This is a note to let you know that I've just added the patch titled
bridge: Clamp forward_delay when enabling STP
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bridge-clamp-forward_delay-when-enabling-stp.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 37b78fb1b1ea0971526422429a9dff4960b51055 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Date: Thu, 12 Sep 2013 17:12:05 +1000
Subject: bridge: Clamp forward_delay when enabling STP
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
[ Upstream commit be4f154d5ef0ca147ab6bcd38857a774133f5450 ]
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@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/bridge/br_private.h | 1 +
net/bridge/br_stp.c | 21 +++++++++++++++------
net/bridge/br_stp_if.c | 12 ++++++++++--
3 files changed, 26 insertions(+), 8 deletions(-)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -492,6 +492,7 @@ extern struct net_bridge_port *br_get_po
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);
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -517,18 +517,27 @@ int br_set_max_age(struct net_bridge *br
}
+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;
}
--- a/net/bridge/br_stp_if.c
+++ b/net/bridge/br_stp_if.c
@@ -126,6 +126,14 @@ static void br_stp_start(struct net_brid
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");
@@ -134,10 +142,10 @@ static void br_stp_start(struct net_brid
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)
Patches currently in stable-queue which might be from herbert@xxxxxxxxxxxxxxxxxxx are
queue-3.0/bridge-clamp-forward_delay-when-enabling-stp.patch
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