6.6-stable review patch. If anyone has any objections, please let me know.
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From: Nikolay Aleksandrov razor@blackwall.org
[ Upstream commit 36c92936e868601fa1f43da6758cf55805043509 ]
Pass the already obtained vlan group pointer to br_mst_vlan_set_state() instead of dereferencing it again. Each caller has already correctly dereferenced it for their context. This change is required for the following suspicious RCU dereference fix. No functional changes intended.
Fixes: 3a7c1661ae13 ("net: bridge: mst: fix vlan use-after-free") Reported-by: syzbot+9bbe2de1bc9d470eb5fe@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=9bbe2de1bc9d470eb5fe Signed-off-by: Nikolay Aleksandrov razor@blackwall.org Link: https://lore.kernel.org/r/20240609103654.914987-2-razor@blackwall.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/bridge/br_mst.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c index 3c66141d34d62..1de72816b0fb2 100644 --- a/net/bridge/br_mst.c +++ b/net/bridge/br_mst.c @@ -73,11 +73,10 @@ int br_mst_get_state(const struct net_device *dev, u16 msti, u8 *state) } EXPORT_SYMBOL_GPL(br_mst_get_state);
-static void br_mst_vlan_set_state(struct net_bridge_port *p, struct net_bridge_vlan *v, +static void br_mst_vlan_set_state(struct net_bridge_vlan_group *vg, + struct net_bridge_vlan *v, u8 state) { - struct net_bridge_vlan_group *vg = nbp_vlan_group(p); - if (br_vlan_get_state(v) == state) return;
@@ -121,7 +120,7 @@ int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state, if (v->brvlan->msti != msti) continue;
- br_mst_vlan_set_state(p, v, state); + br_mst_vlan_set_state(vg, v, state); }
out: @@ -140,13 +139,13 @@ static void br_mst_vlan_sync_state(struct net_bridge_vlan *pv, u16 msti) * it. */ if (v != pv && v->brvlan->msti == msti) { - br_mst_vlan_set_state(pv->port, pv, v->state); + br_mst_vlan_set_state(vg, pv, v->state); return; } }
/* Otherwise, start out in a new MSTI with all ports disabled. */ - return br_mst_vlan_set_state(pv->port, pv, BR_STATE_DISABLED); + return br_mst_vlan_set_state(vg, pv, BR_STATE_DISABLED); }
int br_mst_vlan_set_msti(struct net_bridge_vlan *mv, u16 msti)