wireless: wext: terminate ifr name coming from userspace

ifr name is assumed to be a valid string by the kernel, but nothing
was forcing username to pass a valid string.

In turn, this would cause panics as we tried to access the string
past it's valid memory.

Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 82fd4c9c4a1bf491f094a17c774c3e611c483690..7657ad6bc13d14e16f1775824d229ce8337c21c0 100644 (file)
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -424,6 +424,8 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
                if (copy_from_user(&iwr, arg, sizeof(iwr)))
                        return -EFAULT;
 
+               iwr.ifr_name[sizeof(iwr.ifr_name) - 1] = 0;
+
                return wext_handle_ioctl(net, &iwr, cmd, arg);
        }