Re: mmap to address zero with MAP_FIXED returns ENOPERM for non-root users?

[Eric Smith <eric@brouhaha.com>]

Kyle Moffett wrote:
 > This is a specific security feature designed to reduce the security
 > impact of a kernel NULL-pointer dereference.

Thanks for the explanation!

 > Since you're performing binary translation of a microcontroller, it
 > may be better to perform some kind of minimal memory-map translation
 > as a part of that.

That's exactly what I'd hoped to avoid, as it does result in a 
non-trivial performance hit.  I suppose I can make it a configuration 
option of my translator.

I'm curious, though.  How likely are exploits where I can trick the 
kernel into calling a function at 0 in my virtual address space, but not 
trick it into calling a function at some non-zero address of my choosing?

Best regards,
Eric