netdev - Re: [PATCH] net: dev_addr_list: add address length validation in __hw_addr

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Message-ID: <CAO9wTFhbK-Ckc3bq9X0qdKiyHVqsQgtzSu4RGzkd1d1aAK0vwg@mail.gmail.com>
Date: Tue, 18 Feb 2025 00:57:51 +0530
From: Suchit K <suchitkarunakaran@...il.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: netdev@...r.kernel.org, davem@...emloft.net, horms@...nel.org, 
	skhan@...uxfoundation.org, linux-kernel@...r.kernel.org, 
	linux-kernel-mentees@...ts.linux.dev
Subject: Re: [PATCH] net: dev_addr_list: add address length validation in
 __hw_addr_insert function

Thank you so much for the feedback. I appreciate your time and effort
in reviewing and providing feedback.

On Tue, 18 Feb 2025 at 00:51, Eric Dumazet <edumazet@...gle.com> wrote:
>
> On Mon, Feb 17, 2025 at 8:05 PM Suchit K <suchitkarunakaran@...il.com> wrote:
> >
> > Hi Eric,
> > Thanks for the feedback! I'm new to kernel development and still
> > finding my way around.
> > I wasn't working from a syzbot report on this one; I was just
> > exploring the code and felt there is no parameter validation. I went
> > ahead and made this change based on that impression. I realized my
> > changelog should have been more generic. Sorry about that. Also since
> > it's not based on a syzbot report, is it good to have this change?
> > Your insights and suggestions would be most welcome. I will make the
> > required changes accordingly.
> > Thanks.
>
> I think these checks are not necessary.
>
> 1) The caller (dev_addr_mod) provides non NULL pointers,
>     there is no point adding tests, because if one of them was NULL,
>     a crash would occur before hitting this function.
>
> 2) Your patch would silently hide a real issue if for some reason
> dev->addr_len was too big.