CVE request: kernel: irda: prevent integer underflow in IRLMP_ENUMDEVICES

[Eugene Teo <eugene () redhat com>]

From Dan Rosenbugs :>, "If the user-provided len is less than the 
expected offset, the IRLMP_ENUMDEVICES getsockopt will do a 
copy_to_user() with a very large size value.  While this isn't be a 
security issue on x86 because it will get caught by the access_ok() 
check, it may leak large amounts of kernel heap on other architectures. 
 In any event, this patch fixes it."

http://www.spinics.net/lists/netdev/msg150842.html

Thanks, Eugene2