Return-path: Received: from 128-177-27-249.ip.openhosting.com ([128.177.27.249]:46671 "EHLO jmalinen.user.openhosting.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756746AbYLaPmM (ORCPT ); Wed, 31 Dec 2008 10:42:12 -0500 Message-Id: <20081231154203.845811912@w1.fi> (sfid-20081231_164220_866308_493A6ED7) References: <20081231153834.840526845@w1.fi> Date: Wed, 31 Dec 2008 17:38:36 +0200 From: Jouni Malinen To: Johannes Berg Cc: linux-wireless@vger.kernel.org, Jouni Malinen Subject: [RFC 02/11] mac80211: 802.11w - CCMP for management frames Sender: linux-wireless-owner@vger.kernel.org List-ID: Extend CCMP to support encryption and decryption of unicast management frames. Signed-off-by: Jouni Malinen --- include/linux/ieee80211.h | 23 +++++++++++++++++++++++ net/mac80211/tx.c | 23 ++++++++++++++++++++++- net/mac80211/wpa.c | 18 ++++++++++++------ 3 files changed, 57 insertions(+), 7 deletions(-) --- wireless-testing.orig/net/mac80211/tx.c 2008-12-31 16:46:11.000000000 +0200 +++ wireless-testing/net/mac80211/tx.c 2008-12-31 16:54:08.000000000 +0200 @@ -331,6 +331,22 @@ ieee80211_tx_h_multicast_ps_buf(struct i 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) { @@ -430,10 +446,15 @@ ieee80211_tx_h_select_key(struct ieee802 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; } } --- wireless-testing.orig/net/mac80211/wpa.c 2008-12-31 16:46:11.000000000 +0200 +++ wireless-testing/net/mac80211/wpa.c 2008-12-31 16:54:27.000000000 +0200 @@ -268,7 +268,7 @@ static void ccmp_special_blocks(struct s int encrypted) { __le16 mask_fc; - int a4_included; + int a4_included, mgmt; u8 qos_tid; u8 *b_0, *aad; u16 data_len, len_a; @@ -279,12 +279,15 @@ static void ccmp_special_blocks(struct s 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); @@ -302,8 +305,10 @@ static void ccmp_special_blocks(struct s /* 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) */ @@ -449,7 +454,8 @@ ieee80211_crypto_ccmp_decrypt(struct iee 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; --- wireless-testing.orig/include/linux/ieee80211.h 2008-12-31 16:46:11.000000000 +0200 +++ wireless-testing/include/linux/ieee80211.h 2008-12-31 17:00:34.000000000 +0200 @@ -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, }; @@ -1186,6 +1187,28 @@ static inline u8 *ieee80211_get_DA(struc } /** + * 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)) { + /* + * Action frames, excluding Public Action frames, are Robust + * Management Frames. + */ + u8 *category = ((u8 *) hdr) + 24; + return *category != WLAN_CATEGORY_PUBLIC; + } + + return false; +} + +/** * ieee80211_fhss_chan_to_freq - get channel frequency * @channel: the FHSS channel * -- -- Jouni Malinen PGP id EFC895FA