From 4dd7972d1204c3851a4092cecd2207e05eb29b09 Mon Sep 17 00:00:00 2001 From: Vitaliy Gusev Date: Wed, 1 Oct 2008 01:51:39 -0700 Subject: tcp: Fix NULL dereference in tcp_4_send_ack() Fix NULL dereference in tcp_4_send_ack(). As skb->dev is reset to NULL in tcp_v4_rcv() thus OOPS occurs: BUG: unable to handle kernel NULL pointer dereference at 00000000000004d0 IP: [] tcp_v4_send_ack+0x203/0x250 Stack: ffff810005dbb000 ffff810015c8acc0 e77b2c6e5f861600 a01610802e90cb6d 0a08010100000000 88afffff88afffff 0000000080762be8 0000000115c872e8 0004122000000000 0000000000000001 ffffffff80762b88 0000000000000020 Call Trace: [] tcp_v4_reqsk_send_ack+0x20/0x22 [] tcp_check_req+0x108/0x14c [] ? rt_intern_hash+0x322/0x33c [] tcp_v4_do_rcv+0x399/0x4ec [] ? skb_checksum+0x4f/0x272 [] ? __inet_lookup_listener+0x14a/0x15c [] tcp_v4_rcv+0x6a1/0x701 [] ip_local_deliver_finish+0x157/0x24a [] ip_local_deliver+0x72/0x7c [] ip_rcv_finish+0x38d/0x3b2 [] ? scsi_io_completion+0x19d/0x39e [] ip_rcv+0x2a2/0x2e5 [] netif_receive_skb+0x293/0x303 [] process_backlog+0x80/0xd0 [] ? __rcu_process_callbacks+0x125/0x1b4 [] net_rx_action+0xb9/0x17f [] __do_softirq+0xa3/0x164 [] call_softirq+0x1c/0x28 [] do_softirq+0x34/0x72 [] local_bh_enable_ip+0x3f/0x50 [] _spin_unlock_bh+0x12/0x14 [] release_sock+0xb8/0xc1 [] inet_stream_connect+0x146/0x25c [] ? autoremove_wake_function+0x0/0x38 [] sys_connect+0x68/0x8e [] ? fd_install+0x5f/0x68 [] ? sock_map_fd+0x55/0x62 [] system_call_after_swapgs+0x7b/0x80 Code: 41 10 11 d0 83 d0 00 4d 85 ed 89 45 c0 c7 45 c4 08 00 00 00 74 07 41 8b 45 04 89 45 c8 48 8b 43 20 8b 4d b8 48 8d 55 b0 48 89 de <48> 8b 80 d0 04 00 00 48 8b b8 60 01 00 00 e8 20 ae fe ff 65 48 RIP [] tcp_v4_send_ack+0x203/0x250 RSP CR2: 00000000000004d0 Signed-off-by: Vitaliy Gusev Signed-off-by: David S. Miller --- net/ipv4/tcp_ipv4.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net') diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 1b4fee20fc93..011478e46c40 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -618,7 +618,7 @@ static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, ]; } rep; struct ip_reply_arg arg; - struct net *net = dev_net(skb->dev); + struct net *net = dev_net(skb->dst->dev); memset(&rep.th, 0, sizeof(struct tcphdr)); memset(&arg, 0, sizeof(arg)); -- cgit v1.2.3