diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2013-09-12 17:12:05 +1000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-09-12 23:32:14 -0400 |
| commit | be4f154d5ef0ca147ab6bcd38857a774133f5450 (patch) | |
| tree | a0d1f8c90c823bbecebaf30a02e2b5ad79c97944 | |
| parent | 9a0620133ccce9dd35c00a96405c8d80938c2cc0 (diff) | |
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>
| -rw-r--r-- | net/bridge/br_private.h | 1 | ||||
| -rw-r--r-- | net/bridge/br_stp.c | 21 | ||||
| -rw-r--r-- | net/bridge/br_stp_if.c | 12 |
3 files changed, 26 insertions, 8 deletions
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 598cb0b333c..cda83158a21 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -746,6 +746,7 @@ extern struct net_bridge_port *br_get_port(struct net_bridge *br, extern void br_init_port(struct net_bridge_port *p); extern void br_become_designated_port(struct net_bridge_port *p); +extern void __br_set_forward_delay(struct net_bridge *br, unsigned long t); extern int br_set_forward_delay(struct net_bridge *br, unsigned long x); extern int br_set_hello_time(struct net_bridge *br, unsigned long x); extern int br_set_max_age(struct net_bridge *br, unsigned long x); diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c index f1887ba7fc4..3c86f0538cb 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; } diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c index d45e760141b..108084a0467 100644 --- a/net/bridge/br_stp_if.c +++ b/net/bridge/br_stp_if.c @@ -129,6 +129,14 @@ static void br_stp_start(struct net_bridge *br) char *envp[] = { NULL }; r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); + + spin_lock_bh(&br->lock); + + if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY) + __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY); + else if (br->bridge_forward_delay < BR_MAX_FORWARD_DELAY) + __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY); + if (r == 0) { br->stp_enabled = BR_USER_STP; br_debug(br, "userspace STP started\n"); @@ -137,10 +145,10 @@ static void br_stp_start(struct net_bridge *br) br_debug(br, "using kernel STP\n"); /* To start timers on any ports left in blocking */ - spin_lock_bh(&br->lock); br_port_state_selection(br); - spin_unlock_bh(&br->lock); } + + spin_unlock_bh(&br->lock); } static void br_stp_stop(struct net_bridge *br) |