diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2014-12-16 16:04:56 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-12-16 19:19:41 +0300 |
| commit | 39ec7de7092ba9789f211d112a66bd19d4cb5d36 (patch) | |
| tree | dfa9725a4c54e900c9a60999f29b0f65b72f96fd /drivers/net/macvtap.c | |
| parent | c286bbaf4f56958db2591146145e248c7b9021c5 (diff) | |
| download | linux-39ec7de7092ba9789f211d112a66bd19d4cb5d36.tar.xz | |
macvtap: fix uninitialized access on TUNSETIFF
flags field in ifreq is only 16 bit wide, but
we read it as a 32 bit value.
If userspace doesn't zero-initialize unused fields,
this will lead to failures.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/macvtap.c')
| -rw-r--r-- | drivers/net/macvtap.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 60f7ee5fafbe..80fdb82352fa 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -999,7 +999,7 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, void __user *argp = (void __user *)arg; struct ifreq __user *ifr = argp; unsigned int __user *up = argp; - unsigned int u; + unsigned short u; int __user *sp = argp; int s; int ret; @@ -1014,7 +1014,7 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP)) ret = -EINVAL; else - q->flags = u; + q->flags = (q->flags & ~MACVTAP_FEATURES) | u; return ret; @@ -1027,8 +1027,9 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, } ret = 0; + u = q->flags; if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || - put_user(q->flags, &ifr->ifr_flags)) + put_user(u, &ifr->ifr_flags)) ret = -EFAULT; macvtap_put_vlan(vlan); rtnl_unlock(); |