From be4f154d5ef0ca147ab6bcd38857a774133f5450 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 12 Sep 2013 17:12:05 +1000 Subject: bridge: Clamp forward_delay when enabling STP At some point limits were added to forward_delay. However, the limits are only enforced when STP is enabled. This created a scenario where you could have a value outside the allowed range while STP is disabled, which then stuck around even after STP is enabled. This patch fixes this by clamping the value when we enable STP. I had to move the locking around a bit to ensure that there is no window where someone could insert a value outside the range while we're in the middle of enabling STP. Signed-off-by: Herbert Xu Cheers, Signed-off-by: David S. Miller --- net/bridge/br_stp.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) (limited to 'net/bridge/br_stp.c') diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c index f1887ba7fc43..3c86f0538cbb 100644 --- a/net/bridge/br_stp.c +++ b/net/bridge/br_stp.c @@ -544,18 +544,27 @@ int br_set_max_age(struct net_bridge *br, unsigned long val) } +void __br_set_forward_delay(struct net_bridge *br, unsigned long t) +{ + br->bridge_forward_delay = t; + if (br_is_root_bridge(br)) + br->forward_delay = br->bridge_forward_delay; +} + int br_set_forward_delay(struct net_bridge *br, unsigned long val) { unsigned long t = clock_t_to_jiffies(val); + int err = -ERANGE; + spin_lock_bh(&br->lock); if (br->stp_enabled != BR_NO_STP && (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY)) - return -ERANGE; + goto unlock; - spin_lock_bh(&br->lock); - br->bridge_forward_delay = t; - if (br_is_root_bridge(br)) - br->forward_delay = br->bridge_forward_delay; + __br_set_forward_delay(br, t); + err = 0; + +unlock: spin_unlock_bh(&br->lock); - return 0; + return err; } -- cgit v1.2.3