linux-kernel - Re: [PATCH 14/21] x86/xen: Support objtool vmlinux.o validation in xen-head.S

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: <20210115194601.dkilnfkp6xnhai22@treble>
Date:   Fri, 15 Jan 2021 13:46:01 -0600
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Jürgen Groß <jgross@...e.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Sedat Dilek <sedat.dilek@...il.com>,
        Kees Cook <keescook@...omium.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        clang-built-linux@...glegroups.com,
        Miroslav Benes <mbenes@...e.cz>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: Re: [PATCH 14/21] x86/xen: Support objtool vmlinux.o validation in
 xen-head.S

On Fri, Jan 15, 2021 at 06:17:25AM +0100, Jürgen Groß wrote:
> On 14.01.21 20:40, Josh Poimboeuf wrote:
> > The Xen hypercall page is filled with zeros, causing objtool to fall
> > through all the empty hypercall functions until it reaches a real
> > function, resulting in a stack state mismatch.
> > 
> > The build-time contents of the hypercall page don't matter, since it
> > gets mapped to the hypervisor.
> 
> This sentence is technically wrong: the contents don't matter, as the
> page will be rewritten by the hypervisor.

Thanks, updated for v2.

-- 
Josh