mac80211: Drop unencrypted frames based on key setup (0c7c10c7) · Commits · 戴 / test

When using nl80211, we do not have a mechanism to set sdata->drop_unencrypted. Currently, this breaks code that is supposed to drop unencrypted frames when protection is expected since ieee80211_rx_h_decrypt() is optimized to not set rx->key when the frame is not protected. This patch modifies ieee80211_rx_h_decrypt() to set rx->key for all frames and only skip decryption if the frame is not protected. This allows ieee80211_drop_unencrypted() to correctly drop frames even if drop_unencrypted is not set. The changes here are not enough to handle all cases, though. Additional patches will be needed to implement proper IEEE 802.1X PAE for station mode (currently, this is only used for AP mode) and some additional rules are needed for MFP to drop unprotected Robust Action frames prior to having PTK and IGTK configured. In theory, the unprotected frames could and should be dropped in ieee80211_rx_h_decrypt(). However, due to the special case with EAPOL frames that have to be allowed to be received unprotected even when keys are set, it is simpler to only set rx->key and allow the ieee80211_frame_allowed() function to handle the actual dropping of data frames after 802.11->802.3 header conversion. In addition, unprotected robust management frames are dropped before they are processed. Signed-off-by:

Jouni Malinen <jouni.malinen@atheros.com> Signed-off-by:

John W. Linville <linville@tuxdriver.com>

net/mac80211/rx.c

+21 −9

Original line number	Diff line number	Diff line
		@@ -630,15 +630,6 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
		* possible.
		*/

		if (!ieee80211_has_protected(hdr->frame_control)) {
		if (!ieee80211_is_mgmt(hdr->frame_control) \|\|
		rx->sta == NULL \|\| !test_sta_flags(rx->sta, WLAN_STA_MFP))
		return RX_CONTINUE;
		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);
		if (mmie_keyidx < 0)
		return RX_CONTINUE;
		}

		/*
		* No point in finding a key and decrypting if the frame is neither
		* addressed to us nor a multicast frame.
		@@ -649,8 +640,14 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
		if (rx->sta)
		stakey = rcu_dereference(rx->sta->key);

		if (!ieee80211_has_protected(hdr->frame_control))
		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);

		if (!is_multicast_ether_addr(hdr->addr1) && stakey) {
		rx->key = stakey;
		/* Skip decryption if the frame is not protected. */
		if (!ieee80211_has_protected(hdr->frame_control))
		return RX_CONTINUE;
		} else if (mmie_keyidx >= 0) {
		/* Broadcast/multicast robust management frame / BIP */
		if ((rx->status->flag & RX_FLAG_DECRYPTED) &&
		@@ -661,6 +658,21 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
		mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
		return RX_DROP_MONITOR; /* unexpected BIP keyidx */
		rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
		} else if (!ieee80211_has_protected(hdr->frame_control)) {
		/*
		* The frame was not protected, so skip decryption. However, we
		* need to set rx->key if there is a key that could have been
		* used so that the frame may be dropped if encryption would
		* have been expected.
		*/
		struct ieee80211_key *key = NULL;
		if (ieee80211_is_mgmt(hdr->frame_control) &&
		is_multicast_ether_addr(hdr->addr1) &&
		(key = rcu_dereference(rx->sdata->default_mgmt_key)))
		rx->key = key;
		else if ((key = rcu_dereference(rx->sdata->default_key)))
		rx->key = key;
		return RX_CONTINUE;
		} else {
		/*
		* The device doesn't give us the IV so we won't be

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