linux-kernel - Re: [PATCH v4 1/3] PCI: dwc: allow to limit registers set length

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Message-ID: <f4f731d928293406e093ae9b23583510@agner.ch>
Date:   Thu, 31 Jan 2019 10:08:11 +0100
From:   Stefan Agner <stefan@...er.ch>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Cc:     jingoohan1@...il.com, gustavo.pimentel@...opsys.com,
        l.stach@...gutronix.de, tpiepho@...inj.com,
        leonard.crestez@....com, bhelgaas@...gle.com,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/3] PCI: dwc: allow to limit registers set length

On 30.01.2019 18:54, Lorenzo Pieralisi wrote:
> On Tue, Dec 04, 2018 at 05:55:26PM +0100, Stefan Agner wrote:
>> Add length to the struct dw_pcie and check that the accessors
>> dw_pcie_(rd|wr)_conf() do not read/write beyond that point.
>>
>> Suggested-by: Trent Piepho <tpiepho@...inj.com>
>> Signed-off-by: Stefan Agner <stefan@...er.ch>
>> ---
>> Changes in v4:
>> - Move length check to dw_pcie_rd_conf
>>
>>  .../pci/controller/dwc/pcie-designware-host.c    | 16 ++++++++++++++--
>>  drivers/pci/controller/dwc/pcie-designware.h     |  1 +
>>  2 files changed, 15 insertions(+), 2 deletions(-)
> 
> Hi Stefan,
> 
> I wanted to ask you if this series should be considered for v5.1
> inclusion, it is in the PCI backlog. If it is, let me have a look
> and if it is OK to go I will likely ask you to rebase it.

Yes please. With this last change I did not see any regression anymore
so far.

Andrey Smirnov picked up the second patch: "PCI: imx6: introduce
drvdata". Not sure what the plan is with his patchset, if it gets merged
into v5.1 too then I probably better drop this patch and rebase ontop of
his series.

--
Stefan

> 
> Thanks,
> Lorenzo
> 
>> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
>> index 692dd1b264fb..9fc0f7bd99f0 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
>> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
>> @@ -606,14 +606,20 @@ static int dw_pcie_rd_conf(struct pci_bus *bus, u32 devfn, int where,
>>  			   int size, u32 *val)
>>  {
>>  	struct pcie_port *pp = bus->sysdata;
>> +	struct dw_pcie *pci;
>>
>>  	if (!dw_pcie_valid_device(pp, bus, PCI_SLOT(devfn))) {
>>  		*val = 0xffffffff;
>>  		return PCIBIOS_DEVICE_NOT_FOUND;
>>  	}
>>
>> -	if (bus->number == pp->root_bus_nr)
>> +	if (bus->number == pp->root_bus_nr) {
>> +		pci = to_dw_pcie_from_pp(pp);
>> +		if (pci->dbi_length && where + size > pci->dbi_length)
>> +			return PCIBIOS_BAD_REGISTER_NUMBER;
>> +
>>  		return dw_pcie_rd_own_conf(pp, where, size, val);
>> +	}
>>
>>  	return dw_pcie_rd_other_conf(pp, bus, devfn, where, size, val);
>>  }
>> @@ -622,12 +628,18 @@ static int dw_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
>>  			   int where, int size, u32 val)
>>  {
>>  	struct pcie_port *pp = bus->sysdata;
>> +	struct dw_pcie *pci;
>>
>>  	if (!dw_pcie_valid_device(pp, bus, PCI_SLOT(devfn)))
>>  		return PCIBIOS_DEVICE_NOT_FOUND;
>>
>> -	if (bus->number == pp->root_bus_nr)
>> +	if (bus->number == pp->root_bus_nr) {
>> +		pci = to_dw_pcie_from_pp(pp);
>> +		if (pci->dbi_length && where + size > pci->dbi_length)
>> +			return PCIBIOS_BAD_REGISTER_NUMBER;
>> +
>>  		return dw_pcie_wr_own_conf(pp, where, size, val);
>> +	}
>>
>>  	return dw_pcie_wr_other_conf(pp, bus, devfn, where, size, val);
>>  }
>> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
>> index 9943d8c68335..9cd7bdc94200 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware.h
>> +++ b/drivers/pci/controller/dwc/pcie-designware.h
>> @@ -229,6 +229,7 @@ struct dw_pcie {
>>  	void __iomem		*dbi_base2;
>>  	/* Used when iatu_unroll_enabled is true */
>>  	void __iomem		*atu_base;
>> +	int			dbi_length;
>>  	u32			num_viewport;
>>  	u8			iatu_unroll_enabled;
>>  	struct pcie_port	pp;
>> --
>> 2.19.1
>>