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 <herbert@gondor.apana.org.au>
Cheers,
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index f1887ba..3c86f05 100644
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -544,18 +544,27 @@
}
-int br_set_forward_delay(struct net_bridge *br, unsigned long val)
+void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
{
- unsigned long t = clock_t_to_jiffies(val);
-
- if (br->stp_enabled != BR_NO_STP &&
- (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
- return -ERANGE;
-
- spin_lock_bh(&br->lock);
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))
+ goto unlock;
+
+ __br_set_forward_delay(br, t);
+ err = 0;
+
+unlock:
spin_unlock_bh(&br->lock);
- return 0;
+ return err;
}