kernel.git/net/bridge, branch linux-5.10.y

net: bridge: fix static key check

2026-02-06T15:40:11Z

[ Upstream commit cc0cf10fdaeadf5542d64a55b5b4120d3df90b7d ] Fix the check if netfilter's static keys are available. netfilter defines and exports static keys if CONFIG_JUMP_LABEL is enabled. (HAVE_JUMP_LABEL is never defined.) Fixes: 971502d77faa ("bridge: netfilter: unroll NF_HOOK helper in bridge input path") Signed-off-by: Martin Kaiser Reviewed-by: Florian Westphal Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260127101925.1754425-1-martin@kaiser.cx Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

bridge: fix C-VLAN preservation in 802.1ad vlan_tunnel egress

2026-01-19T12:12:10Z

[ Upstream commit 3128df6be147768fe536986fbb85db1d37806a9f ] When using an 802.1ad bridge with vlan_tunnel, the C-VLAN tag is incorrectly stripped from frames during egress processing. br_handle_egress_vlan_tunnel() uses skb_vlan_pop() to remove the S-VLAN from hwaccel before VXLAN encapsulation. However, skb_vlan_pop() also moves any "next" VLAN from the payload into hwaccel: /* move next vlan tag to hw accel tag */ __skb_vlan_pop(skb, &vlan_tci); __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci); For QinQ frames where the C-VLAN sits in the payload, this moves it to hwaccel where it gets lost during VXLAN encapsulation. Fix by calling __vlan_hwaccel_clear_tag() directly, which clears only the hwaccel S-VLAN and leaves the payload untouched. This path is only taken when vlan_tunnel is enabled and tunnel_info is configured, so 802.1Q bridges are unaffected. Tested with 802.1ad bridge + VXLAN vlan_tunnel, verified C-VLAN preserved in VXLAN payload via tcpdump. Fixes: 11538d039ac6 ("bridge: vlan dst_metadata hooks in ingress and egress paths") Signed-off-by: Alexandre Knecht Reviewed-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20251228020057.2788865-1-knecht.alexandre@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: bridge: Describe @tunnel_hash member in net_bridge_vlan_group struct

2026-01-19T12:11:54Z

[ Upstream commit f79f9b7ace1713e4b83888c385f5f55519dfb687 ] Sphinx reports kernel-doc warning: WARNING: ./net/bridge/br_private.h:267 struct member 'tunnel_hash' not described in 'net_bridge_vlan_group' Fix it by describing @tunnel_hash member. Fixes: efa5356b0d9753 ("bridge: per vlan dst_metadata netlink support") Signed-off-by: Bagas Sanjaya Acked-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20251218042936.24175-2-bagasdotme@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

bridge: Redirect to backup port when port is administratively down

2025-12-06T21:08:11Z

[ Upstream commit 3d05b24429e1de7a17c8fdccb04a04dbc8ad297b ] If a backup port is configured for a bridge port, the bridge will redirect known unicast traffic towards the backup port when the primary port is administratively up but without a carrier. This is useful, for example, in MLAG configurations where a system is connected to two switches and there is a peer link between both switches. The peer link serves as the backup port in case one of the switches loses its connection to the multi-homed system. In order to avoid flooding when the primary port loses its carrier, the bridge does not flush dynamic FDB entries pointing to the port upon STP disablement, if the port has a backup port. The above means that known unicast traffic destined to the primary port will be blackholed when the port is put administratively down, until the FDB entries pointing to it are aged-out. Given that the current behavior is quite weird and unlikely to be depended on by anyone, amend the bridge to redirect to the backup port also when the primary port is administratively down and not only when it does not have a carrier. The change is motivated by a report from a user who expected traffic to be redirected to the backup port when the primary port was put administratively down while debugging a network issue. Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250812080213.325298-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

netfilter: nft_reject: unify reject init and dump into nft_reject

2025-08-28T14:22:59Z

[ Upstream commit 312ca575a50543a886a5dfa2af1e72aa6a5b601e ] Bridge family is using the same static init and dump function as inet. This patch removes duplicate code unifying these functions body into nft_reject.c so they can be reused in the rest of families supporting reject verdict. Signed-off-by: Jose M. Guisado Gomez Signed-off-by: Pablo Neira Ayuso Stable-dep-of: 91a79b792204 ("netfilter: nf_reject: don't leak dst refcount for loopback packets") Signed-off-by: Sasha Levin

netfilter: bridge: Move specific fragmented packet to slow_path instead of dropping it

2025-06-27T10:04:03Z

[ Upstream commit aa04c6f45b9224b949aa35d4fa5f8d0ba07b23d4 ] The config NF_CONNTRACK_BRIDGE will change the bridge forwarding for fragmented packets. The original bridge does not know that it is a fragmented packet and forwards it directly, after NF_CONNTRACK_BRIDGE is enabled, function nf_br_ip_fragment and br_ip6_fragment will check the headroom. In original br_forward, insufficient headroom of skb may indeed exist, but there's still a way to save the skb in the device driver after dev_queue_xmit.So droping the skb will change the original bridge forwarding in some cases. Fixes: 3c171f496ef5 ("netfilter: bridge: add connection tracking system") Signed-off-by: Huajian Yang Reviewed-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

bridge: netfilter: Fix forwarding of fragmented packets

2025-06-04T12:37:07Z

[ Upstream commit 91b6dbced0ef1d680afdd69b14fc83d50ebafaf3 ] When netfilter defrag hooks are loaded (due to the presence of conntrack rules, for example), fragmented packets entering the bridge will be defragged by the bridge's pre-routing hook (br_nf_pre_routing() -> ipv4_conntrack_defrag()). Later on, in the bridge's post-routing hook, the defragged packet will be fragmented again. If the size of the largest fragment is larger than what the kernel has determined as the destination MTU (using ip_skb_dst_mtu()), the defragged packet will be dropped. Before commit ac6627a28dbf ("net: ipv4: Consolidate ipv4_mtu and ip_dst_mtu_maybe_forward"), ip_skb_dst_mtu() would return dst_mtu() as the destination MTU. Assuming the dst entry attached to the packet is the bridge's fake rtable one, this would simply be the bridge's MTU (see fake_mtu()). However, after above mentioned commit, ip_skb_dst_mtu() ends up returning the route's MTU stored in the dst entry's metrics. Ideally, in case the dst entry is the bridge's fake rtable one, this should be the bridge's MTU as the bridge takes care of updating this metric when its MTU changes (see br_change_mtu()). Unfortunately, the last operation is a no-op given the metrics attached to the fake rtable entry are marked as read-only. Therefore, ip_skb_dst_mtu() ends up returning 1500 (the initial MTU value) and defragged packets are dropped during fragmentation when dealing with large fragments and high MTU (e.g., 9k). Fix by moving the fake rtable entry's metrics to be per-bridge (in a similar fashion to the fake rtable entry itself) and marking them as writable, thereby allowing MTU changes to be reflected. Fixes: 62fa8a846d7d ("net: Implement read-only protection and COW'ing of metrics.") Fixes: 33eb9873a283 ("bridge: initialize fake_rtable metrics") Reported-by: Venkat Venkatsubra Closes: https://lore.kernel.org/netdev/PH0PR10MB4504888284FF4CBA648197D0ACB82@PH0PR10MB4504.namprd10.prod.outlook.com/ Tested-by: Venkat Venkatsubra Signed-off-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250515084848.727706-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: bridge: xmit: make sure we have at least eth header len bytes

2024-11-17T13:59:37Z

commit 8bd67ebb50c0145fd2ca8681ab65eb7e8cde1afc upstream. syzbot triggered an uninit value[1] error in bridge device's xmit path by sending a short (less than ETH_HLEN bytes) skb. To fix it check if we can actually pull that amount instead of assuming. Tested with dropwatch: drop at: br_dev_xmit+0xb93/0x12d0 [bridge] (0xffffffffc06739b3) origin: software timestamp: Mon May 13 11:31:53 2024 778214037 nsec protocol: 0x88a8 length: 2 original length: 2 drop reason: PKT_TOO_SMALL [1] BUG: KMSAN: uninit-value in br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65 br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3547 __dev_queue_xmit+0x34db/0x5350 net/core/dev.c:4341 dev_queue_xmit include/linux/netdevice.h:3091 [inline] __bpf_tx_skb net/core/filter.c:2136 [inline] __bpf_redirect_common net/core/filter.c:2180 [inline] __bpf_redirect+0x14a6/0x1620 net/core/filter.c:2187 ____bpf_clone_redirect net/core/filter.c:2460 [inline] bpf_clone_redirect+0x328/0x470 net/core/filter.c:2432 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2238 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] bpf_test_run+0x499/0xc30 net/bpf/test_run.c:425 bpf_prog_test_run_skb+0x14ea/0x1f20 net/bpf/test_run.c:1058 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4269 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5678 __do_sys_bpf kernel/bpf/syscall.c:5767 [inline] __se_sys_bpf kernel/bpf/syscall.c:5765 [inline] __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5765 x64_sys_call+0x96b/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+a63a1f6a062033cf0f40@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=a63a1f6a062033cf0f40 Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Randy MacLeod Signed-off-by: Greg Kroah-Hartman

netfilter: br_netfilter: fix panic with metadata_dst skb

2024-10-17T13:08:34Z

[ Upstream commit f9ff7665cd128012868098bbd07e28993e314fdb ] Fix a kernel panic in the br_netfilter module when sending untagged traffic via a VxLAN device. This happens during the check for fragmentation in br_nf_dev_queue_xmit. It is dependent on: 1) the br_netfilter module being loaded; 2) net.bridge.bridge-nf-call-iptables set to 1; 3) a bridge with a VxLAN (single-vxlan-device) netdevice as a bridge port; 4) untagged frames with size higher than the VxLAN MTU forwarded/flooded When forwarding the untagged packet to the VxLAN bridge port, before the netfilter hooks are called, br_handle_egress_vlan_tunnel is called and changes the skb_dst to the tunnel dst. The tunnel_dst is a metadata type of dst, i.e., skb_valid_dst(skb) is false, and metadata->dst.dev is NULL. Then in the br_netfilter hooks, in br_nf_dev_queue_xmit, there's a check for frames that needs to be fragmented: frames with higher MTU than the VxLAN device end up calling br_nf_ip_fragment, which in turns call ip_skb_dst_mtu. The ip_dst_mtu tries to use the skb_dst(skb) as if it was a valid dst with valid dst->dev, thus the crash. This case was never supported in the first place, so drop the packet instead. PING 10.0.0.2 (10.0.0.2) from 0.0.0.0 h1-eth0: 2000(2028) bytes of data. [ 176.291791] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000110 [ 176.292101] Mem abort info: [ 176.292184] ESR = 0x0000000096000004 [ 176.292322] EC = 0x25: DABT (current EL), IL = 32 bits [ 176.292530] SET = 0, FnV = 0 [ 176.292709] EA = 0, S1PTW = 0 [ 176.292862] FSC = 0x04: level 0 translation fault [ 176.293013] Data abort info: [ 176.293104] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 176.293488] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 176.293787] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 176.293995] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000043ef5000 [ 176.294166] [0000000000000110] pgd=0000000000000000, p4d=0000000000000000 [ 176.294827] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 176.295252] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel veth br_netfilter bridge stp llc ipv6 crct10dif_ce [ 176.295923] CPU: 0 PID: 188 Comm: ping Not tainted 6.8.0-rc3-g5b3fbd61b9d1 #2 [ 176.296314] Hardware name: linux,dummy-virt (DT) [ 176.296535] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 176.296808] pc : br_nf_dev_queue_xmit+0x390/0x4ec [br_netfilter] [ 176.297382] lr : br_nf_dev_queue_xmit+0x2ac/0x4ec [br_netfilter] [ 176.297636] sp : ffff800080003630 [ 176.297743] x29: ffff800080003630 x28: 0000000000000008 x27: ffff6828c49ad9f8 [ 176.298093] x26: ffff6828c49ad000 x25: 0000000000000000 x24: 00000000000003e8 [ 176.298430] x23: 0000000000000000 x22: ffff6828c4960b40 x21: ffff6828c3b16d28 [ 176.298652] x20: ffff6828c3167048 x19: ffff6828c3b16d00 x18: 0000000000000014 [ 176.298926] x17: ffffb0476322f000 x16: ffffb7e164023730 x15: 0000000095744632 [ 176.299296] x14: ffff6828c3f1c880 x13: 0000000000000002 x12: ffffb7e137926a70 [ 176.299574] x11: 0000000000000001 x10: ffff6828c3f1c898 x9 : 0000000000000000 [ 176.300049] x8 : ffff6828c49bf070 x7 : 0008460f18d5f20e x6 : f20e0100bebafeca [ 176.300302] x5 : ffff6828c7f918fe x4 : ffff6828c49bf070 x3 : 0000000000000000 [ 176.300586] x2 : 0000000000000000 x1 : ffff6828c3c7ad00 x0 : ffff6828c7f918f0 [ 176.300889] Call trace: [ 176.301123] br_nf_dev_queue_xmit+0x390/0x4ec [br_netfilter] [ 176.301411] br_nf_post_routing+0x2a8/0x3e4 [br_netfilter] [ 176.301703] nf_hook_slow+0x48/0x124 [ 176.302060] br_forward_finish+0xc8/0xe8 [bridge] [ 176.302371] br_nf_hook_thresh+0x124/0x134 [br_netfilter] [ 176.302605] br_nf_forward_finish+0x118/0x22c [br_netfilter] [ 176.302824] br_nf_forward_ip.part.0+0x264/0x290 [br_netfilter] [ 176.303136] br_nf_forward+0x2b8/0x4e0 [br_netfilter] [ 176.303359] nf_hook_slow+0x48/0x124 [ 176.303803] __br_forward+0xc4/0x194 [bridge] [ 176.304013] br_flood+0xd4/0x168 [bridge] [ 176.304300] br_handle_frame_finish+0x1d4/0x5c4 [bridge] [ 176.304536] br_nf_hook_thresh+0x124/0x134 [br_netfilter] [ 176.304978] br_nf_pre_routing_finish+0x29c/0x494 [br_netfilter] [ 176.305188] br_nf_pre_routing+0x250/0x524 [br_netfilter] [ 176.305428] br_handle_frame+0x244/0x3cc [bridge] [ 176.305695] __netif_receive_skb_core.constprop.0+0x33c/0xecc [ 176.306080] __netif_receive_skb_one_core+0x40/0x8c [ 176.306197] __netif_receive_skb+0x18/0x64 [ 176.306369] process_backlog+0x80/0x124 [ 176.306540] __napi_poll+0x38/0x17c [ 176.306636] net_rx_action+0x124/0x26c [ 176.306758] __do_softirq+0x100/0x26c [ 176.307051] ____do_softirq+0x10/0x1c [ 176.307162] call_on_irq_stack+0x24/0x4c [ 176.307289] do_softirq_own_stack+0x1c/0x2c [ 176.307396] do_softirq+0x54/0x6c [ 176.307485] __local_bh_enable_ip+0x8c/0x98 [ 176.307637] __dev_queue_xmit+0x22c/0xd28 [ 176.307775] neigh_resolve_output+0xf4/0x1a0 [ 176.308018] ip_finish_output2+0x1c8/0x628 [ 176.308137] ip_do_fragment+0x5b4/0x658 [ 176.308279] ip_fragment.constprop.0+0x48/0xec [ 176.308420] __ip_finish_output+0xa4/0x254 [ 176.308593] ip_finish_output+0x34/0x130 [ 176.308814] ip_output+0x6c/0x108 [ 176.308929] ip_send_skb+0x50/0xf0 [ 176.309095] ip_push_pending_frames+0x30/0x54 [ 176.309254] raw_sendmsg+0x758/0xaec [ 176.309568] inet_sendmsg+0x44/0x70 [ 176.309667] __sys_sendto+0x110/0x178 [ 176.309758] __arm64_sys_sendto+0x28/0x38 [ 176.309918] invoke_syscall+0x48/0x110 [ 176.310211] el0_svc_common.constprop.0+0x40/0xe0 [ 176.310353] do_el0_svc+0x1c/0x28 [ 176.310434] el0_svc+0x34/0xb4 [ 176.310551] el0t_64_sync_handler+0x120/0x12c [ 176.310690] el0t_64_sync+0x190/0x194 [ 176.311066] Code: f9402e61 79402aa2 927ff821 f9400023 (f9408860) [ 176.315743] ---[ end trace 0000000000000000 ]--- [ 176.316060] Kernel panic - not syncing: Oops: Fatal exception in interrupt [ 176.316371] Kernel Offset: 0x37e0e3000000 from 0xffff800080000000 [ 176.316564] PHYS_OFFSET: 0xffff97d780000000 [ 176.316782] CPU features: 0x0,88000203,3c020000,0100421b [ 176.317210] Memory Limit: none [ 176.317527] ---[ end Kernel panic - not syncing: Oops: Fatal Exception in interrupt ]---\ Fixes: 11538d039ac6 ("bridge: vlan dst_metadata hooks in ingress and egress paths") Reviewed-by: Ido Schimmel Signed-off-by: Andy Roulin Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241001154400.22787-2-aroulin@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN

2024-09-12T09:06:47Z

[ Upstream commit bee2ef946d3184e99077be526567d791c473036f ] When userspace wants to take over a fdb entry by setting it as EXTERN_LEARNED, we set both flags BR_FDB_ADDED_BY_EXT_LEARN and BR_FDB_ADDED_BY_USER in br_fdb_external_learn_add(). If the bridge updates the entry later because its port changed, we clear the BR_FDB_ADDED_BY_EXT_LEARN flag, but leave the BR_FDB_ADDED_BY_USER flag set. If userspace then wants to take over the entry again, br_fdb_external_learn_add() sees that BR_FDB_ADDED_BY_USER and skips setting the BR_FDB_ADDED_BY_EXT_LEARN flags, thus silently ignores the update. Fix this by always allowing to set BR_FDB_ADDED_BY_EXT_LEARN regardless if this was a user fdb entry or not. Fixes: 710ae7287737 ("net: bridge: Mark FDB entries that were added by user as such") Signed-off-by: Jonas Gorski Acked-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20240903081958.29951-1-jonas.gorski@bisdn.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin