Re: [PATCH] flow_dissector: fix uninit-value in __skb_flow_dissect() for ETH_ADDRS

["Zhou, Yun" <yun.zhou@windriver.com>]

On 6/3/26 16:54, Jiayuan Chen wrote:
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>
> On 6/3/26 4:33 PM, Eric Dumazet wrote:
>> On Wed, Jun 3, 2026 at 1:16 AM Zhou, Yun <yun.zhou@windriver.com> wrote:
>>>
>>>
>>> On 6/3/26 13:44, Eric Dumazet wrote:
>>>> CAUTION: This email comes from a non Wind River email account!
>>>> Do not click links or open attachments unless you recognize the 
>>>> sender and know the content is safe.
>>>>
>>>> On Tue, Jun 2, 2026 at 8:08 PM Yun Zhou <yun.zhou@windriver.com> 
>>>> wrote:
>>>> Please add a Closes: tag
>>> I will add a Closes link in v2.
>>> Closes: https://syzkaller.appspot.com/bug?extid=fa2f5b1fb06147be5e16
>>>> I found some not relevant syzbot report :
>>>>
>>>> https://lore.kernel.org/netdev/6a196faf.c16d89a8.217f2c.0002.GAE@google.com/ 
>>>>
>>> This should be the same issue. And it can be reproduced by
>>> https://syzkaller.appspot.com/text?tag=ReproC&x=12924152580000
>> Please investigate which device allowed to send an Ethernet packet
>> smaller than the ethernet header.
>>
>> We do not want to add tests all over the places, we should fix the 
>> origin.
>>
>> Look for dev->min_header_len
>>
>> Thanks.
>
>
> It's TUN.
>
> I think we should reject loading "tc filter ... flower eth_dst
> aa:bb:cc:dd:ee:ff ... " if dev->hard_header_len <
> sizeof(flow_dissector_key_eth_addrs)
>
I will add checks in fl_change()

Thanks very much for your suggestion.