From: Markus Wichmann <nullplan@gmx.net>
To: musl@lists.openwall.com
Subject: Re: [musl] SIGSEGV with TEXTREL
Date: Fri, 25 Sep 2020 22:49:37 +0200 [thread overview]
Message-ID: <20200925204937.GB7997@voyager> (raw)
In-Reply-To: <7318ee2c-17f5-99a9-12e4-622fe94cbfe2@gmail.com>
On Fri, Sep 25, 2020 at 04:13:19PM -0400, Dominic Chen wrote:
> On 9/25/2020 2:58 PM, Rich Felker wrote:
> > large code model, (2) all security policies have to be
> > turned off that prevent exec+write mappings for this to
> > work at all which is not acceptable in many environments.
>
> I don't see how (2) applies. Both glibc and the previous patch only
> remap text segments writable during relocation processing, and then
> remap them back read-only immediately afterwards. If you're referring to
> W^X, text segments don't need to be executable during relocation
> processing either, so that can be avoided.
>
Some security mechanisms prevent mapping anything executable that has
ever been writable. I believe SELinux can be set up this way, but I am
not sure. Of course, this interferes with some interpreters, since it
essentially prevents dynamic recompilation, but that is a specific use
case users of SELinux might be willing to sacrifice.
Ciao,
Markus
next prev parent reply other threads:[~2020-09-25 20:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-25 3:50 Dominic Chen
2020-09-25 9:37 ` Szabolcs Nagy
2020-09-25 18:58 ` Rich Felker
2020-09-25 20:13 ` Dominic Chen
2020-09-25 20:49 ` Markus Wichmann [this message]
2020-09-25 22:46 ` Rich Felker
2020-09-26 0:32 ` Dominic Chen
2020-09-26 4:14 ` Fangrui Song
2020-09-26 9:09 ` Szabolcs Nagy
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