Re: [PATCH 4.9 25/30] USB: core: only clean up what we allocated

[Nathan Chancellor]

On Tue, Mar 26, 2019 at 03:30:04PM +0900, Greg Kroah-Hartman wrote:
> 4.9-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> 
> commit 32fd87b3bbf5f7a045546401dfe2894dbbf4d8c3 upstream.
> 
> When cleaning up the configurations, make sure we only free the number
> of configurations and interfaces that we could have allocated.
> 
> Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> Cc: stable <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> 
> ---
>  drivers/usb/core/config.c |    9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> --- a/drivers/usb/core/config.c
> +++ b/drivers/usb/core/config.c
> @@ -763,18 +763,21 @@ void usb_destroy_configuration(struct us
>  		return;
>  
>  	if (dev->rawdescriptors) {
> -		for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
> +		for (i = 0; i < dev->descriptor.bNumConfigurations &&
> +				i < USB_MAXCONFIG; i++)
>  			kfree(dev->rawdescriptors[i]);
>  
>  		kfree(dev->rawdescriptors);
>  		dev->rawdescriptors = NULL;
>  	}
>  
> -	for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
> +	for (c = 0; c < dev->descriptor.bNumConfigurations &&
> +			c < USB_MAXCONFIG; c++) {
>  		struct usb_host_config *cf = &dev->config[c];
>  
>  		kfree(cf->string);
> -		for (i = 0; i < cf->desc.bNumInterfaces; i++) {
> +		for (i = 0; i < cf->desc.bNumInterfaces &&
> +				i < USB_MAXINTERFACES; i++) {
>  			if (cf->intf_cache[i])
>  				kref_put(&cf->intf_cache[i]->ref,
>  					  usb_release_interface_cache);
> 
> 

You reverted this upstream in commit cf4df407e0d7 ("Revert "USB: core:
only clean up what we allocated"") in favor of commit 48a4ff1c7bb5
("USB: core: prevent malicious bNumInterfaces overflow"), which has been
in this tree since 4.9.71.

Sorry for not catching this earlier,
Nathan