linux-kernel - Re: [patch 5/9] x86/ioport: Reduce ioperm impact for sane usage further

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]

Date:   Thu, 7 Nov 2019 11:13:57 +0100
From:   Willy Tarreau <w@....eu>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        the arch/x86 maintainers <x86@...nel.org>,
        Stephen Hemminger <stephen@...workplumber.org>,
        Juergen Gross <jgross@...e.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [patch 5/9] x86/ioport: Reduce ioperm impact for sane usage
 further

On Thu, Nov 07, 2019 at 11:00:27AM +0100, Thomas Gleixner wrote:
> Changing ioperm(single port, port range) to be ioperm(all) is going to
> break a bunch of test cases which actually check whether the permission is
> restricted to a single I/O port or the requested port range.

But out of curiosity, are these solely test cases or things that real
applications do ? We could imagine having a sysctl entry to indicate
whether or not we want strict compatibility with older code in which
case we'd take the slow path, or a modernized behavior using only the
fast path. If we managed to deal with mmap_min_addr over time, I think
it should be manageable to deal with the rare applications using ioperm().

Willy