Re: [PATCHv4] mac80211: fix NULL pointer dereference in ieee80211_compatible_rates

[Johannes Berg <johannes@sipsolutions.net>]

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On Mon, 2008-05-19 at 16:59 +0200, Helmut Schaa wrote:
> Fix a possible NULL pointer dereference in ieee80211_compatible_rates 
> introduced in the patch "mac80211: fix association with some APs". If no bss
> is available just use all supported rates in the association request.
> 
> Signed-off-by: Helmut Schaa <hschaa@suse.de>

Thanks.
Acked-by: Johannes Berg <johannes@sipsolutions.net>

> ---
> 
> diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
> index 76ad4ed..7aff784 100644
> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -722,6 +722,15 @@ static void ieee80211_send_assoc(struct net_device *dev,
>  		if (bss->wmm_ie)
>  			wmm = 1;
>  		ieee80211_rx_bss_put(dev, bss);
> +
> +		/* get all rates supported by the device and the AP as
> +		 * some APs don't like getting a superset of their rates
> +		 * in the association request (e.g. D-Link DAP 1353 in
> +		 * b-only mode) */
> +		rates_len = ieee80211_compatible_rates(bss, sband, &rates);
> +	} else {
> +		rates = ~0;
> +		rates_len = sband->n_bitrates;
>  	}
>  
>  	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
> @@ -752,10 +761,7 @@ static void ieee80211_send_assoc(struct net_device *dev,
>  	*pos++ = ifsta->ssid_len;
>  	memcpy(pos, ifsta->ssid, ifsta->ssid_len);
>  
> -	/* all supported rates should be added here but some APs
> -	 * (e.g. D-Link DAP 1353 in b-only mode) don't like that
> -	 * Therefore only add rates the AP supports */
> -	rates_len = ieee80211_compatible_rates(bss, sband, &rates);
> +	/* add all rates which were marked to be used above */
>  	supp_rates_len = rates_len;
>  	if (supp_rates_len > 8)
>  		supp_rates_len = 8;
> 

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