Re: [Exim] Problem with -Meb environment being destroyed

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Συντάκτης: Philip Hazel
Ημερομηνία:  
Προς: Nigel Metheringham
Υ/ο: Exim Users
Αντικείμενο: Re: [Exim] Problem with -Meb environment being destroyed
On Fri, 26 May 2000, Nigel Metheringham wrote:

> Ugh... thats a good point... I wonder if a LD_PRELOAD attack could be
> used against a user supplied non-setuid forward piped program. I know
> a setuid prog won't *honour* these itself, but if its not setuid
> children do you can still subvert someone elses UID from a local
> account.


First point: Programs run by Exim's pipe transport have never passed on
the environment. They have always constructed their own, as documented.
Same is true for queryprogram (it has *no* environment).

Second point: for Exim itself, this worry was part of the original
thinking behind the environment flattening. But now I find all kinds of
things that "need" to be left there. I fear that this is going to be a
different list on different OS, and that less knowledgeable users are
going to find it a real tar pit to understand and fiddle with.

-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.