(0000) knlGS:0000000000000000
[  261.183012] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  261.189013] CR2: 00005579244fe000 CR3: 0000000119bf4000 CR4: 00000000001006e0
[  261.198158] Call Trace:
[  261.199018]  ? dst_output+0x180/0x180
[  261.205011]  ? save_trace+0x300/0x300
[  261.209018]  ? ip_copy_metadata+0xb00/0xb00
[  261.213034]  ? sched_clock_local+0xd4/0x140
[  261.218158]  ? kill_l4proto+0x120/0x120 [nf_conntrack]
[  261.223014]  ? rt_cpu_seq_stop+0x10/0x10
[  261.227014]  ? find_held_lock+0x39/0x1c0
[  261.233008]  ip_finish_output+0x51d/0xb50
[  261.237006]  ? ip_fragment.constprop.56+0x220/0x220
[  261.243011]  ? nf_ct_l4proto_register_one+0x5b0/0x5b0 [nf_conntrack]
[  261.250152]  ? rcu_is_watching+0x77/0x120
[  261.255010]  ? nf_nat_ipv4_out+0x1e/0x2b0 [nf_nat_ipv4]
[  261.261033]  ? nf_hook_slow+0xb1/0x160
[  261.265007]  ip_output+0x1c7/0x710
[  261.269005]  ? ip_mc_output+0x13f0/0x13f0
[  261.273002]  ? __local_bh_enable_ip+0xe9/0x1b0
[  261.278152]  ? ip_fragment.constprop.56+0x220/0x220
[  261.282996]  ? nf_hook_slow+0xb1/0x160
[  261.287007]  raw_sendmsg+0x21f9/0x4420
[  261.291008]  ? dst_output+0x180/0x180
[  261.297003]  ? sched_clock_cpu+0x126/0x170
[  261.301003]  ? find_held_lock+0x39/0x1c0
[  261.306155]  ? stop_critical_timings+0x420/0x420
[  261.311004]  ? check_flags.part.36+0x450/0x450
[  261.315005]  ? _raw_spin_unlock_irq+0x29/0x40
[  261.320995]  ? _raw_spin_unlock_irq+0x29/0x40
[  261.326142]  ? cyc2ns_read_end+0x10/0x10
[  261.330139]  ? raw_bind+0x280/0x280
[  261.334138]  ? sched_clock_cpu+0x126/0x170
[  261.338995]  ? check_flags.part.36+0x450/0x450
[  261.342991]  ? __lock_acquire+0x4500/0x4500
[  261.348994]  ? inet_sendmsg+0x11c/0x500
[  261.352989]  ? dst_output+0x180/0x180
[  261.357012]  inet_sendmsg+0x11c/0x500
[ ... ]

v2:
 - clear skb->sk at reassembly routine.(Eric Dumarzet)

Fixes: fa0f527358bd ("ip: use rb trees for IP frag queue.")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>





A kernel crash occurrs when defragmented packet is fragmented
in ip_do_fragment().
In defragment routine, skb_orphan() is called and
skb->ip_defrag_offset is set. but skb->sk and
skb->ip_defrag_offset are same union member. so that
frag->sk is not NULL.
Hence crash occurrs in skb->sk check routine in ip_do_fragment() when
defragmented packet is fragmented.

test commands:
   %iptables -t nat -I POSTROUTING -j MASQUERADE
   %hping3 192.168.4.2 -s 1000 -p 2000 -d 60000

splat looks like:
[  261.069429] kernel BUG at net/ipv4/ip_output.c:636!
[  261.075753] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[  261.083854] CPU: 1 PID: 1349 Comm: hping3 Not tainted 4.19.0-rc2+ #3
[  261.100977] RIP: 0010:ip_do_fragment+0x1613/0x2600
[  261.106945] Code: e8 e2 38 e3 fe 4c 8b 44 24 18 48 8b 74 24 08 e9 92 f6 ff ff 80 3c 02 00 0f 85 da 07 00 00 48 8b b5 d0 00 00 00 e9 25 f6 ff ff <0f> 0b 0f 0b 44 8b 54 24 58 4c 8b 4c 24 18 4c 8b 5c 24 60 4c 8b 6c
[  261.127015] RSP: 0018:ffff8801031cf2c0 EFLAGS: 00010202
[  261.134156] RAX: 1ffff1002297537b RBX: ffffed0020639e6e RCX: 0000000000000004
[  261.142156] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880114ba9bd8
[  261.150157] RBP: ffff880114ba8a40 R08: ffffed0022975395 R09: ffffed0022975395
[  261.158157] R10: 0000000000000001 R11: ffffed0022975394 R12: ffff880114ba9ca4
[  261.166159] R13: 0000000000000010 R14: ffff880114ba9bc0 R15: dffffc0000000000
[  261.174169] FS:  00007fbae2199700(0000) GS:ffff88011b400000(0000) knlGS:0000000000000000
[  261.183012] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  261.189013] CR2: 00005579244fe000 CR3: 0000000119bf4000 CR4: 00000000001006e0
[  261.198158] Call Trace:
[  261.199018]  ? dst_output+0x180/0x180
[  261.205011]  ? save_trace+0x300/0x300
[  261.209018]  ? ip_copy_metadata+0xb00/0xb00
[  261.213034]  ? sched_clock_local+0xd4/0x140
[  261.218158]  ? kill_l4proto+0x120/0x120 [nf_conntrack]
[  261.223014]  ? rt_cpu_seq_stop+0x10/0x10
[  261.227014]  ? find_held_lock+0x39/0x1c0
[  261.233008]  ip_finish_output+0x51d/0xb50
[  261.237006]  ? ip_fragment.constprop.56+0x220/0x220
[  261.243011]  ? nf_ct_l4proto_register_one+0x5b0/0x5b0 [nf_conntrack]
[  261.250152]  ? rcu_is_watching+0x77/0x120
[  261.255010]  ? nf_nat_ipv4_out+0x1e/0x2b0 [nf_nat_ipv4]
[  261.261033]  ? nf_hook_slow+0xb1/0x160
[  261.265007]  ip_output+0x1c7/0x710
[  261.269005]  ? ip_mc_output+0x13f0/0x13f0
[  261.273002]  ? __local_bh_enable_ip+0xe9/0x1b0
[  261.278152]  ? ip_fragment.constprop.56+0x220/0x220
[  261.282996]  ? nf_hook_slow+0xb1/0x160
[  261.287007]  raw_sendmsg+0x21f9/0x4420
[  261.291008]  ? dst_output+0x180/0x180
[  261.297003]  ? sched_clock_cpu+0x126/0x170
[  261.301003]  ? find_held_lock+0x39/0x1c0
[  261.306155]  ? stop_critical_timings+0x420/0x420
[  261.311004]  ? check_flags.part.36+0x450/0x450
[  261.315005]  ? _raw_spin_unlock_irq+0x29/0x40
[  261.320995]  ? _raw_spin_unlock_irq+0x29/0x40
[  261.326142]  ? cyc2ns_read_end+0x10/0x10
[  261.330139]  ? raw_bind+0x280/0x280
[  261.334138]  ? sched_clock_cpu+0x126/0x170
[  261.338995]  ? check_flags.part.36+0x450/0x450
[  261.342991]  ? __lock_acquire+0x4500/0x4500
[  261.348994]  ? inet_sendmsg+0x11c/0x500
[  261.352989]  ? dst_output+0x180/0x180
[  261.357012]  inet_sendmsg+0x11c/0x500
[ ... ]

v2:
 - clear skb->sk at reassembly routine.(Eric Dumarzet)

Fixes: fa0f527358bd ("ip: use rb trees for IP frag queue.")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>







netfilter: ip6t_rpfilter: set F_IFACE for linklocal addresses
2018-08-16T17:36:58+00:00

Florian Westphal
fw@strlen.de

2018-07-25T19:38:43+00:00

da786717e0894886301ed2536843c13f9e8fd53e

Roman reports that DHCPv6 client no longer sees replies from server
due to

ip6tables -t raw -A PREROUTING -m rpfilter --invert -j DROP

rule.  We need to set the F_IFACE flag for linklocal addresses, they
are scoped per-device.

Fixes: 47b7e7f82802 ("netfilter: don't set F_IFACE on ipv6 fib lookups")
Reported-by: Roman Mamedov <rm@romanrm.net>
Tested-by: Roman Mamedov <rm@romanrm.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>





Roman reports that DHCPv6 client no longer sees replies from server
due to

ip6tables -t raw -A PREROUTING -m rpfilter --invert -j DROP

rule.  We need to set the F_IFACE flag for linklocal addresses, they
are scoped per-device.

Fixes: 47b7e7f82802 ("netfilter: don't set F_IFACE on ipv6 fib lookups")
Reported-by: Roman Mamedov <rm@romanrm.net>
Tested-by: Roman Mamedov <rm@romanrm.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>