linux/net/bridge, branch v6.3

net: bridge: switchdev: don't notify FDB entries with "master dynamic"

2023-04-20T07:20:14Z

There is a structural problem in switchdev, where the flag bits in struct switchdev_notifier_fdb_info (added_by_user, is_local etc) only represent a simplified / denatured view of what's in struct net_bridge_fdb_entry :: flags (BR_FDB_ADDED_BY_USER, BR_FDB_LOCAL etc). Each time we want to pass more information about struct net_bridge_fdb_entry :: flags to struct switchdev_notifier_fdb_info (here, BR_FDB_STATIC), we find that FDB entries were already notified to switchdev with no regard to this flag, and thus, switchdev drivers had no indication whether the notified entries were static or not. For example, this command: ip link add br0 type bridge && ip link set swp0 master br0 bridge fdb add dev swp0 00:01:02:03:04:05 master dynamic has never worked as intended with switchdev. It causes a struct net_bridge_fdb_entry to be passed to br_switchdev_fdb_notify() which has a single flag set: BR_FDB_ADDED_BY_USER. This is further passed to the switchdev notifier chain, where interested drivers have no choice but to assume this is a static (does not age) and sticky (does not migrate) FDB entry. So currently, all drivers offload it to hardware as such, as can be seen below ("offload" is set). bridge fdb get 00:01:02:03:04:05 dev swp0 master 00:01:02:03:04:05 dev swp0 offload master br0 The software FDB entry expires $ageing_time centiseconds after the kernel last sees a packet with this MAC SA, and the bridge notifies its deletion as well, so it eventually disappears from hardware too. This is a problem, because it is actually desirable to start offloading "master dynamic" FDB entries correctly - they should expire $ageing_time centiseconds after the *hardware* port last sees a packet with this MAC SA - and this is how the current incorrect behavior was discovered. With an offloaded data plane, it can be expected that software only sees exception path packets, so an otherwise active dynamic FDB entry would be aged out by software sooner than it should. With the change in place, these FDB entries are no longer offloaded: bridge fdb get 00:01:02:03:04:05 dev swp0 master 00:01:02:03:04:05 dev swp0 master br0 and this also constitutes a better way (assuming a backport to stable kernels) for user space to determine whether the kernel has the capability of doing something sane with these or not. As opposed to "master dynamic" FDB entries, on the current behavior of which no one currently depends on (which can be deduced from the lack of kselftests), Ido Schimmel explains that entries with the "extern_learn" flag (BR_FDB_ADDED_BY_EXT_LEARN) should still be notified to switchdev, since the spectrum driver listens to them (and this is kind of okay, because although they are treated identically to "static", they are expected to not age, and to roam). Fixes: 6b26b51b1d13 ("net: bridge: Add support for notifying devices about FDB add/del") Link: https://lore.kernel.org/netdev/20230327115206.jk5q5l753aoelwus@skbuf/ Signed-off-by: Vladimir Oltean Reviewed-by: Jesse Brandeburg Reviewed-by: Ido Schimmel Tested-by: Ido Schimmel Link: https://lore.kernel.org/r/20230418155902.898627-1-vladimir.oltean@nxp.com Signed-off-by: Paolo Abeni

netfilter: br_netfilter: fix recent physdev match breakage

2023-04-06T09:33:52Z

Recent attempt to ensure PREROUTING hook is executed again when a decrypted ipsec packet received on a bridge passes through the network stack a second time broke the physdev match in INPUT hook. We can't discard the nf_bridge info strct from sabotage_in hook, as this is needed by the physdev match. Keep the struct around and handle this with another conditional instead. Fixes: 2b272bb558f1 ("netfilter: br_netfilter: disable sabotage_in hook after first suppression") Reported-and-tested-by: Farid BENAMROUCHE Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

2023-02-23T05:25:23Z

Pablo Neira Ayuso says: ==================== Netfilter fixes for net 1) Fix broken listing of set elements when table has an owner. 2) Fix conntrack refcount leak in ctnetlink with related conntrack entries, from Hangyu Hua. 3) Fix use-after-free/double-free in ctnetlink conntrack insert path, from Florian Westphal. 4) Fix ip6t_rpfilter with VRF, from Phil Sutter. 5) Fix use-after-free in ebtables reported by syzbot, also from Florian. 6) Use skb->len in xt_length to deal with IPv6 jumbo packets, from Xin Long. 7) Fix NETLINK_LISTEN_ALL_NSID with ctnetlink, from Florian Westphal. 8) Fix memleak in {ip_,ip6_,arp_}tables in ENOMEM error case, from Pavel Tikhomirov. * git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf: netfilter: x_tables: fix percpu counter block leak on error path when creating new netns netfilter: ctnetlink: make event listener tracking global netfilter: xt_length: use skb len to match in length_mt6 netfilter: ebtables: fix table blob use-after-free netfilter: ip6t_rpfilter: Fix regression with VRF interfaces netfilter: conntrack: fix rmmod double-free race netfilter: ctnetlink: fix possible refcount leak in ctnetlink_create_conntrack() netfilter: nf_tables: allow to fetch set elements when table has an owner ==================== Link: https://lore.kernel.org/r/20230222092137.88637-1-pablo@netfilter.org Signed-off-by: Jakub Kicinski

netfilter: ebtables: fix table blob use-after-free

2023-02-21T23:22:31Z

We are not allowed to return an error at this point. Looking at the code it looks like ret is always 0 at this point, but its not. t = find_table_lock(net, repl->name, &ret, &ebt_mutex); ... this can return a valid table, with ret != 0. This bug causes update of table->private with the new blob, but then frees the blob right away in the caller. Syzbot report: BUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 Read of size 4 at addr ffffc90005425000 by task kworker/u4:4/74 Workqueue: netns cleanup_net Call Trace: kasan_report+0xbf/0x1f0 mm/kasan/report.c:517 __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613 ... ip(6)tables appears to be ok (ret should be 0 at this point) but make this more obvious. Fixes: c58dd2dd443c ("netfilter: Can't fail and free after table replacement") Reported-by: syzbot+f61594de72d6705aea03@syzkaller.appspotmail.com Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

net: bridge: make kobj_type structure constant

2023-02-15T04:48:08Z

Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.") the driver core allows the usage of const struct kobj_type. Take advantage of this to constify the structure definition to prevent modification at runtime. Signed-off-by: Thomas Weißschuh Acked-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski

bridge: mcast: Move validation to a policy

2023-02-11T03:21:13Z

Future patches are going to move parts of the bridge MDB code to the common rtnetlink code in preparation for VXLAN MDB support. To facilitate code sharing between both drivers, move the validation of the top level attributes in RTM_{NEW,DEL}MDB messages to a policy that will eventually be moved to the rtnetlink code. Use 'NLA_NESTED' for 'MDBA_SET_ENTRY_ATTRS' instead of NLA_POLICY_NESTED() as this attribute is going to be validated using different policies in the underlying drivers. Signed-off-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski

bridge: mcast: Remove pointless sequence generation counter assignment

2023-02-11T03:21:13Z

The purpose of the sequence generation counter in the netlink callback is to identify if a multipart dump is consistent or not by calling nl_dump_check_consistent() whenever a message is generated. The function is not invoked by the MDB code, rendering the sequence generation counter assignment pointless. Remove it. Note that even if the function was invoked, we still could not accurately determine if the dump is consistent or not, as there is no sequence generation counter for MDB entries, unlike nexthop objects, for example. Signed-off-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski

bridge: mcast: Use correct define in MDB dump

2023-02-11T03:21:13Z

'MDB_PG_FLAGS_PERMANENT' and 'MDB_PERMANENT' happen to have the same value, but the latter is uAPI and cannot change, so use it when dumping an MDB entry. Signed-off-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski

net: bridge: Add netlink knobs for number / maximum MDB entries

2023-02-06T08:48:26Z

The previous patch added accounting for number of MDB entries per port and per port-VLAN, and the logic to verify that these values stay within configured bounds. However it didn't provide means to actually configure those bounds or read the occupancy. This patch does that. Two new netlink attributes are added for the MDB occupancy: IFLA_BRPORT_MCAST_N_GROUPS for the per-port occupancy and BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS for the per-port-VLAN occupancy. And another two for the maximum number of MDB entries: IFLA_BRPORT_MCAST_MAX_GROUPS for the per-port maximum, and BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS for the per-port-VLAN one. Note that the two new IFLA_BRPORT_ attributes prompt bumping of RTNL_SLAVE_MAX_TYPE to size the slave attribute tables large enough. The new attributes are used like this: # ip link add name br up type bridge vlan_filtering 1 mcast_snooping 1 \ mcast_vlan_snooping 1 mcast_querier 1 # ip link set dev v1 master br # bridge vlan add dev v1 vid 2 # bridge vlan set dev v1 vid 1 mcast_max_groups 1 # bridge mdb add dev br port v1 grp 230.1.2.3 temp vid 1 # bridge mdb add dev br port v1 grp 230.1.2.4 temp vid 1 Error: bridge: Port-VLAN is already in 1 groups, and mcast_max_groups=1. # bridge link set dev v1 mcast_max_groups 1 # bridge mdb add dev br port v1 grp 230.1.2.3 temp vid 2 Error: bridge: Port is already in 1 groups, and mcast_max_groups=1. # bridge -d link show 5: v1@v2: mtu 1500 master br [...] [...] mcast_n_groups 1 mcast_max_groups 1 # bridge -d vlan show port vlan-id br 1 PVID Egress Untagged state forwarding mcast_router 1 v1 1 PVID Egress Untagged [...] mcast_n_groups 1 mcast_max_groups 1 2 [...] mcast_n_groups 0 mcast_max_groups 0 Signed-off-by: Petr Machata Acked-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller

net: bridge: Maintain number of MDB entries in net_bridge_mcast_port

2023-02-06T08:48:26Z

The MDB maintained by the bridge is limited. When the bridge is configured for IGMP / MLD snooping, a buggy or malicious client can easily exhaust its capacity. In SW datapath, the capacity is configurable through the IFLA_BR_MCAST_HASH_MAX parameter, but ultimately is finite. Obviously a similar limit exists in the HW datapath for purposes of offloading. In order to prevent the issue of unilateral exhaustion of MDB resources, introduce two parameters in each of two contexts: - Per-port and per-port-VLAN number of MDB entries that the port is member in. - Per-port and (when BROPT_MCAST_VLAN_SNOOPING_ENABLED is enabled) per-port-VLAN maximum permitted number of MDB entries, or 0 for no limit. The per-port multicast context is used for tracking of MDB entries for the port as a whole. This is available for all bridges. The per-port-VLAN multicast context is then only available on VLAN-filtering bridges on VLANs that have multicast snooping on. With these changes in place, it will be possible to configure MDB limit for bridge as a whole, or any one port as a whole, or any single port-VLAN. Note that unlike the global limit, exhaustion of the per-port and per-port-VLAN maximums does not cause disablement of multicast snooping. It is also permitted to configure the local limit larger than hash_max, even though that is not useful. In this patch, introduce only the accounting for number of entries, and the max field itself, but not the means to toggle the max. The next patch introduces the netlink APIs to toggle and read the values. Signed-off-by: Petr Machata Acked-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller