Return-path: Received: from mga14.intel.com ([143.182.124.37]:55604 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755286Ab0DHD0E (ORCPT ); Wed, 7 Apr 2010 23:26:04 -0400 Subject: Re: [PATCH] mac80211: fix paged RX crypto From: Zhu Yi To: Johannes Berg Cc: John Linville , linux-wireless In-Reply-To: <1270632416.3858.6.camel@jlt3.sipsolutions.net> References: <1270632416.3858.6.camel@jlt3.sipsolutions.net> Content-Type: text/plain; charset="UTF-8" Date: Thu, 08 Apr 2010 11:22:31 +0800 Message-ID: <1270696951.10745.11.camel@debian> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, 2010-04-07 at 17:26 +0800, Johannes Berg wrote: > From: Johannes Berg > > WEP crypto was broken, but upon finding the problem > it is evident that other things were broken by the > paged RX patch as well. > > To fix it, for now move the linearising in front. > This means that we linearise all frames, which is > not at all what we want, but at least it fixes the > problem for now. > > Signed-off-by: Johannes Berg > Acked-by: Zhu Yi I thought it over. We don't need to handle nonlinear skb in ieee80211_get_mmie_keyidx(), because we only need to touch fields out of 802.11 header for management frames, and we have already skb_linearize all management frames before. Now we just need to handle WEP IV correctly. How about this patch? Signed-off-by: Zhu Yi diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 14366d4..a8f11f6 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -894,6 +894,7 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) rx->key = key; return RX_CONTINUE; } else { + u8 keyid; /* * The device doesn't give us the IV so we won't be * able to look up the key. That's ok though, we @@ -916,7 +917,8 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) * no need to call ieee80211_wep_get_keyidx, * it verifies a bunch of things we've done already */ - keyidx = rx->skb->data[hdrlen + 3] >> 6; + skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1); + keyidx = keyid >> 6; rx->key = rcu_dereference(rx->sdata->keys[keyidx]); @@ -937,9 +939,6 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) return RX_DROP_MONITOR; } - if (skb_linearize(rx->skb)) - return RX_DROP_UNUSABLE; - /* Check for weak IVs if possible */ if (rx->sta && rx->key->conf.alg == ALG_WEP && ieee80211_is_data(hdr->frame_control) && @@ -948,6 +947,9 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) ieee80211_wep_is_weak_iv(rx->skb, rx->key)) rx->sta->wep_weak_iv_count++; + if (skb_linearize(rx->skb)) + return RX_DROP_UNUSABLE; + switch (rx->key->conf.alg) { case ALG_WEP: result = ieee80211_crypto_wep_decrypt(rx);