kernel/linux.git/net/bridge, branch v7.1.12

netfilter: bridge: release template ct on non-IP path

2026-08-19T16:20:28+00:00

commit d45cc8020d7c0a9f01dee42ff5c40bc14c9af72f upstream. A bridge nftables ct zone set rule can attach a conntrack template to an skb before nf_ct_bridge_pre() sees it. For non-IPv4 and non-IPv6 EtherTypes, nf_ct_bridge_pre() currently overwrites skb->_nfct with IP_CT_UNTRACKED without releasing the existing template reference. That makes the per-cpu template, and any temporary templates allocated for concurrent use, unreachable and leaks memory until the host runs out of slab. Reset the skb conntrack state before marking the frame untracked so the existing template reference is dropped on the non-IP path. Fixes: 3c171f496ef5 ("netfilter: bridge: add connection tracking system") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zhiling Zou Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman

net: bridge: mrp: fix uninitialised bytes on the wire

2026-08-19T16:20:24+00:00

commit 63488dba65ef91373ef616575b32eb0eb21459f4 upstream. br_mrp_alloc_test_skb() builds MRP test frames on an skb from dev_alloc_skb(), which does not clear the linear data area. On the MRA ring-role branch the sub-option TLV header is appended with sub_tlv = skb_put(skb, sizeof(*sub_tlv)); sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR; so sub_tlv->length is never written, and the two trailing alignment bytes are appended with a bare skb_put() that does not clear them either. The neighbouring oui and sub_opt regions are explicitly zeroed, so three uninitialised bytes are left in every MRA MRP_Test frame that goes out. Put the sub-option TLV header and the alignment padding in a single skb_put_zero(), which clears both. The AUTO_MGR sub-TLV carries no payload, so the zeroed length field is already the value it should have. Fixes: f7458934b079 ("net: bridge: mrp: Update the Test frames for MRA") Suggested-by: Nikolay Aleksandrov Cc: stable@vger.kernel.org Signed-off-by: Baul Lee Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260729131941.10254-1-baul.lee@xbow.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

netfilter: ebt_nflog: pin the NFLOG backend

2026-08-19T16:20:24+00:00

commit 30825970339c107bacaf7f61af90fcdb1f597ca1 upstream. nf_log_unregister() runs after the per-net teardown so its final RCU grace period also drains readers that obtained the logger from a per-net binding. However, ebt_nflog passes an explicit ULOG log type to nf_log_packet() without holding a reference on the selected logger module, unlike the xt_NFLOG and nft_log frontends. An ebtables nflog rule can therefore remain callable while nfnetlink_log is unloaded. The resulting interleaving is: CPU 0 CPU 1 nfnetlink_log_fini() unregister_pernet_subsys() kfree(nfnl_log_pernet(net)) ebt_nflog_tg() nf_log_packet() nfulnl_log_packet() instance_lookup_get_rcu() The global ULOG logger is still registered at this point, so CPU 1 dereferences the per-net state after CPU 0 has freed it. KASAN reported: BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu Read of size 8 at addr ff110001052e6210 by task poc/92 Call Trace: instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log] nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log] nf_log_packet+0x204/0x300 ebt_nflog_tg+0x351/0x550 ebt_do_table+0xedf/0x22b0 Allocated by task 90: __kmalloc_noprof+0x186/0x470 ops_init+0x6d/0x420 register_pernet_operations+0x2f6/0x670 register_pernet_subsys+0x23/0x40 Freed by task 93: kfree+0x131/0x3c0 ops_undo_list+0x3e3/0x700 unregister_pernet_operations+0x232/0x490 unregister_pernet_subsys+0x1c/0x30 nfnetlink_log_fini+0x34/0x450 [nfnetlink_log] Acquire the ULOG logger module reference when an ebt_nflog rule is validated and release it when the rule is destroyed. Request the NFLOG backend for legacy callers when needed, matching xt_NFLOG. This prevents module teardown until all ebt_nflog rules have stopped using the logger. Fixes: c83fa19603bd ("netfilter: nf_log: don't call synchronize_rcu in nf_log_unset") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman

net: bridge: stop fast-leave after deleting a port group

2026-08-09T18:26:46+00:00

commit a39789f211b8a4125f0c70e05b30cf715f4f187d upstream. br_multicast_leave_group() iterates mp->ports with pp = &p->next in its fast-leave path. After br_multicast_del_pg() removes p, continuing the loop advances pp through the deleted entry. If multicast-to-unicast was enabled, the bridge can hold multiple port groups for the same port and group with different source MAC addresses. Once multicast-to-unicast is disabled, br_port_group_equal() matches those entries by port only. A fast leave can then delete one entry and continue from its stale next pointer, leaving mp->ports pointing at a deleted port group. Fast leave only needs to remove one matching port group. Break after br_multicast_del_pg() so the loop stops before dereferencing the removed entry. Fixes: 6db6f0eae605 ("bridge: multicast to unicast") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zhiling Zou Signed-off-by: Ren Wei Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/1cf0898872ef7c72d5f4c0304414a192c6dac591.1784707712.git.zhilinz@nebusec.ai Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: bridge: mrp: fix Option TLV length in MRP_Test frames

2026-08-09T18:26:30+00:00

[ Upstream commit 5546da86894d5906f131b05890705a7abf949d84 ] oui is a pointer, so sizeof(oui) is the pointer size. The MRA Option TLV thus advertises a wrong length (15 vs 10 on x86_64), causing misparsing of the frame on peers. Fix is to replace with sizeof(*oui). Fixes: f7458934b079 ("net: bridge: mrp: Update the Test frames for MRA") Signed-off-by: David Corvaglia Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260726062605.2746-1-david@corvaglia.dev Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: bridge: vlan: fix vlan range dumps starting with pvid

2026-08-03T09:25:35+00:00

[ Upstream commit 43171c97e4714bf601b468401b37732244639c21 ] There is a bug in all range dumps that rely on br_vlan_can_enter_range() when the PVID is a range starting VLAN, all following VLANs that match its flags can enter the range, but when the range is filled in only the PVID VLAN is dumped and the rest of the range is discarded because br_vlan_fill_vids() checks for the PVID flag. Since the PVID VLAN can be only one, we need to break ranges around it, the best way to do that consistently for all is to alter br_vlan_can_enter_range() to take into account the PVID and return false to break the range when it's matched. Before the fix: $ ip l add br0 type bridge vlan_filtering 1 $ ip l add dumdum type dummy $ ip l set dumdum master br0 $ ip l set br0 up $ ip l set dumdum up $ bridge vlan add dev dumdum vid 1 pvid untagged master $ bridge vlan add dev dumdum vid 2 untagged master $ bridge vlan show dev dumdum # use legacy dump to show all vlans port vlan-id dumdum 1 PVID Egress Untagged 2 Egress Untagged $ bridge -d vlan show dev dumdum # use the new dump (RTM_GETVLAN) port vlan-id dumdum 1 PVID Egress Untagged state forwarding mcast_router 1 VLAN 2 is missing, and if there are more matching VLANs afterwards they'd be missing too. After the fix: [ same setup steps ] $ bridge vlan show dev dumdum port vlan-id dumdum 1 PVID Egress Untagged 2 Egress Untagged $ bridge -d vlan show dev dumdum # use the new dump (RTM_GETVLAN) port vlan-id dumdum 1 PVID Egress Untagged state forwarding mcast_router 1 2 Egress Untagged state forwarding mcast_router 1 Fixes: 0ab558795184 ("net: bridge: vlan: add rtm range support") Signed-off-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260721140922.682265-2-razor@blackwall.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

bridge: stp: Fix a potential use-after-free when deleting a bridge

2026-07-24T14:20:34+00:00

[ Upstream commit 2a00517db8de4be7df3d483b215c5544fb30a191 ] The three STP timers are not supposed to be armed while the bridge is administratively down. They are synchronously deactivated when the bridge is put administratively down and the various call sites check for 'IFF_UP' before arming them. This check is missing from br_topology_change_detection() and it is possible to engineer a situation in which the topology change timer is armed while the bridge is administratively down, resulting in a use-after-free [1] when the bridge is deleted. Fix by adding the missing check and for good measures synchronously shutdown the three timers when the bridge is deleted. [1] ODEBUG: free active (active state 0) object: ffff88811662b9b0 object type: timer_list hint: br_topology_change_timer_expired (net/bridge/br_stp_timer.c:120) WARNING: lib/debugobjects.c:629 at debug_print_object+0x1bc/0x450, CPU#9: ip/359 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Noam Rathaus Reported-by: Neil Young Acked-by: Nikolay Aleksandrov Signed-off-by: Ido Schimmel Reviewed-by: Breno Leitao Link: https://patch.msgid.link/20260629072117.497959-1-idosch@nvidia.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

netfilter: nft_meta_bridge: fix NFT_META_BRI_IIFPVID stack leak

2026-07-24T14:20:21+00:00

[ Upstream commit 27dd2997746d54ebc079bb13161cc1bdd401d4a6 ] This needs to test for nonzero retval. Fixes: c54c7c685494 ("netfilter: nft_meta_bridge: add NFT_META_BRI_IIFPVID support") Closes: https://sashiko.dev/#/patchset/20260618061631.21919-1-fw%40strlen.de Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nft_meta_bridge: add validate callback for get operations

2026-07-24T14:20:20+00:00

[ Upstream commit bff1c8b49a9cb5c04af20f4e7d43bf4af5863bc6 ] Blamed commit added NFT_META_BRI_IIFHWADDR to the set validate callback, yet this is a get operation. Add a get validate callback and move the NFT_META_BRI_IIFHWADDR key there. AFAICS this is harmless, NFT_META_BRI_IIFHWADDR can deal with a NULL input device and the set handler ignores a NFT_META_BRI_IIFHWADDR operation, but it allows to read 4 bytes off bridge skb->cb[]. Fixes: cbd2257dc96e ("netfilter: nft_meta_bridge: introduce NFT_META_BRI_IIFHWADDR support") Signed-off-by: Florian Westphal Reviewed-by: Fernando Fernandez Mancera Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

bridge: cfm: reject invalid CCM interval at configuration time

2026-07-24T14:19:49+00:00

[ Upstream commit f3e02edd8322b31b8e6517faa6ba053bf29d1e26 ] ccm_tx_work_expired() re-arms itself via queue_delayed_work() using the configured exp_interval converted by interval_to_us(). When exp_interval is BR_CFM_CCM_INTERVAL_NONE or out of range, interval_to_us() returns 0, causing the worker to fire immediately in a tight loop that allocates skbs until OOM. Fix this by validating exp_interval at configuration time: - Constrain IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL to the valid range [BR_CFM_CCM_INTERVAL_3_3_MS, BR_CFM_CCM_INTERVAL_10_MIN] in the netlink policy so userspace cannot set an invalid value. - Reject starting CCM TX in br_cfm_cc_ccm_tx() when exp_interval has not yet been configured (defaults to 0 from kzalloc). Fixes: 2be665c3940d ("bridge: cfm: Netlink SET configuration Interface.") Reported-by: Weiming Shi Signed-off-by: Xiang Mei Acked-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260609065116.2818837-1-xmei5@asu.edu Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin