linux-kernel - Re: [PATCH] wifi: brcmfmac: Adjust n_channels usage for __counted

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8f225be1-647b-4421-b6b5-a2098f807d05@redhat.com>
Date: Sat, 27 Jan 2024 14:15:10 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Kees Cook <keescook@...omium.org>, Arend van Spriel <aspriel@...il.com>
Cc: Franky Lin <franky.lin@...adcom.com>,
 Hante Meuleman <hante.meuleman@...adcom.com>, Kalle Valo <kvalo@...nel.org>,
 Chi-hsien Lin <chi-hsien.lin@...ineon.com>, Ian Lin <ian.lin@...ineon.com>,
 Johannes Berg <johannes.berg@...el.com>,
 Wright Feng <wright.feng@...ress.com>, Hector Martin <marcan@...can.st>,
 linux-wireless@...r.kernel.org, brcm80211-dev-list.pdl@...adcom.com,
 "Gustavo A. R. Silva" <gustavoars@...nel.org>,
 Linus Walleij <linus.walleij@...aro.org>,
 Jisoo Jang <jisoo.jang@...sei.ac.kr>, Aloka Dixit <quic_alokad@...cinc.com>,
 John Keeping <john@...ping.me.uk>, Jeff Johnson <quic_jjohnson@...cinc.com>,
 linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: Re: [PATCH] wifi: brcmfmac: Adjust n_channels usage for __counted_by

Hi,

On 1/26/24 23:31, Kees Cook 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 index.
> 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]
>  3783 |                 req->channels[req->n_channels++] = chan;
>       |                               ~~~~~~~~~~~~~~~^~
> 
> Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by")
> Cc: Arend van Spriel <aspriel@...il.com>
> Cc: Franky Lin <franky.lin@...adcom.com>
> Cc: Hante Meuleman <hante.meuleman@...adcom.com>
> Cc: Kalle Valo <kvalo@...nel.org>
> Cc: Chi-hsien Lin <chi-hsien.lin@...ineon.com>
> Cc: Ian Lin <ian.lin@...ineon.com>
> Cc: Johannes Berg <johannes.berg@...el.com>
> Cc: Wright Feng <wright.feng@...ress.com>
> Cc: Hector Martin <marcan@...can.st>
> Cc: linux-wireless@...r.kernel.org
> Cc: brcm80211-dev-list.pdl@...adcom.com
> Signed-off-by: Kees Cook <keescook@...omium.org>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@...hat.com>

Regards,

Hans



> ---
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> index 133c5ea6429c..28d6a30cc010 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> @@ -3779,8 +3779,10 @@ static int brcmf_internal_escan_add_info(struct cfg80211_scan_request *req,
>  		if (req->channels[i] == chan)
>  			break;
>  	}
> -	if (i == req->n_channels)
> -		req->channels[req->n_channels++] = chan;
> +	if (i == req->n_channels) {
> +		req->n_channels++;
> +		req->channels[i] = chan;
> +	}
>  
>  	for (i = 0; i < req->n_ssids; i++) {
>  		if (req->ssids[i].ssid_len == ssid_len &&