@@ -3459,6 +3459,28 @@ static int bond_xmit_hash_policy_l34(struct sk_buff *skb, int count)
/*-------------------------- Device entry points ----------------------------*/
+static void bond_work_init_all(struct bonding *bond)
+{
+ INIT_DELAYED_WORK(&bond->mcast_work,
+ bond_resend_igmp_join_requests_delayed);
+ INIT_DELAYED_WORK(&bond->alb_work, bond_alb_monitor);
+ INIT_DELAYED_WORK(&bond->mii_work, bond_mii_monitor);
+ if (bond->params.mode == BOND_MODE_ACTIVEBACKUP)
+ INIT_DELAYED_WORK(&bond->arp_work, bond_activebackup_arp_mon);
+ else
+ INIT_DELAYED_WORK(&bond->arp_work, bond_loadbalance_arp_mon);
+ INIT_DELAYED_WORK(&bond->ad_work, bond_3ad_state_machine_handler);
+}
+
+static void bond_work_cancel_all(struct bonding *bond)
+{
+ cancel_delayed_work_sync(&bond->mii_work);
+ cancel_delayed_work_sync(&bond->arp_work);
+ cancel_delayed_work_sync(&bond->alb_work);
+ cancel_delayed_work_sync(&bond->ad_work);
+ cancel_delayed_work_sync(&bond->mcast_work);
+}
+
static int bond_open(struct net_device *bond_dev)
{
struct bonding *bond = netdev_priv(bond_dev);
@@ -3481,41 +3503,27 @@ static int bond_open(struct net_device *bond_dev)
}
read_unlock(&bond->lock);
- INIT_DELAYED_WORK(&bond->mcast_work, bond_resend_igmp_join_requests_delayed);
+ bond_work_init_all(bond);
if (bond_is_lb(bond)) {
/* bond_alb_initialize must be called before the timer
* is started.
*/
- if (bond_alb_initialize(bond, (bond->params.mode == BOND_MODE_ALB))) {
- /* something went wrong - fail the open operation */
+ if (bond_alb_initialize(bond, (bond->params.mode == BOND_MODE_ALB)))
return -ENOMEM;
- }
-
- INIT_DELAYED_WORK(&bond->alb_work, bond_alb_monitor);
queue_delayed_work(bond->wq, &bond->alb_work, 0);
}
- if (bond->params.miimon) { /* link check interval, in milliseconds. */
- INIT_DELAYED_WORK(&bond->mii_work, bond_mii_monitor);
+ if (bond->params.miimon) /* link check interval, in milliseconds. */
queue_delayed_work(bond->wq, &bond->mii_work, 0);
- }
if (bond->params.arp_interval) { /* arp interval, in milliseconds. */
- if (bond->params.mode == BOND_MODE_ACTIVEBACKUP)
- INIT_DELAYED_WORK(&bond->arp_work,
- bond_activebackup_arp_mon);
- else
- INIT_DELAYED_WORK(&bond->arp_work,
- bond_loadbalance_arp_mon);
-
queue_delayed_work(bond->wq, &bond->arp_work, 0);
if (bond->params.arp_validate)
bond->recv_probe = bond_arp_rcv;
}
if (bond->params.mode == BOND_MODE_8023AD) {
- INIT_DELAYED_WORK(&bond->ad_work, bond_3ad_state_machine_handler);
queue_delayed_work(bond->wq, &bond->ad_work, 0);
/* register to receive LACPDUs */
bond->recv_probe = bond_3ad_lacpdu_recv;
@@ -3530,34 +3538,10 @@ static int bond_close(struct net_device *bond_dev)
struct bonding *bond = netdev_priv(bond_dev);
write_lock_bh(&bond->lock);
-
bond->send_peer_notif = 0;
-
write_unlock_bh(&bond->lock);
- if (bond->params.miimon) { /* link check interval, in milliseconds. */
- cancel_delayed_work_sync(&bond->mii_work);
- }
-
- if (bond->params.arp_interval) { /* arp interval, in milliseconds. */
- cancel_delayed_work_sync(&bond->arp_work);
- }
-
- switch (bond->params.mode) {
- case BOND_MODE_8023AD:
- cancel_delayed_work_sync(&bond->ad_work);
- break;
- case BOND_MODE_TLB:
- case BOND_MODE_ALB:
- cancel_delayed_work_sync(&bond->alb_work);
- break;
- default:
- break;
- }
-
- if (delayed_work_pending(&bond->mcast_work))
- cancel_delayed_work_sync(&bond->mcast_work);
-
+ bond_work_cancel_all(bond);
if (bond_is_lb(bond)) {
/* Must be called only after all
* slaves have been released
@@ -4436,26 +4420,6 @@ static void bond_setup(struct net_device *bond_dev)
bond_dev->features |= bond_dev->hw_features;
}
-static void bond_work_cancel_all(struct bonding *bond)
-{
- if (bond->params.miimon && delayed_work_pending(&bond->mii_work))
- cancel_delayed_work_sync(&bond->mii_work);
-
- if (bond->params.arp_interval && delayed_work_pending(&bond->arp_work))
- cancel_delayed_work_sync(&bond->arp_work);
-
- if (bond->params.mode == BOND_MODE_ALB &&
- delayed_work_pending(&bond->alb_work))
- cancel_delayed_work_sync(&bond->alb_work);
-
- if (bond->params.mode == BOND_MODE_8023AD &&
- delayed_work_pending(&bond->ad_work))
- cancel_delayed_work_sync(&bond->ad_work);
-
- if (delayed_work_pending(&bond->mcast_work))
- cancel_delayed_work_sync(&bond->mcast_work);
-}
-
/*
* Destroy a bonding device.
* Must be under rtnl_lock when this function is called.
@@ -4706,12 +4670,14 @@ static int bond_check_params(struct bond_params *params)
arp_ip_count++) {
/* not complete check, but should be good enough to
catch mistakes */
- if (!isdigit(arp_ip_target[arp_ip_count][0])) {
+ __be32 ip = in_aton(arp_ip_target[arp_ip_count]);
+ if (!isdigit(arp_ip_target[arp_ip_count][0])
+ || ip == 0
+ || ip == htonl(INADDR_BROADCAST)) {
pr_warning("Warning: bad arp_ip_target module parameter (%s), ARP monitoring will not be performed\n",
arp_ip_target[arp_ip_count]);
arp_interval = 0;
} else {
- __be32 ip = in_aton(arp_ip_target[arp_ip_count]);
arp_target[arp_ip_count] = ip;
}
}
@@ -513,6 +513,8 @@ static ssize_t bonding_store_arp_interval(struct device *d,
int new_value, ret = count;
struct bonding *bond = to_bond(d);
+ if (!rtnl_trylock())
+ return restart_syscall();
if (sscanf(buf, "%d", &new_value) != 1) {
pr_err("%s: no arp_interval value specified.\n",
bond->dev->name);
@@ -539,10 +541,6 @@ static ssize_t bonding_store_arp_interval(struct device *d,
pr_info("%s: ARP monitoring cannot be used with MII monitoring. %s Disabling MII monitoring.\n",
bond->dev->name, bond->dev->name);
bond->params.miimon = 0;
- if (delayed_work_pending(&bond->mii_work)) {
- cancel_delayed_work(&bond->mii_work);
- flush_workqueue(bond->wq);
- }
}
if (!bond->params.arp_targets[0]) {
pr_info("%s: ARP monitoring has been set up, but no ARP targets have been specified.\n",
@@ -554,19 +552,12 @@ static ssize_t bonding_store_arp_interval(struct device *d,
* timer will get fired off when the open function
* is called.
*/
- if (!delayed_work_pending(&bond->arp_work)) {
- if (bond->params.mode == BOND_MODE_ACTIVEBACKUP)
- INIT_DELAYED_WORK(&bond->arp_work,
- bond_activebackup_arp_mon);
- else
- INIT_DELAYED_WORK(&bond->arp_work,
- bond_loadbalance_arp_mon);
-
- queue_delayed_work(bond->wq, &bond->arp_work, 0);
- }
+ cancel_delayed_work_sync(&bond->mii_work);
+ queue_delayed_work(bond->wq, &bond->arp_work, 0);
}
out:
+ rtnl_unlock();
return ret;
}
static DEVICE_ATTR(arp_interval, S_IRUGO | S_IWUSR,
@@ -962,6 +953,8 @@ static ssize_t bonding_store_miimon(struct device *d,
int new_value, ret = count;
struct bonding *bond = to_bond(d);
+ if (!rtnl_trylock())
+ return restart_syscall();
if (sscanf(buf, "%d", &new_value) != 1) {
pr_err("%s: no miimon value specified.\n",
bond->dev->name);
@@ -993,10 +986,6 @@ static ssize_t bonding_store_miimon(struct device *d,
bond->params.arp_validate =
BOND_ARP_VALIDATE_NONE;
}
- if (delayed_work_pending(&bond->arp_work)) {
- cancel_delayed_work(&bond->arp_work);
- flush_workqueue(bond->wq);
- }
}
if (bond->dev->flags & IFF_UP) {
@@ -1005,15 +994,12 @@ static ssize_t bonding_store_miimon(struct device *d,
* timer will get fired off when the open function
* is called.
*/
- if (!delayed_work_pending(&bond->mii_work)) {
- INIT_DELAYED_WORK(&bond->mii_work,
- bond_mii_monitor);
- queue_delayed_work(bond->wq,
- &bond->mii_work, 0);
- }
+ cancel_delayed_work_sync(&bond->arp_work);
+ queue_delayed_work(bond->wq, &bond->mii_work, 0);
}
}
out:
+ rtnl_unlock();
return ret;
}
static DEVICE_ATTR(miimon, S_IRUGO | S_IWUSR,
@@ -1582,6 +1568,7 @@ static ssize_t bonding_store_slaves_active(struct device *d,
goto out;
}
+ read_lock(&bond->lock);
bond_for_each_slave(bond, slave, i) {
if (!bond_is_active_slave(slave)) {
if (new_value)
@@ -1590,6 +1577,7 @@ static ssize_t bonding_store_slaves_active(struct device *d,
slave->inactive = 1;
}
}
+ read_unlock(&bond->lock);
out:
return ret;
}
This patch aims to fix multiple race conditions, missing module parameter checks and workqueue usage. First I would give three observations which will be used later. Observation 1: if (delayed_work_pending(wq)) cancel_delayed_work(wq) This usage is wrong because the pending bit is cleared just before the work's fn is executed and if the function re-arms itself we might end up with the work still running. It is safe to call cancel_delayed_work_sync() even if the work is not queued at all. Observation 2: Use of INIT_DELAYED_WORK() Work needs to be initialized only once prior to (de/en)queueing. Observation 3: IFF_UPP is set only after ndo_open is called Bugs: 1. Race between bonding_store_miimon() and bonding_store_arp_interval() Because of Obs.1 we can end up having both works enqueued. 2. Multiple races with INIT_DELAYED_WORK() Since the works are not protected by anything between INIT_DELAYED_WORK() and calls to (en/de)queue it is possible for races between the following functions: (races are also possible between calls to INIT_DELAYED_WORK() and workqueue code) bonding_store_miimon() - bonding_store_arp_interval(), bond_close(), bond_open(), enqueued functions bonding_store_arp_interval() - bonding_store_miimon(), bond_close(), bond_open(), enqueued functions 3. Race between bonding_store_slaves_active() and slave manipulation functions The bond_for_each_slave use in bonding_store_slaves_active() is not protected by any synchronization mechanisms. NULL pointer dereference is easy to reach. 4. By Obs.1 we need to change bond_cancel_all() 5. The module can be loaded with arp_ip_target="255.255.255.255" which makes it impossible to remove as the function in sysfs checks for that value, so we make the argument checks consistent with sysfs. Bugs 1 and 2 are fixed by moving all work initializations in bond_open which by Obs. 2 and Obs. 3 and the fact that we make sure that all works are cancelled in bond_close(), is guaranteed not to have any work enqueued. Also RTNL lock is now acquired in bonding_store_miimon/arp_interval so they can't race with bond_close and bond_open. The opposing work is cancelled only if the IFF_UPP flag is set and it is cancelled unconditionally. The opposing work is already cancelled if the interface is down so no need to cancel it again. This way we don't need new synchronizations for the bonding workqueue. Bug 3 is fixed by acquiring the read_lock for the slave walk. Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com> --- drivers/net/bonding/bond_main.c | 94 +++++++++++++--------------------------- drivers/net/bonding/bond_sysfs.c | 36 +++++---------- 2 files changed, 42 insertions(+), 88 deletions(-)