linux-kernel - Re: [RFC] Warn the user when they could overflow mapcount

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180208185648.GB9524@bombadil.infradead.org>
Date:   Thu, 8 Feb 2018 10:56:48 -0800
From:   Matthew Wilcox <willy@...radead.org>
To:     Daniel Micay <danielmicay@...il.com>
Cc:     Jann Horn <jannh@...gle.com>, linux-mm@...ck.org,
        Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        kernel list <linux-kernel@...r.kernel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [RFC] Warn the user when they could overflow mapcount

On Thu, Feb 08, 2018 at 01:05:33PM -0500, Daniel Micay wrote:
> The standard map_max_count / pid_max are very low and there are many
> situations where either or both need to be raised.

[snip good reasons]

> I do think the default value in the documentation should be fixed but
> if there's a clear problem with raising these it really needs to be
> fixed. Google either of the sysctl names and look at all the people
> running into issues and needing to raise them. It's only going to
> become more common to raise these with people trying to use lots of
> fine-grained sandboxing. Process-per-request is back in style.

So we should make the count saturate instead, then?  That's going to
be interesting.