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| author | Xin Long <lucien.xin@gmail.com> | 2017-06-20 15:42:38 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-06-20 15:31:43 -0400 |
| commit | d5494acb88aa9dd1325079c9b8855008a52c19b3 (patch) | |
| tree | b7e42e5b3ad94c6b60dd77168d32d6c50180da63 /net | |
| parent | 7044f429e70d987cdc780f26a9b9951970645966 (diff) | |
| download | linux-d5494acb88aa9dd1325079c9b8855008a52c19b3.tar.gz linux-d5494acb88aa9dd1325079c9b8855008a52c19b3.tar.bz2 linux-d5494acb88aa9dd1325079c9b8855008a52c19b3.zip | |
dccp: call inet_add_protocol after register_pernet_subsys in dccp_v4_init
Now dccp_ipv4 works as a kernel module. During loading this module, if
one dccp packet is being recieved after inet_add_protocol but before
register_pernet_subsys in which v4_ctl_sk is initialized, a null pointer
dereference may be triggered because of init_net.dccp.v4_ctl_sk is 0x0.
Jianlin found this issue when the following call trace occurred:
[ 171.950177] BUG: unable to handle kernel NULL pointer dereference at 0000000000000110
[ 171.951007] IP: [<ffffffffc0558364>] dccp_v4_ctl_send_reset+0xc4/0x220 [dccp_ipv4]
[...]
[ 171.984629] Call Trace:
[ 171.984859] <IRQ>
[ 171.985061]
[ 171.985213] [<ffffffffc0559a53>] dccp_v4_rcv+0x383/0x3f9 [dccp_ipv4]
[ 171.985711] [<ffffffff815ca054>] ip_local_deliver_finish+0xb4/0x1f0
[ 171.986309] [<ffffffff815ca339>] ip_local_deliver+0x59/0xd0
[ 171.986852] [<ffffffff810cd7a4>] ? update_curr+0x104/0x190
[ 171.986956] [<ffffffff815c9cda>] ip_rcv_finish+0x8a/0x350
[ 171.986956] [<ffffffff815ca666>] ip_rcv+0x2b6/0x410
[ 171.986956] [<ffffffff810c83b4>] ? task_cputime+0x44/0x80
[ 171.986956] [<ffffffff81586f22>] __netif_receive_skb_core+0x572/0x7c0
[ 171.986956] [<ffffffff810d2c51>] ? trigger_load_balance+0x61/0x1e0
[ 171.986956] [<ffffffff81587188>] __netif_receive_skb+0x18/0x60
[ 171.986956] [<ffffffff8158841e>] process_backlog+0xae/0x180
[ 171.986956] [<ffffffff8158799d>] net_rx_action+0x16d/0x380
[ 171.986956] [<ffffffff81090b7f>] __do_softirq+0xef/0x280
[ 171.986956] [<ffffffff816b6a1c>] call_softirq+0x1c/0x30
This patch is to move inet_add_protocol after register_pernet_subsys in
dccp_v4_init, so that v4_ctl_sk is initialized before any incoming dccp
packets are processed.
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/dccp/ipv4.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index f75482bdee9a..f85d901f4e3f 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -1033,33 +1033,34 @@ static int __init dccp_v4_init(void) { int err = proto_register(&dccp_v4_prot, 1); - if (err != 0) + if (err) goto out; - err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP); - if (err != 0) - goto out_proto_unregister; - inet_register_protosw(&dccp_v4_protosw); err = register_pernet_subsys(&dccp_v4_ops); if (err) goto out_destroy_ctl_sock; + + err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP); + if (err) + goto out_proto_unregister; + out: return err; +out_proto_unregister: + unregister_pernet_subsys(&dccp_v4_ops); out_destroy_ctl_sock: inet_unregister_protosw(&dccp_v4_protosw); - inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP); -out_proto_unregister: proto_unregister(&dccp_v4_prot); goto out; } static void __exit dccp_v4_exit(void) { + inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP); unregister_pernet_subsys(&dccp_v4_ops); inet_unregister_protosw(&dccp_v4_protosw); - inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP); proto_unregister(&dccp_v4_prot); } |