[NET]: Don't implement dev_ifname32 inline

The current implementation of dev_ifname makes maintenance difficult
because updates to the implementation of the ioctl have to made in two
places.  So this patch updates dev_ifname32 to do a classic 32/64
structure conversion and call sys_ioctl like the rest of the
compat calls do.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 11 deletions

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 37310b0e8107..d917e4a26a43 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -324,22 +324,21 @@ struct ifconf32 {
 
 static int dev_ifname32(unsigned int fd, unsigned int cmd, unsigned long arg)
 {
-        struct net_device *dev;
-        struct ifreq32 ifr32;
+        struct ifreq __user *uifr;
         int err;
 
-        if (copy_from_user(&ifr32, compat_ptr(arg), sizeof(ifr32)))
+        uifr = compat_alloc_user_space(sizeof(struct ifreq));
+        if (copy_in_user(uifr, compat_ptr(arg), sizeof(struct ifreq32)));
                 return -EFAULT;
 
-        dev = dev_get_by_index(ifr32.ifr_ifindex);
-        if (!dev)
-                return -ENODEV;
+        err = sys_ioctl(fd, SIOCGIFNAME, (unsigned long)uifr);
+        if (err)
+                return err;
 
-        strlcpy(ifr32.ifr_name, dev->name, sizeof(ifr32.ifr_name));
-        dev_put(dev);
-        
-        err = copy_to_user(compat_ptr(arg), &ifr32, sizeof(ifr32));
-        return (err ? -EFAULT : 0);
+        if (copy_in_user(compat_ptr(arg), uifr, sizeof(struct ifreq32)))
+                return -EFAULT;
+
+        return 0;
 }
 
 static int dev_ifconf(unsigned int fd, unsigned int cmd, unsigned long arg)