linux-kernel - Re: [PATCH] vsprintf: Do not break early boot with probing addresses

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20190510050709.GA1831@jagdpanzerIV>
Date:   Fri, 10 May 2019 14:07:09 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Petr Mladek <pmladek@...e.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        "Tobin C . Harding" <me@...in.cc>, Michal Hocko <mhocko@...e.cz>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-kernel@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        linuxppc-dev@...ts.ozlabs.org, Russell Currey <ruscur@...sell.cc>,
        Christophe Leroy <christophe.leroy@....fr>,
        Stephen Rothwell <sfr@...abs.org>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        linux-arch@...r.kernel.org, linux-s390@...r.kernel.org,
        Martin Schwidefsky <schwidefsky@...ibm.com>
Subject: Re: [PATCH] vsprintf: Do not break early boot with probing addresses

On (05/09/19 21:47), Linus Torvalds wrote:
>    [ Sorry about html and mobile crud, I'm not at the computer right now ]
>    How about we just undo the whole misguided probe_kernel_address() thing?

But the problem will remain - %pS/%pF on PPC (and some other arch-s)
do dereference_function_descriptor(), which calls probe_kernel_address().
So if probe_kernel_address() starts to dump_stack(), then we are heading
towards stack overflow. Unless I'm totally missing something.

	-ss