There is no defined mechanism to pass network namespace information into /sbin/bridge-stp therefore don't even try to invoke it except for bridge devices in the initial network namespace. It is possible for unprivileged users to cause /sbin/bridge-stp to be invoked for any network device name which if /sbin/bridge-stp does not guard against unreasonable arguments or being invoked twice on the same network device could cause problems. Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> --- net/bridge/br_stp_if.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c index 5396ff08af32..742fa89528ab 100644 --- a/net/bridge/br_stp_if.c +++ b/net/bridge/br_stp_if.c @@ -142,7 +142,9 @@ static void br_stp_start(struct net_bridge *br) char *envp[] = { NULL }; struct net_bridge_port *p; - r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); + r = -ENOENT; + if (dev_net(br->dev) == &init_net) + r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); spin_lock_bh(&br->lock); -- 2.2.1