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From: Kalle Valo <kvalo@kernel.org>
To: Arend Van Spriel <aspriel@gmail.com>
Cc: Kees Cook <keescook@chromium.org>,  Franky Lin
 <franky.lin@broadcom.com>,  Hante Meuleman <hante.meuleman@broadcom.com>,
  Chi-hsien Lin <chi-hsien.lin@infineon.com>,  Ian Lin
 <ian.lin@infineon.com>,  Johannes Berg <johannes.berg@intel.com>,  Wright
 Feng <wright.feng@cypress.com>,  Hector Martin <marcan@marcan.st>,
  linux-wireless@vger.kernel.org,  brcm80211-dev-list.pdl@broadcom.com,
  "Gustavo A. R. Silva" <gustavoars@kernel.org>,  Linus Walleij
 <linus.walleij@linaro.org>,  Jisoo Jang <jisoo.jang@yonsei.ac.kr>,  Hans
 de Goede <hdegoede@redhat.com>,  Aloka Dixit <quic_alokad@quicinc.com>,
  John Keeping <john@keeping.me.uk>,  Jeff Johnson
 <quic_jjohnson@quicinc.com>,  linux-kernel@vger.kernel.org,
  linux-hardening@vger.kernel.org
Subject: Re: [PATCH] wifi: brcmfmac: Adjust n_channels usage for __counted_by
References: <20240126223150.work.548-kees@kernel.org>
	<170678189299.2736043.11616312910656558919.kvalo@kernel.org>
	<a91c6a28-6762-41cf-bb85-09e79f3d29d4@gmail.com>
	<d4855223-4323-43f1-9a29-e279e2cb128c@gmail.com>
Date: Fri, 02 Feb 2024 12:34:54 +0200
In-Reply-To: <d4855223-4323-43f1-9a29-e279e2cb128c@gmail.com> (Arend Van
	Spriel's message of "Fri, 2 Feb 2024 11:00:51 +0100")
Message-ID: <87v877tar5.fsf@kernel.org>
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Arend Van Spriel <aspriel@gmail.com> writes:

> On 2/2/2024 10:58 AM, Arend Van Spriel wrote:
>
>> On 2/1/2024 11:04 AM, Kalle Valo wrote:
>>> Kees Cook <keescook@chromium.org> wrote:
>>>
>>>> After commit e3eac9f32ec0 ("wifi: cfg80211: Annotate struct
>>>> cfg80211_scan_request with __counted_by"), the compiler may enforce
>>>> dynamic array indexing of req->channels to stay below n_channels. As a
>>>> result, n_channels needs to be increased _before_ accessing the newly
>>>> added array index. Increment it first, then use "i" for the prior inde=
x.
>>>> Solves this warning in the coming GCC that has __counted_by support:
>>>>
>>>> ../drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c: In
>>>> function 'brcmf_internal_escan_add_info':
>>>> ../drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:3783:46=
: warning: operation on 'req->
>>>> n_channels' may be undefined [-Wsequence-point]
>>>> =C2=A0 3783 |=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 req->channels[req->n_channels++] =
=3D chan;
>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
 ~~~~~~~~~~~~~~~^~
>>>>
>>>> Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct
>>>> cfg80211_scan_request with __counted_by")
>>>> Cc: Arend van Spriel <aspriel@gmail.com>
>>>> Cc: Franky Lin <franky.lin@broadcom.com>
>>>> Cc: Hante Meuleman <hante.meuleman@broadcom.com>
>>>> Cc: Kalle Valo <kvalo@kernel.org>
>>>> Cc: Chi-hsien Lin <chi-hsien.lin@infineon.com>
>>>> Cc: Ian Lin <ian.lin@infineon.com>
>>>> Cc: Johannes Berg <johannes.berg@intel.com>
>>>> Cc: Wright Feng <wright.feng@cypress.com>
>>>> Cc: Hector Martin <marcan@marcan.st>
>>>> Cc: linux-wireless@vger.kernel.org
>>>> Cc: brcm80211-dev-list.pdl@broadcom.com
>>>> Signed-off-by: Kees Cook <keescook@chromium.org>
>>>> Reviewed-by: Hans de Goede <hdegoede@redhat.com>
>>>> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
>>>> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>>>
>>> I'm planning to queue this for wireless tree. Arend, ack?
>> This slipped past my broadcom email. As the Fixes commit is in 6.7 I
>> would say ACK.

Thanks.

> Cc: to stable?

Is commit e3eac9f32ec0 in stable releases? (I don't follow stable and
don't know what commits they take.) I propose that as we have Fixes tag
let's not add cc but instead let stable maintainers to decide.

--=20
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