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	id 1mGFgz-00CbW0-CL; Wed, 18 Aug 2021 09:08:53 +0200
Message-ID: <11db2cdc5316b51f3fa2f34e813a458e455c763d.camel@sipsolutions.net>
Subject: Re: [PATCH v2 44/63] mac80211: Use memset_after() to clear tx status
From: Johannes Berg <johannes@sipsolutions.net>
To: Kees Cook <keescook@chromium.org>, linux-kernel@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>, Jakub Kicinski
 <kuba@kernel.org>,  linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
 "Gustavo A. R. Silva" <gustavoars@kernel.org>, Greg Kroah-Hartman
 <gregkh@linuxfoundation.org>,  Andrew Morton <akpm@linux-foundation.org>,
 dri-devel@lists.freedesktop.org, linux-staging@lists.linux.dev, 
 linux-block@vger.kernel.org, linux-kbuild@vger.kernel.org, 
 clang-built-linux@googlegroups.com, Rasmus Villemoes
 <linux@rasmusvillemoes.dk>,  linux-hardening@vger.kernel.org
Date: Wed, 18 Aug 2021 09:08:52 +0200
In-Reply-To: <20210818060533.3569517-45-keescook@chromium.org>
References: <20210818060533.3569517-1-keescook@chromium.org>
	 <20210818060533.3569517-45-keescook@chromium.org>
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On Tue, 2021-08-17 at 23:05 -0700, Kees Cook wrote:
> 
> @@ -275,12 +275,11 @@ static void carl9170_tx_release(struct kref *ref)
>  	if (WARN_ON_ONCE(!ar))
>  		return;
>  
> 
> 
> 
> -	BUILD_BUG_ON(
> -	    offsetof(struct ieee80211_tx_info, status.ack_signal) != 20);
> -
> -	memset(&txinfo->status.ack_signal, 0,
> -	       sizeof(struct ieee80211_tx_info) -
> -	       offsetof(struct ieee80211_tx_info, status.ack_signal));
> +	/*
> +	 * Should this call ieee80211_tx_info_clear_status() instead of clearing
> +	 * manually? txinfo->status.rates do not seem to be used here.
> +	 */

Since you insist, I went digging :)

It should not, carl9170_tx_fill_rateinfo() has filled the rate
information before we get to this point.

johannes