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2024-10-09netfilter: xtables: avoid NFPROTO_UNSPEC where neededFlorian Westphal1-10/+23
syzbot managed to call xt_cluster match via ebtables: WARNING: CPU: 0 PID: 11 at net/netfilter/xt_cluster.c:72 xt_cluster_mt+0x196/0x780 [..] ebt_do_table+0x174b/0x2a40 Module registers to NFPROTO_UNSPEC, but it assumes ipv4/ipv6 packet processing. As this is only useful to restrict locally terminating TCP/UDP traffic, register this for ipv4 and ipv6 family only. Pablo points out that this is a general issue, direct users of the set/getsockopt interface can call into targets/matches that were only intended for use with ip(6)tables. Check all UNSPEC matches and targets for similar issues: - matches and targets are fine except if they assume skb_network_header() is valid -- this is only true when called from inet layer: ip(6) stack pulls the ip/ipv6 header into linear data area. - targets that return XT_CONTINUE or other xtables verdicts must be restricted too, they are incompatbile with the ebtables traverser, e.g. EBT_CONTINUE is a completely different value than XT_CONTINUE. Most matches/targets are changed to register for NFPROTO_IPV4/IPV6, as they are provided for use by ip(6)tables. The MARK target is also used by arptables, so register for NFPROTO_ARP too. While at it, bail out if connbytes fails to enable the corresponding conntrack family. This change passes the selftests in iptables.git. Reported-by: syzbot+256c348558aa5cf611a9@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netfilter-devel/66fec2e2.050a0220.9ec68.0047.GAE@google.com/ Fixes: 0269ea493734 ("netfilter: xtables: add cluster match") Signed-off-by: Florian Westphal <fw@strlen.de> Co-developed-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner1-4/+1
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-24netfilter: xt_checksum: ignore gso skbsFlorian Westphal1-1/+21
Satish Patel reports a skb_warn_bad_offload() splat caused by -j CHECKSUM rules: -A POSTROUTING -p tcp -m tcp --sport 80 -j CHECKSUM The CHECKSUM target has never worked with GSO skbs, and the above rule makes no sense as kernel will handle checksum updates on transmit. Unfortunately, there are 3rd party tools that install such rules, so we cannot reject this from the config plane without potential breakage. Amend Kconfig text to clarify that the CHECKSUM target is only useful in virtualized environments, where old dhcp clients that use AF_PACKET used to discard UDP packets with a 'bad' header checksum and add a one-time warning in case such rule isn't restricted to UDP. v2: check IP6T_F_PROTO flag before cmp (Michal Kubecek) Reported-by: Satish Patel <satish.txt@gmail.com> Reported-by: Markos Chandras <markos.chandras@suse.com> Reported-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: Florian Westphal <fw@strlen.de> Reviewed-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-02-14netfilter: x_tables: use pr ratelimiting in all remaining spotsFlorian Westphal1-1/+2
Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-02-14netfilter: x_tables: remove pr_info where possibleFlorian Westphal1-3/+2
remove several pr_info messages that cannot be triggered with iptables, the check is only to ensure input is sane. iptables(8) already prints error messages in these cases. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2010-07-15netfilter: add CHECKSUM targetMichael S. Tsirkin1-0/+70
This adds a `CHECKSUM' target, which can be used in the iptables mangle table. You can use this target to compute and fill in the checksum in a packet that lacks a checksum. This is particularly useful, if you need to work around old applications such as dhcp clients, that do not work well with checksum offloads, but don't want to disable checksum offload in your device. The problem happens in the field with virtualized applications. For reference, see Red Hat bz 605555, as well as http://www.spinics.net/lists/kvm/msg37660.html Typical expected use (helps old dhclient binary running in a VM): iptables -A POSTROUTING -t mangle -p udp --dport bootpc \ -j CHECKSUM --checksum-fill Includes fixes by Jan Engelhardt <jengelh@medozas.de> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Patrick McHardy <kaber@trash.net>