linux-kernel - Re: [PATCH v7 5/6] x86/signal: Detect and prevent an alternate signal stack overflow

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: <CALCETrVRz8kvqxk2Xg5=c_0YWcgofXnqPb3uZRcca9pphE0sHg@mail.gmail.com>
Date:   Thu, 25 Mar 2021 21:58:54 -0700
From:   Andy Lutomirski <luto@...nel.org>
To:     Andy Lutomirski <luto@...nel.org>
Cc:     Andrew Cooper <andrew.cooper3@...rix.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Borislav Petkov <bp@...e.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>, X86 ML <x86@...nel.org>,
        Len Brown <len.brown@...el.com>,
        Dave Hansen <dave.hansen@...el.com>,
        "H. J. Lu" <hjl.tools@...il.com>,
        Dave Martin <Dave.Martin@....com>,
        Jann Horn <jannh@...gle.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        "Carlos O'Donell" <carlos@...hat.com>,
        Tony Luck <tony.luck@...el.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        libc-alpha <libc-alpha@...rceware.org>,
        linux-arch <linux-arch@...r.kernel.org>,
        Linux API <linux-api@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "Bae, Chang Seok" <chang.seok.bae@...el.com>
Subject: Re: [PATCH v7 5/6] x86/signal: Detect and prevent an alternate signal
 stack overflow

I forgot to mention why I cc'd all you fine Xen folk:

On Thu, Mar 25, 2021 at 11:13 AM Andy Lutomirski <luto@...nel.org> wrote:

>
> >         } else if (IS_ENABLED(CONFIG_X86_32) &&
> >                    !onsigstack &&
> >                    regs->ss != __USER_DS &&

This bit here seems really dubious on Xen PV.  Honestly it seems
dubious everywhere, but especially on Xen PV.

--Andy