linux-kernel - Re: SELinux mprotect EACCES/execheap for memory segment directly adjacent to heap

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Date:   Thu, 14 Dec 2023 12:12:43 +0100
From:   Ondrej Mosnacek <omosnace@...hat.com>
To:     Bagas Sanjaya <bagasdotme@...il.com>
Cc:     SELinux Mailing List <selinux@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Paul Moore <paul@...l-moore.com>,
        David Hildenbrand <david@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Stephen Smalley <stephen.smalley.work@...il.com>,
        Eric Paris <eparis@...isplace.org>,
        Ilija Tovilo <ilija.tovilo@...com>
Subject: Re: SELinux mprotect EACCES/execheap for memory segment directly
 adjacent to heap

On Thu, Dec 14, 2023 at 12:00 PM Bagas Sanjaya <bagasdotme@...il.com> wrote:
>
> Hi all,
>
> I forward a Bugzilla report [1]. As you may know, many developers don't
> take a look on Bugzilla (especially linux-kernel@...nel-bugs.kernel.org
> as no one subscribes to the generic component).
>
> The original reporter (Ilija Tovilo) writes:
>
> > Hi! We're running into an issue with SELinux where mprotect will result in a EACCES due to the execheap policy since Kernel 6.6. This happens when the mmap-ed segment lies directly adjacent to the heap. I think this is caused by the following patch:
> >
> > https://github.com/torvalds/linux/commit/68df1baf158fddc07b6f0333e4c81fe1ccecd6ff
<snip the details>

Hi,

this already has a fix pending in the mm tree:
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?h=mm-hotfixes-stable&id=d3bb89ea9c13e5a98d2b7a0ba8e50a77893132cb

More context:
https://lore.kernel.org/selinux/CAFqZXNv0SVT0fkOK6neP9AXbj3nxJ61JAY4+zJzvxqJaeuhbFw@mail.gmail.com/
https://lore.kernel.org/all/20231207152525.2607420-1-wangkefeng.wang@huawei.com/T/

-- 
Ondrej Mosnacek
Senior Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.