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: <20180417155407.49c981b3@windsurf.numericable.fr>
Date:   Tue, 17 Apr 2018 15:54:07 +0200
From:   Thomas Petazzoni <thomas.petazzoni@...tlin.com>
To:     Jacopo Mondi <jacopo+renesas@...ndi.org>
Cc:     ysato@...rs.sourceforge.jp, dalias@...c.org,
        thomas.petazzoni@...e-electrons.com, robin.murphy@....com,
        geert@...ux-m68k.org, linux-renesas-soc@...r.kernel.org,
        linux-sh@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] sh: mm: Fix unprotected access to struct device

Hello,

On Tue, 17 Apr 2018 15:35:23 +0200, Jacopo Mondi wrote:
> With commit ce88313069c36eef80f21fd7 ("arch/sh: make the DMA mapping
> operations observe dev->dma_pfn_offset") the generic DMA allocation
> function on which the SH 'dma_alloc_coherent()' function relies on,
> access the 'dma_pfn_offset' field of struct device.
> 
> Unfortunately the 'dma_generic_alloc_coherent()' function is called from
> several places with a NULL struct device argument, halting the CPU
> during the boot process.
> 
> This patch fixes the issue protecting access to dev->dma_pfn_offset,
> with a trivial check for validity. It also passes a valid 'struct device'
> in the 'platform_resource_setup_memory' function which is the main user
> of 'dma_alloc_coherent()', and inserting a WARN_ON() check to make future
> (and existing) bogus users of this function they're should provide a valid
> 'struct device' whenever possible.
> 
> Fixes: ce88313069c36eef80f21fd7 ("arch/sh: make the DMA mapping operations observe dev->dma_pfn_offset")
> Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>

I would have done two commits here, one to fix:

  dma_alloc_coherent(&pdev->dev, memsize, &dma_handle, GFP_KERNEL);

and one to switch to the WARN_ON + if(dev) model. But I don't really
care either way, so:

Reviewed-by: Thomas Petazzoni <thomas.petazzoni@...tlin.com>

Note that even with the if (dev) check, you don't avoid all possible
regressions. For example, some parts of the sh_eth driver were passing
a non-NULL struct device, but it was the wrong struct device (the one
inside struct net_device, and not the one part of struct
platform_device). I fixed that for sh_eth, but there could be other
drivers doing bogus things.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ