linux.git/net/bridge, branch v5.12.5

net: bridge: fix error in br_multicast_add_port when CONFIG_NET_SWITCHDEV=n

2021-05-19T08:56:45+00:00

commit 68f5c12abbc9b6f8c5eea16c62f8b7be70793163 upstream.

When CONFIG_NET_SWITCHDEV is disabled, the shim for switchdev_port_attr_set
inside br_mc_disabled_update returns -EOPNOTSUPP. This is not caught,
and propagated to the caller of br_multicast_add_port, preventing ports
from joining the bridge.

Reported-by: Christian Borntraeger 
Fixes: ae1ea84b33da ("net: bridge: propagate error code and extack from br_mc_disabled_update")
Signed-off-by: Vladimir Oltean 
Acked-by: Florian Fainelli 
Tested-by: Christian Borntraeger 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: bridge: propagate error code and extack from br_mc_disabled_update

2021-05-19T08:56:16+00:00

[ Upstream commit ae1ea84b33dab45c7b6c1754231ebda5959b504c ]

Some Ethernet switches might only be able to support disabling multicast
snooping globally, which is an issue for example when several bridges
span the same physical device and request contradictory settings.

Propagate the return value of br_mc_disabled_update() such that this
limitation is transmitted correctly to user-space.

Signed-off-by: Florian Fainelli 
Signed-off-by: Vladimir Oltean 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: bridge: when suppression is enabled exclude RARP packets

2021-05-19T08:56:12+00:00

[ Upstream commit 0353b4a96b7a9f60fe20d1b3ebd4931a4085f91c ]

Recently we had an interop issue where RARP packets got suppressed with
bridge neigh suppression enabled, but the check in the code was meant to
suppress GARP. Exclude RARP packets from it which would allow some VMWare
setups to work, to quote the report:
"Those RARP packets usually get generated by vMware to notify physical
switches when vMotion occurs. vMware may use random sip/tip or just use
sip=tip=0. So the RARP packet sometimes get properly flooded by the vtep
and other times get dropped by the logic"

Reported-by: Amer Abdalamer 
Signed-off-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: bridge: mcast: fix broken length + header check for MRDv6 Adv.

2021-05-14T08:53:05+00:00

[ Upstream commit 99014088156cd78867d19514a0bc771c4b86b93b ]

The IPv6 Multicast Router Advertisements parsing has the following two
issues:

For one thing, ICMPv6 MRD Advertisements are smaller than ICMPv6 MLD
messages (ICMPv6 MRD Adv.: 8 bytes vs. ICMPv6 MLDv1/2: >= 24 bytes,
assuming MLDv2 Reports with at least one multicast address entry).
When ipv6_mc_check_mld_msg() tries to parse an Multicast Router
Advertisement its MLD length check will fail - and it will wrongly
return -EINVAL, even if we have a valid MRD Advertisement. With the
returned -EINVAL the bridge code will assume a broken packet and will
wrongly discard it, potentially leading to multicast packet loss towards
multicast routers.

The second issue is the MRD header parsing in
br_ip6_multicast_mrd_rcv(): It wrongly checks for an ICMPv6 header
immediately after the IPv6 header (IPv6 next header type). However
according to RFC4286, section 2 all MRD messages contain a Router Alert
option (just like MLD). So instead there is an IPv6 Hop-by-Hop option
for the Router Alert between the IPv6 and ICMPv6 header, again leading
to the bridge wrongly discarding Multicast Router Advertisements.

To fix these two issues, introduce a new return value -ENODATA to
ipv6_mc_check_mld() to indicate a valid ICMPv6 packet with a hop-by-hop
option which is not an MLD but potentially an MRD packet. This also
simplifies further parsing in the bridge code, as ipv6_mc_check_mld()
already fully checks the ICMPv6 header and hop-by-hop option.

These issues were found and fixed with the help of the mrdisc tool
(https://github.com/troglobit/mrdisc).

Fixes: 4b3087c7e37f ("bridge: Snoop Multicast Router Advertisements")
Signed-off-by: Linus Lüssing 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

netfilter: bridge: add pre_exit hooks for ebtable unregistration

2021-04-10T19:16:54+00:00

Just like ip/ip6/arptables, the hooks have to be removed, then
synchronize_rcu() has to be called to make sure no more packets are being
processed before the ruleset data is released.

Place the hook unregistration in the pre_exit hook, then call the new
ebtables pre_exit function from there.

Years ago, when first netns support got added for netfilter+ebtables,
this used an older (now removed) netfilter hook unregister API, that did
a unconditional synchronize_rcu().

Now that all is done with call_rcu, ebtable_{filter,nat,broute} pernet exit
handlers may free the ebtable ruleset while packets are still in flight.

This can only happens on module removal, not during netns exit.

The new function expects the table name, not the table struct.

This is because upcoming patch set (targeting -next) will remove all
net->xt.{nat,filter,broute}_table instances, this makes it necessary
to avoid external references to those member variables.

The existing APIs will be converted, so follow the upcoming scheme of
passing name + hook type instead.

Fixes: aee12a0a3727e ("ebtables: remove nf_hook_register usage")
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

net: bridge: don't notify switchdev for local FDB addresses

2021-03-23T21:39:41+00:00

As explained in this discussion:
https://lore.kernel.org/netdev/20210117193009.io3nungdwuzmo5f7@skbuf/

the switchdev notifiers for FDB entries managed to have a zero-day bug.
The bridge would not say that this entry is local:

ip link add br0 type bridge
ip link set swp0 master br0
bridge fdb add dev swp0 00:01:02:03:04:05 master local

and the switchdev driver would be more than happy to offload it as a
normal static FDB entry. This is despite the fact that 'local' and
non-'local' entries have completely opposite directions: a local entry
is locally terminated and not forwarded, whereas a static entry is
forwarded and not locally terminated. So, for example, DSA would install
this entry on swp0 instead of installing it on the CPU port as it should.

There is an even sadder part, which is that the 'local' flag is implicit
if 'static' is not specified, meaning that this command produces the
same result of adding a 'local' entry:

bridge fdb add dev swp0 00:01:02:03:04:05 master

I've updated the man pages for 'bridge', and after reading it now, it
should be pretty clear to any user that the commands above were broken
and should have never resulted in the 00:01:02:03:04:05 address being
forwarded (this behavior is coherent with non-switchdev interfaces):
https://patchwork.kernel.org/project/netdevbpf/cover/20210211104502.2081443-1-olteanv@gmail.com/
If you're a user reading this and this is what you want, just use:

bridge fdb add dev swp0 00:01:02:03:04:05 master static

Because switchdev should have given drivers the means from day one to
classify FDB entries as local/non-local, but didn't, it means that all
drivers are currently broken. So we can just as well omit the switchdev
notifications for local FDB entries, which is exactly what this patch
does to close the bug in stable trees. For further development work
where drivers might want to trap the local FDB entries to the host, we
can add a 'bool is_local' to br_switchdev_fdb_call_notifiers(), and
selectively make drivers act upon that bit, while all the others ignore
those entries if the 'is_local' bit is set.

Fixes: 6b26b51b1d13 ("net: bridge: Add support for notifying devices about FDB add/del")
Signed-off-by: Vladimir Oltean 
Signed-off-by: David S. Miller

bridge: mrp: Update br_mrp to use new return values of br_mrp_switchdev

2021-02-16T22:47:46+00:00

Check the return values of the br_mrp_switchdev function.
In case of:
- BR_MRP_NONE, return the error to userspace,
- BR_MRP_SW, continue with SW implementation,
- BR_MRP_HW, continue without SW implementation,

Signed-off-by: Horatiu Vultur 
Signed-off-by: David S. Miller

bridge: mrp: Extend br_mrp_switchdev to detect better the errors

2021-02-16T22:47:46+00:00

This patch extends the br_mrp_switchdev functions to be able to have a
better understanding what cause the issue and if the SW needs to be used
as a backup.

There are the following cases:
- when the code is compiled without CONFIG_NET_SWITCHDEV. In this case
  return success so the SW can continue with the protocol. Depending
  on the function, it returns 0 or BR_MRP_SW.
- when code is compiled with CONFIG_NET_SWITCHDEV and the driver doesn't
  implement any MRP callbacks. In this case the HW can't run MRP so it
  just returns -EOPNOTSUPP. So the SW will stop further to configure the
  node.
- when code is compiled with CONFIG_NET_SWITCHDEV and the driver fully
  supports any MRP functionality. In this case the SW doesn't need to do
  anything. The functions will return 0 or BR_MRP_HW.
- when code is compiled with CONFIG_NET_SWITCHDEV and the HW can't run
  completely the protocol but it can help the SW to run it. For
  example, the HW can't support completely MRM role(can't detect when it
  stops receiving MRP Test frames) but it can redirect these frames to
  CPU. In this case it is possible to have a SW fallback. The SW will
  try initially to call the driver with sw_backup set to false, meaning
  that the HW should implement completely the role. If the driver returns
  -EOPNOTSUPP, the SW will try again with sw_backup set to false,
  meaning that the SW will detect when it stops receiving the frames but
  it needs HW support to redirect the frames to CPU. In case the driver
  returns 0 then the SW will continue to configure the node accordingly.

Signed-off-by: Horatiu Vultur 
Signed-off-by: David S. Miller

bridge: mrp: Add 'enum br_mrp_hw_support'

2021-02-16T22:47:46+00:00

Add the enum br_mrp_hw_support that is used by the br_mrp_switchdev
functions to allow the SW to detect the cases where HW can't implement
the functionality or when SW is used as a backup.

Signed-off-by: Horatiu Vultur 
Signed-off-by: David S. Miller

net: bridge: fix br_vlan_filter_toggle stub when CONFIG_BRIDGE_VLAN_FILTERING=n

2021-02-15T21:15:10+00:00

The prototype of br_vlan_filter_toggle was updated to include a netlink
extack, but the stub definition wasn't, which results in a build error
when CONFIG_BRIDGE_VLAN_FILTERING=n.

Fixes: 9e781401cbfc ("net: bridge: propagate extack through store_bridge_parm")
Signed-off-by: Vladimir Oltean 
Signed-off-by: David S. Miller