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2022-10-19netfilter: rpfilter/fib: Set ->flowic_uid correctly for user namespaces.Guillaume Nault1-0/+1
Currently netfilter's rpfilter and fib modules implicitely initialise ->flowic_uid with 0. This is normally the root UID. However, this isn't the case in user namespaces, where user ID 0 is mapped to a different kernel UID. By initialising ->flowic_uid with sock_net_uid(), we get the root UID of the user namespace, thus keeping the same behaviour whether or not we're running in a user namepspace. Note, this is similar to commit 8bcfd0925ef1 ("ipv4: add missing initialization for flowi4_uid"), which fixed the rp_filter sysctl. Fixes: 622ec2c9d524 ("net: core: add UID to flows, rules, and routes") Signed-off-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-10-12netfilter: rpfilter/fib: Populate flowic_l3mdev fieldPhil Sutter1-1/+1
Use the introduced field for correct operation with VRF devices instead of conditionally overwriting flowic_oif. This is a partial revert of commit b575b24b8eee3 ("netfilter: Fix rpfilter dropping vrf packets by mistake"), implementing a simpler solution. Signed-off-by: Phil Sutter <phil@nwl.cc> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: Florian Westphal <fw@strlen.de>
2022-09-21netfilter: rpfilter: Remove unused variable 'ret'.Guillaume Nault1-1/+0
Commit 91a178258aea ("netfilter: rpfilter: Convert rpfilter_lookup_reverse to new dev helper") removed the need for the 'ret' variable. This went unnoticed because of the __maybe_unused annotation. Signed-off-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: Florian Westphal <fw@strlen.de>
2021-01-19netfilter: rpfilter: mask ecn bits before fib lookupGuillaume Nault1-1/+1
RT_TOS() only masks one of the two ECN bits. Therefore rpfilter_mt() treats Not-ECT or ECT(1) packets in a different way than those with ECT(0) or CE. Reproducer: Create two netns, connected with a veth: $ ip netns add ns0 $ ip netns add ns1 $ ip link add name veth01 netns ns0 type veth peer name veth10 netns ns1 $ ip -netns ns0 link set dev veth01 up $ ip -netns ns1 link set dev veth10 up $ ip -netns ns0 address add 192.0.2.10/32 dev veth01 $ ip -netns ns1 address add 192.0.2.11/32 dev veth10 Add a route to ns1 in ns0: $ ip -netns ns0 route add 192.0.2.11/32 dev veth01 In ns1, only packets with TOS 4 can be routed to ns0: $ ip -netns ns1 route add 192.0.2.10/32 tos 4 dev veth10 Ping from ns0 to ns1 works regardless of the ECN bits, as long as TOS is 4: $ ip netns exec ns0 ping -Q 4 192.0.2.11 # TOS 4, Not-ECT ... 0% packet loss ... $ ip netns exec ns0 ping -Q 5 192.0.2.11 # TOS 4, ECT(1) ... 0% packet loss ... $ ip netns exec ns0 ping -Q 6 192.0.2.11 # TOS 4, ECT(0) ... 0% packet loss ... $ ip netns exec ns0 ping -Q 7 192.0.2.11 # TOS 4, CE ... 0% packet loss ... Now use iptable's rpfilter module in ns1: $ ip netns exec ns1 iptables-legacy -t raw -A PREROUTING -m rpfilter --invert -j DROP Not-ECT and ECT(1) packets still pass: $ ip netns exec ns0 ping -Q 4 192.0.2.11 # TOS 4, Not-ECT ... 0% packet loss ... $ ip netns exec ns0 ping -Q 5 192.0.2.11 # TOS 4, ECT(1) ... 0% packet loss ... But ECT(0) and ECN packets are dropped: $ ip netns exec ns0 ping -Q 6 192.0.2.11 # TOS 4, ECT(0) ... 100% packet loss ... $ ip netns exec ns0 ping -Q 7 192.0.2.11 # TOS 4, CE ... 100% packet loss ... After this patch, rpfilter doesn't drop ECT(0) and CE packets anymore. Fixes: 8f97339d3feb ("netfilter: add ipv4 reverse path filter match") Signed-off-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2019-07-16netfilter: Fix rpfilter dropping vrf packets by mistakeMiaohe Lin1-0/+1
When firewalld is enabled with ipv4/ipv6 rpfilter, vrf ipv4/ipv6 packets will be dropped. Vrf device will pass through netfilter hook twice. One with enslaved device and another one with l3 master device. So in device may dismatch witch out device because out device is always enslaved device.So failed with the check of the rpfilter and drop the packets by mistake. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> 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>
2018-09-20netfilter: rpfilter: Convert rpfilter_lookup_reverse to new dev helperDavid Ahern1-16/+1
Convert rpfilter_lookup_reverse to the new device checking helper and remove the duplicate code. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-17net/ipv4: Initialize proto and ports in flow structDavid Ahern1-1/+1
Updating the FIB tracepoint for the recent change to allow rules using the protocol and ports exposed a few places where the entries in the flow struct are not initialized. For __fib_validate_source add the call to fib4_rules_early_flow_dissect since it is invoked for the input path. For netfilter, add the memset on the flow struct to avoid future problems like this. In ip_route_input_slow need to set the fields if the skb dissection does not happen. Fixes: bfff4862653b ("net: fib_rules: support for match on ip_proto, sport and dport") Signed-off-by: David Ahern <dsahern@gmail.com> Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-14netfilter: x_tables: use pr ratelimiting in all remaining spotsFlorian Westphal1-1/+1
Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-02-14netfilter: x_tables: rate-limit table mismatch warningsFlorian Westphal1-2/+2
Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2017-01-16netfilter: rpfilter: fix incorrect loopback packet judgmentLiping Zhang1-4/+4
Currently, we check the existing rtable in PREROUTING hook, if RTCF_LOCAL is set, we assume that the packet is loopback. But this assumption is incorrect, for example, a packet encapsulated in ipsec transport mode was received and routed to local, after decapsulation, it would be delivered to local again, and the rtable was not dropped, so RTCF_LOCAL check would trigger. But actually, the packet was not loopback. So for these normal loopback packets, we can check whether the in device is IFF_LOOPBACK or not. For these locally generated broadcast/multicast, we can check whether the skb->pkt_type is PACKET_LOOPBACK or not. Finally, there's a subtle difference between nft fib expr and xtables rpfilter extension, user can add the following nft rule to do strict rpfilter check: # nft add rule x y meta iif eth0 fib saddr . iif oif != eth0 drop So when the packet is loopback, it's better to store the in device instead of the LOOPBACK_IFINDEX, otherwise, after adding the above nft rule, locally generated broad/multicast packets will be dropped incorrectly. Fixes: f83a7ea2075c ("netfilter: xt_rpfilter: skip locally generated broadcast/multicast, too") Fixes: f6d0cbcf09c5 ("netfilter: nf_tables: add fib expression") Signed-off-by: Liping Zhang <zlpnobody@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2016-12-07netfilter: rpfilter: bypass ipv4 lbcast packets with zeronet sourceLiping Zhang1-3/+5
Otherwise, DHCP Discover packets(0.0.0.0->255.255.255.255) may be dropped incorrectly. Signed-off-by: Liping Zhang <zlpnobody@gmail.com> Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2016-11-03netfilter: x_tables: move hook state into xt_action_param structurePablo Neira Ayuso1-1/+1
Place pointer to hook state in xt_action_param structure instead of copying the fields that we need. After this change xt_action_param fits into one cacheline. This patch also adds a set of new wrapper functions to fetch relevant hook state structure fields. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-10-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-3/+1
Conflicts: net/ipv6/xfrm6_output.c net/openvswitch/flow_netlink.c net/openvswitch/vport-gre.c net/openvswitch/vport-vxlan.c net/openvswitch/vport.c net/openvswitch/vport.h The openvswitch conflicts were overlapping changes. One was the egress tunnel info fix in 'net' and the other was the vport ->send() op simplification in 'net-next'. The xfrm6_output.c conflicts was also a simplification overlapping a bug fix. Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-12netfilter: ipt_rpfilter: remove the nh_scope test in rpfilter_lookup_reverselucien1-3/+1
--accept-local option works for res.type == RTN_LOCAL, which should be from the local table, but there, the fib_info's nh->nh_scope = RT_SCOPE_NOWHERE ( > RT_SCOPE_HOST). in fib_create_info(). if (cfg->fc_scope == RT_SCOPE_HOST) { struct fib_nh *nh = fi->fib_nh; /* Local address is added. */ if (nhs != 1 || nh->nh_gw) goto err_inval; nh->nh_scope = RT_SCOPE_NOWHERE; <=== nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); err = -ENODEV; if (!nh->nh_dev) goto failure; but in our rpfilter_lookup_reverse(): if (dev_match || flags & XT_RPFILTER_LOOSE) return FIB_RES_NH(res).nh_scope <= RT_SCOPE_HOST; if nh->nh_scope > RT_SCOPE_HOST, it will fail. --accept-local option will never be passed. it seems the test is bogus and can be removed to fix this issue. if (dev_match || flags & XT_RPFILTER_LOOSE) return FIB_RES_NH(res).nh_scope <= RT_SCOPE_HOST; ipv6 does not have this issue. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-09-18netfilter: x_tables: Use par->net instead of computing from the passed net ↵Eric W. Biederman1-3/+2
devices Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-06-24net: ipv4 sysctl option to ignore routes when nexthop link is downAndy Gospodarek1-1/+1
This feature is only enabled with the new per-interface or ipv4 global sysctls called 'ignore_routes_with_linkdown'. net.ipv4.conf.all.ignore_routes_with_linkdown = 0 net.ipv4.conf.default.ignore_routes_with_linkdown = 0 net.ipv4.conf.lo.ignore_routes_with_linkdown = 0 ... When the above sysctls are set, will report to userspace that a route is dead and will no longer resolve to this nexthop when performing a fib lookup. This will signal to userspace that the route will not be selected. The signalling of a RTNH_F_DEAD is only passed to userspace if the sysctl is enabled and link is down. This was done as without it the netlink listeners would have no idea whether or not a nexthop would be selected. The kernel only sets RTNH_F_DEAD internally if the interface has IFF_UP cleared. With the new sysctl set, the following behavior can be observed (interface p8p1 is link-down): default via 10.0.5.2 dev p9p1 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 dead linkdown 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 dead linkdown 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 90.0.0.1 via 70.0.0.2 dev p7p1 src 70.0.0.1 cache local 80.0.0.1 dev lo src 80.0.0.1 cache <local> 80.0.0.2 via 10.0.5.2 dev p9p1 src 10.0.5.15 cache While the route does remain in the table (so it can be modified if needed rather than being wiped away as it would be if IFF_UP was cleared), the proper next-hop is chosen automatically when the link is down. Now interface p8p1 is linked-up: default via 10.0.5.2 dev p9p1 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 192.168.56.0/24 dev p2p1 proto kernel scope link src 192.168.56.2 90.0.0.1 via 80.0.0.2 dev p8p1 src 80.0.0.1 cache local 80.0.0.1 dev lo src 80.0.0.1 cache <local> 80.0.0.2 dev p8p1 src 80.0.0.1 cache and the output changes to what one would expect. If the sysctl is not set, the following output would be expected when p8p1 is down: default via 10.0.5.2 dev p9p1 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 linkdown 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 linkdown 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 Since the dead flag does not appear, there should be no expectation that the kernel would skip using this route due to link being down. v2: Split kernel changes into 2 patches, this actually makes a behavioral change if the sysctl is set. Also took suggestion from Alex to simplify code by only checking sysctl during fib lookup and suggestion from Scott to add a per-interface sysctl. v3: Code clean-ups to make it more readable and efficient as well as a reverse path check fix. v4: Drop binary sysctl v5: Whitespace fixups from Dave v6: Style changes from Dave and checkpatch suggestions v7: One more checkpatch fixup Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com> Signed-off-by: Dinesh Dutt <ddutt@cumulusnetworks.com> Acked-by: Scott Feldman <sfeldma@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-16ipv4, fib: pass LOOPBACK_IFINDEX instead of 0 to flowi4_iifCong Wang1-4/+1
As suggested by Julian: Simply, flowi4_iif must not contain 0, it does not look logical to ignore all ip rules with specified iif. because in fib_rule_match() we do: if (rule->iifindex && (rule->iifindex != fl->flowi_iif)) goto out; flowi4_iif should be LOOPBACK_IFINDEX by default. We need to move LOOPBACK_IFINDEX to include/net/flow.h: 1) It is mostly used by flowi_iif 2) Fix the following compile error if we use it in flow.h by the patches latter: In file included from include/linux/netfilter.h:277:0, from include/net/netns/netfilter.h:5, from include/net/net_namespace.h:21, from include/linux/netdevice.h:43, from include/linux/icmpv6.h:12, from include/linux/ipv6.h:61, from include/net/ipv6.h:16, from include/linux/sunrpc/clnt.h:27, from include/linux/nfs_fs.h:30, from init/do_mounts.c:32: include/net/flow.h: In function ‘flowi4_init_output’: include/net/flow.h:84:32: error: ‘LOOPBACK_IFINDEX’ undeclared (first use in this function) Cc: Eric Biederman <ebiederm@xmission.com> Cc: Julian Anastasov <ja@ssi.bg> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-19netfilter: xt_rpfilter: skip locally generated broadcast/multicast, tooFlorian Westphal1-1/+7
Alex Efros reported rpfilter module doesn't match following packets: IN=br.qemu SRC=192.168.2.1 DST=192.168.2.255 [ .. ] (netfilter bugzilla #814). Problem is that network stack arranges for the locally generated broadcasts to appear on the interface they were sent out, so the IFF_LOOPBACK check doesn't trigger. As -m rpfilter is restricted to PREROUTING, we can check for existing rtable instead, it catches locally-generated broad/multicast case, too. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2012-08-09net: Loopback ifindex is constant nowPavel Emelyanov1-1/+1
As pointed out, there are places, that access net->loopback_dev->ifindex and after ifindex generation is made per-net this value becomes constant equals 1. So go ahead and introduce the LOOPBACK_IFINDEX constant and use it where appropriate. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-04netfilter: add ipv4 reverse path filter matchFlorian Westphal1-0/+141
This tries to do the same thing as fib_validate_source(), but differs in several aspects. The most important difference is that the reverse path filter built into fib_validate_source uses the oif as iif when performing the reverse lookup. We do not do this, as the oif is not yet known by the time the PREROUTING hook is invoked. We can't wait until FORWARD chain because by the time FORWARD is invoked ipv4 forward path may have already sent icmp messages is response to to-be-discarded-via-rpfilter packets. To avoid the such an additional lookup in PREROUTING, Patrick McHardy suggested to attach the path information directly in the match (i.e., just do what the standard ipv4 path does a bit earlier in PREROUTING). This works, but it also has a few caveats. Most importantly, when using marks in PREROUTING to re-route traffic based on the nfmark, -m rpfilter would have to be used after the nfmark has been set; otherwise the nfmark would have no effect (because the route is already attached). Another problem would be interaction with -j TPROXY, as this target sets an nfmark and uses ACCEPT instead of continue, i.e. such a version of -m rpfilter cannot be used for the initial to-be-intercepted packets. In case in turns out that the oif is required, we can add Patricks suggestion with a new match option (e.g. --rpf-use-oif) to keep ruleset compatibility. Another difference to current builtin ipv4 rpfilter is that packets subject to ipsec transformation are not automatically excluded. If you want this, simply combine -m rpfilter with the policy match. Packets arriving on loopback interfaces always match. Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>