linux-kernel - Re: [PATCH v2 02/17] vdso: Clean header inclusion in getrandom

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: <51adbe91-3c3a-4baa-bb39-29df98a6eea5@csgroup.eu>
Date: Mon, 26 Aug 2024 12:45:40 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: "Jason A. Donenfeld" <Jason@...c4.com>
Cc: Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin
 <npiggin@...il.com>, Naveen N Rao <naveen@...nel.org>,
 Andy Lutomirski <luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
 Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
 Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
 "H. Peter Anvin" <hpa@...or.com>, Theodore Ts'o <tytso@....edu>,
 Arnd Bergmann <arnd@...db.de>, Andrew Morton <akpm@...ux-foundation.org>,
 Steven Rostedt <rostedt@...dmis.org>, Masami Hiramatsu
 <mhiramat@...nel.org>, Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 Vincenzo Frascino <vincenzo.frascino@....com>, Shuah Khan
 <shuah@...nel.org>, linuxppc-dev@...ts.ozlabs.org,
 linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
 linux-arch@...r.kernel.org, linux-mm@...ck.org,
 linux-trace-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v2 02/17] vdso: Clean header inclusion in getrandom

Le 26/08/2024 à 10:58, Jason A. Donenfeld a écrit :
> On Mon, Aug 26, 2024 at 10:37:49AM +0200, Christophe Leroy wrote:
>>
>>
>> Le 26/08/2024 à 10:07, Jason A. Donenfeld a écrit :
>>> On Thu, Aug 22, 2024 at 09:13:10AM +0200, Christophe Leroy wrote:
>>>>    
>>>> +#define _PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
>>>> +#define _PAGE_MASK (~(_PAGE_SIZE - 1))
>>>
>>> If PAGE_SIZE isn't defined at this point, why not just call it PAGE_SIZE
>>> instead of _PAGE_SIZE? But if that's the case, why not put the vdso
>>> definition of PAGE_SIZE into some vdso header included by this file?
>>
>> It was working ok on powerpc but on x86 I got:
> 
> Seems like there might be some more fiddling to do, then? Or did you
> conclude it's impossible?

Maybe someone who knows x86 in details could helps but after a first 
look I gave up because it looks very x86 specific, indeed that's 
x86/asm/vdso/gettimeofday.h that pulls several x86/asm/ headers , and 
the same type of issue might arise for any new architecture coming in.

For me it looked cleaner to just do as commit cffaefd15a8f ("vdso: Use 
CONFIG_PAGE_SHIFT in vdso/datapage.h") and not use PAGE_SIZE at all. But 
I didn't want to directly use (1UL << CONFIG_PAGE_SHIFT) and (~(1UL << 
(CONFIG_PAGE_SHIFT - 1))) in the code directly hence the new macros with 
a leading underscore to avoid any conflict with existing macros.

Christophe