linux-kernel - Re: [PATCH v2 32/33] s390: Implement the architecture-specific kmsan functions

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: <13e3e073f6ed6aa48b39ec16add85baa677d17b4.camel@linux.ibm.com>
Date:   Mon, 11 Dec 2023 11:39:47 +0100
From:   Ilya Leoshkevich <iii@...ux.ibm.com>
To:     Alexander Potapenko <glider@...gle.com>
Cc:     Alexander Gordeev <agordeev@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Christoph Lameter <cl@...ux.com>,
        David Rientjes <rientjes@...gle.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Marco Elver <elver@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Pekka Enberg <penberg@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Hyeonggon Yoo <42.hyeyoo@...il.com>,
        kasan-dev@...glegroups.com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linux-s390@...r.kernel.org,
        linux-trace-kernel@...r.kernel.org,
        Mark Rutland <mark.rutland@....com>,
        Roman Gushchin <roman.gushchin@...ux.dev>,
        Sven Schnelle <svens@...ux.ibm.com>
Subject: Re: [PATCH v2 32/33] s390: Implement the architecture-specific
 kmsan functions

On Mon, 2023-12-11 at 11:26 +0100, Alexander Potapenko wrote:
> > +static inline void *arch_kmsan_get_meta_or_null(void *addr, bool
> > is_origin)
> > +{
> > +       if (addr >= (void *)&S390_lowcore &&
> > +           addr < (void *)(&S390_lowcore + 1)) {
> > +               /*
> > +                * Different lowcores accessed via S390_lowcore are
> > described
> > +                * by the same struct page. Resolve the prefix
> > manually in
> > +                * order to get a distinct struct page.
> > +                */
> > +               addr += (void *)lowcore_ptr[raw_smp_processor_id()]
> > -
> > +                       (void *)&S390_lowcore;
> > +               return kmsan_get_metadata(addr, is_origin);
> > +       }
> > +       return NULL;
> > +}
> 
> Is there a possibility for infinite recursion here? E.g. can
> `lowcore_ptr[raw_smp_processor_id()]` point somewhere in between
> `(void *)&S390_lowcore` and `(void *)(&S390_lowcore + 1))`?

No, it's allocated with __get_free_pages() or memblock_alloc_low().
But since this question came up, I should probably add a check and
a WARN_ON_ONCE() here.