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authorThomas Gleixner <tglx@linutronix.de>2016-12-11 18:31:22 +0100
committerDavid S. Miller <davem@davemloft.net>2016-12-16 13:25:06 -0500
commite28ceeb10cd1883a4b6528c17a2b1f2024e35cad (patch)
tree19b7812558e8fbef8247ed8c4dbee9ad0ca89fee
parent3e1ed981b7a903ba81199d4d25b80c6bba705160 (diff)
downloadlinux-e28ceeb10cd1883a4b6528c17a2b1f2024e35cad.tar.bz2
net/3com/3c515: Fix timer handling, prevent leaks and crashes
The timer handling in this driver is broken in several ways: - corkscrew_open() initializes and arms a timer before requesting the device interrupt. If the request fails the timer stays armed. A second call to corkscrew_open will unconditionally reinitialize the quued timer and arm it again. Also a immediate device removal will leave the timer queued because close() is not called (open() failed) and therefore nothing issues del_timer(). The reinitialization corrupts the link chain in the timer wheel hash bucket and causes a NULL pointer dereference when the timer wheel tries to operate on that hash bucket. Immediate device removal lets the link chain poke into freed and possibly reused memory. Solution: Arm the timer after the successful irq request. - corkscrew_close() uses del_timer() On close the timer is disarmed with del_timer() which lets the following code race against a concurrent timer expiry function. Solution: Use del_timer_sync() instead - corkscrew_close() calls del_timer() unconditionally del_timer() is invoked even if the timer was never initialized. This works by chance because the struct containing the timer is zeroed at allocation time. Solution: Move the setup of the timer into corkscrew_setup(). Reported-by: Matthew Whitehead <tedheadster@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ethernet/3com/3c515.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/net/ethernet/3com/3c515.c b/drivers/net/ethernet/3com/3c515.c
index b9f4c463e516..be5b80103bec 100644
--- a/drivers/net/ethernet/3com/3c515.c
+++ b/drivers/net/ethernet/3com/3c515.c
@@ -627,6 +627,8 @@ static int corkscrew_setup(struct net_device *dev, int ioaddr,
spin_lock_init(&vp->lock);
+ setup_timer(&vp->timer, corkscrew_timer, (unsigned long) dev);
+
/* Read the station address from the EEPROM. */
EL3WINDOW(0);
for (i = 0; i < 0x18; i++) {
@@ -707,6 +709,7 @@ static int corkscrew_open(struct net_device *dev)
{
int ioaddr = dev->base_addr;
struct corkscrew_private *vp = netdev_priv(dev);
+ bool armtimer = false;
__u32 config;
int i;
@@ -731,12 +734,7 @@ static int corkscrew_open(struct net_device *dev)
if (corkscrew_debug > 1)
pr_debug("%s: Initial media type %s.\n",
dev->name, media_tbl[dev->if_port].name);
-
- init_timer(&vp->timer);
- vp->timer.expires = jiffies + media_tbl[dev->if_port].wait;
- vp->timer.data = (unsigned long) dev;
- vp->timer.function = corkscrew_timer; /* timer handler */
- add_timer(&vp->timer);
+ armtimer = true;
} else
dev->if_port = vp->default_media;
@@ -776,6 +774,9 @@ static int corkscrew_open(struct net_device *dev)
return -EAGAIN;
}
+ if (armtimer)
+ mod_timer(&vp->timer, jiffies + media_tbl[dev->if_port].wait);
+
if (corkscrew_debug > 1) {
EL3WINDOW(4);
pr_debug("%s: corkscrew_open() irq %d media status %4.4x.\n",
@@ -1426,7 +1427,7 @@ static int corkscrew_close(struct net_device *dev)
dev->name, rx_nocopy, rx_copy, queued_packet);
}
- del_timer(&vp->timer);
+ del_timer_sync(&vp->timer);
/* Turn off statistics ASAP. We update lp->stats below. */
outw(StatsDisable, ioaddr + EL3_CMD);