Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754556AbbKWJyX (ORCPT ); Mon, 23 Nov 2015 04:54:23 -0500 Received: from www62.your-server.de ([213.133.104.62]:56763 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754369AbbKWJyU (ORCPT ); Mon, 23 Nov 2015 04:54:20 -0500 Message-ID: <5652E248.2030802@iogearbox.net> Date: Mon, 23 Nov 2015 10:54:16 +0100 From: Daniel Borkmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: romieu@fr.zoreil.com, vinschen@redhat.com CC: =?windows-1252?Q?Toralf_F=F6rster?= , Linux Kernel , netdev@vger.kernel.org, nic_swsd@realtek.com Subject: Re: network card doesn't recovered itself after a SYN flooding attack References: <56519E2B.8050500@gmx.de> In-Reply-To: <56519E2B.8050500@gmx.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit X-Authenticated-Sender: daniel@iogearbox.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4590 Lines: 61 [ cc'ing netdev and r8169 folks ] On 11/22/2015 11:51 AM, Toralf F?rster wrote: > At 22th of November at 21:26 UTC my server (64 bit stable Gentoo hardened) suffered from a DDoS attack. > > From the kern.log: > > > Nov 20 22:26:29 tor-relay kernel: [2431358.124515] TCP: request_sock_TCP: Possible SYN flooding on port 80. Sending cookies. Check SNMP counters. > Nov 20 22:26:48 tor-relay kernel: [2431377.216133] ------------[ cut here ]------------ > Nov 20 22:26:48 tor-relay kernel: [2431377.216141] WARNING: CPU: 7 PID: 12421 at net/sched/sch_generic.c:303 dev_watchdog+0x272/0x280() > Nov 20 22:26:48 tor-relay kernel: [2431377.216143] NETDEV WATCHDOG: enp3s0 (r8169): transmit queue 0 timed out > Nov 20 22:26:48 tor-relay kernel: [2431377.216145] Modules linked in: > Nov 20 22:26:48 tor-relay kernel: [2431377.216148] af_packet nf_log_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables nf_log_ipv4 nf_log_common xt_LOG xt_multiport nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack iptable_filter ip_tables i2c_i801 i2c_core tpm_tis tpm thermal processor battery atkbd x86_pkg_temp_thermal button microcode fan > Nov 20 22:26:48 tor-relay kernel: [2431377.216173] CPU: 7 PID: 12421 Comm: emerge Not tainted 4.1.7-hardened-r1 #1 > Nov 20 22:26:48 tor-relay kernel: [2431377.216174] Hardware name: System manufacturer System Product Name/P8H77-M PRO, BIOS 0922 09/10/2012 > Nov 20 22:26:48 tor-relay kernel: [2431377.216176] ffffffff994fa966 0000000000000000 ffffffff99bced09 ffff88041fbc3d18 > Nov 20 22:26:48 tor-relay kernel: [2431377.216179] ffffffff99983e26 0000000000000000 ffff88041fbc3d68 ffff88041fbc3d58 > Nov 20 22:26:48 tor-relay kernel: [2431377.216182] ffffffff9947f08a ffff88041fbc3d48 ffffffff99bced09 000000000000012f > Nov 20 22:26:48 tor-relay kernel: [2431377.216185] Call Trace: > Nov 20 22:26:48 tor-relay kernel: [2431377.216187] [] ? print_modules+0x76/0xe0 > Nov 20 22:26:48 tor-relay kernel: [2431377.216198] [] dump_stack+0x45/0x5d > Nov 20 22:26:48 tor-relay kernel: [2431377.216203] [] warn_slowpath_common+0x8a/0xd0 > Nov 20 22:26:48 tor-relay kernel: [2431377.216205] [] warn_slowpath_fmt+0x5a/0x70 > Nov 20 22:26:48 tor-relay kernel: [2431377.216210] [] ? task_tick_fair+0x2a8/0x760 > Nov 20 22:26:48 tor-relay kernel: [2431377.216213] [] dev_watchdog+0x272/0x280 > Nov 20 22:26:48 tor-relay kernel: [2431377.216216] [] ? dev_deactivate_queue+0x70/0x70 > Nov 20 22:26:48 tor-relay kernel: [2431377.216219] [] call_timer_fn+0x47/0x140 > Nov 20 22:26:48 tor-relay kernel: [2431377.216222] [] run_timer_softirq+0x291/0x450 > Nov 20 22:26:48 tor-relay kernel: [2431377.216224] [] ? dev_deactivate_queue+0x70/0x70 > Nov 20 22:26:48 tor-relay kernel: [2431377.216228] [] __do_softirq+0xf8/0x290 > Nov 20 22:26:48 tor-relay kernel: [2431377.216230] [] irq_exit+0x9d/0xb0 > Nov 20 22:26:48 tor-relay kernel: [2431377.216235] [] smp_apic_timer_interrupt+0x55/0x70 > Nov 20 22:26:48 tor-relay kernel: [2431377.216237] [] apic_timer_interrupt+0x97/0xa0 > Nov 20 22:26:48 tor-relay kernel: [2431377.216239] > Nov 20 22:26:48 tor-relay kernel: [2431377.216241] ---[ end trace 93431a9382c0a11a ]--- > Nov 20 22:26:48 tor-relay kernel: [2431377.237826] r8169 0000:03:00.0 enp3s0: link up > Nov 20 22:28:18 tor-relay kernel: [2431467.175659] r8169 0000:03:00.0 enp3s0: link up > Nov 20 22:28:30 tor-relay kernel: [2431479.172562] r8169 0000:03:00.0 enp3s0: link up > Nov 20 22:28:42 tor-relay kernel: [2431491.164472] r8169 0000:03:00.0 enp3s0: link up > Nov 20 22:28:54 tor-relay kernel: [2431503.170416] r8169 0000:03:00.0 enp3s0: link up > Nov 20 22:29:06 tor-relay kernel: [2431515.148333] r8169 0000:03:00.0 enp3s0: link up > Nov 20 22:29:18 tor-relay kernel: [2431527.143293] r8169 0000:03:00.0 enp3s0: link up > Nov 20 22:29:30 tor-relay kernel: [2431539.142164] r8169 0000:03:00.0 enp3s0: link up > Nov 20 22:29:42 tor-relay kernel: [2431551.124104] r8169 0000:03:00.0 enp3s0: link up > ... > Nov 22 10:56:24 tor-relay kernel: [2562675.624512] r8169 0000:03:00.0 enp3s0: link up > > > > The last line repeated and the network was down till I initiated a hardware reset. > > It looks for me that the attack turned the network card into a state from which it couldn't recovered itself, or ? > Anything what I should change here at the system to avoid such a hang ? > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/