Re: [PATCH v2 4/4] venus: hfi_parser: Add check to keep the number of codecs within range

[Bryan O'Donoghue]

On 11/08/2023 09:49, Vikash Garodia wrote:
> On 8/11/2023 2:12 PM, Bryan O'Donoghue wrote:
> > On 11/08/2023 07:04, Vikash Garodia wrote:
> > > On 8/10/2023 5:03 PM, Bryan O'Donoghue wrote:
> > > > On 10/08/2023 03:25, Vikash Garodia wrote:
> > > > > +    if (hweight_long(core->dec_codecs) + hweight_long(core->enc_codecs) >
> > > > > MAX_CODEC_NUM)
> > > > > +        return;
> > > > > +
> > > >
> > > > Shouldn't this be >= ?
> > > Not needed. Lets take a hypothetical case when core->dec_codecs has initial 16
> > > (0-15) bits set and core->enc_codecs has next 16 bits (16-31) set. The bit count
> > > would be 32. The codec loop after this check would run on caps array index 0-31.
> > > I do not see a possibility for OOB access in this case.
> > >
> > > > struct hfi_plat_caps caps[MAX_CODEC_NUM];
> > > >
> > > > ---
> > > > bod
> >
> > Are you not doing a general defensive coding pass in this series ie
> >
> > "[PATCH v2 2/4] venus: hfi: fix the check to handle session buffer requirement"
>
> In "PATCH v2 2/4", there is a possibility if the check does not consider "=".
> Here in this patch, I do not see a possibility.
>
> > ---
> > bod

But surely hweight_long(core->dec_codecs) + 
hweight_long(core->enc_codecs) == MAX_CODEC_NUM is an invalid offset ?

---
bod