kernel/linux.git/net/ipv6/netfilter, branch v6.12.92

netfilter: x_tables: unregister the templates first

2026-06-01T15:46:25+00:00

[ Upstream commit d338693d778579b676a61346849bebd892427158 ] When the module is going away we need to zap the template first. Else there is a small race window where userspace could instantiate a new table after the pernet exit function has removed the current table. Fixes: fdacd57c79b7 ("netfilter: x_tables: never register tables by default") Reported-by: Tristan Madani Reviewed-by: Tristan Madani Closes: https://lore.kernel.org/netfilter-devel/20260429175613.1459342-1-tristmd@gmail.com/ Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ip6t_hbh: reject oversized option lists

2026-06-01T15:46:18+00:00

commit 4322dcde6b4173c2d8e8e6118ed290794263bcc8 upstream. struct ip6t_opts stores at most IP6T_OPTS_OPTSNR option descriptors, but hbh_mt6_check() does not reject larger optsnr values supplied from userspace. Validate optsnr in the rule setup path so only match data that fits the fixed-size opts array can be installed. This follows the existing xtables pattern of rejecting invalid user-provided counts in checkentry() and keeps the packet matching path unchanged. `struct ip6t_opts` has a fixed `opts[IP6T_OPTS_OPTSNR]` array, where `IP6T_OPTS_OPTSNR` is 16, then off-by-one array access is possible: [ 137.924693][ T8692] UBSAN: array-index-out-of-bounds in ../net/ipv6/netfilter/ip6t_hbh.c:110:29 [ 137.926167][ T8692] index 16 is out of range for type '__u16 [16]' Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@kernel.org Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Xin Liu Signed-off-by: Zhengchuan Liang Signed-off-by: Ren Wei Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman

netfilter: ip6t_eui64: reject invalid MAC header for all packets

2026-04-22T11:18:54+00:00

[ Upstream commit fdce0b3590f724540795b874b4c8850c90e6b0a8 ] `eui64_mt6()` derives a modified EUI-64 from the Ethernet source address and compares it with the low 64 bits of the IPv6 source address. The existing guard only rejects an invalid MAC header when `par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()` can still reach `eth_hdr(skb)` even when the MAC header is not valid. Fix this by removing the `par->fragoff != 0` condition so that packets with an invalid MAC header are rejected before accessing `eth_hdr(skb)`. Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2") Reported-by: Yifan Wu Reported-by: Juefei Pu Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Suggested-by: Xin Liu Tested-by: Ren Wei Signed-off-by: Zhengchuan Liang Signed-off-by: Ren Wei Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin

netfilter: ip6t_rt: reject oversized addrnr in rt_mt6_check()

2026-04-02T11:09:36+00:00

[ Upstream commit 9d3f027327c2fa265f7f85ead41294792c3296ed ] Reject rt match rules whose addrnr exceeds IP6T_RT_HOPS. rt_mt6() expects addrnr to stay within the bounds of rtinfo->addrs[]. Validate addrnr during rule installation so malformed rules are rejected before the match logic can use an out-of-range value. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Yifan Wu Reported-by: Juefei Pu Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Suggested-by: Xin Liu Tested-by: Yuhang Zheng Signed-off-by: Ren Wei Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

ipv6: adopt dst_dev() helper

2026-01-08T09:15:01+00:00

[ Upstream commit 1caf27297215a5241f9bfc9c07336349d9034ee3 ] Use the new helper as a step to deal with potential dst->dev races. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250630121934.3399505-9-edumazet@google.com Signed-off-by: Jakub Kicinski [Harshit: Backport to 6.12.y, pulled this is a prerequisite] Stable-dep-of: 99a2ace61b21 ("net: use dst_dev_rcu() in sk_setup_caps()") Signed-off-by: Harshit Mogalapalli Signed-off-by: Greg Kroah-Hartman

netfilter: nf_reject: don't reply to icmp error messages

2025-11-13T20:34:23+00:00

[ Upstream commit db99b2f2b3e2cd8227ac9990ca4a8a31a1e95e56 ] tcp reject code won't reply to a tcp reset. But the icmp reject 'netdev' family versions will reply to icmp dst-unreach errors, unlike icmp_send() and icmp6_send() which are used by the inet family implementation (and internally by the REJECT target). Check for the icmp(6) type and do not respond if its an unreachable error. Without this, something like 'ip protocol icmp reject', when used in a netdev chain attached to 'lo', cause a packet loop. Same for two hosts that both use such a rule: each error packet will be replied to. Such situation persist until the (bogus) rule is amended to ratelimit or checks the icmp type before the reject statement. As the inet versions don't do this make the netdev ones follow along. Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin

netfilter: nf_reject: don't leak dst refcount for loopback packets

2025-08-28T14:31:16+00:00

[ Upstream commit 91a79b792204313153e1bdbbe5acbfc28903b3a5 ] recent patches to add a WARN() when replacing skb dst entry found an old bug: WARNING: include/linux/skbuff.h:1165 skb_dst_check_unset include/linux/skbuff.h:1164 [inline] WARNING: include/linux/skbuff.h:1165 skb_dst_set include/linux/skbuff.h:1210 [inline] WARNING: include/linux/skbuff.h:1165 nf_reject_fill_skb_dst+0x2a4/0x330 net/ipv4/netfilter/nf_reject_ipv4.c:234 [..] Call Trace: nf_send_unreach+0x17b/0x6e0 net/ipv4/netfilter/nf_reject_ipv4.c:325 nft_reject_inet_eval+0x4bc/0x690 net/netfilter/nft_reject_inet.c:27 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] .. This is because blamed commit forgot about loopback packets. Such packets already have a dst_entry attached, even at PRE_ROUTING stage. Instead of checking hook just check if the skb already has a route attached to it. Fixes: f53b9b0bdc59 ("netfilter: introduce support for reject at prerouting stage") Signed-off-by: Florian Westphal Link: https://patch.msgid.link/20250820123707.10671-1-fw@strlen.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

netfilter: nf_tables: nft_fib: consistent l3mdev handling

2025-06-19T13:31:53+00:00

[ Upstream commit 9a119669fb1924cd9658c16da39a5a585e129e50 ] fib has two modes: 1. Obtain output device according to source or destination address 2. Obtain the type of the address, e.g. local, unicast, multicast. 'fib daddr type' should return 'local' if the address is configured in this netns or unicast otherwise. 'fib daddr . iif type' should return 'local' if the address is configured on the input interface or unicast otherwise, i.e. more restrictive. However, if the interface is part of a VRF, then 'fib daddr type' returns unicast even if the address is configured on the incoming interface. This is broken for both ipv4 and ipv6. In the ipv4 case, inet_dev_addr_type must only be used if the 'iif' or 'oif' (strict mode) was requested. Else inet_addr_type_dev_table() needs to be used and the correct dev argument must be passed as well so the correct fib (vrf) table is used. In the ipv6 case, the bug is similar, without strict mode, dev is NULL so .flowi6_l3mdev will be set to 0. Add a new 'nft_fib_l3mdev_master_ifindex_rcu()' helper and use that to init the .l3mdev structure member. For ipv6, use it from nft_fib6_flowi_init() which gets called from both the 'type' and the 'route' mode eval functions. This provides consistent behaviour for all modes for both ipv4 and ipv6: If strict matching is requested, the input respectively output device of the netfilter hooks is used. Otherwise, use skb->dev to obtain the l3mdev ifindex. Without this, most type checks in updated nft_fib.sh selftest fail: FAIL: did not find veth0 . 10.9.9.1 . local in fibtype4 FAIL: did not find veth0 . dead:1::1 . local in fibtype6 FAIL: did not find veth0 . dead:9::1 . local in fibtype6 FAIL: did not find tvrf . 10.0.1.1 . local in fibtype4 FAIL: did not find tvrf . 10.9.9.1 . local in fibtype4 FAIL: did not find tvrf . dead:1::1 . local in fibtype6 FAIL: did not find tvrf . dead:9::1 . local in fibtype6 FAIL: fib expression address types match (iif in vrf) (fib errounously returns 'unicast' for all of them, even though all of these addresses are local to the vrf). Fixes: f6d0cbcf09c5 ("netfilter: nf_tables: add fib expression") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nf_tables: nft_fib_ipv6: fix VRF ipv4/ipv6 result discrepancy

2025-06-19T13:31:52+00:00

[ Upstream commit 8b53f46eb430fe5b42d485873b85331d2de2c469 ] With a VRF, ipv4 and ipv6 FIB expression behave differently. fib daddr . iif oif Will return the input interface name for ipv4, but the real device for ipv6. Example: If VRF device name is tvrf and real (incoming) device is veth0. First round is ok, both ipv4 and ipv6 will yield 'veth0'. But in the second round (incoming device will be set to "tvrf"), ipv4 will yield "tvrf" whereas ipv6 returns "veth0" for the second round too. This makes ipv6 behave like ipv4. A followup patch will add a test case for this, without this change it will fail with: get element inet t fibif6iif { tvrf . dead:1::99 . tvrf } ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAIL: did not find tvrf . dead:1::99 . tvrf in fibif6iif Alternatively we could either not do anything at all or change ipv4 to also return the lower/real device, however, nft (userspace) doc says "iif: if fib lookup provides a route then check its output interface is identical to the packets input interface." which is what the nft fib ipv4 behaviour is. Fixes: f6d0cbcf09c5 ("netfilter: nf_tables: add fib expression") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: fib: avoid lookup if socket is available

2025-05-02T05:59:05+00:00

commit eaaff9b6702e99be5d79135f2afa9fc48a0d59e0 upstream. In case the fib match is used from the input hook we can avoid the fib lookup if early demux assigned a socket for us: check that the input interface matches sk-cached one. Rework the existing 'lo bypass' logic to first check sk, then for loopback interface type to elide the fib lookup. This speeds up fib matching a little, before: 93.08 GBit/s (no rules at all) 75.1 GBit/s ("fib saddr . iif oif missing drop" in prerouting) 75.62 GBit/s ("fib saddr . iif oif missing drop" in input) After: 92.48 GBit/s (no rules at all) 75.62 GBit/s (fib rule in prerouting) 90.37 GBit/s (fib rule in input). Numbers for the 'no rules' and 'prerouting' are expected to closely match in-between runs, the 3rd/input test case exercises the the 'avoid lookup if cached ifindex in sk matches' case. Test used iperf3 via veth interface, lo can't be used due to existing loopback test. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman