diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-08-15 13:09:51 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-16 02:06:34 +0200 |
| commit | 12d94a804946af291e24b80fc53ec86264765781 (patch) | |
| tree | 3b5a06908e100ce2934e37100bbe1f8a1937fd25 /net | |
| parent | Merge tag 'wireless-drivers-for-davem-2017-08-15' of git://git.kernel.org/pub... (diff) | |
| download | linux-12d94a804946af291e24b80fc53ec86264765781.tar.xz linux-12d94a804946af291e24b80fc53ec86264765781.zip | |
ipv6: fix NULL dereference in ip6_route_dev_notify()
Based on a syzkaller report [1], I found that a per cpu allocation
failure in snmp6_alloc_dev() would then lead to NULL dereference in
ip6_route_dev_notify().
It seems this is a very old bug, thus no Fixes tag in this submission.
Let's add in6_dev_put_clear() helper, as we will probably use
it elsewhere (once available/present in net-next)
[1]
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 17294 Comm: syz-executor6 Not tainted 4.13.0-rc2+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019f456680 task.stack: ffff8801c6e58000
RIP: 0010:__read_once_size include/linux/compiler.h:250 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:26 [inline]
RIP: 0010:refcount_sub_and_test+0x7d/0x1b0 lib/refcount.c:178
RSP: 0018:ffff8801c6e5f1b0 EFLAGS: 00010202
RAX: 0000000000000037 RBX: dffffc0000000000 RCX: ffffc90005d25000
RDX: ffff8801c6e5f218 RSI: ffffffff82342bbf RDI: 0000000000000001
RBP: ffff8801c6e5f240 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10038dcbe37
R13: 0000000000000006 R14: 0000000000000001 R15: 00000000000001b8
FS: 00007f21e0429700(0000) GS:ffff8801dc100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001ddbc22000 CR3: 00000001d632b000 CR4: 00000000001426e0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
refcount_dec_and_test+0x1a/0x20 lib/refcount.c:211
in6_dev_put include/net/addrconf.h:335 [inline]
ip6_route_dev_notify+0x1c9/0x4a0 net/ipv6/route.c:3732
notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93
__raw_notifier_call_chain kernel/notifier.c:394 [inline]
raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
call_netdevice_notifiers_info+0x51/0x90 net/core/dev.c:1678
call_netdevice_notifiers net/core/dev.c:1694 [inline]
rollback_registered_many+0x91c/0xe80 net/core/dev.c:7107
rollback_registered+0x1be/0x3c0 net/core/dev.c:7149
register_netdevice+0xbcd/0xee0 net/core/dev.c:7587
register_netdev+0x1a/0x30 net/core/dev.c:7669
loopback_net_init+0x76/0x160 drivers/net/loopback.c:214
ops_init+0x10a/0x570 net/core/net_namespace.c:118
setup_net+0x313/0x710 net/core/net_namespace.c:294
copy_net_ns+0x27c/0x580 net/core/net_namespace.c:418
create_new_namespaces+0x425/0x880 kernel/nsproxy.c:107
unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:206
SYSC_unshare kernel/fork.c:2347 [inline]
SyS_unshare+0x653/0xfa0 kernel/fork.c:2297
entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4512c9
RSP: 002b:00007f21e0428c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000718150 RCX: 00000000004512c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000062020200
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b973d
R13: 00000000ffffffff R14: 000000002001d000 R15: 00000000000002dd
Code: 50 2b 34 82 c7 00 f1 f1 f1 f1 c7 40 04 04 f2 f2 f2 c7 40 08 f3 f3
f3 f3 e8 a1 43 39 ff 4c 89 f8 48 8b 95 70 ff ff ff 48 c1 e8 03 <0f> b6
0c 18 4c 89 f8 83 e0 07 83 c0 03 38 c8 7c 08 84 c9 0f 85
RIP: __read_once_size include/linux/compiler.h:250 [inline] RSP:
ffff8801c6e5f1b0
RIP: atomic_read arch/x86/include/asm/atomic.h:26 [inline] RSP:
ffff8801c6e5f1b0
RIP: refcount_sub_and_test+0x7d/0x1b0 lib/refcount.c:178 RSP:
ffff8801c6e5f1b0
---[ end trace e441d046c6410d31 ]---
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/route.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 99d4727f2b18..94d6a13d47f0 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -3721,10 +3721,10 @@ static int ip6_route_dev_notify(struct notifier_block *this, /* NETDEV_UNREGISTER could be fired for multiple times by * netdev_wait_allrefs(). Make sure we only call this once. */ - in6_dev_put(net->ipv6.ip6_null_entry->rt6i_idev); + in6_dev_put_clear(&net->ipv6.ip6_null_entry->rt6i_idev); #ifdef CONFIG_IPV6_MULTIPLE_TABLES - in6_dev_put(net->ipv6.ip6_prohibit_entry->rt6i_idev); - in6_dev_put(net->ipv6.ip6_blk_hole_entry->rt6i_idev); + in6_dev_put_clear(&net->ipv6.ip6_prohibit_entry->rt6i_idev); + in6_dev_put_clear(&net->ipv6.ip6_blk_hole_entry->rt6i_idev); #endif } |