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:   Wed, 20 Dec 2017 11:28:29 +0100
From:   Tomasz Nowicki <tn@...ihalf.com>
To:     Alex Williamson <alex.williamson@...hat.com>,
        Tomasz Nowicki <tomasz.nowicki@...iumnetworks.com>
Cc:     joro@...tes.org, robin.murphy@....com, will.deacon@....com,
        lorenzo.pieralisi@....com, bhelgaas@...gle.com,
        Jayachandran.Nair@...ium.com, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        linux-acpi@...r.kernel.org, iommu@...ts.linux-foundation.org,
        Ganapatrao.Kulkarni@...ium.com, mw@...ihalf.com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V1 1/1] iommu: Make sure device's ID array elements are
 unique

On 19.12.2017 17:37, Alex Williamson wrote:
> On Tue, 19 Dec 2017 16:20:21 +0100
> Tomasz Nowicki <tomasz.nowicki@...iumnetworks.com> wrote:
> 
>> While iterating over DMA aliases for a PCI device, for some rare cases
>> (i.e. PCIe-to-PCI/X bridges) we may get exactly the same ID as initial child
>> device. In turn, the same ID may get registered for a device multiple times.
>> Eventually IOMMU  driver may try to configure the same ID within domain
>> multiple times too which for some IOMMU drivers is illegal and causes kernel
>> panic.
>>
>> Rule out ID duplication prior to device ID array registration.
>>
>> CC: stable@...r.kernel.org	# v4.14+
> 
> You've identified a release, is there a specific commit this fixes?

Yes, it was triggered by converting drm_pci_init() to 
pci_register_driver() in ast_drv.c

Fixes: 10631d724def ("drm/pci: Deprecate drm_pci_init/exit completely
")

> 
>> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@...iumnetworks.com>
>> ---
>>   drivers/iommu/iommu.c | 28 ++++++++++++++++++++++++++++
>>   1 file changed, 28 insertions(+)
>>
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 3de5c0b..9b2c138 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -1945,6 +1945,31 @@ void iommu_fwspec_free(struct device *dev)
>>   }
>>   EXPORT_SYMBOL_GPL(iommu_fwspec_free);
>>   
>> +static void iommu_fwspec_remove_ids_dup(struct device *dev, u32 *ids,
>> +					int *num_ids)
>> +{
>> +	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
>> +	int i, j, k, valid_ids = *num_ids;
>> +
>> +	for (i = 0; i < valid_ids; i++) {
>> +		for (j = 0; j < fwspec->num_ids; j++) {
>> +			if (ids[i] != fwspec->ids[j])
>> +				continue;
>> +
>> +			dev_info(dev, "found 0x%x ID duplication, skipped\n",
>> +				 ids[i]);
>> +
>> +			for (k = i + 1; k < valid_ids; k++)
>> +				ids[k - 1] = ids[k];
> 
> Use memmove()?

Right.

> 
>> +
>> +			valid_ids--;
>> +			break;
> 
> At this point ids[i] is not the ids[i] that we tested for dupes, it's
> what was ids[i + 1], but we're going to i++ on the next iteration and
> we therefore never test that entry.

Good point.

Now the fundamental question is where we should put the patch, here or 
in SMMUv3 driver as per Robin suggestion.

Thanks,
Tomasz

Powered by blists - more mailing lists