linux-kernel - Re: [PATCH] PCI: Fix pcibios_update

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]

Date:	Mon, 02 Feb 2015 16:23:56 +0000
From:	Marc Zyngier <marc.zyngier@....com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
CC:	Thomas Gleixner <tglx@...utronix.de>,
	Jiang Liu <jiang.liu@...ux.intel.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Andre Przywara <Andre.Przywara@....com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	linux-arm <linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] PCI: Fix pcibios_update_irq misuse of irq number

On 02/02/15 15:57, Bjorn Helgaas wrote:
> On Wed, Jan 28, 2015 at 8:51 AM, Marc Zyngier <marc.zyngier@....com> wrote:
>> pcibios_update_irq writes an irq number into the config space
>> of a given PCI device, but ignores the fact that this number
>> is a virtual interrupt number, which might be a very different
>> value from what the underlying hardware is using.
>>
>> The obvious fix is to fetch the HW interrupt number from the
>> corresponding irq_data structure. This is slightly complicated
>> by the fact that this interrupt might be services by a stacked
>> domain.
>>
>> This has been tested on KVM with kvmtool.
>>
>> Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
>> Tested-by: Andre Przywara <andre.przywara@....com>
>> Signed-off-by: Marc Zyngier <marc.zyngier@....com>
> 
> Jiang, are you OK with this patch as-is now, since it isn't used on x86?
> 
> Marc, Lorenzo, I assume this actually fixes a bug.  Can we get any
> more details about what happens when you hit the bug, and how you
> reproduced it (what platform, driver, etc.)?

It definitely fixes a bug. This has been found by running a KVM guest
using kvmtool PCI emulation, where the following things happen:

- Guest programs a virtual (bogus) interrupt number in the PCI device
config space (virtio disk in this case)
- kvmtool uses that interrupt number as is, without any other form of
validation
- Either the injection fails (because the interrupt is out of the range
of the virtual interrupt controller) -> virtio PCI device goes dead
- or the injection succeeds because this is a valid interrupt number,
but signals an unrelated peripheral -> virtio PCI device goes dead.

This can be trivially reproduced on any ARM PCI system that requires
legacy interrupts (i.e. no MSI support), and that uses a GIC interrupt
controller. Doing it in a VM is just much more convenient.

Hope this helps,

	M.
-- 
Jazz is not dead. It just smells funny...
--
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/