Description of problem:
Struct ca is copied from userspace.  It is not checked whether the "device"
field is NULL terminated.  This potentially leads to BUG() inside of
alloc_netdev_mqs() and/or information leak by creating a device with a name
made of contents of kernel stack.

References:
http://seclists.org/oss-sec/2011/q1/309
https://lkml.org/lkml/2011/2/14/50

Acknowledgements:
                  
Red Hat would like to thank Vasiliy Kulikov of Openwall for reporting this issue.