From fb7333367632c67d8b6b06fb8d906cdabb11b02a Mon Sep 17 00:00:00 2001 From: Jouni Malinen Date: Thu, 8 Jan 2009 13:32:00 +0200 Subject: [PATCH] mac80211: 802.11w - CCMP for management frames Extend CCMP to support encryption and decryption of unicast management frames. Signed-off-by: Jouni Malinen Acked-by: Johannes Berg Signed-off-by: John W. Linville --- include/linux/ieee80211.h | 30 ++++++++++++++++++++++++++++++ net/mac80211/tx.c | 23 ++++++++++++++++++++++- net/mac80211/wpa.c | 18 ++++++++++++------ 3 files changed, 64 insertions(+), 7 deletions(-) diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h index cade2556af0e..d5165895f316 100644 --- a/include/linux/ieee80211.h +++ b/include/linux/ieee80211.h @@ -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 diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index cd6bc87eec73..50c6c4fabea5 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -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; } } diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index 7aa63caf8d50..aff46adde3f0 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -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; -- 2.39.5