[TUHS] The evolution of Unix facilities and architecture

Dave Horsfall dave at horsfall.org
Sat May 13 10:26:12 AEST 2017


On Fri, 12 May 2017, Random832 wrote:

> > > 	if (xp->x_count!=1 || xp->x_iptr->i_mode&ISVTX)
> > > 		goto error;
> > 
> > Err, isn't that the sticky bit, not the setuid bit?
> 
> The sticky bit makes it keep the image in memory when there are no 
> processes using it. I assume x_count is determining whether there are 
> processes using it. So, taken together, these checks are "is there or 
> might there be in the future a process, other than the one being 
> debugged, using this exact copy of the image rather than loading it from 
> the disk".

I know that, but the discussion was about the SUID bit, and the ability to 
modify the in-core image of a set-uid program being run...

-- 
Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."


More information about the TUHS mailing list