Re: [PATCH v3] iio: light: Add check for array bounds in veml6075_read_int_time_ms

[Jonathan Cameron]

On Sat, 22 Feb 2025 16:45:19 +0000
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:

> On Sat, 22 Feb 2025 16:43:37 +0000
> Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> 
> > On Thu, 20 Feb 2025 17:34:36 +0000
> > Karan Sanghavi <karansanghvi98@xxxxxxxxx> wrote:
> >   
> > > The array contains only 5 elements, but the index calculated by
> > > veml6075_read_int_time_index can range from 0 to 7,
> > > which could lead to out-of-bounds access. The check prevents this issue.
> > > 
> > > Coverity Issue
> > > CID 1574309: (#1 of 1): Out-of-bounds read (OVERRUN)
> > > overrun-local: Overrunning array veml6075_it_ms of 5 4-byte
> > > elements at element index 7 (byte offset 31) using
> > > index int_index (which evaluates to 7)
> > > 
> > > Fixes: 3b82f43238ae ("iio: light: add VEML6075 UVA and UVB light sensor driver")
> > > Signed-off-by: Karan Sanghavi <karansanghvi98@xxxxxxxxx>
> > > ---    
> > Superficially this looks hardening against malicious or broken hardware.
> > That is fine to add, but not worth backporting or (in my opinion) adding a fixes
> > tag.  
> Ah I see Javier asked for the fixes tag.  Ok.  Maybe just add a note that
> the hardware is not expected to return such an out of bounds value.
> 
> That will help me to remember we don't need to rush this one upstream!
I guess you don't have time so I made the changes requested and applied.
(mostly so I can stop tracking the status!)

Jonathan

> 
> Jonathan
> 
> >   
> > >  drivers/iio/light/veml6075.c | 7 ++++++-
> > >  1 file changed, 6 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/iio/light/veml6075.c b/drivers/iio/light/veml6075.c
> > > index 05d4c0e9015d..5dd951f6e989 100644
> > > --- a/drivers/iio/light/veml6075.c
> > > +++ b/drivers/iio/light/veml6075.c
> > > @@ -201,7 +201,12 @@ static int veml6075_read_int_time_index(struct veml6075_data *data)
> > >  	if (ret < 0)
> > >  		return ret;
> > >  
> > > -	return FIELD_GET(VEML6075_CONF_IT, conf);
> > > +	int int_index = FIELD_GET(VEML6075_CONF_IT, conf);
> > > +
> > > +	if (int_index >= ARRAY_SIZE(veml6075_it_ms))
> > > +		return -EINVAL;
> > > +
> > > +	return int_index;
> > >  }
> > >  
> > >  static int veml6075_read_int_time_ms(struct veml6075_data *data, int *val)    
> >   
> 
>