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

[Greg Kroah-Hartman]

On Sat, Mar 30, 2019 at 10:18:38AM -0700, Nathan Chancellor wrote:
> 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,

Not a problem, thanks for letting me know, I've now queued up the fix
everywhere.

thanks,

greg k-h