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: <20080129132304.GD2537@mea-ext.zmailer.org>
Date:	Tue, 29 Jan 2008 15:23:04 +0200
From:	Matti Aarnio <matti.aarnio@...iler.org>
To:	Yoav Artzi <yoavar@...ckpoint.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Sending IOCTLs from 32-bit userland to 64-bit Kernel module

On Tue, Jan 29, 2008 at 02:13:26PM +0200, Yoav Artzi wrote:
> Hi,
>
>
> I have a 32-bit user land application which sends an IOCTL to a 64-bit 
> Kernel module. I have a few different cmd codes that I can send through the 
> IOCTL. For some reason I seem to always get the same IOCTL cmd from user 
> land, no matter what the ioctl() call is given. This cmd code that I get 
> has some bytes (W/R and the module code) that are OK, but the rest is just 
> garbage or zeros. This was originally a 32-bit system, and we are no 
> converting the Kernel module to 64-bit, so maybe there's something special 
> for 32-64 communication that miss.

In x86_64 kernel there is an adaptation layer that translates 32-bit ioctl:s
to kernel internal 64-bit ones, when absolutely necessary.

If you do not need to pass pointers in your ioctl(), then typedef:in passed
parameters with explicite size may save you from lots of trouble:

   struct cpioctl {
        long     var;   /* definite trouble 32-bit vs. 64-bit */
        uint32_t var2;  /* no troubles... */
        uint64_t var3;
   };

After that, the only issue is that 32-bit user space ioctl() passes
a pointer that is valid in 32-bit space only, bit that is handled by
the common layer without need to make specific adaptation routine.

.. however if the structure has pointer to elsewere in memory, then
things get complicated really fast.


> I am working on Linux Kernel v2.6.18.
> Thanks
--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ