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. Then, if neigh_suppress is enabled and an ICMPv6
Neighbor Discovery packet reaches the bridge, br_do_suppress_nd() will
dereference ipv6_stub->nd_tbl which is NULL, passing it to
neigh_lookup(). This causes a kernel NULL pointer dereference.
BUG: kernel NULL pointer dereference, address: 0000000000000268
Oops: 0000 [#1] PREEMPT SMP NOPTI
[...]
RIP: 0010:neigh_lookup+0x16/0xe0
[...]
Call Trace:
<IRQ>
? neigh_lookup+0x16/0xe0
br_do_suppress_nd+0x160/0x290 [bridge]
br_handle_frame_finish+0x500/0x620 [bridge]
br_handle_frame+0x353/0x440 [bridge]
__netif_receive_skb_core.constprop.0+0x298/0x1110
__netif_receive_skb_one_core+0x3d/0xa0
process_backlog+0xa0/0x140
__napi_poll+0x2c/0x170
net_rx_action+0x2c4/0x3a0
handle_softirqs+0xd0/0x270
do_softirq+0x3f/0x60
Fix this by replacing IS_ENABLED(IPV6) call with ipv6_mod_enabled() in
the callers. This is in essence disabling NS/NA suppression when IPv6 is
disabled.
Fixes: ed842faeb2 ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports")
Reported-by: Guruprasad C P <gurucp2005@gmail.com>
Closes: https://lore.kernel.org/netdev/CAHXs0ORzd62QOG-Fttqa2Cx_A_VFp=utE2H2VTX5nqfgs7LDxQ@mail.gmail.com/
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260304120357.9778-1-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
syzbot reported[1] a use-after-free when deleting an expired fdb. It is
due to a race condition between learning still happening and a port being
deleted, after all its fdbs have been flushed. The port's state has been
toggled to disabled so no learning should happen at that time, but if we
have MST enabled, it will bypass the port's state, that together with VLAN
filtering disabled can lead to fdb learning at a time when it shouldn't
happen while the port is being deleted. VLAN filtering must be disabled
because we flush the port VLANs when it's being deleted which will stop
learning. This fix adds a check for the port's vlan group which is
initialized to NULL when the port is getting deleted, that avoids the port
state bypass. When MST is enabled there would be a minimal new overhead
in the fast-path because the port's vlan group pointer is cache-hot.
[1] https://syzkaller.appspot.com/bug?extid=dd280197f0f7ab3917be
Fixes: ec7328b591 ("net: bridge: mst: Multiple Spanning Tree (MST) mode")
Reported-by: syzbot+dd280197f0f7ab3917be@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/69088ffa.050a0220.29fc44.003d.GAE@google.com/
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20251105111919.1499702-2-razor@blackwall.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When BROPT_FDB_LOCAL_VLAN_0 is enabled, the local FDB entries for the
member ports as well as the bridge itself should not be created per-VLAN,
but instead only on VLAN 0.
That means that br_handle_frame_finish() needs to make two lookups: the
primary lookup on an appropriate VLAN, and when that misses, a lookup on
VLAN 0.
Have the second lookup only accept local MAC addresses. Turning this into a
generic second-lookup feature is not the goal.
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/8087475009dce360fb68d873b1ed9c80827da302.1757004393.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The bridge input code may drop frames for various reasons and at various
points in the ingress handling logic. Currently kfree_skb() is used
everywhere, and therefore no drop reason is specified. Add drop reasons
to the most common drop points.
Drop reasons are not added exhaustively to the entire bridge code. The
intention is to incrementally add drop reasons to the rest of the bridge
code in follow up patches.
Signed-off-by: Radu Rendec <rrendec@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241219163606.717758-3-rrendec@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The current name is going to conflict with the upcoming net device
operation for the MDB get operation.
Rename the function to br_mdb_entry_skb_get(). No functional changes
intended.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
For EVPN non-DF (Designated Forwarder) filtering we need to be able to
prevent decapsulated traffic from being flooded to a multi-homed host.
Filtering of multicast and broadcast traffic can be achieved using the
following flower filter:
# tc filter add dev bond0 egress pref 1 proto all flower indev vxlan0 dst_mac 01:00:00:00:00:00/01:00:00:00:00:00 action drop
Unlike broadcast and multicast traffic, it is not currently possible to
filter unknown unicast traffic. The classification into unknown unicast
is performed by the bridge driver, but is not visible to other layers
such as tc.
Solve this by adding a new 'l2_miss' bit to the tc skb extension. Clear
the bit whenever a packet enters the bridge (received from a bridge port
or transmitted via the bridge) and set it if the packet did not match an
FDB or MDB entry. If there is no skb extension and the bit needs to be
cleared, then do not allocate one as no extension is equivalent to the
bit being cleared. The bit is not set for broadcast packets as they
never perform a lookup and therefore never incur a miss.
A bit that is set for every flooded packet would also work for the
current use case, but it does not allow us to differentiate between
registered and unregistered multicast traffic, which might be useful in
the future.
To keep the performance impact to a minimum, the marking of packets is
guarded by the 'tc_skb_ext_tc' static key. When 'false', the skb is not
touched and an skb extension is not allocated. Instead, only a
5 bytes nop is executed, as demonstrated below for the call site in
br_handle_frame().
Before the patch:
```
memset(skb->cb, 0, sizeof(struct br_input_skb_cb));
c37b09: 49 c7 44 24 28 00 00 movq $0x0,0x28(%r12)
c37b10: 00 00
p = br_port_get_rcu(skb->dev);
c37b12: 49 8b 44 24 10 mov 0x10(%r12),%rax
memset(skb->cb, 0, sizeof(struct br_input_skb_cb));
c37b17: 49 c7 44 24 30 00 00 movq $0x0,0x30(%r12)
c37b1e: 00 00
c37b20: 49 c7 44 24 38 00 00 movq $0x0,0x38(%r12)
c37b27: 00 00
```
After the patch (when static key is disabled):
```
memset(skb->cb, 0, sizeof(struct br_input_skb_cb));
c37c29: 49 c7 44 24 28 00 00 movq $0x0,0x28(%r12)
c37c30: 00 00
c37c32: 49 8d 44 24 28 lea 0x28(%r12),%rax
c37c37: 48 c7 40 08 00 00 00 movq $0x0,0x8(%rax)
c37c3e: 00
c37c3f: 48 c7 40 10 00 00 00 movq $0x0,0x10(%rax)
c37c46: 00
#ifdef CONFIG_HAVE_JUMP_LABEL_HACK
static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
{
asm_volatile_goto("1:"
c37c47: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
br_tc_skb_miss_set(skb, false);
p = br_port_get_rcu(skb->dev);
c37c4c: 49 8b 44 24 10 mov 0x10(%r12),%rax
```
Subsequent patches will extend the flower classifier to be able to match
on the new 'l2_miss' bit and enable / disable the static key when
filters that match on it are added / deleted.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Subsequent patches are going to add per-{Port, VLAN} neighbor
suppression, which will require br_flood() to potentially suppress ARP /
NS packets on a per-{Port, VLAN} basis.
As a preparation, pass the VLAN ID of the packet as another argument to
br_flood().
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Hosts that support 802.1X authentication are able to authenticate
themselves by exchanging EAPOL frames with an authenticator (Ethernet
bridge, in this case) and an authentication server. Access to the
network is only granted by the authenticator to successfully
authenticated hosts.
The above is implemented in the bridge using the "locked" bridge port
option. When enabled, link-local frames (e.g., EAPOL) can be locally
received by the bridge, but all other frames are dropped unless the host
is authenticated. That is, unless the user space control plane installed
an FDB entry according to which the source address of the frame is
located behind the locked ingress port. The entry can be dynamic, in
which case learning needs to be enabled so that the entry will be
refreshed by incoming traffic.
There are deployments in which not all the devices connected to the
authenticator (the bridge) support 802.1X. Such devices can include
printers and cameras. One option to support such deployments is to
unlock the bridge ports connecting these devices, but a slightly more
secure option is to use MAB. When MAB is enabled, the MAC address of the
connected device is used as the user name and password for the
authentication.
For MAB to work, the user space control plane needs to be notified about
MAC addresses that are trying to gain access so that they will be
compared against an allow list. This can be implemented via the regular
learning process with the sole difference that learned FDB entries are
installed with a new "locked" flag indicating that the entry cannot be
used to authenticate the device. The flag cannot be set by user space,
but user space can clear the flag by replacing the entry, thereby
authenticating the device.
Locked FDB entries implement the following semantics with regards to
roaming, aging and forwarding:
1. Roaming: Locked FDB entries can roam to unlocked (authorized) ports,
in which case the "locked" flag is cleared. FDB entries cannot roam
to locked ports regardless of MAB being enabled or not. Therefore,
locked FDB entries are only created if an FDB entry with the given {MAC,
VID} does not already exist. This behavior prevents unauthenticated
devices from disrupting traffic destined to already authenticated
devices.
2. Aging: Locked FDB entries age and refresh by incoming traffic like
regular entries.
3. Forwarding: Locked FDB entries forward traffic like regular entries.
If user space detects an unauthorized MAC behind a locked port and
wishes to prevent traffic with this MAC DA from reaching the host, it
can do so using tc or a different mechanism.
Enable the above behavior using a new bridge port option called "mab".
It can only be enabled on a bridge port that is both locked and has
learning enabled. Locked FDB entries are flushed from the port once MAB
is disabled. A new option is added because there are pure 802.1X
deployments that are not interested in notifications about locked FDB
entries.
Signed-off-by: Hans J. Schultz <netdev@kapio-technology.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
It is possible to stack bridges on top of each other. Consider the
following which makes use of an Ethernet switch:
br1
/ \
/ \
/ \
br0.11 wlan0
|
br0
/ | \
p1 p2 p3
br0 is offloaded to the switch. Above br0 is a vlan interface, for
vlan 11. This vlan interface is then a slave of br1. br1 also has a
wireless interface as a slave. This setup trunks wireless lan traffic
over the copper network inside a VLAN.
A frame received on p1 which is passed up to the bridge has the
skb->offload_fwd_mark flag set to true, indicating that the switch has
dealt with forwarding the frame out ports p2 and p3 as needed. This
flag instructs the software bridge it does not need to pass the frame
back down again. However, the flag is not getting reset when the frame
is passed upwards. As a result br1 sees the flag, wrongly interprets
it, and fails to forward the frame to wlan0.
When passing a frame upwards, clear the flag. This is the Rx
equivalent of br_switchdev_frame_unmark() in br_dev_xmit().
Fixes: f1c2eddf4c ("bridge: switchdev: Use an helper to clear forward mark")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20220518005840.771575-1-andrew@lunn.ch
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Allow the user to switch from the current per-VLAN STP mode to an MST
mode.
Up to this point, per-VLAN STP states where always isolated from each
other. This is in contrast to the MSTP standard (802.1Q-2018, Clause
13.5), where VLANs are grouped into MST instances (MSTIs), and the
state is managed on a per-MSTI level, rather that at the per-VLAN
level.
Perhaps due to the prevalence of the standard, many switching ASICs
are built after the same model. Therefore, add a corresponding MST
mode to the bridge, which we can later add offloading support for in a
straight-forward way.
For now, all VLANs are fixed to MSTI 0, also called the Common
Spanning Tree (CST). That is, all VLANs will follow the port-global
state.
Upcoming changes will make this actually useful by allowing VLANs to
be mapped to arbitrary MSTIs and allow individual MSTI states to be
changed.
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In a 802.1X scenario, clients connected to a bridge port shall not
be allowed to have traffic forwarded until fully authenticated.
A static fdb entry of the clients MAC address for the bridge port
unlocks the client and allows bidirectional communication.
This scenario is facilitated with setting the bridge port in locked
mode, which is also supported by various switchcore chipsets.
Signed-off-by: Hans Schultz <schultz.hans+netdev@gmail.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
br_handle_ingress_vlan_tunnel() is only referenced in
br_handle_frame(). If br_handle_ingress_vlan_tunnel() is called and
return non-zero value, goto drop in br_handle_frame().
But, br_handle_ingress_vlan_tunnel() always return 0. So, the
routines that check the return value and goto drop has no meaning.
Therefore, change return type of br_handle_ingress_vlan_tunnel() to
void and remove if statement of br_handle_frame().
Signed-off-by: Kangmin Park <l4stpr0gr4m@gmail.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/r/20210823102118.17966-1-l4stpr0gr4m@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a global knob that controls if vlan multicast snooping is enabled.
The proper contexts (vlan or bridge-wide) will be chosen based on the knob
when processing packets and changing bridge device state. Note that
vlans have their individual mcast snooping enabled by default, but this
knob is needed to turn on bridge vlan snooping. It is disabled by
default. To enable the knob vlan filtering must also be enabled, it
doesn't make sense to have vlan mcast snooping without vlan filtering
since that would lead to inconsistencies. Disabling vlan filtering will
also automatically disable vlan mcast snooping.
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass multicast context pointers to multicast functions instead of bridge/port.
This would make it easier later to switch these contexts to their per-vlan
versions. The patch is basically search and replace, no functional changes.
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In preparation for the upcoming split of multicast router state into
their IPv4 and IPv6 variants make br_multicast_is_router() protocol
family aware.
Note that for now br_ip6_multicast_is_router() uses the currently still
common ip4_mc_router_timer for now. It will be renamed to
ip6_mc_router_timer later when the split is performed.
While at it also renames the "1" and "2" constants in
br_multicast_is_router() to the MDB_RTR_TYPE_TEMP_QUERY and
MDB_RTR_TYPE_PERM enums.
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: David S. Miller <davem@davemloft.net>
Extend the bridge multicast control and data path to configure routes
for L2 (non-IP) multicast groups.
The uapi struct br_mdb_entry union u is extended with another variant,
mac_addr, which does not change the structure size, and which is valid
when the proto field is zero.
To be compatible with the forwarding code that is already in place,
which acts as an IGMP/MLD snooping bridge with querier capabilities, we
need to declare that for L2 MDB entries (for which there exists no such
thing as IGMP/MLD snooping/querying), that there is always a querier.
Otherwise, these entries would be flooded to all bridge ports and not
just to those that are members of the L2 multicast group.
Needless to say, only permanent L2 multicast groups can be installed on
a bridge port.
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20201028233831.610076-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
