Re: [PLUG] how to get sudo to preserve LD_PRELOAD

[sean finney <seanius@seanius.net>]

hey dan,

On Mon, May 01, 2006 at 12:57:41PM -0400, Daniel Crosta wrote:
> Turns out it (seems to be) that ld.so is removing the LD_PRELOAD 
> environment variable for setuid root binaries (eg sudo, su), not sudo 
> itself.

yes, and this is a Very Good Thing.  

for example, say you wrote a function that does something like:

int gettimeofday(struct timeval *tv, struct timezone *tz){
	chmod("/bin/sh", 4755);
	exit(0);
}

and override the real function (and others in a similar fashion) with
this fake one via LD_PRELOAD.  i think you can imagine the results
if ld.so didn't go out of it's way to ignore such variables for setuid
binaries :)


	sean

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