From: Kees Cook <keescook@chromium.org>
To: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Johannes Berg <johannes@sipsolutions.net>,
Nathan Chancellor <nathan@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] wifi: nl80211: Avoid address calculations via out of bounds array indexing
Date: Tue, 30 Apr 2024 14:00:57 -0700 [thread overview]
Message-ID: <202404301358.CEA4B3D@keescook> (raw)
In-Reply-To: <9983345a-d590-4a78-94ca-6d96832860b1@quicinc.com>
On Tue, Apr 30, 2024 at 12:59:57PM -0700, Jeff Johnson wrote:
> On 4/30/2024 3:01 AM, Johannes Berg wrote:
> > This really doesn't even seem right, shouldn't do pointer arithmetic on
> > void pointers.
>
> FWIW I argued this in the past in another context and Linus gave his opinion:
>
> https://lore.kernel.org/all/CAHk-=whFKYMrF6euVvziW+drw7-yi1pYdf=uccnzJ8k09DoTXA@mail.gmail.com/
I was going to make the same argument. :) For this case, (void *) is
superior because we need to perform byte-granular arithmetic and we need
to use the implicit cast to the assigned variable's type.
The reason not to use the channels[] array is because we're not addressing
anything in the array -- we're addressing past it. Better to use the
correct allocation base.
-Kees
--
Kees Cook
prev parent reply other threads:[~2024-04-30 21:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 22:01 [PATCH] wifi: nl80211: Avoid address calculations via out of bounds array indexing Kees Cook
2024-04-25 18:13 ` Nathan Chancellor
2024-05-07 10:46 ` Johannes Berg
2024-05-07 14:21 ` Nathan Chancellor
2024-04-30 10:01 ` Johannes Berg
2024-04-30 19:59 ` Jeff Johnson
2024-04-30 21:00 ` Kees Cook [this message]
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