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Commit fb733336 authored by Jouni Malinen's avatar Jouni Malinen Committed by John W. Linville
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mac80211: 802.11w - CCMP for management frames 



Extend CCMP to support encryption and decryption of unicast management
frames.

Signed-off-by: default avatarJouni Malinen <j@w1.fi>
Acked-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 5394af4d

include/linux/ieee80211.h

+30 −0
Original line number Diff line number Diff line
@@ -1030,6 +1030,7 @@ enum ieee80211_category { 
	WLAN_CATEGORY_QOS = 1,

	WLAN_CATEGORY_DLS = 2,

	WLAN_CATEGORY_BACK = 3,

	WLAN_CATEGORY_PUBLIC = 4,

	WLAN_CATEGORY_WMM = 17,

};
@@ -1185,6 +1186,35 @@ static inline u8 *ieee80211_get_DA(struct ieee80211_hdr *hdr) 
		return hdr->addr1;

}



/**

 * ieee80211_is_robust_mgmt_frame - check if frame is a robust management frame

 * @hdr: the frame (buffer must include at least the first octet of payload)

 */

static inline bool ieee80211_is_robust_mgmt_frame(struct ieee80211_hdr *hdr)

{

	if (ieee80211_is_disassoc(hdr->frame_control) ||

	    ieee80211_is_deauth(hdr->frame_control))

		return true;



	if (ieee80211_is_action(hdr->frame_control)) {

		u8 *category;



		/*

		 * Action frames, excluding Public Action frames, are Robust

		 * Management Frames. However, if we are looking at a Protected

		 * frame, skip the check since the data may be encrypted and

		 * the frame has already been found to be a Robust Management

		 * Frame (by the other end).

		 */

		if (ieee80211_has_protected(hdr->frame_control))

			return true;

		category = ((u8 *) hdr) + 24;

		return *category != WLAN_CATEGORY_PUBLIC;

	}



	return false;

}



/**

 * ieee80211_fhss_chan_to_freq - get channel frequency

 * @channel: the FHSS channel

net/mac80211/tx.c

+22 −1
Original line number Diff line number Diff line
@@ -330,6 +330,22 @@ ieee80211_tx_h_multicast_ps_buf(struct ieee80211_tx_data *tx) 
	return TX_CONTINUE;

}



static int ieee80211_use_mfp(__le16 fc, struct sta_info *sta,

			     struct sk_buff *skb)

{

	if (!ieee80211_is_mgmt(fc))

		return 0;



	if (sta == NULL || !test_sta_flags(sta, WLAN_STA_MFP))

		return 0;



	if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *)

					    skb->data))

		return 0;



	return 1;

}



static ieee80211_tx_result

ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)

{
@@ -428,10 +444,15 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx) 
			if (ieee80211_is_auth(hdr->frame_control))

				break;

		case ALG_TKIP:

		case ALG_CCMP:

			if (!ieee80211_is_data_present(hdr->frame_control))

				tx->key = NULL;

			break;

		case ALG_CCMP:

			if (!ieee80211_is_data_present(hdr->frame_control) &&

			    !ieee80211_use_mfp(hdr->frame_control, tx->sta,

					       tx->skb))

				tx->key = NULL;

			break;

		}

	}

net/mac80211/wpa.c

+12 −6
Original line number Diff line number Diff line
@@ -266,7 +266,7 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, 
				int encrypted)

{

	__le16 mask_fc;

	int a4_included;

	int a4_included, mgmt;

	u8 qos_tid;

	u8 *b_0, *aad;

	u16 data_len, len_a;
@@ -277,12 +277,15 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, 
	aad = scratch + 4 * AES_BLOCK_LEN;



	/*

	 * Mask FC: zero subtype b4 b5 b6

	 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)

	 * Retry, PwrMgt, MoreData; set Protected

	 */

	mgmt = ieee80211_is_mgmt(hdr->frame_control);

	mask_fc = hdr->frame_control;

	mask_fc &= ~cpu_to_le16(0x0070 | IEEE80211_FCTL_RETRY |

	mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |

				IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);

	if (!mgmt)

		mask_fc &= ~cpu_to_le16(0x0070);

	mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);



	hdrlen = ieee80211_hdrlen(hdr->frame_control);
@@ -300,8 +303,10 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, 


	/* First block, b_0 */

	b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */

	/* Nonce: QoS Priority | A2 | PN */

	b_0[1] = qos_tid;

	/* Nonce: Nonce Flags | A2 | PN

	 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)

	 */

	b_0[1] = qos_tid | (mgmt << 4);

	memcpy(&b_0[2], hdr->addr2, ETH_ALEN);

	memcpy(&b_0[8], pn, CCMP_PN_LEN);

	/* l(m) */
@@ -446,7 +451,8 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) 


	hdrlen = ieee80211_hdrlen(hdr->frame_control);



	if (!ieee80211_is_data(hdr->frame_control))

	if (!ieee80211_is_data(hdr->frame_control) &&

	    !ieee80211_is_robust_mgmt_frame(hdr))

		return RX_CONTINUE;



	data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;