[NET]: Fix race when opening a proc file while a network namespace is exiting.

[firefly-linux-kernel-4.4.55.git] / fs / compat_ioctl.c

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 37310b0e81076caf3d5e5970530c3b1325e9e7aa..d917e4a26a433f43f27e50a5f5e0a537583ff73c 100644 (file)
--- 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)