kernel/linux.git/drivers/net/vxlan, branch v6.6.143

vxlan: vnifilter: fix spurious notification on VNI update

2026-06-19T11:39:28+00:00

[ Upstream commit 84683b5b60c7274e2c8f7f413d39d78d3db5540f ] When a VNI is re-added with the same attributes (e.g. same group or no group), vxlan_vni_update() sends a spurious RTM_NEWTUNNEL notification even though nothing changed. The bug is that 'if (changed)' tests whether the pointer is non-NULL, not the bool value it points to. Since every caller passes a valid pointer, the condition is always true and the notification fires unconditionally. Fix by dereferencing the pointer: 'if (*changed)'. Reproducer: # ip link add vxlan100 type vxlan dstport 4789 local 10.0.0.1 \ nolearning external vnifilter # ip link set vxlan100 up # bridge monitor vni & # bridge vni add vni 1000 dev vxlan100 # bridge vni add vni 1000 dev vxlan100 # spurious notification Fixes: f9c4bb0b245c ("vxlan: vni filtering support on collect metadata device") Signed-off-by: Andy Roulin Reviewed-by: Petr Machata Link: https://patch.msgid.link/20260602185138.253265-3-aroulin@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vxlan: vnifilter: send notification on VNI add

2026-06-19T11:39:28+00:00

[ Upstream commit aa6ca1c5c338907817374b59f7551fd855a88754 ] When a new VNI is added to a vxlan device with vnifilter enabled, no RTM_NEWTUNNEL notification is sent to userspace. This means 'bridge monitor vni' never shows VNI add events, even though VNI delete events are reported correctly. The bug is in vxlan_vni_add(), where the notification is guarded by 'if (changed)'. The 'changed' flag is set by vxlan_vni_update_group() only when the multicast group or remote IP is modified, but for a new VNI added without a group (e.g. in L3 VxLAN interface scenarios), the function returns early without setting changed=true. Since this is a new VNI, the notification should be sent unconditionally. The notification is not guarded by the return value of vxlan_vni_update_group() because, at this point, the VNI has already been inserted into the hash table and list with no rollback on error. The VNI will be visible in 'bridge vni show' regardless, so userspace should be informed. This is consistent with vxlan_vni_del() which also notifies unconditionally. The 'if (changed)' guard remains correct in vxlan_vni_update(), which handles the case where a VNI already exists and is being re-added -- there, we only want to notify if the group/remote actually changed. Reproducer: # ip link add vxlan100 type vxlan dstport 4789 local 10.0.0.1 \ nolearning external vnifilter # ip link set vxlan100 up # bridge monitor vni & # bridge vni add vni 1000 dev vxlan100 # no notification # bridge vni delete vni 1000 dev vxlan100 # notification received Fixes: f9c4bb0b245c ("vxlan: vni filtering support on collect metadata device") Reported-by: Chirag Shah Signed-off-by: Andy Roulin Reviewed-by: Petr Machata Link: https://patch.msgid.link/20260602185138.253265-2-aroulin@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()

2026-06-19T11:39:11+00:00

[ Upstream commit 7d9ef0cb271555d8cf39fefe6c981e1493b25ecf ] skb_tunnel_check_pmtu() can change skb->head. Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF. Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c. Found by Sashiko. Fixes: 4cb47a8644cc ("tunnels: PMTU discovery support for directly bridged IP packets") Signed-off-by: Eric Dumazet Reviewed-by: Stefano Brivio Link: https://patch.msgid.link/20260525203642.2389723-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vxlan: validate ND option lengths in vxlan_na_create

2026-04-11T12:19:32+00:00

commit afa9a05e6c4971bd5586f1b304e14d61fb3d9385 upstream. vxlan_na_create() walks ND options according to option-provided lengths. A malformed option can make the parser advance beyond the computed option span or use a too-short source LLADDR option payload. Validate option lengths against the remaining NS option area before advancing, and only read source LLADDR when the option is large enough for an Ethernet address. Fixes: 4b29dba9c085 ("vxlan: fix nonfunctional neigh_reduce()") Cc: stable@vger.kernel.org Reported-by: Yifan Wu Reported-by: Juefei Pu Tested-by: Ao Zhou Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Suggested-by: Xin Liu Signed-off-by: Yang Yang Reviewed-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260326034441.2037420-4-n05ec@lzu.edu.cn Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: vxlan: fix nd_tbl NULL dereference when IPv6 is disabled

2026-03-25T10:05:42+00:00

[ Upstream commit 168ff39e4758897d2eee4756977d036d52884c7e ] When booting with the 'ipv6.disable=1' parameter, the nd_tbl is never initialized because inet6_init() exits before ndisc_init() is called which initializes it. If an IPv6 packet is injected into the interface, route_shortcircuit() is called and a NULL pointer dereference happens on neigh_lookup(). BUG: kernel NULL pointer dereference, address: 0000000000000380 Oops: Oops: 0000 [#1] SMP NOPTI [...] RIP: 0010:neigh_lookup+0x20/0x270 [...] Call Trace: vxlan_xmit+0x638/0x1ef0 [vxlan] dev_hard_start_xmit+0x9e/0x2e0 __dev_queue_xmit+0xbee/0x14e0 packet_sendmsg+0x116f/0x1930 __sys_sendto+0x1f5/0x200 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x12f/0x1590 entry_SYSCALL_64_after_hwframe+0x76/0x7e Fix this by adding an early check on route_shortcircuit() when protocol is ETH_P_IPV6. Note that ipv6_mod_enabled() cannot be used here because VXLAN can be built-in even when IPv6 is built as a module. Fixes: e15a00aafa4b ("vxlan: add ipv6 route short circuit support") Signed-off-by: Fernando Fernandez Mancera Link: https://patch.msgid.link/20260304120357.9778-2-fmancera@suse.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vxlan: Do not treat dst cache initialization errors as fatal

2025-06-27T10:08:56+00:00

[ Upstream commit 20c76dadc783759fd3819d289c72be590660cc8b ] FDB entries are allocated in an atomic context as they can be added from the data path when learning is enabled. After converting the FDB hash table to rhashtable, the insertion rate will be much higher (*) which will entail a much higher rate of per-CPU allocations via dst_cache_init(). When adding a large number of entries (e.g., 256k) in a batch, a small percentage (< 0.02%) of these per-CPU allocations will fail [1]. This does not happen with the current code since the insertion rate is low enough to give the per-CPU allocator a chance to asynchronously create new chunks of per-CPU memory. Given that: a. Only a small percentage of these per-CPU allocations fail. b. The scenario where this happens might not be the most realistic one. c. The driver can work correctly without dst caches. The dst_cache_*() APIs first check that the dst cache was properly initialized. d. The dst caches are not always used (e.g., 'tos inherit'). It seems reasonable to not treat these allocation failures as fatal. Therefore, do not bail when dst_cache_init() fails and suppress warnings by specifying '__GFP_NOWARN'. [1] percpu: allocation failed, size=40 align=8 atomic=1, atomic alloc failed, no space left (*) 97% reduction in average latency of vxlan_fdb_update() when adding 256k entries in a batch. Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Link: https://patch.msgid.link/20250415121143.345227-14-idosch@nvidia.com Reviewed-by: Nikolay Aleksandrov Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

vxlan: Annotate FDB data races

2025-06-04T12:42:12+00:00

[ Upstream commit f6205f8215f12a96518ac9469ff76294ae7bd612 ] The 'used' and 'updated' fields in the FDB entry structure can be accessed concurrently by multiple threads, leading to reports such as [1]. Can be reproduced using [2]. Suppress these reports by annotating these accesses using READ_ONCE() / WRITE_ONCE(). [1] BUG: KCSAN: data-race in vxlan_xmit / vxlan_xmit write to 0xffff942604d263a8 of 8 bytes by task 286 on cpu 0: vxlan_xmit+0xb29/0x2380 dev_hard_start_xmit+0x84/0x2f0 __dev_queue_xmit+0x45a/0x1650 packet_xmit+0x100/0x150 packet_sendmsg+0x2114/0x2ac0 __sys_sendto+0x318/0x330 __x64_sys_sendto+0x76/0x90 x64_sys_call+0x14e8/0x1c00 do_syscall_64+0x9e/0x1a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff942604d263a8 of 8 bytes by task 287 on cpu 2: vxlan_xmit+0xadf/0x2380 dev_hard_start_xmit+0x84/0x2f0 __dev_queue_xmit+0x45a/0x1650 packet_xmit+0x100/0x150 packet_sendmsg+0x2114/0x2ac0 __sys_sendto+0x318/0x330 __x64_sys_sendto+0x76/0x90 x64_sys_call+0x14e8/0x1c00 do_syscall_64+0x9e/0x1a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000fffbac6e -> 0x00000000fffbac6f Reported by Kernel Concurrency Sanitizer on: CPU: 2 UID: 0 PID: 287 Comm: mausezahn Not tainted 6.13.0-rc7-01544-gb4b270f11a02 #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 [2] #!/bin/bash set +H echo whitelist > /sys/kernel/debug/kcsan echo !vxlan_xmit > /sys/kernel/debug/kcsan ip link add name vx0 up type vxlan id 10010 dstport 4789 local 192.0.2.1 bridge fdb add 00:11:22:33:44:55 dev vx0 self static dst 198.51.100.1 taskset -c 0 mausezahn vx0 -a own -b 00:11:22:33:44:55 -c 0 -q & taskset -c 2 mausezahn vx0 -a own -b 00:11:22:33:44:55 -c 0 -q & Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250204145549.1216254-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vxlan: Join / leave MC group after remote changes

2025-06-04T12:42:08+00:00

[ Upstream commit d42d543368343c0449a4e433b5f02e063a86209c ] When a vxlan netdevice is brought up, if its default remote is a multicast address, the device joins the indicated group. Therefore when the multicast remote address changes, the device should leave the current group and subscribe to the new one. Similarly when the interface used for endpoint communication is changed in a situation when multicast remote is configured. This is currently not done. Both vxlan_igmp_join() and vxlan_igmp_leave() can however fail. So it is possible that with such fix, the netdevice will end up in an inconsistent situation where the old group is not joined anymore, but joining the new group fails. Should we join the new group first, and leave the old one second, we might end up in the opposite situation, where both groups are joined. Undoing any of this during rollback is going to be similarly problematic. One solution would be to just forbid the change when the netdevice is up. However in vnifilter mode, changing the group address is allowed, and these problems are simply ignored (see vxlan_vni_update_group()): # ip link add name br up type bridge vlan_filtering 1 # ip link add vx1 up master br type vxlan external vnifilter local 192.0.2.1 dev lo dstport 4789 # bridge vni add dev vx1 vni 200 group 224.0.0.1 # tcpdump -i lo & # bridge vni add dev vx1 vni 200 group 224.0.0.2 18:55:46.523438 IP 0.0.0.0 > 224.0.0.22: igmp v3 report, 1 group record(s) 18:55:46.943447 IP 0.0.0.0 > 224.0.0.22: igmp v3 report, 1 group record(s) # bridge vni dev vni group/remote vx1 200 224.0.0.2 Having two different modes of operation for conceptually the same interface is silly, so in this patch, just do what the vnifilter code does and deal with the errors by crossing fingers real hard. The vnifilter code leaves old before joining new, and in case of join / leave failures does not roll back the configuration changes that have already been applied, but bails out of joining if it could not leave. Do the same here: leave before join, apply changes unconditionally and do not attempt to join if we couldn't leave. Signed-off-by: Petr Machata Reviewed-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

vxlan: vnifilter: Fix unlocked deletion of default FDB entry

2025-05-09T07:43:57+00:00

[ Upstream commit 087a9eb9e5978e3ba362e1163691e41097e8ca20 ] When a VNI is deleted from a VXLAN device in 'vnifilter' mode, the FDB entry associated with the default remote (assuming one was configured) is deleted without holding the hash lock. This is wrong and will result in a warning [1] being generated by the lockdep annotation that was added by commit ebe642067455 ("vxlan: Create wrappers for FDB lookup"). Reproducer: # ip link add vx0 up type vxlan dstport 4789 external vnifilter local 192.0.2.1 # bridge vni add vni 10010 remote 198.51.100.1 dev vx0 # bridge vni del vni 10010 dev vx0 Fix by acquiring the hash lock before the deletion and releasing it afterwards. Blame the original commit that introduced the issue rather than the one that exposed it. [1] WARNING: CPU: 3 PID: 392 at drivers/net/vxlan/vxlan_core.c:417 vxlan_find_mac+0x17f/0x1a0 [...] RIP: 0010:vxlan_find_mac+0x17f/0x1a0 [...] Call Trace: __vxlan_fdb_delete+0xbe/0x560 vxlan_vni_delete_group+0x2ba/0x940 vxlan_vni_del.isra.0+0x15f/0x580 vxlan_process_vni_filter+0x38b/0x7b0 vxlan_vnifilter_process+0x3bb/0x510 rtnetlink_rcv_msg+0x2f7/0xb70 netlink_rcv_skb+0x131/0x360 netlink_unicast+0x426/0x710 netlink_sendmsg+0x75a/0xc20 __sock_sendmsg+0xc1/0x150 ____sys_sendmsg+0x5aa/0x7b0 ___sys_sendmsg+0xfc/0x180 __sys_sendmsg+0x121/0x1b0 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Fixes: f9c4bb0b245c ("vxlan: vni filtering support on collect metadata device") Signed-off-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250423145131.513029-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vxlan: check vxlan_vnigroup_init() return value

2025-02-21T12:57:07+00:00

[ Upstream commit 5805402dcc56241987bca674a1b4da79a249bab7 ] vxlan_init() must check vxlan_vnigroup_init() success otherwise a crash happens later, spotted by syzbot. Oops: general protection fault, probably for non-canonical address 0xdffffc000000002c: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000160-0x0000000000000167] CPU: 0 UID: 0 PID: 7313 Comm: syz-executor147 Not tainted 6.14.0-rc1-syzkaller-00276-g69b54314c975 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:vxlan_vnigroup_uninit+0x89/0x500 drivers/net/vxlan/vxlan_vnifilter.c:912 Code: 00 48 8b 44 24 08 4c 8b b0 98 41 00 00 49 8d 86 60 01 00 00 48 89 c2 48 89 44 24 10 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 4d 04 00 00 49 8b 86 60 01 00 00 48 ba 00 00 00 RSP: 0018:ffffc9000cc1eea8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff8672effb RDX: 000000000000002c RSI: ffffffff8672ecb9 RDI: ffff8880461b4f18 RBP: ffff8880461b4ef4 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000020000 R13: ffff8880461b0d80 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007fecfa95d6c0(0000) GS:ffff88806a600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fecfa95cfb8 CR3: 000000004472c000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vxlan_uninit+0x1ab/0x200 drivers/net/vxlan/vxlan_core.c:2942 unregister_netdevice_many_notify+0x12d6/0x1f30 net/core/dev.c:11824 unregister_netdevice_many net/core/dev.c:11866 [inline] unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11736 register_netdevice+0x1829/0x1eb0 net/core/dev.c:10901 __vxlan_dev_create+0x7c6/0xa30 drivers/net/vxlan/vxlan_core.c:3981 vxlan_newlink+0xd1/0x130 drivers/net/vxlan/vxlan_core.c:4407 rtnl_newlink_create net/core/rtnetlink.c:3795 [inline] __rtnl_newlink net/core/rtnetlink.c:3906 [inline] Fixes: f9c4bb0b245c ("vxlan: vni filtering support on collect metadata device") Reported-by: syzbot+6a9624592218c2c5e7aa@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/67a9d9b4.050a0220.110943.002d.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Cc: Roopa Prabhu Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20250210105242.883482-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin