From: David Bauer Date: Thu, 16 Apr 2020 19:30:27 +0000 (+0200) Subject: mac80211: drop data frames without key on encrypted links X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=0f1b5ce2f5d07c1358f2da417133cd18e62fd9b9;p=oweals%2Fopenwrt.git mac80211: drop data frames without key on encrypted links If we know that we have an encrypted link (based on having had a key configured for TX in the past) then drop all data frames in the key selection handler if there's no key anymore. This fixes an issue with mac80211 internal TXQs - there we can buffer frames for an encrypted link, but then if the key is no longer there when they're dequeued, the frames are sent without encryption. This happens if a station is disconnected while the frames are still on the TXQ. Detecting that a link should be encrypted based on a first key having been configured for TX is fine as there are no use cases for a connection going from with encryption to no encryption. With extended key IDs, however, there is a case of having a key configured for only decryption, so we can't just trigger this behaviour on a key being configured. Cc: stable@vger.kernel.org Reported-by: Jouni Malinen Signed-off-by: Johannes Berg Signed-off-by: Luca Coelho Signed-off-by: David Bauer --- diff --git a/package/kernel/mac80211/patches/subsys/314-mac80211-drop-data-frames-without-key-on-encrypted-l.patch b/package/kernel/mac80211/patches/subsys/314-mac80211-drop-data-frames-without-key-on-encrypted-l.patch new file mode 100644 index 0000000000..54e09af3b3 --- /dev/null +++ b/package/kernel/mac80211/patches/subsys/314-mac80211-drop-data-frames-without-key-on-encrypted-l.patch @@ -0,0 +1,148 @@ +From a0761a301746ec2d92d7fcb82af69c0a6a4339aa Mon Sep 17 00:00:00 2001 +From: Johannes Berg +Date: Thu, 26 Mar 2020 15:09:42 +0200 +Subject: mac80211: drop data frames without key on encrypted links + +If we know that we have an encrypted link (based on having had +a key configured for TX in the past) then drop all data frames +in the key selection handler if there's no key anymore. + +This fixes an issue with mac80211 internal TXQs - there we can +buffer frames for an encrypted link, but then if the key is no +longer there when they're dequeued, the frames are sent without +encryption. This happens if a station is disconnected while the +frames are still on the TXQ. + +Detecting that a link should be encrypted based on a first key +having been configured for TX is fine as there are no use cases +for a connection going from with encryption to no encryption. +With extended key IDs, however, there is a case of having a key +configured for only decryption, so we can't just trigger this +behaviour on a key being configured. + +Cc: stable@vger.kernel.org +Reported-by: Jouni Malinen +Signed-off-by: Johannes Berg +Signed-off-by: Luca Coelho +--- + net/mac80211/debugfs_sta.c | 3 ++- + net/mac80211/key.c | 20 ++++++++++++-------- + net/mac80211/sta_info.h | 1 + + net/mac80211/tx.c | 12 +++++++++--- + 4 files changed, 24 insertions(+), 12 deletions(-) + +--- a/net/mac80211/debugfs_sta.c ++++ b/net/mac80211/debugfs_sta.c +@@ -5,7 +5,7 @@ + * Copyright 2007 Johannes Berg + * Copyright 2013-2014 Intel Mobile Communications GmbH + * Copyright(c) 2016 Intel Deutschland GmbH +- * Copyright (C) 2018 - 2019 Intel Corporation ++ * Copyright (C) 2018 - 2020 Intel Corporation + */ + + #include +@@ -78,6 +78,7 @@ static const char * const sta_flag_names + FLAG(MPSP_OWNER), + FLAG(MPSP_RECIPIENT), + FLAG(PS_DELIVER), ++ FLAG(USES_ENCRYPTION), + #undef FLAG + }; + +--- a/net/mac80211/key.c ++++ b/net/mac80211/key.c +@@ -6,7 +6,7 @@ + * Copyright 2007-2008 Johannes Berg + * Copyright 2013-2014 Intel Mobile Communications GmbH + * Copyright 2015-2017 Intel Deutschland GmbH +- * Copyright 2018-2019 Intel Corporation ++ * Copyright 2018-2020 Intel Corporation + */ + + #include +@@ -262,22 +262,29 @@ static void ieee80211_key_disable_hw_acc + sta ? sta->sta.addr : bcast_addr, ret); + } + +-int ieee80211_set_tx_key(struct ieee80211_key *key) ++static int _ieee80211_set_tx_key(struct ieee80211_key *key, bool force) + { + struct sta_info *sta = key->sta; + struct ieee80211_local *local = key->local; + + assert_key_lock(local); + ++ set_sta_flag(sta, WLAN_STA_USES_ENCRYPTION); ++ + sta->ptk_idx = key->conf.keyidx; + +- if (!ieee80211_hw_check(&local->hw, AMPDU_KEYBORDER_SUPPORT)) ++ if (force || !ieee80211_hw_check(&local->hw, AMPDU_KEYBORDER_SUPPORT)) + clear_sta_flag(sta, WLAN_STA_BLOCK_BA); + ieee80211_check_fast_xmit(sta); + + return 0; + } + ++int ieee80211_set_tx_key(struct ieee80211_key *key) ++{ ++ return _ieee80211_set_tx_key(key, false); ++} ++ + static void ieee80211_pairwise_rekey(struct ieee80211_key *old, + struct ieee80211_key *new) + { +@@ -441,11 +448,8 @@ static int ieee80211_key_replace(struct + if (pairwise) { + rcu_assign_pointer(sta->ptk[idx], new); + if (new && +- !(new->conf.flags & IEEE80211_KEY_FLAG_NO_AUTO_TX)) { +- sta->ptk_idx = idx; +- clear_sta_flag(sta, WLAN_STA_BLOCK_BA); +- ieee80211_check_fast_xmit(sta); +- } ++ !(new->conf.flags & IEEE80211_KEY_FLAG_NO_AUTO_TX)) ++ _ieee80211_set_tx_key(new, true); + } else { + rcu_assign_pointer(sta->gtk[idx], new); + } +--- a/net/mac80211/sta_info.h ++++ b/net/mac80211/sta_info.h +@@ -98,6 +98,7 @@ enum ieee80211_sta_info_flags { + WLAN_STA_MPSP_OWNER, + WLAN_STA_MPSP_RECIPIENT, + WLAN_STA_PS_DELIVER, ++ WLAN_STA_USES_ENCRYPTION, + + NUM_WLAN_STA_FLAGS, + }; +--- a/net/mac80211/tx.c ++++ b/net/mac80211/tx.c +@@ -590,10 +590,13 @@ ieee80211_tx_h_select_key(struct ieee802 + struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb); + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data; + +- if (unlikely(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT)) ++ if (unlikely(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT)) { + tx->key = NULL; +- else if (tx->sta && +- (key = rcu_dereference(tx->sta->ptk[tx->sta->ptk_idx]))) ++ return TX_CONTINUE; ++ } ++ ++ if (tx->sta && ++ (key = rcu_dereference(tx->sta->ptk[tx->sta->ptk_idx]))) + tx->key = key; + else if (ieee80211_is_group_privacy_action(tx->skb) && + (key = rcu_dereference(tx->sdata->default_multicast_key))) +@@ -654,6 +657,9 @@ ieee80211_tx_h_select_key(struct ieee802 + if (!skip_hw && tx->key && + tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) + info->control.hw_key = &tx->key->conf; ++ } else if (!ieee80211_is_mgmt(hdr->frame_control) && tx->sta && ++ test_sta_flag(tx->sta, WLAN_STA_USES_ENCRYPTION)) { ++ return TX_DROP; + } + + return TX_CONTINUE;