netdev - Re: [PATCH v2 2/4] wifi: libertas: only add RSN/WPA IE in lbs_add_wpa

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Date:   Fri, 13 Jan 2023 10:52:31 +0100
From:   Simon Horman <simon.horman@...igine.com>
To:     Doug Brown <doug@...morgal.com>
Cc:     Dan Williams <dcbw@...hat.com>, Kalle Valo <kvalo@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        libertas-dev@...ts.infradead.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH v2 2/4] wifi: libertas: only add RSN/WPA IE in
 lbs_add_wpa_tlv

On Sat, Jan 07, 2023 at 05:30:14PM -0800, Doug Brown wrote:
> The existing code only converts the first IE to a TLV, but it returns a
> value that takes the length of all IEs into account. When there is more
> than one IE (which happens with modern wpa_supplicant versions for
> example), the returned length is too long and extra junk TLVs get sent
> to the firmware, resulting in an association failure.
> 
> Fix this by finding the first RSN or WPA IE and only adding that. This
> has the extra benefit of working properly if the RSN/WPA IE isn't the
> first one in the IE buffer.
> 
> While we're at it, clean up the code to use the available structs like
> the other lbs_add_* functions instead of directly manipulating the TLV
> buffer.
> 
> Signed-off-by: Doug Brown <doug@...morgal.com>
> ---
>  drivers/net/wireless/marvell/libertas/cfg.c | 28 +++++++++++++--------
>  1 file changed, 18 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/wireless/marvell/libertas/cfg.c b/drivers/net/wireless/marvell/libertas/cfg.c
> index 3e065cbb0af9..5cd78fefbe4c 100644
> --- a/drivers/net/wireless/marvell/libertas/cfg.c
> +++ b/drivers/net/wireless/marvell/libertas/cfg.c
> @@ -416,10 +416,20 @@ static int lbs_add_cf_param_tlv(u8 *tlv)
>  
>  static int lbs_add_wpa_tlv(u8 *tlv, const u8 *ie, u8 ie_len)
>  {
> -	size_t tlv_len;
> +	struct mrvl_ie_data *wpatlv = (struct mrvl_ie_data *)tlv;
> +	const struct element *wpaie;
> +
> +	/* Find the first RSN or WPA IE to use */
> +	wpaie = cfg80211_find_elem(WLAN_EID_RSN, ie, ie_len);
> +	if (!wpaie)
> +		wpaie = cfg80211_find_vendor_elem(WLAN_OUI_MICROSOFT,
> +						  WLAN_OUI_TYPE_MICROSOFT_WPA,
> +						  ie, ie_len);
> +	if (!wpaie || wpaie->datalen > 128)
> +		return 0;
>  
>  	/*
> -	 * We need just convert an IE to an TLV. IEs use u8 for the header,
> +	 * Convert the found IE to a TLV. IEs use u8 for the header,
>  	 *   u8      type
>  	 *   u8      len
>  	 *   u8[]    data
> @@ -428,14 +438,12 @@ static int lbs_add_wpa_tlv(u8 *tlv, const u8 *ie, u8 ie_len)
>  	 *   __le16  len
>  	 *   u8[]    data
>  	 */
> -	*tlv++ = *ie++;
> -	*tlv++ = 0;
> -	tlv_len = *tlv++ = *ie++;
> -	*tlv++ = 0;
> -	while (tlv_len--)
> -		*tlv++ = *ie++;
> -	/* the TLV is two bytes larger than the IE */
> -	return ie_len + 2;
> +	wpatlv->header.type = wpaie->id;
> +	wpatlv->header.len = wpaie->datalen;

Hi Doug,

For correctness should type and len be converted to little endian,
f.e. using cpu_to_le16() ?

Likewise in patch 4/4.

> +	memcpy(wpatlv->data, wpaie->data, wpaie->datalen);
> +
> +	/* Return the total number of bytes added to the TLV buffer */
> +	return sizeof(struct mrvl_ie_header) + wpaie->datalen;
>  }
>  
>  /*
> -- 
> 2.34.1
>