Re: [PATCH] brcmfmac: fix a loop exit condition

From: Matthias Brugger <mbrugger@suse.com>
To: Dan Carpenter <dan.carpenter@oracle.com>,
	Arend van Spriel <aspriel@gmail.com>
Cc: Franky Lin <franky.lin@broadcom.com>,
	Hante Meuleman <hante.meuleman@broadcom.com>,
	Chi-hsien Lin <chi-hsien.lin@infineon.com>,
	Wright Feng <wright.feng@infineon.com>,
	Chung-hsien Hsu <chung-hsien.hsu@infineon.com>,
	Kalle Valo <kvalo@codeaurora.org>,
	Hans deGoede <hdegoede@redhat.com>,
	linux-wireless@vger.kernel.org,
	brcm80211-dev-list.pdl@broadcom.com,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] brcmfmac: fix a loop exit condition
Date: Fri, 23 Apr 2021 13:56:58 +0200	[thread overview]
Message-ID: <d433c141-5066-07c9-8ce8-d271cc70f287@suse.com> (raw)
In-Reply-To: <YIKzmoMiTdToaIyP@mwanda>

On 23/04/2021 13:46, Dan Carpenter wrote:
> This code is supposed to loop over the whole board_type[] string.  The
> current code kind of works just because ascii values start 97 and the
> string is likely shorter than that so it will break when we hit the NUL
> terminator.  But really the condition should be "i < len" instead of
> "i < board_type[i]".
> 
> Fixes: 29e354ebeeec ("brcmfmac: Transform compatible string for FW loading")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Good catch, I actually have serious doubts about whatever I was thinking when
writing that line of code.

Reviewed-by: Matthias Brugger <mbrugger@suse.com>

> ---
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> index a7554265f95f..9b75e396fc50 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> @@ -34,7 +34,7 @@ void brcmf_of_probe(struct device *dev, enum brcmf_bus_type bus_type,
>  		len = strlen(tmp) + 1;
>  		board_type = devm_kzalloc(dev, len, GFP_KERNEL);
>  		strscpy(board_type, tmp, len);
> -		for (i = 0; i < board_type[i]; i++) {
> +		for (i = 0; i < len; i++) {
>  			if (board_type[i] == '/')
>  				board_type[i] = '-';
>  		}
> 