I know very little about how Linux works internally, and I use proprietary video card drivers in Ubuntu. Given Linux's internal handling of driver binaries, how much damage would these be able to cause if they contained malicious code?
Quite a bit - not total kernel access, given the GPL symbol table export restrictions, but at least as much as a process running as root in user space.
That said, it's quite likely that such malicious behavior would be detected by somebody.
