target/linux/generic/backport-5.15/773-v5.18-2-net-dsa-Avoid-cross-chip-syncing-of-VLAN-filtering.patch

   1 From 108dc8741c203e9d6ce4e973367f1bac20c7192b Mon Sep 17 00:00:00 2001
   2 From: Tobias Waldekranz <tobias@waldekranz.com>
   3 Date: Mon, 24 Jan 2022 22:09:44 +0100
   4 Subject: net: dsa: Avoid cross-chip syncing of VLAN filtering
   5
   6 Changes to VLAN filtering are not applicable to cross-chip
   7 notifications.
   8
   9 On a system like this:
  10
  11 .-----.   .-----.   .-----.
  12 | sw1 +---+ sw2 +---+ sw3 |
  13 '-1-2-'   '-1-2-'   '-1-2-'
  14
  15 Before this change, upon sw1p1 leaving a bridge, a call to
  16 dsa_port_vlan_filtering would also be made to sw2p1 and sw3p1.
  17
  18 In this scenario:
  19
  20 .---------.   .-----.   .-----.
  21 |   sw1   +---+ sw2 +---+ sw3 |
  22 '-1-2-3-4-'   '-1-2-'   '-1-2-'
  23
  24 When sw1p4 would leave a bridge, dsa_port_vlan_filtering would be
  25 called for sw2 and sw3 with a non-existing port - leading to array
  26 out-of-bounds accesses and crashes on mv88e6xxx.
  27
  28 Fixes: d371b7c92d19 ("net: dsa: Unset vlan_filtering when ports leave the bridge")
  29 Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
  30 Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
  31 Signed-off-by: David S. Miller <davem@davemloft.net>
  32 ---
  33  net/dsa/switch.c | 8 +++++---
  34  1 file changed, 5 insertions(+), 3 deletions(-)
  35
  36 --- a/net/dsa/switch.c
  37 +++ b/net/dsa/switch.c
  38 @@ -180,9 +180,11 @@ static int dsa_switch_bridge_leave(struc
  39                                                 info->sw_index, info->port,
  40                                                 info->br);
  41
  42 -       err = dsa_switch_sync_vlan_filtering(ds, info);
  43 -       if (err)
  44 -               return err;
  45 +       if (ds->dst->index == info->tree_index && ds->index == info->sw_index) {
  46 +               err = dsa_switch_sync_vlan_filtering(ds, info);
  47 +               if (err)
  48 +                       return err;
  49 +       }
  50
  51         return dsa_tag_8021q_bridge_leave(ds, info);
  52  }