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authorPaolo Abeni <pabeni@redhat.com>2018-02-12 18:49:39 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-15 10:56:56 +0100
commit4260816d4785cbf3f5efa1300e63ba47b80db7ee (patch)
treeb111e9c1033dd8c3cc70d1e9e8c6baca2787e3bf
parentea2699504d334d557ade9fc83e66ad695201333a (diff)
netfilter: x_tables: fix missing timer initialization in xt_LED
commit 10414014bc085aac9f787a5890b33b5605fbcfc4 upstream. syzbot reported that xt_LED may try to use the ledinternal->timer without previously initializing it: ------------[ cut here ]------------ kernel BUG at kernel/time/timer.c:958! invalid opcode: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 1826 Comm: kworker/1:2 Not tainted 4.15.0+ #306 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:__mod_timer kernel/time/timer.c:958 [inline] RIP: 0010:mod_timer+0x7d6/0x13c0 kernel/time/timer.c:1102 RSP: 0018:ffff8801d24fe9f8 EFLAGS: 00010293 RAX: ffff8801d25246c0 RBX: ffff8801aec6cb50 RCX: ffffffff816052c6 RDX: 0000000000000000 RSI: 00000000fffbd14b RDI: ffff8801aec6cb68 RBP: ffff8801d24fec98 R08: 0000000000000000 R09: 1ffff1003a49fd6c R10: ffff8801d24feb28 R11: 0000000000000005 R12: dffffc0000000000 R13: ffff8801d24fec70 R14: 00000000fffbd14b R15: ffff8801af608f90 FS: 0000000000000000(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000206d6fd0 CR3: 0000000006a22001 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: led_tg+0x1db/0x2e0 net/netfilter/xt_LED.c:75 ip6t_do_table+0xc2a/0x1a30 net/ipv6/netfilter/ip6_tables.c:365 ip6table_raw_hook+0x65/0x80 net/ipv6/netfilter/ip6table_raw.c:42 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline] nf_hook_slow+0xba/0x1a0 net/netfilter/core.c:483 nf_hook.constprop.27+0x3f6/0x830 include/linux/netfilter.h:243 NF_HOOK include/linux/netfilter.h:286 [inline] ndisc_send_skb+0xa51/0x1370 net/ipv6/ndisc.c:491 ndisc_send_ns+0x38a/0x870 net/ipv6/ndisc.c:633 addrconf_dad_work+0xb9e/0x1320 net/ipv6/addrconf.c:4008 process_one_work+0xbbf/0x1af0 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:429 Code: 85 2a 0b 00 00 4d 8b 3c 24 4d 85 ff 75 9f 4c 8b bd 60 fd ff ff e8 bb 57 10 00 65 ff 0d 94 9a a1 7e e9 d9 fc ff ff e8 aa 57 10 00 <0f> 0b e8 a3 57 10 00 e9 14 fb ff ff e8 99 57 10 00 4c 89 bd 70 RIP: __mod_timer kernel/time/timer.c:958 [inline] RSP: ffff8801d24fe9f8 RIP: mod_timer+0x7d6/0x13c0 kernel/time/timer.c:1102 RSP: ffff8801d24fe9f8 ---[ end trace f661ab06f5dd8b3d ]--- The ledinternal struct can be shared between several different xt_LED targets, but the related timer is currently initialized only if the first target requires it. Fix it by unconditionally initializing the timer struct. v1 -> v2: call del_timer_sync() unconditionally, too. Fixes: 268cb38e1802 ("netfilter: x_tables: add LED trigger target") Reported-by: syzbot+10c98dc5725c6c8fc7fb@syzkaller.appspotmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/netfilter/xt_LED.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/net/netfilter/xt_LED.c b/net/netfilter/xt_LED.c
index 0971634e5444..18d3af5e1098 100644
--- a/net/netfilter/xt_LED.c
+++ b/net/netfilter/xt_LED.c
@@ -142,9 +142,10 @@ static int led_tg_check(const struct xt_tgchk_param *par)
goto exit_alloc;
}
- /* See if we need to set up a timer */
- if (ledinfo->delay > 0)
- timer_setup(&ledinternal->timer, led_timeout_callback, 0);
+ /* Since the letinternal timer can be shared between multiple targets,
+ * always set it up, even if the current target does not need it
+ */
+ timer_setup(&ledinternal->timer, led_timeout_callback, 0);
list_add_tail(&ledinternal->list, &xt_led_triggers);
@@ -181,8 +182,7 @@ static void led_tg_destroy(const struct xt_tgdtor_param *par)
list_del(&ledinternal->list);
- if (ledinfo->delay > 0)
- del_timer_sync(&ledinternal->timer);
+ del_timer_sync(&ledinternal->timer);
led_trigger_unregister(&ledinternal->netfilter_led_trigger);