linux-kernel - Re: compat

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: <200704262337.56240.arnd@arndb.de>
Date:	Thu, 26 Apr 2007 23:37:55 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Paul Fulghum <paulkf@...rogate.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: compat_ioctl question

On Thursday 26 April 2007, Paul Fulghum wrote:
> I need to add ioctl translations for my driver to
> allow 32 bit access on 64 bit systems.
> 
> After digging through the kernel code there seems to be
> 3 methods of doing this:
> 
> 1. define compat_ioctl() file operation for device and
>     implement translation code in individual driver
> 2. add COMPATIBLE_IOCTL entry to include/linux/compat_ioctl.h
>     to mark an ioctl code as the same in any environment
> 3. add HANDLE_IOCTL entry to fs/compat_ioctl.c with translation code
>     implemented in the same file
> 
> There is no way to implement #1 for a tty driver without
> modifying the kernel tty code to allow registration of a
> compat_ioctl() handler.
> 
> #3 would put a lot of driver specific stuff in a common
> kernel file. This method also seems to break if there
> is an ioctl code collision.
> 
> All of these methods involve changes to code outside of my driver.
> 
> --
> 
> Before I spend a lot of time on this I need to know what the
> officially sanctioned method is. I haven't found any definitive
> documentation and a review of mailing list archives does not
> suggest a prevailing opinion.
> 
> Does anyone have pointers on which way would be most likely
> to be accepted as a patch?

It depends a lot on what your specific driver does in the ioctl
handler, but normally you should define a compat_ioctl() function.
What driver are you talking about?

	Arnd <><
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/