Description of problem:
Struct tmp is copied from userspace.  It is not checked whether the "name"
field is NULL terminated.  This may lead to buffer overflow and passing
contents of kernel stack as a module name to try_then_request_module() and,
consequently, to modprobe commandline.  It would be seen by all userspace
processes.

References:
http://seclists.org/oss-sec/2011/q1/309
https://lkml.org/lkml/2011/2/14/51

Acknowledgements:                                                                

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