linux-kernel - Re: [PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS and !pagefault

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: <CALCETrXRu2hZgZgQhzSv_Xf3CVKfM4hAg0rA5g=KDTG9wedbsw@mail.gmail.com>
Date:	Sun, 29 May 2016 09:52:26 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Andy Lutomirski <luto@...nel.org>, X86 ML <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Kees Cook <keescook@...omium.org>,
	Brian Gerst <brgerst@...il.com>
Subject: Re: [PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS
 and !pagefault_disabled()

On Wed, May 25, 2016 at 8:33 AM, Borislav Petkov <bp@...en8.de> wrote:
> On Tue, May 24, 2016 at 03:48:44PM -0700, Andy Lutomirski wrote:
>> +     if (unlikely(!is_user_ds && !pagefault_disabled())) {
>> +             if (extra < TASK_SIZE_MAX) {
>> +                     /*
>> +                      * Accessing user address under KERNEL_DS.  This is a
>> +                      * bug and should be fixed, but OOPSing is not helpful
>> +                      * for exploit mitigation.
>> +                      */
>> +                     WARN_ONCE(1, "BUG: uaccess fault at 0x%lx with KERNEL_DS\n",
>
>                         WARN and BUG?
>
> Also, let's have this string and the one below differ for finding out
> where we are during debugging.

Done.