linux/net/netfilter
Gao Feng 8d11350f5f netfilter: seqadj: Fix the wrong ack adjust for the RST packet without ack
It is valid that the TCP RST packet which does not set ack flag, and bytes
of ack number are zero. But current seqadj codes would adjust the "0" ack
to invalid ack number. Actually seqadj need to check the ack flag before
adjust it for these RST packets.

The following is my test case

client is 10.26.98.245, and add one iptable rule:
iptables  -I INPUT -p tcp --sport 12345 -m connbytes --connbytes 2:
--connbytes-dir reply --connbytes-mode packets -j REJECT --reject-with
tcp-reset
This iptables rule could generate on TCP RST without ack flag.

server:10.172.135.55
Enable the synproxy with seqadjust by the following iptables rules
iptables -t raw -A PREROUTING -i eth0 -p tcp -d 10.172.135.55 --dport 12345
-m tcp --syn -j CT --notrack

iptables -A INPUT -i eth0 -p tcp -d 10.172.135.55 --dport 12345 -m conntrack
--ctstate INVALID,UNTRACKED -j SYNPROXY --sack-perm --timestamp --wscale 7
--mss 1460
iptables -A OUTPUT -o eth0 -p tcp -s 10.172.135.55 --sport 12345 -m conntrack
--ctstate INVALID,UNTRACKED -m tcp --tcp-flags SYN,RST,ACK SYN,ACK -j ACCEPT

The following is my test result.

1. packet trace on client
root@routers:/tmp# tcpdump -i eth0 tcp port 12345 -n
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
IP 10.26.98.245.45154 > 10.172.135.55.12345: Flags [S], seq 3695959829,
win 29200, options [mss 1460,sackOK,TS val 452367884 ecr 0,nop,wscale 7],
length 0
IP 10.172.135.55.12345 > 10.26.98.245.45154: Flags [S.], seq 546723266,
ack 3695959830, win 0, options [mss 1460,sackOK,TS val 15643479 ecr 452367884,
nop,wscale 7], length 0
IP 10.26.98.245.45154 > 10.172.135.55.12345: Flags [.], ack 1, win 229,
options [nop,nop,TS val 452367885 ecr 15643479], length 0
IP 10.172.135.55.12345 > 10.26.98.245.45154: Flags [.], ack 1, win 226,
options [nop,nop,TS val 15643479 ecr 452367885], length 0
IP 10.26.98.245.45154 > 10.172.135.55.12345: Flags [R], seq 3695959830,
win 0, length 0

2. seqadj log on server
[62873.867319] Adjusting sequence number from 602341895->546723267,
ack from 3695959830->3695959830
[62873.867644] Adjusting sequence number from 602341895->546723267,
ack from 3695959830->3695959830
[62873.869040] Adjusting sequence number from 3695959830->3695959830,
ack from 0->55618628

To summarize, it is clear that the seqadj codes adjust the 0 ack when receive
one TCP RST packet without ack.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2016-09-25 14:54:01 +02:00
..
ipset netfilter: ipset: fix race condition in ipset save, swap and delete 2016-03-28 17:57:45 +02:00
ipvs ipvs: use nf_ct_kill helper 2016-08-12 00:43:52 +02:00
core.c netfilter: replace list_head with single linked list 2016-09-25 14:38:48 +02:00
Kconfig netfilter: nf_tables: add number generator expression 2016-08-22 11:42:22 +02:00
Makefile netfilter: nf_tables: add number generator expression 2016-08-22 11:42:22 +02:00
nf_conntrack_acct.c netfilter: Remove uses of seq_<foo> return values 2015-03-18 10:51:35 +01:00
nf_conntrack_amanda.c net: Remove state argument from skb_find_text() 2015-02-22 15:59:54 -05:00
nf_conntrack_broadcast.c
nf_conntrack_core.c netfilter: Remove explicit rcu_read_lock in nf_hook_slow 2016-09-24 21:29:53 +02:00
nf_conntrack_ecache.c netfilter: don't rely on DYING bit to detect when destroy event was sent 2016-08-30 11:43:08 +02:00
nf_conntrack_expect.c netfilter: nf_ct_expect: remove the redundant slash when policy name is empty 2016-08-09 10:38:46 +02:00
nf_conntrack_extend.c netfilter: move nat hlist_head to nf_conn 2016-07-11 11:47:50 +02:00
nf_conntrack_ftp.c netfilter: ftp: Remove the useless code 2016-09-07 10:38:00 +02:00
nf_conntrack_h323_asn1.c netfilter: nf_conntrack_h323: fix off-by-one in DecodeQ931 2016-07-11 12:32:45 +02:00
nf_conntrack_h323_main.c netfilter: Remove explicit rcu_read_lock in nf_hook_slow 2016-09-24 21:29:53 +02:00
nf_conntrack_h323_types.c
nf_conntrack_helper.c netfilter: Remove explicit rcu_read_lock in nf_hook_slow 2016-09-24 21:29:53 +02:00
nf_conntrack_irc.c netfilter: Add helper array register/unregister functions 2016-07-21 02:31:53 +02:00
nf_conntrack_l3proto_generic.c netfilter: Convert print_tuple functions to return void 2014-11-05 14:10:33 -05:00
nf_conntrack_labels.c netfilter: connlabels: move set helper to xt_connlabel 2016-07-22 17:05:10 +02:00
nf_conntrack_netbios_ns.c
nf_conntrack_netlink.c netfilter: conntrack: remove packet hotpath stats 2016-09-12 19:59:39 +02:00
nf_conntrack_pptp.c netfilter: conntrack: get rid of conntrack timer 2016-08-30 11:43:09 +02:00
nf_conntrack_proto_dccp.c netfilter: conntrack: Only need first 4 bytes to get l4proto ports 2016-08-12 00:41:08 +02:00
nf_conntrack_proto_generic.c netfilter: remove ip_conntrack* sysctl compat code 2016-08-13 13:27:13 +02:00
nf_conntrack_proto_gre.c netfilter: gre: Use consistent GRE and PTTP header structure instead of the ones defined by netfilter 2016-09-07 10:36:52 +02:00
nf_conntrack_proto_sctp.c netfilter: remove ip_conntrack* sysctl compat code 2016-08-13 13:27:13 +02:00
nf_conntrack_proto_tcp.c netfilter: remove ip_conntrack* sysctl compat code 2016-08-13 13:27:13 +02:00
nf_conntrack_proto_udp.c netfilter: remove ip_conntrack* sysctl compat code 2016-08-13 13:27:13 +02:00
nf_conntrack_proto_udplite.c netfilter: conntrack: Only need first 4 bytes to get l4proto ports 2016-08-12 00:41:08 +02:00
nf_conntrack_proto.c netfilter: remove ip_conntrack* sysctl compat code 2016-08-13 13:27:13 +02:00
nf_conntrack_sane.c netfilter: Add helper array register/unregister functions 2016-07-21 02:31:53 +02:00
nf_conntrack_seqadj.c netfilter: seqadj: Fix the wrong ack adjust for the RST packet without ack 2016-09-25 14:54:01 +02:00
nf_conntrack_sip.c netfilter: nf_ct_sip: allow tab character in SIP headers 2016-09-07 13:53:43 +02:00
nf_conntrack_snmp.c netfilter: nf_ct_snmp: add include file 2013-01-18 00:28:18 +01:00
nf_conntrack_standalone.c netfilter: conntrack: remove packet hotpath stats 2016-09-12 19:59:39 +02:00
nf_conntrack_tftp.c netfilter: Add helper array register/unregister functions 2016-07-21 02:31:53 +02:00
nf_conntrack_timeout.c netfilter: cttimeout: add netns support 2015-12-14 12:48:58 +01:00
nf_conntrack_timestamp.c netfilter: nf_ct_timestamp: Fix BUG_ON after netns deletion 2013-12-20 14:58:29 +01:00
nf_dup_netdev.c net: remove skb_sender_cpu_clear() 2016-03-01 17:36:47 -05:00
nf_internals.h netfilter: replace list_head with single linked list 2016-09-25 14:38:48 +02:00
nf_log_common.c netfilter: bridge: add helpers for fetching physin/outdev 2015-04-08 16:49:08 +02:00
nf_log.c netfilter: log: Check param to avoid overflow in nf_log_set 2016-08-30 11:52:32 +02:00
nf_nat_amanda.c netfilter: add my copyright statements 2013-04-18 20:27:55 +02:00
nf_nat_core.c netfilter: conntrack: get rid of conntrack timer 2016-08-30 11:43:09 +02:00
nf_nat_ftp.c netfilter: nf_ct_helper: better logging for dropped packets 2013-02-19 02:48:05 +01:00
nf_nat_helper.c netfilter: nf_conntrack: make sequence number adjustments usuable without NAT 2013-08-28 00:26:48 +02:00
nf_nat_irc.c netfilter: nf_nat: fix access to uninitialized buffer in IRC NAT helper 2014-01-06 14:17:17 +01:00
nf_nat_proto_common.c netfilter: use IS_ENABLED() macro 2014-06-30 11:38:03 +02:00
nf_nat_proto_dccp.c net: Change pseudohdr argument of inet_proto_csum_replace* to be a bool 2015-08-17 21:33:06 -07:00
nf_nat_proto_sctp.c netfilter: use IS_ENABLED() macro 2014-06-30 11:38:03 +02:00
nf_nat_proto_tcp.c net: Change pseudohdr argument of inet_proto_csum_replace* to be a bool 2015-08-17 21:33:06 -07:00
nf_nat_proto_udp.c net: Change pseudohdr argument of inet_proto_csum_replace* to be a bool 2015-08-17 21:33:06 -07:00
nf_nat_proto_udplite.c net: Change pseudohdr argument of inet_proto_csum_replace* to be a bool 2015-08-17 21:33:06 -07:00
nf_nat_proto_unknown.c netfilter: add protocol independent NAT core 2012-08-30 03:00:14 +02:00
nf_nat_redirect.c netfilter: nf_nat_redirect: add missing NULL pointer check 2015-10-27 06:54:56 +01:00
nf_nat_sip.c netfilter: replace strnicmp with strncasecmp 2014-10-14 02:18:24 +02:00
nf_nat_tftp.c netfilter: nf_ct_helper: better logging for dropped packets 2013-02-19 02:48:05 +01:00
nf_queue.c netfilter: replace list_head with single linked list 2016-09-25 14:38:48 +02:00
nf_sockopt.c netfilter: don't use mutex_lock_interruptible() 2014-08-08 16:47:23 +02:00
nf_synproxy_core.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2015-09-05 21:57:42 -07:00
nf_tables_api.c netfilter: nf_tables: validate maximum value of u32 netlink attributes 2016-09-23 09:29:02 +02:00
nf_tables_core.c netfilter: nf_tables: check tprot_set first when we use xt.thoff 2016-09-23 09:30:26 +02:00
nf_tables_inet.c netfilter: Add the missed return value check of nft_register_chain_type 2016-09-12 19:54:45 +02:00
nf_tables_netdev.c netfilter: Add the missed return value check of nft_register_chain_type 2016-09-12 19:54:45 +02:00
nf_tables_trace.c netfilter: nf_tables: check tprot_set first when we use xt.thoff 2016-09-23 09:30:26 +02:00
nfnetlink_acct.c netfilter: nfnetlink_acct: fix race between nfacct del and xt_nfacct destroy 2016-08-18 15:16:36 +02:00
nfnetlink_cthelper.c netfilter: Remove explicit rcu_read_lock in nf_hook_slow 2016-09-24 21:29:53 +02:00
nfnetlink_cttimeout.c netfilter: cttimeout: fix use after free error when delete netns 2016-08-18 15:17:00 +02:00
nfnetlink_log.c netfilter: Remove explicit rcu_read_lock in nf_hook_slow 2016-09-24 21:29:53 +02:00
nfnetlink_queue.c netfilter: replace list_head with single linked list 2016-09-25 14:38:48 +02:00
nfnetlink.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-02-23 00:09:14 -05:00
nft_bitwise.c netfilter: nf_tables: validate maximum value of u32 netlink attributes 2016-09-23 09:29:02 +02:00
nft_byteorder.c netfilter: nf_tables: validate maximum value of u32 netlink attributes 2016-09-23 09:29:02 +02:00
nft_cmp.c netfilter: nf_tables: validate maximum value of u32 netlink attributes 2016-09-23 09:29:02 +02:00
nft_compat.c netfilter: nft_compat: fix crash when related match/target module is removed 2016-07-23 12:25:00 +02:00
nft_counter.c libnl: nla_put_be64(): align on a 64-bit area 2016-04-23 20:13:24 -04:00
nft_ct.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 2016-07-24 22:02:36 -07:00
nft_dup_netdev.c netfilter: nf_tables: add packet duplication to the netdev family 2016-01-03 21:04:23 +01:00
nft_dynset.c netfilter: nft_dynset: allow to invert match criteria 2016-09-12 18:49:50 +02:00
nft_exthdr.c netfilter: nf_tables: validate maximum value of u32 netlink attributes 2016-09-23 09:29:02 +02:00
nft_fwd_netdev.c netfilter: nf_tables: add forward expression to the netdev family 2016-01-04 17:48:38 +01:00
nft_hash.c netfilter: nft_hash: fix hash overflow validation 2016-09-13 10:49:23 +02:00
nft_immediate.c netfilter: nf_tables: validate maximum value of u32 netlink attributes 2016-09-23 09:29:02 +02:00
nft_limit.c libnl: nla_put_be64(): align on a 64-bit area 2016-04-23 20:13:24 -04:00
nft_log.c netfilter: nft_log: fix snaplen does not truncate packets 2016-07-21 02:32:34 +02:00
nft_lookup.c netfilter: nft_lookup: remove superfluous element found check 2016-09-23 09:30:48 +02:00
nft_masq.c netfilter: nft_masq: support port range 2016-03-02 20:05:27 +01:00
nft_meta.c netfilter: nf_tables: ensure proper initialization of nft_pktinfo fields 2016-09-12 18:51:57 +02:00
nft_nat.c netfilter: nf_tables: switch registers to 32 bit addressing 2015-04-13 17:17:29 +02:00
nft_numgen.c netfilter: nft_numgen: add number generation offset 2016-09-22 16:33:05 +02:00
nft_payload.c netfilter: nf_tables: check tprot_set first when we use xt.thoff 2016-09-23 09:30:26 +02:00
nft_queue.c netfilter: nft_queue: add _SREG_QNUM attr to select the queue number 2016-09-23 09:29:50 +02:00
nft_quota.c netfilter: nft_quota: introduce nft_overquota() 2016-09-07 11:02:06 +02:00
nft_redir.c netfilter: nf_tables: add register parsing/dumping helpers 2015-04-13 17:17:28 +02:00
nft_reject_inet.c ipv4: Push struct net down into nf_send_reset 2015-09-29 20:21:31 +02:00
nft_reject.c netfilter; Add some missing default cases to switch statements in nft_reject. 2015-04-27 13:20:34 -04:00
nft_set_hash.c netfilter: nf_tables: honor NLM_F_EXCL flag in set element insertion 2016-08-26 17:30:20 +02:00
nft_set_rbtree.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 2016-09-06 12:45:26 -07:00
x_tables.c netfilter: x_tables: speed up jump target validation 2016-07-18 21:35:23 +02:00
xt_addrtype.c netfilter: x_tables: Use par->net instead of computing from the passed net devices 2015-09-18 21:58:25 +02:00
xt_AUDIT.c netfilter: Convert uses of __constant_<foo> to <foo> 2014-03-13 14:13:19 +01:00
xt_bpf.c net: filter: split 'struct sk_filter' into socket and bpf parts 2014-08-02 15:03:58 -07:00
xt_cgroup.c netfilter: implement xt_cgroup cgroup2 path match 2015-12-14 20:34:55 +01:00
xt_CHECKSUM.c
xt_CLASSIFY.c
xt_cluster.c net: use reciprocal_scale() helper 2014-08-23 12:21:21 -07:00
xt_comment.c
xt_connbytes.c netfilter: Convert pr_warning to pr_warn 2014-09-10 12:40:10 -07:00
xt_connlabel.c netfilter: connlabels: move set helper to xt_connlabel 2016-07-22 17:05:10 +02:00
xt_connlimit.c netfilter: Enhance the codes used to get random once 2016-09-23 09:30:36 +02:00
xt_connmark.c netfilter: Fix FSF address in file headers 2013-12-06 12:37:57 -05:00
xt_CONNSECMARK.c
xt_conntrack.c netfilter: use_nf_conn_expires helper in more places 2016-08-12 00:43:13 +02:00
xt_cpu.c
xt_CT.c netfilter: cttimeout: add netns support 2015-12-14 12:48:58 +01:00
xt_dccp.c
xt_devgroup.c
xt_dscp.c
xt_DSCP.c netfilter: fix various sparse warnings 2014-11-13 12:14:42 +01:00
xt_ecn.c
xt_esp.c
xt_hashlimit.c netfilter: Remove checks of seq_printf() return values 2014-11-05 14:11:02 -05:00
xt_helper.c netfilter: Remove explicit rcu_read_lock in nf_hook_slow 2016-09-24 21:29:53 +02:00
xt_hl.c
xt_HL.c
xt_HMARK.c net: use reciprocal_scale() helper 2014-08-23 12:21:21 -07:00
xt_IDLETIMER.c netfilter: IDLETIMER: fix race condition when destroy the target 2016-04-29 14:28:48 +02:00
xt_ipcomp.c netfilter: xt_ipcomp: Use ntohs to ease sparse warning 2014-02-19 11:41:25 +01:00
xt_iprange.c
xt_ipvs.c ipvs: Pass ipvs into conn_out_get 2015-09-24 09:34:41 +09:00
xt_l2tp.c netfilter: introduce l2tp match extension 2014-01-09 21:36:39 +01:00
xt_LED.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-08-05 18:46:26 -07:00
xt_length.c
xt_limit.c netfilter: add my copyright statements 2013-04-18 20:27:55 +02:00
xt_LOG.c netfilter: x_tables: Use par->net instead of computing from the passed net devices 2015-09-18 21:58:25 +02:00
xt_mac.c netfilter: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:18 -04:00
xt_mark.c netfilter: xt_MARK: Add ARP support 2015-05-14 13:00:27 +02:00
xt_multiport.c
xt_nat.c netfilter: xt_nat: fix incorrect hooks for SNAT and DNAT targets 2012-10-15 13:39:12 +02:00
xt_NETMAP.c netfilter: combine ipt_NETMAP and ip6t_NETMAP 2012-09-21 12:11:08 +02:00
xt_nfacct.c netfilter: nfnetlink_acct: report overquota to the right netns 2016-08-18 00:38:23 +02:00
xt_NFLOG.c netfilter: xt_NFLOG: nflog-range does not truncate packets 2016-06-24 11:03:23 +02:00
xt_NFQUEUE.c netfilter: xt_NFQUEUE: separate reusable code 2013-12-07 23:20:45 +01:00
xt_osf.c netfilter: xt_osf: remove unused variable 2016-02-29 13:59:43 +01:00
xt_owner.c netfilter: Allow xt_owner in any user namespace 2016-06-23 13:58:55 +02:00
xt_physdev.c netfilter: physdev: add missed blank 2016-08-12 00:42:14 +02:00
xt_pkttype.c
xt_policy.c
xt_quota.c
xt_rateest.c net_sched: add 64bit rate estimators 2013-06-11 02:51:03 -07:00
xt_RATEEST.c netfilter: Enhance the codes used to get random once 2016-09-23 09:30:36 +02:00
xt_realm.c
xt_recent.c netfilter: Enhance the codes used to get random once 2016-09-23 09:30:36 +02:00
xt_REDIRECT.c netfilter: combine IPv4 and IPv6 nf_nat_redirect code in one module 2014-11-27 13:08:42 +01:00
xt_repldata.h net: netfilter: LLVMLinux: vlais-netfilter 2014-06-07 11:44:39 -07:00
xt_sctp.c
xt_SECMARK.c
xt_set.c netfilter: ipset: Fix coding styles reported by checkpatch.pl 2015-06-14 10:40:18 +02:00
xt_socket.c tcp/dccp: do not touch listener sk_refcnt under synflood 2016-04-04 22:11:20 -04:00
xt_state.c
xt_statistic.c net: replace macros net_random and net_srandom with direct calls to prandom 2014-01-14 15:15:25 -08:00
xt_string.c net: Remove state argument from skb_find_text() 2015-02-22 15:59:54 -05:00
xt_tcpmss.c
xt_TCPMSS.c netfilter: xt_TCPMSS: Refactor the codes to decrease one condition check and more readable 2016-09-24 21:13:21 +02:00
xt_TCPOPTSTRIP.c net: Change pseudohdr argument of inet_proto_csum_replace* to be a bool 2015-08-17 21:33:06 -07:00
xt_tcpudp.c netfilter: Convert FWINV<[foo]> macros and uses to NF_INVF 2016-07-03 10:55:07 +02:00
xt_TEE.c netfilter: Add the missed return value check of register_netdevice_notifier 2016-09-12 19:54:43 +02:00
xt_time.c netfilter: xt_time: add support to ignore day transition 2012-09-24 14:29:01 +02:00
xt_TPROXY.c netfilter: tproxy: properly refcount tcp listeners 2016-08-18 00:51:13 +02:00
xt_TRACE.c netfilter: xt_TRACE: add explicitly nf_logger_find_get call 2016-06-23 13:26:49 +02:00
xt_u32.c