Commit d9d52832 authored by Jiri Bohac's avatar Jiri Bohac Committed by David S. Miller
Browse files

bonding: fix a race condition in calls to slave MII ioctls



In mii monitor mode, bond_check_dev_link() calls the the ioctl
handler of slave devices. It stores the ndo_do_ioctl function
pointer to a static (!) ioctl variable and later uses it to call the
handler with the IOCTL macro.

If another thread executes bond_check_dev_link() at the same time
(even with a different bond, which none of the locks prevent), a
race condition occurs. If the two racing slaves have different
drivers, this may result in one driver's ioctl handler being
called with a pointer to a net_device controlled with a different
driver, resulting in unpredictable breakage.

Unless I am overlooking something, the "static" must be a
copy'n'paste error (?).
Signed-off-by: default avatarJiri Bohac <jbohac@suse.cz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 03f191ba
......@@ -691,7 +691,7 @@ static int bond_check_dev_link(struct bonding *bond,
struct net_device *slave_dev, int reporting)
{
const struct net_device_ops *slave_ops = slave_dev->netdev_ops;
static int (*ioctl)(struct net_device *, struct ifreq *, int);
int (*ioctl)(struct net_device *, struct ifreq *, int);
struct ifreq ifr;
struct mii_ioctl_data *mii;
......
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