linux-kernel - Re: [PATCH 09/13] PCI: obey iomem restrictions for procfs mmap

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: <20201007184634.GA3259641@bjorn-Precision-5520>
Date:   Wed, 7 Oct 2020 13:46:34 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Daniel Vetter <daniel.vetter@...ll.ch>
Cc:     DRI Development <dri-devel@...ts.freedesktop.org>,
        LKML <linux-kernel@...r.kernel.org>, kvm@...r.kernel.org,
        linux-mm@...ck.org, linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-media@...r.kernel.org,
        linux-s390@...r.kernel.org,
        Daniel Vetter <daniel.vetter@...el.com>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Kees Cook <keescook@...omium.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        John Hubbard <jhubbard@...dia.com>,
        Jérôme Glisse <jglisse@...hat.com>,
        Jan Kara <jack@...e.cz>, Bjorn Helgaas <bhelgaas@...gle.com>,
        linux-pci@...r.kernel.org
Subject: Re: [PATCH 09/13] PCI: obey iomem restrictions for procfs mmap

On Wed, Oct 07, 2020 at 06:44:22PM +0200, Daniel Vetter wrote:
> There's three ways to access pci bars from userspace: /dev/mem, sysfs
> files, and the old proc interface. Two check against
> iomem_is_exclusive, proc never did. And with CONFIG_IO_STRICT_DEVMEM,
> this starts to matter, since we don't want random userspace having
> access to pci bars while a driver is loaded and using it.
> 
> Fix this.

Please mention *how* you're fixing this.  I know you can sort of
deduce it from the first paragraph, but it's easy to save readers the
trouble.

s/pci/PCI/
s/bars/BARs/
Capitalize subject to match other patches.

> References: 90a545e98126 ("restrict /dev/mem to idle io memory ranges")
> Signed-off-by: Daniel Vetter <daniel.vetter@...el.com>
> Cc: Jason Gunthorpe <jgg@...pe.ca>
> Cc: Kees Cook <keescook@...omium.org>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: John Hubbard <jhubbard@...dia.com>
> Cc: Jérôme Glisse <jglisse@...hat.com>
> Cc: Jan Kara <jack@...e.cz>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: linux-mm@...ck.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: linux-samsung-soc@...r.kernel.org
> Cc: linux-media@...r.kernel.org
> Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> Cc: linux-pci@...r.kernel.org
> ---
>  drivers/pci/proc.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
> index d35186b01d98..3a2f90beb4cb 100644
> --- a/drivers/pci/proc.c
> +++ b/drivers/pci/proc.c
> @@ -274,6 +274,11 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma)
>  		else
>  			return -EINVAL;
>  	}
> +
> +	if (dev->resource[i].flags & IORESOURCE_MEM &&
> +	    iomem_is_exclusive(dev->resource[i].start))
> +		return -EINVAL;
> +
>  	ret = pci_mmap_page_range(dev, i, vma,
>  				  fpriv->mmap_state, write_combine);
>  	if (ret < 0)
> -- 
> 2.28.0
>