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Re: PATCH: proc_do_stop and rpctrace

From: Ognyan Kulev
Subject: Re: PATCH: proc_do_stop and rpctrace
Date: Sat, 16 Aug 2003 11:16:57 +0300
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030714 Debian/1.4-2

Marcus Brinkmann wrote:
On Sat, Aug 09, 2003 at 05:33:29PM -0400, Roland McGrath wrote:
The concern I have about this patch per se is proc calling thread_resume on
a random port from the user.  This is at least a DoS opportunity.  It also
points to a more general problem rpctrace has--servers make comparisons
between ports from the user (rpctrace) and ports outside rpctrace's sphere
of interposition.  I bet "rpctrace ln foo bar" (dir_link) gets EXDEV too.

Shall I revert the patch?

proc also uses the task port given by rpctrace. So one can write a program that passes fake task port to proc, and when proc tries to handle the fake process in some way, the whole proc server will hang because it is single-threaded. Isn't it principally like the thread_resume case?

Ognyan Kulev <ogi@{fmi.uni-sofia.bg,fsa-bg.org}>
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