linux-kernel - Re: [PATCH 4/4] refcount: Report failures through CHECK_DATA

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: <CAGXu5jLvpq6B80aN44JCOfHrov5LKX1_9r4aWb7LNM7pAW_SEQ@mail.gmail.com>
Date:   Sun, 5 Feb 2017 15:33:36 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     "Reshetova, Elena" <elena.reshetova@...el.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        "H. Peter Anvin" <h.peter.anvin@...el.com>,
        Will Deacon <will.deacon@....com>,
        David Windsor <dwindsor@...il.com>,
        Hans Liljestrand <ishkamiel@...il.com>,
        David Howells <dhowells@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>,
        "kernel-hardening@...ts.openwall.com" 
        <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH 4/4] refcount: Report failures through CHECK_DATA_CORRUPTION

On Sun, Feb 5, 2017 at 7:40 AM, Peter Zijlstra <peterz@...radead.org> wrote:
> On Fri, Feb 03, 2017 at 03:26:52PM -0800, Kees Cook wrote:
>> This converts from WARN_ON() to CHECK_DATA_CORRUPTION() in the
>> CONFIG_DEBUG_REFCOUNT case. Additionally moves refcount_t sanity check
>> conditionals into regular function flow. Since CHECK_DATA_CORRUPTION()
>> is marked __much_check, we override few cases where the failure has
>> already been handled but we want to explicitly report it.
>>
>> Signed-off-by: Kees Cook <keescook@...omium.org>
>> ---
>>  include/linux/refcount.h | 35 ++++++++++++++++++++++-------------
>>  lib/Kconfig.debug        |  2 ++
>>  2 files changed, 24 insertions(+), 13 deletions(-)
>>
>> diff --git a/include/linux/refcount.h b/include/linux/refcount.h
>> index 5b89cad62237..ef32910c7dd8 100644
>> --- a/include/linux/refcount.h
>> +++ b/include/linux/refcount.h
>> @@ -43,10 +43,10 @@
>>  #include <linux/spinlock.h>
>>
>>  #if CONFIG_DEBUG_REFCOUNT
>> -#define REFCOUNT_WARN(cond, str) WARN_ON(cond)
>> +#define REFCOUNT_CHECK(cond, str) CHECK_DATA_CORRUPTION(cond, str)
>
> OK, so that goes back to a full WARN() which will make the generated
> code gigantic due to the whole printk() trainwreck :/

Hrm, perhaps we need three levels? WARN_ON, WARN, and BUG?

-Kees

-- 
Kees Cook
Pixel Security