[PATCH v2 1/3] ath10k: Fix shared WEP

[PATCH v2 1/3] ath10k: Fix shared WEP

[Sujith Manoharan]

From: Sujith Manoharan <c_manoha@qca.qualcomm.com>

When static keys are used in shared WEP, when a
station is associated, message 3 is sent with an
encrypted payload. But, for subsequent
authentications that are triggered without a
deauth, the auth frame is decrypted by the HW.

To handle this, check if the WEP keys have already
been set for the peer and if so, mark the
frame as decrypted. This scenario can happen
when a station changes its default TX key and initiates
a new authentication sequence.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
---
 drivers/net/wireless/ath/ath10k/mac.c | 25 ++++++++++++++++++++++++
 drivers/net/wireless/ath/ath10k/mac.h |  4 ++++
 drivers/net/wireless/ath/ath10k/wmi.c | 36 +++++++++++++++++++++++++++++++++++
 3 files changed, 65 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 1245ac8..fb95d4d 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -179,6 +179,31 @@ static int ath10k_clear_peer_keys(struct ath10k_vif *arvif,
 	return first_errno;
 }
 
+bool ath10k_mac_is_peer_wep_key_set(struct ath10k *ar, const u8 *addr,
+				    u8 keyidx)
+{
+	struct ath10k_peer *peer;
+	int i;
+
+	lockdep_assert_held(&ar->data_lock);
+
+	/* We don't know which vdev this peer belongs to,
+	 * since WMI doesn't give us that information.
+	 *
+	 * FIXME: multi-bss needs to be handled.
+	 */
+	peer = ath10k_peer_find(ar, 0, addr);
+	if (!peer)
+		return false;
+
+	for (i = 0; i < ARRAY_SIZE(peer->keys); i++) {
+		if (peer->keys[i] && peer->keys[i]->keyidx == keyidx)
+			return true;
+	}
+
+	return false;
+}
+
 static int ath10k_clear_vdev_key(struct ath10k_vif *arvif,
 				 struct ieee80211_key_conf *key)
 {
diff --git a/drivers/net/wireless/ath/ath10k/mac.h b/drivers/net/wireless/ath/ath10k/mac.h
index 4e3c989..6829611 100644
--- a/drivers/net/wireless/ath/ath10k/mac.h
+++ b/drivers/net/wireless/ath/ath10k/mac.h
@@ -21,6 +21,8 @@
 #include <net/mac80211.h>
 #include "core.h"
 
+#define WEP_KEYID_SHIFT 6
+
 struct ath10k_generic_iter {
 	struct ath10k *ar;
 	int ret;
@@ -41,6 +43,8 @@ void ath10k_mgmt_over_wmi_tx_work(struct work_struct *work);
 void ath10k_halt(struct ath10k *ar);
 void ath10k_mac_vif_beacon_free(struct ath10k_vif *arvif);
 void ath10k_drain_tx(struct ath10k *ar);
+bool ath10k_mac_is_peer_wep_key_set(struct ath10k *ar, const u8 *addr,
+				    u8 keyidx);
 
 static inline struct ath10k_vif *ath10k_vif_to_arvif(struct ieee80211_vif *vif)
 {
diff --git a/drivers/net/wireless/ath/ath10k/wmi.c b/drivers/net/wireless/ath/ath10k/wmi.c
index c300a53..c7e4b9f 100644
--- a/drivers/net/wireless/ath/ath10k/wmi.c
+++ b/drivers/net/wireless/ath/ath10k/wmi.c
@@ -1113,6 +1113,40 @@ static inline u8 get_rate_idx(u32 rate, enum ieee80211_band band)
 	return rate_idx;
 }
 
+/* If keys are configured, HW decrypts all frames
+ * with protected bit set. Mark such frames as decrypted.
+ */
+static void ath10k_wmi_handle_wep_reauth(struct ath10k *ar,
+					 struct sk_buff *skb,
+					 struct ieee80211_rx_status *status)
+{
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+	unsigned int hdrlen;
+	bool peer_key;
+	u8 *addr, keyidx;
+
+	if (!ieee80211_is_auth(hdr->frame_control) ||
+	    !ieee80211_has_protected(hdr->frame_control))
+		return;
+
+	hdrlen = ieee80211_hdrlen(hdr->frame_control);
+	if (skb->len < (hdrlen + IEEE80211_WEP_IV_LEN))
+		return;
+
+	keyidx = skb->data[hdrlen + (IEEE80211_WEP_IV_LEN - 1)] >> WEP_KEYID_SHIFT;
+	addr = ieee80211_get_SA(hdr);
+
+	spin_lock_bh(&ar->data_lock);
+	peer_key = ath10k_mac_is_peer_wep_key_set(ar, addr, keyidx);
+	spin_unlock_bh(&ar->data_lock);
+
+	if (peer_key) {
+		ath10k_dbg(ar, ATH10K_DBG_MAC,
+			   "mac wep key present for peer %pM\n", addr);
+		status->flag |= RX_FLAG_DECRYPTED;
+	}
+}
+
 static int ath10k_wmi_event_mgmt_rx(struct ath10k *ar, struct sk_buff *skb)
 {
 	struct wmi_mgmt_rx_event_v1 *ev_v1;
@@ -1200,6 +1234,8 @@ static int ath10k_wmi_event_mgmt_rx(struct ath10k *ar, struct sk_buff *skb)
 	hdr = (struct ieee80211_hdr *)skb->data;
 	fc = le16_to_cpu(hdr->frame_control);
 
+	ath10k_wmi_handle_wep_reauth(ar, skb, status);
+
 	/* FW delivers WEP Shared Auth frame with Protected Bit set and
 	 * encrypted payload. However in case of PMF it delivers decrypted
 	 * frames with Protected Bit set. */
-- 
2.1.3

[PATCH v2 2/3] ath10k: Fix locking for WEP keys

[Sujith Manoharan]

From: Sujith Manoharan <c_manoha@qca.qualcomm.com>

peer->keys needs to be protected by data_lock
since it is also accessed from the WMI path.

Both install() and clear() routines for peer
keys modify the key contents, so use the data_lock
to avoid races.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
---
 drivers/net/wireless/ath/ath10k/core.h | 2 ++
 drivers/net/wireless/ath/ath10k/mac.c  | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index 8f86bd3..73da1bb 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -218,6 +218,8 @@ struct ath10k_peer {
 	int vdev_id;
 	u8 addr[ETH_ALEN];
 	DECLARE_BITMAP(peer_ids, ATH10K_MAX_NUM_PEER_IDS);
+
+	/* protected by ar->data_lock */
 	struct ieee80211_key_conf *keys[WMI_MAX_KEY_INDEX + 1];
 };
 
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index fb95d4d..01de6f3 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -136,7 +136,9 @@ static int ath10k_install_peer_wep_keys(struct ath10k_vif *arvif,
 		if (ret)
 			return ret;
 
+		spin_lock_bh(&ar->data_lock);
 		peer->keys[i] = arvif->wep_keys[i];
+		spin_unlock_bh(&ar->data_lock);
 	}
 
 	return 0;
@@ -173,7 +175,9 @@ static int ath10k_clear_peer_keys(struct ath10k_vif *arvif,
 			ath10k_warn(ar, "failed to remove peer wep key %d: %d\n",
 				    i, ret);
 
+		spin_lock_bh(&ar->data_lock);
 		peer->keys[i] = NULL;
+		spin_unlock_bh(&ar->data_lock);
 	}
 
 	return first_errno;
-- 
2.1.3

[PATCH v2 3/3] ath10k: Fix bug reported by lockdep

[Sujith Manoharan]

From: Sujith Manoharan <c_manoha@qca.qualcomm.com>

ath10k_tx_wep_key_work() acquires conf_mutex, so
cancelling it when conf_mutex is already taken
in ath10k_remove_interface() is incorrect, so
move it outside the lock.

Snippet from the lockdep report:

kernel: ======================================================
kernel: [ INFO: possible circular locking dependency detected ]
kernel: 3.18.0-rc5-wl-debug #34 Tainted: G           O
kernel: -------------------------------------------------------
kernel: hostapd/451 is trying to acquire lock:
kernel:  ((&arvif->wep_key_work)){+.+...}, at: [<ffffffff810872d5>] flush_work+0x5/0x290
kernel: but task is already holding lock:
kernel:  (&ar->conf_mutex){+.+.+.}, at: [<ffffffffa0b99f00>] ath10k_remove_interface+0x40/0x290 [ath10k_core]
kernel: which lock already depends on the new lock.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
---
 drivers/net/wireless/ath/ath10k/mac.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 01de6f3..cf1e579 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -3043,10 +3043,10 @@ static void ath10k_remove_interface(struct ieee80211_hw *hw,
 	struct ath10k_vif *arvif = ath10k_vif_to_arvif(vif);
 	int ret;
 
-	mutex_lock(&ar->conf_mutex);
-
 	cancel_work_sync(&arvif->wep_key_work);
 
+	mutex_lock(&ar->conf_mutex);
+
 	spin_lock_bh(&ar->data_lock);
 	ath10k_mac_vif_beacon_cleanup(arvif);
 	spin_unlock_bh(&ar->data_lock);
-- 
2.1.3

Re: [PATCH v2 1/3] ath10k: Fix shared WEP

[Kalle Valo]

Sujith Manoharan <sujith@msujith.org> writes:

> From: Sujith Manoharan <c_manoha@qca.qualcomm.com>
>
> When static keys are used in shared WEP, when a
> station is associated, message 3 is sent with an
> encrypted payload. But, for subsequent
> authentications that are triggered without a
> deauth, the auth frame is decrypted by the HW.
>
> To handle this, check if the WEP keys have already
> been set for the peer and if so, mark the
> frame as decrypted. This scenario can happen
> when a station changes its default TX key and initiates
> a new authentication sequence.
>
> Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>

Thanks, all three applied.

-- 
Kalle Valo