Re: [PATCH] bus: mhi: core: Validate channel ID when processing command completions

[Manivannan Sadhasivam]

On Mon, May 24, 2021 at 10:12:28AM +0530, Manivannan Sadhasivam wrote:
> On Mon, Apr 26, 2021 at 04:58:58PM -0700, Bhaumik Bhatt wrote:
> > MHI reads the channel ID from the event ring element sent by the
> > device which can be any value between 0 and 255. In order to
> > prevent any out of bound accesses, add a check against the maximum
> > number of channels supported by the controller and those channels
> > not configured yet so as to skip processing of that event ring
> > element.
> > 
> > Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device")
> > Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
> 
> Applied to mhi-next!
> 

Sorry this has been applied to mhi-next!

Thanks,
Mani

> Thanks,
> Mani
> 
> > ---
> >  drivers/bus/mhi/core/main.c | 15 ++++++++++-----
> >  1 file changed, 10 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> > index 22acde1..ed07421 100644
> > --- a/drivers/bus/mhi/core/main.c
> > +++ b/drivers/bus/mhi/core/main.c
> > @@ -773,11 +773,16 @@ static void mhi_process_cmd_completion(struct mhi_controller *mhi_cntrl,
> >  	cmd_pkt = mhi_to_virtual(mhi_ring, ptr);
> >  
> >  	chan = MHI_TRE_GET_CMD_CHID(cmd_pkt);
> > -	mhi_chan = &mhi_cntrl->mhi_chan[chan];
> > -	write_lock_bh(&mhi_chan->lock);
> > -	mhi_chan->ccs = MHI_TRE_GET_EV_CODE(tre);
> > -	complete(&mhi_chan->completion);
> > -	write_unlock_bh(&mhi_chan->lock);
> > +	WARN_ON(chan >= mhi_cntrl->max_chan);
> > +
> > +	if (chan < mhi_cntrl->max_chan &&
> > +	    mhi_cntrl->mhi_chan[chan].configured) {
> > +		mhi_chan = &mhi_cntrl->mhi_chan[chan];
> > +		write_lock_bh(&mhi_chan->lock);
> > +		mhi_chan->ccs = MHI_TRE_GET_EV_CODE(tre);
> > +		complete(&mhi_chan->completion);
> > +		write_unlock_bh(&mhi_chan->lock);
> > +	}
> >  
> >  	mhi_del_ring_element(mhi_cntrl, mhi_ring);
> >  }
> > -- 
> > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> > a Linux Foundation Collaborative Project
> >