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Date:   Fri, 11 Aug 2023 14:19:05 +0530
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Subject: Re: [PATCH v2 4/4] venus: hfi_parser: Add check to keep the number of
 codecs within range
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To:     Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
        <stanimir.k.varbanov@gmail.com>, <agross@kernel.org>,
        <andersson@kernel.org>, <konrad.dybcio@linaro.org>,
        <mchehab@kernel.org>, <hans.verkuil@cisco.com>,
        <tfiga@chromium.org>
CC:     <linux-media@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>
References: <1691634304-2158-1-git-send-email-quic_vgarodia@quicinc.com>
 <1691634304-2158-5-git-send-email-quic_vgarodia@quicinc.com>
 <fec4a8c7-206f-7af8-4ea9-c919a677bf7e@linaro.org>
 <2214c31b-eca2-012e-a100-21252a724e7c@quicinc.com>
 <8b72ce47-c338-2061-f11a-c0a608686d8c@linaro.org>
From:   Vikash Garodia <quic_vgarodia@quicinc.com>
In-Reply-To: <8b72ce47-c338-2061-f11a-c0a608686d8c@linaro.org>
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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