From: Florian Weimer <fweimer@redhat.com>
To: Rich Felker <dalias@libc.org>
Cc: Joshua Hudson <joshudson@gmail.com>, musl@lists.openwall.com
Subject: Re: Re: posix_spawn
Date: Tue, 01 Oct 2019 09:05:18 +0200 [thread overview]
Message-ID: <87pnjhvtch.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <20191001025543.GB16318@brightrain.aerifal.cx> (Rich Felker's message of "Mon, 30 Sep 2019 22:55:43 -0400")
* Rich Felker:
> This is not safe and creates a false sense that something broken might
> work. Moreover it's a vulnerability to use it this way. You have a
> window where different tasks sharing VM space are executing with
> different privilege levels, and thereby one is able to seize execution
> of the other and achieve its privilege level.
That's a non-sequitur. A shared address space does not necessarily mean
that execution under one set of credentials will have unrestricted
effects on executions under different credentials within the same
address space. If the executions themselves are constrained, this can
be completely safe. It is true that if there is one unconstrained
execution in an address space, then the whole thing is tainted, but that
this isn't the relevant scenario for things like file servers (which do
not execute code on behalf of clients).
I don't know where you got this idea, but it is wrong. I'm sorry.
next prev parent reply other threads:[~2019-10-01 7:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-30 21:15 posix_spawn Joshua Hudson
2019-09-30 22:36 ` posix_spawn Rich Felker
2019-10-01 1:58 ` Joshua Hudson
2019-10-01 2:21 ` Rich Felker
2019-10-01 2:41 ` Joshua Hudson
2019-10-01 2:55 ` Rich Felker
2019-10-01 7:05 ` Florian Weimer [this message]
2019-10-01 11:42 ` Rich Felker
2019-10-01 14:07 ` posix_spawn Joshua Hudson
2019-10-01 14:15 ` posix_spawn Florian Weimer
2019-10-01 14:44 ` posix_spawn Rich Felker
2019-10-01 15:06 ` Rich Felker
2019-10-16 12:40 ` Florian Weimer
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