Re: [PATCH] PCI: prevent out of bounds access in numa_node override

[Bjorn Helgaas]

Hi Sasha,

On Sun, Oct 04, 2015 at 05:49:29PM -0400, Sasha Levin wrote:
> Commit 63692df1 ("PCI: Allow numa_node override via sysfs") didn't check that
> the numa node provided by userspace is valid. Passing a node number too high
> would attempt to access invalid memory and trigger a kernel panic.
> 
> Fixes: 63692df1 ("PCI: Allow numa_node override via sysfs")
> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
> ---
>  drivers/pci/pci-sysfs.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 312f23a..e9abca8 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -216,7 +216,7 @@ static ssize_t numa_node_store(struct device *dev,
>  	if (ret)
>  		return ret;
>  
> -	if (!node_online(node))
> +	if (node > MAX_NUMNODES || !node_online(node))

This needs to be "node >= MAX_NUMNODES", doesn't it?  I'll fix it up if
you agree.

Looks like a candidate for stable.

>  		return -EINVAL;
>  
>  	add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
> -- 
> 1.7.10.4
> 
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