linux-kernel - Re: [PATCH 1/2] PCI: dwc: allow to limit registers set length

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Message-ID: <20190206180242.GA3328@e107981-ln.cambridge.arm.com>
Date:   Wed, 6 Feb 2019 18:02:42 +0000
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Stefan Agner <stefan@...er.ch>, gustavo.pimentel@...opsys.com
Cc:     jingoohan1@...il.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 1/2] PCI: dwc: allow to limit registers set length

On Wed, Feb 06, 2019 at 10:57:31AM +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
> Changes in v5:
> - Rebased ontop of pci/dwc
> 
>  .../pci/controller/dwc/pcie-designware-host.c    | 16 ++++++++++++++--
>  drivers/pci/controller/dwc/pcie-designware.h     |  1 +
>  2 files changed, 15 insertions(+), 2 deletions(-)

Hi Gustavo,

I need your ACK on this patch to proceed, thanks.

Lorenzo

> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 45ff5e4f8af6..bad54204fb52 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -612,14 +612,20 @@ 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);
>  }
> @@ -628,12 +634,18 @@ 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 279000255ad1..d1d95119a422 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -226,6 +226,7 @@ struct dw_pcie_ops {
>  struct dw_pcie {
>  	struct device		*dev;
>  	void __iomem		*dbi_base;
> +	int			dbi_length;
>  	void __iomem		*dbi_base2;
>  	/* Used when iatu_unroll_enabled is true */
>  	void __iomem		*atu_base;
> -- 
> 2.20.1
>