Re: [PATCH next] tee: qcom: prevent potential off by one read

[Dan Carpenter <dan.carpenter@linaro.org>]

On Wed, Sep 24, 2025 at 08:48:29AM +1000, Amirreza Zarrabi wrote:
> On 9/18/2025 7:50 PM, Dan Carpenter wrote:
> > Re-order these checks to check if "i" is a valid array index before using
> > it.  This prevents a potential off by one read access.
> > 
> > Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > ---
> >  drivers/tee/qcomtee/call.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> > index cc17a48d0ab7..ac134452cc9c 100644
> > --- a/drivers/tee/qcomtee/call.c
> > +++ b/drivers/tee/qcomtee/call.c
> > @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
> >  	}
> >  
> >  	/* Release any IO and OO objects not processed. */
> > -	for (; u[i].type && i < num_params; i++) {
> > +	for (; i < num_params && u[i].type; i++) {
> >  		if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
> >  		    u[i].type == QCOMTEE_ARG_TYPE_IO)
> >  			qcomtee_object_put(u[i].o);
> 
> This is not required, considering the sequence of clean up, this
> would never happen. `i` at least have been accessed once in the
> switch above.

Only the first iteration has been accessed.  The rest no.

regards,
dan carpenter