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Alexey Kodanev authored
Found that when randomized tcp offsets are enabled (by default) TCP client can still start new connections without them. Later, if server does active close and re-uses sockets in TIME-WAIT state, new SYN from client can be rejected on PAWS check inside tcp_timewait_state_process(), because either tw_ts_recent or rcv_tsval doesn't really have an offset set. Here is how to reproduce it with LTP netstress tool: netstress -R 1 & netstress -H 127.0.0.1 -lr 1000000 -a1 [...] < S seq 1956977072 win 43690 TS val 295618 ecr 459956970 > . ack 1956911535 win 342 TS val 459967184 ecr 1547117608 < R seq 1956911535 win 0 length 0 +1. < S seq 1956977072 win 43690 TS val 296640 ecr 459956970 > S. seq 657450664 ack 1956977073 win 43690 TS val 459968205 ecr 296640 Fixes: 95a22cae ("tcp: randomize tcp timestamp offsets for each connection") Signed-off-by:
Alexey Kodanev <alexey.kodanev@oracle.com> Acked-by:
Eric Dumazet <edumazet@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
Alexey Kodanev authoredFound that when randomized tcp offsets are enabled (by default) TCP client can still start new connections without them. Later, if server does active close and re-uses sockets in TIME-WAIT state, new SYN from client can be rejected on PAWS check inside tcp_timewait_state_process(), because either tw_ts_recent or rcv_tsval doesn't really have an offset set. Here is how to reproduce it with LTP netstress tool: netstress -R 1 & netstress -H 127.0.0.1 -lr 1000000 -a1 [...] < S seq 1956977072 win 43690 TS val 295618 ecr 459956970 > . ack 1956911535 win 342 TS val 459967184 ecr 1547117608 < R seq 1956911535 win 0 length 0 +1. < S seq 1956977072 win 43690 TS val 296640 ecr 459956970 > S. seq 657450664 ack 1956977073 win 43690 TS val 459968205 ecr 296640 Fixes: 95a22cae ("tcp: randomize tcp timestamp offsets for each connection") Signed-off-by:
Alexey Kodanev <alexey.kodanev@oracle.com> Acked-by:
Eric Dumazet <edumazet@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
tcp_ipv6.c 50.83 KiB
/*
* TCP over IPv6
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* Based on:
* linux/net/ipv4/tcp.c
* linux/net/ipv4/tcp_input.c
* linux/net/ipv4/tcp_output.c
*
* Fixes:
* Hideaki YOSHIFUJI : sin6_scope_id support
* YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
* Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
* a single port at the same time.
* YOSHIFUJI Hideaki @USAGI: convert /proc/net/tcp6 to seq_file.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/bottom_half.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/jiffies.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/ipsec.h>
#include <linux/times.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/random.h>
#include <net/tcp.h>
#include <net/ndisc.h>
#include <net/inet6_hashtables.h>
#include <net/inet6_connection_sock.h>
#include <net/ipv6.h>
#include <net/transp_v6.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/ip6_checksum.h>
#include <net/inet_ecn.h>
#include <net/protocol.h>
#include <net/xfrm.h>
#include <net/snmp.h>
#include <net/dsfield.h>
#include <net/timewait_sock.h>
#include <net/inet_common.h>
#include <net/secure_seq.h>
#include <net/busy_poll.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <crypto/hash.h>
#include <linux/scatterlist.h>