linux-kernel - [PATCH 5.8 116/124] net: bridge: fdb: dont flush ext

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20201012133152.464287592@linuxfoundation.org>
Date:   Mon, 12 Oct 2020 15:32:00 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Nikolay Aleksandrov <nikolay@...dia.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 5.8 116/124] net: bridge: fdb: dont flush ext_learn entries

From: Nikolay Aleksandrov <nikolay@...dia.com>

commit f2f3729fb65c5c2e6db234e6316b71a7bdc4b30b upstream.

When a user-space software manages fdb entries externally it should
set the ext_learn flag which marks the fdb entry as externally managed
and avoids expiring it (they're treated as static fdbs). Unfortunately
on events where fdb entries are flushed (STP down, netlink fdb flush
etc) these fdbs are also deleted automatically by the bridge. That in turn
causes trouble for the managing user-space software (e.g. in MLAG setups
we lose remote fdb entries on port flaps).
These entries are completely externally managed so we should avoid
automatically deleting them, the only exception are offloaded entries
(i.e. BR_FDB_ADDED_BY_EXT_LEARN + BR_FDB_OFFLOADED). They are flushed as
before.

Fixes: eb100e0e24a2 ("net: bridge: allow to add externally learned entries from user-space")
Signed-off-by: Nikolay Aleksandrov <nikolay@...dia.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 net/bridge/br_fdb.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -404,6 +404,8 @@ void br_fdb_delete_by_port(struct net_br

 		if (!do_all)
 			if (test_bit(BR_FDB_STATIC, &f->flags) ||
+			    (test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &f->flags) &&
+			     !test_bit(BR_FDB_OFFLOADED, &f->flags)) ||
 			    (vid && f->key.vlan_id != vid))
 				continue;