kernel/linux.git/drivers/net/vxlan, branch v6.18.36

vxlan: vnifilter: fix spurious notification on VNI update

2026-06-19T11:43:55+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

2026-06-19T11:43:55+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()

2026-06-09T10:28:28+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

2026-04-11T12:26:46+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

2026-03-12T11:10:01+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

net: vxlan: prevent NULL deref in vxlan_xmit_one

2025-12-18T13:03:26+00:00

[ Upstream commit 1f73a56f986005f0bc64ed23873930e2ee4f5911 ] Neither sock4 nor sock6 pointers are guaranteed to be non-NULL in vxlan_xmit_one, e.g. if the iface is brought down. This can lead to the following NULL dereference: BUG: kernel NULL pointer dereference, address: 0000000000000010 Oops: Oops: 0000 [#1] SMP NOPTI RIP: 0010:vxlan_xmit_one+0xbb3/0x1580 Call Trace: vxlan_xmit+0x429/0x610 dev_hard_start_xmit+0x55/0xa0 __dev_queue_xmit+0x6d0/0x7f0 ip_finish_output2+0x24b/0x590 ip_output+0x63/0x110 Mentioned commits changed the code path in vxlan_xmit_one and as a side effect the sock4/6 pointer validity checks in vxlan(6)_get_route were lost. Fix this by adding back checks. Since both commits being fixed were released in the same version (v6.7) and are strongly related, bundle the fixes in a single commit. Reported-by: Liang Li Fixes: 6f19b2c136d9 ("vxlan: use generic function for tunnel IPv4 route lookup") Fixes: 2aceb896ee18 ("vxlan: use generic function for tunnel IPv6 route lookup") Cc: Beniamino Galvani Signed-off-by: Antoine Tenart Reviewed-by: Ido Schimmel Tested-by: Ido Schimmel Link: https://patch.msgid.link/20251126102627.74223-1-atenart@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vxlan: Make vxlan_fdb_find_uc() more robust against NPDs

2025-09-10T01:27:33+00:00

first_remote_rcu() can return NULL if the FDB entry points to an FDB nexthop group instead of a remote destination. However, unlike other users of first_remote_rcu(), NPD cannot currently happen in vxlan_fdb_find_uc() as it is only invoked by one driver which vetoes the creation of FDB nexthops. Make the function more robust by making sure the remote destination is only dereferenced if it is not NULL. Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Reviewed-by: Wang Liang Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250908075141.125087-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski

vxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects

2025-09-02T23:57:00+00:00

When the "proxy" option is enabled on a VXLAN device, the device will suppress ARP requests and IPv6 Neighbor Solicitation messages if it is able to reply on behalf of the remote host. That is, if a matching and valid neighbor entry is configured on the VXLAN device whose MAC address is not behind the "any" remote (0.0.0.0 / ::). The code currently assumes that the FDB entry for the neighbor's MAC address points to a valid remote destination, but this is incorrect if the entry is associated with an FDB nexthop group. This can result in a NPD [1][3] which can be reproduced using [2][4]. Fix by checking that the remote destination exists before dereferencing it. [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] CPU: 4 UID: 0 PID: 365 Comm: arping Not tainted 6.17.0-rc2-virtme-g2a89cb21162c #2 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014 RIP: 0010:vxlan_xmit+0xb58/0x15f0 [...] Call Trace: dev_hard_start_xmit+0x5d/0x1c0 __dev_queue_xmit+0x246/0xfd0 packet_sendmsg+0x113a/0x1850 __sock_sendmsg+0x38/0x70 __sys_sendto+0x126/0x180 __x64_sys_sendto+0x24/0x30 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [2] #!/bin/bash ip address add 192.0.2.1/32 dev lo ip nexthop add id 1 via 192.0.2.2 fdb ip nexthop add id 10 group 1 fdb ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 4789 proxy ip neigh add 192.0.2.3 lladdr 00:11:22:33:44:55 nud perm dev vx0 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10 arping -b -c 1 -s 192.0.2.1 -I vx0 192.0.2.3 [3] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] CPU: 13 UID: 0 PID: 372 Comm: ndisc6 Not tainted 6.17.0-rc2-virtmne-g6ee90cb26014 #3 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1v996), BIOS 1.17.0-4.fc41 04/01/2x014 RIP: 0010:vxlan_xmit+0x803/0x1600 [...] Call Trace: dev_hard_start_xmit+0x5d/0x1c0 __dev_queue_xmit+0x246/0xfd0 ip6_finish_output2+0x210/0x6c0 ip6_finish_output+0x1af/0x2b0 ip6_mr_output+0x92/0x3e0 ip6_send_skb+0x30/0x90 rawv6_sendmsg+0xe6e/0x12e0 __sock_sendmsg+0x38/0x70 __sys_sendto+0x126/0x180 __x64_sys_sendto+0x24/0x30 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f383422ec77 [4] #!/bin/bash ip address add 2001:db8:1::1/128 dev lo ip nexthop add id 1 via 2001:db8:1::1 fdb ip nexthop add id 10 group 1 fdb ip link add name vx0 up type vxlan id 10010 local 2001:db8:1::1 dstport 4789 proxy ip neigh add 2001:db8:1::3 lladdr 00:11:22:33:44:55 nud perm dev vx0 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10 ndisc6 -r 1 -s 2001:db8:1::1 -w 1 2001:db8:1::3 vx0 Fixes: 1274e1cc4226 ("vxlan: ecmp support for mac fdb entries") Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250901065035.159644-3-idosch@nvidia.com Signed-off-by: Jakub Kicinski

vxlan: Fix NPD when refreshing an FDB entry with a nexthop object

2025-09-02T23:56:59+00:00

VXLAN FDB entries can point to either a remote destination or an FDB nexthop group. The latter is usually used in EVPN deployments where learning is disabled. However, when learning is enabled, an incoming packet might try to refresh an FDB entry that points to an FDB nexthop group and therefore does not have a remote. Such packets should be dropped, but they are only dropped after dereferencing the non-existent remote, resulting in a NPD [1] which can be reproduced using [2]. Fix by dropping such packets earlier. Remove the misleading comment from first_remote_rcu(). [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] CPU: 13 UID: 0 PID: 361 Comm: mausezahn Not tainted 6.17.0-rc1-virtme-g9f6b606b6b37 #1 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014 RIP: 0010:vxlan_snoop+0x98/0x1e0 [...] Call Trace: vxlan_encap_bypass+0x209/0x240 encap_bypass_if_local+0xb1/0x100 vxlan_xmit_one+0x1375/0x17e0 vxlan_xmit+0x6b4/0x15f0 dev_hard_start_xmit+0x5d/0x1c0 __dev_queue_xmit+0x246/0xfd0 packet_sendmsg+0x113a/0x1850 __sock_sendmsg+0x38/0x70 __sys_sendto+0x126/0x180 __x64_sys_sendto+0x24/0x30 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [2] #!/bin/bash ip address add 192.0.2.1/32 dev lo ip address add 192.0.2.2/32 dev lo ip nexthop add id 1 via 192.0.2.3 fdb ip nexthop add id 10 group 1 fdb ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 12345 localbypass ip link add name vx1 up type vxlan id 10020 local 192.0.2.2 dstport 54321 learning bridge fdb add 00:11:22:33:44:55 dev vx0 self static dst 192.0.2.2 port 54321 vni 10020 bridge fdb add 00:aa:bb:cc:dd:ee dev vx1 self static nhid 10 mausezahn vx0 -a 00:aa:bb:cc:dd:ee -b 00:11:22:33:44:55 -c 1 -q Fixes: 1274e1cc4226 ("vxlan: ecmp support for mac fdb entries") Reported-by: Marlin Cremers Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250901065035.159644-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski

vxlan: remove redundant conversion of vni in vxlan_nl2conf

2025-07-24T00:09:29+00:00

The IFLA_VXLAN_ID data has been converted to local variable vni in vxlan_nl2conf(), there is no need to do it again when set conf->vni. Signed-off-by: Wang Liang Acked-by: Nikolay Aleksandrov Reviewed-by: Petr Machata Link: https://patch.msgid.link/20250722093049.1527505-1-wangliang74@huawei.com Signed-off-by: Jakub Kicinski