From b74a072d8fb71d3c9ffba4a17d5943e63266fb38 Mon Sep 17 00:00:00 2001 From: Ruoyu Wang Date: Fri, 14 Aug 2026 21:40:53 +0800 Subject: [PATCH] net: bridge: Reject descending VLAN tunnel ranges A pair of descending VLAN and tunnel IDs can pass the tunnel range span check. The VLAN subtraction produces a negative int, which is converted to unsigned when compared with the u32 tunnel ID subtraction. It can therefore equal the wrapped tunnel ID delta. The range loop then performs no iterations. Since the batched notification handling added a post-loop error check, this leaves err uninitialized and makes the request's return value unpredictable. Reject descending VLAN ranges before comparing the spans. Valid ascending and single-entry ranges remain unchanged, while malformed descending ranges consistently return -EINVAL. This issue was found by a static analysis checker and confirmed by manual source review. Fixes: 94339443686b ("net: bridge: notify on vlan tunnel changes done via the old api") Signed-off-by: Ruoyu Wang Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260814134053.1387275-1-ruoyuw560@gmail.com Signed-off-by: David S. Miller Signed-off-by: Jakub Kicinski --- net/bridge/br_netlink_tunnel.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/bridge/br_netlink_tunnel.c b/net/bridge/br_netlink_tunnel.c index a713668ea34f..e7eceab5b515 100644 --- a/net/bridge/br_netlink_tunnel.c +++ b/net/bridge/br_netlink_tunnel.c @@ -302,7 +302,8 @@ int br_process_vlan_tunnel_info(const struct net_bridge *br, if (!(tinfo_last->flags & BRIDGE_VLAN_INFO_RANGE_BEGIN)) return -EINVAL; - if ((tinfo_curr->vid - tinfo_last->vid) != + if (tinfo_curr->vid < tinfo_last->vid || + (tinfo_curr->vid - tinfo_last->vid) != (tinfo_curr->tunid - tinfo_last->tunid)) return -EINVAL; t = tinfo_last->tunid;