staging: wfx: implement 802.11 key handling

wfx_set_key() mostly copy bytes on correct offsets. A big piece of code
for a simple work. Unfortunately, I did not found any way to factorize
it.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20190919142527.31797-20-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/Makefile

@@ -14,6 +14,7 @@ wfx-y := \
 	data_rx.o \
 	scan.o \
 	sta.o \
+	key.o \
 	main.o \
 	sta.o \
 	debug.o

drivers/staging/wfx/key.c

@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Key management related functions.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#include <net/mac80211.h>
+
+#include "key.h"
+#include "wfx.h"
+#include "hif_tx_mib.h"
+
+static int wfx_alloc_key(struct wfx_dev *wdev)
+{
+	int idx;
+
+	idx = ffs(~wdev->key_map) - 1;
+	if (idx < 0 || idx >= MAX_KEY_ENTRIES)
+		return -1;
+
+	wdev->key_map |= BIT(idx);
+	wdev->keys[idx].entry_index = idx;
+	return idx;
+}
+
+static void wfx_free_key(struct wfx_dev *wdev, int idx)
+{
+	BUG_ON(!(wdev->key_map & BIT(idx)));
+	memset(&wdev->keys[idx], 0, sizeof(wdev->keys[idx]));
+	wdev->key_map &= ~BIT(idx);
+}
+
+static uint8_t fill_wep_pair(struct hif_wep_pairwise_key *msg,
+			     struct ieee80211_key_conf *key, u8 *peer_addr)
+{
+	WARN_ON(key->keylen > sizeof(msg->key_data));
+	msg->key_length = key->keylen;
+	memcpy(msg->key_data, key->key, key->keylen);
+	ether_addr_copy(msg->peer_address, peer_addr);
+	return HIF_KEY_TYPE_WEP_PAIRWISE;
+}
+
+static uint8_t fill_wep_group(struct hif_wep_group_key *msg,
+			      struct ieee80211_key_conf *key)
+{
+	WARN_ON(key->keylen > sizeof(msg->key_data));
+	msg->key_id = key->keyidx;
+	msg->key_length = key->keylen;
+	memcpy(msg->key_data, key->key, key->keylen);
+	return HIF_KEY_TYPE_WEP_DEFAULT;
+}
+
+static uint8_t fill_tkip_pair(struct hif_tkip_pairwise_key *msg,
+			      struct ieee80211_key_conf *key, u8 *peer_addr)
+{
+	uint8_t *keybuf = key->key;
+
+	WARN_ON(key->keylen != sizeof(msg->tkip_key_data)
+			       + sizeof(msg->tx_mic_key)
+			       + sizeof(msg->rx_mic_key));
+	memcpy(msg->tkip_key_data, keybuf, sizeof(msg->tkip_key_data));
+	keybuf += sizeof(msg->tkip_key_data);
+	memcpy(msg->tx_mic_key, keybuf, sizeof(msg->tx_mic_key));
+	keybuf += sizeof(msg->tx_mic_key);
+	memcpy(msg->rx_mic_key, keybuf, sizeof(msg->rx_mic_key));
+	ether_addr_copy(msg->peer_address, peer_addr);
+	return HIF_KEY_TYPE_TKIP_PAIRWISE;
+}
+
+static uint8_t fill_tkip_group(struct hif_tkip_group_key *msg,
+			       struct ieee80211_key_conf *key,
+			       struct ieee80211_key_seq *seq,
+			       enum nl80211_iftype iftype)
+{
+	uint8_t *keybuf = key->key;
+
+	WARN_ON(key->keylen != sizeof(msg->tkip_key_data)
+			       + 2 * sizeof(msg->rx_mic_key));
+	msg->key_id = key->keyidx;
+	memcpy(msg->rx_sequence_counter, &seq->tkip.iv16, sizeof(seq->tkip.iv16));
+	memcpy(msg->rx_sequence_counter + sizeof(uint16_t), &seq->tkip.iv32, sizeof(seq->tkip.iv32));
+	memcpy(msg->tkip_key_data, keybuf, sizeof(msg->tkip_key_data));
+	keybuf += sizeof(msg->tkip_key_data);
+	if (iftype == NL80211_IFTYPE_AP)
+		// Use Tx MIC Key
+		memcpy(msg->rx_mic_key, keybuf + 0, sizeof(msg->rx_mic_key));
+	else
+		// Use Rx MIC Key
+		memcpy(msg->rx_mic_key, keybuf + 8, sizeof(msg->rx_mic_key));
+	return HIF_KEY_TYPE_TKIP_GROUP;
+}
+
+static uint8_t fill_ccmp_pair(struct hif_aes_pairwise_key *msg,
+			      struct ieee80211_key_conf *key, u8 *peer_addr)
+{
+	WARN_ON(key->keylen != sizeof(msg->aes_key_data));
+	ether_addr_copy(msg->peer_address, peer_addr);
+	memcpy(msg->aes_key_data, key->key, key->keylen);
+	return HIF_KEY_TYPE_AES_PAIRWISE;
+}
+
+static uint8_t fill_ccmp_group(struct hif_aes_group_key *msg,
+			       struct ieee80211_key_conf *key,
+			       struct ieee80211_key_seq *seq)
+{
+	WARN_ON(key->keylen != sizeof(msg->aes_key_data));
+	memcpy(msg->aes_key_data, key->key, key->keylen);
+	memcpy(msg->rx_sequence_counter, seq->ccmp.pn, sizeof(seq->ccmp.pn));
+	memreverse(msg->rx_sequence_counter, sizeof(seq->ccmp.pn));
+	msg->key_id = key->keyidx;
+	return HIF_KEY_TYPE_AES_GROUP;
+}
+
+static uint8_t fill_sms4_pair(struct hif_wapi_pairwise_key *msg,
+			      struct ieee80211_key_conf *key, u8 *peer_addr)
+{
+	uint8_t *keybuf = key->key;
+
+	WARN_ON(key->keylen != sizeof(msg->wapi_key_data)
+			       + sizeof(msg->mic_key_data));
+	ether_addr_copy(msg->peer_address, peer_addr);
+	memcpy(msg->wapi_key_data, keybuf, sizeof(msg->wapi_key_data));
+	keybuf += sizeof(msg->wapi_key_data);
+	memcpy(msg->mic_key_data, keybuf, sizeof(msg->mic_key_data));
+	msg->key_id = key->keyidx;
+	return HIF_KEY_TYPE_WAPI_PAIRWISE;
+}
+
+static uint8_t fill_sms4_group(struct hif_wapi_group_key *msg,
+			       struct ieee80211_key_conf *key)
+{
+	uint8_t *keybuf = key->key;
+
+	WARN_ON(key->keylen != sizeof(msg->wapi_key_data)
+			       + sizeof(msg->mic_key_data));
+	memcpy(msg->wapi_key_data, keybuf, sizeof(msg->wapi_key_data));
+	keybuf += sizeof(msg->wapi_key_data);
+	memcpy(msg->mic_key_data, keybuf, sizeof(msg->mic_key_data));
+	msg->key_id = key->keyidx;
+	return HIF_KEY_TYPE_WAPI_GROUP;
+}
+
+static uint8_t fill_aes_cmac_group(struct hif_igtk_group_key *msg,
+				   struct ieee80211_key_conf *key,
+				   struct ieee80211_key_seq *seq)
+{
+	WARN_ON(key->keylen != sizeof(msg->igtk_key_data));
+	memcpy(msg->igtk_key_data, key->key, key->keylen);
+	memcpy(msg->ipn, seq->aes_cmac.pn, sizeof(seq->aes_cmac.pn));
+	memreverse(msg->ipn, sizeof(seq->aes_cmac.pn));
+	msg->key_id = key->keyidx;
+	return HIF_KEY_TYPE_IGTK_GROUP;
+}
+
+static int wfx_add_key(struct wfx_vif *wvif, struct ieee80211_sta *sta,
+		       struct ieee80211_key_conf *key)
+{
+	int ret;
+	struct hif_req_add_key *k;
+	struct ieee80211_key_seq seq;
+	struct wfx_dev *wdev = wvif->wdev;
+	int idx = wfx_alloc_key(wvif->wdev);
+	bool pairwise = key->flags & IEEE80211_KEY_FLAG_PAIRWISE;
+
+	WARN_ON(key->flags & IEEE80211_KEY_FLAG_PAIRWISE && !sta);
+	ieee80211_get_key_rx_seq(key, 0, &seq);
+	if (idx < 0)
+		return -EINVAL;
+	k = &wdev->keys[idx];
+	k->int_id = wvif->id;
+	if (key->cipher == WLAN_CIPHER_SUITE_WEP40 || key->cipher ==  WLAN_CIPHER_SUITE_WEP104) {
+		if (pairwise)
+			k->type = fill_wep_pair(&k->key.wep_pairwise_key, key, sta->addr);
+		else
+			k->type = fill_wep_group(&k->key.wep_group_key, key);
+	} else if (key->cipher == WLAN_CIPHER_SUITE_TKIP) {
+		if (pairwise)
+			k->type = fill_tkip_pair(&k->key.tkip_pairwise_key, key, sta->addr);
+		else
+			k->type = fill_tkip_group(&k->key.tkip_group_key, key, &seq, wvif->vif->type);
+	} else if (key->cipher == WLAN_CIPHER_SUITE_CCMP) {
+		if (pairwise)
+			k->type = fill_ccmp_pair(&k->key.aes_pairwise_key, key, sta->addr);
+		else
+			k->type = fill_ccmp_group(&k->key.aes_group_key, key, &seq);
+	} else if (key->cipher ==  WLAN_CIPHER_SUITE_SMS4) {
+		if (pairwise)
+			k->type = fill_sms4_pair(&k->key.wapi_pairwise_key, key, sta->addr);
+		else
+			k->type = fill_sms4_group(&k->key.wapi_group_key, key);
+	} else if (key->cipher ==  WLAN_CIPHER_SUITE_AES_CMAC) {
+		k->type = fill_aes_cmac_group(&k->key.igtk_group_key, key, &seq);
+	} else {
+		dev_warn(wdev->dev, "unsupported key type %d\n", key->cipher);
+		wfx_free_key(wdev, idx);
+		return -EOPNOTSUPP;
+	}
+	ret = hif_add_key(wdev, k);
+	if (ret) {
+		wfx_free_key(wdev, idx);
+		return -EOPNOTSUPP;
+	}
+	key->flags |= IEEE80211_KEY_FLAG_PUT_IV_SPACE |
+		      IEEE80211_KEY_FLAG_RESERVE_TAILROOM;
+	key->hw_key_idx = idx;
+	return 0;
+}
+
+static int wfx_remove_key(struct wfx_vif *wvif, struct ieee80211_key_conf *key)
+{
+	WARN(key->hw_key_idx >= MAX_KEY_ENTRIES, "corrupted hw_key_idx");
+	wfx_free_key(wvif->wdev, key->hw_key_idx);
+	return hif_remove_key(wvif->wdev, key->hw_key_idx);
+}
+
+int wfx_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
+		struct ieee80211_vif *vif, struct ieee80211_sta *sta,
+		struct ieee80211_key_conf *key)
+{
+	int ret = -EOPNOTSUPP;
+	struct wfx_vif *wvif = (struct wfx_vif *) vif->drv_priv;
+
+	mutex_lock(&wvif->wdev->conf_mutex);
+	if (cmd == SET_KEY)
+		ret = wfx_add_key(wvif, sta, key);
+	if (cmd == DISABLE_KEY)
+		ret = wfx_remove_key(wvif, key);
+	mutex_unlock(&wvif->wdev->conf_mutex);
+	return ret;
+}
+
+int wfx_upload_keys(struct wfx_vif *wvif)
+{
+	int i;
+	struct hif_req_add_key *key;
+	struct wfx_dev *wdev = wvif->wdev;
+
+	for (i = 0; i < ARRAY_SIZE(wdev->keys); i++) {
+		if (wdev->key_map & BIT(i)) {
+			key = &wdev->keys[i];
+			if (key->int_id == wvif->id)
+				hif_add_key(wdev, key);
+		}
+	}
+	return 0;
+}
+
+void wfx_wep_key_work(struct work_struct *work)
+{
+	struct wfx_vif *wvif = container_of(work, struct wfx_vif, wep_key_work);
+
+	wfx_tx_flush(wvif->wdev);
+	hif_wep_default_key_id(wvif, wvif->wep_default_key_id);
+	wfx_pending_requeue(wvif->wdev, wvif->wep_pending_skb);
+	wvif->wep_pending_skb = NULL;
+	wfx_tx_unlock(wvif->wdev);
+}

drivers/staging/wfx/key.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Implementation of mac80211 API.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#ifndef WFX_KEY_H
+#define WFX_KEY_H
+
+#include <net/mac80211.h>
+
+struct wfx_dev;
+struct wfx_vif;
+
+int wfx_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
+		struct ieee80211_vif *vif, struct ieee80211_sta *sta,
+		struct ieee80211_key_conf *key);
+int wfx_upload_keys(struct wfx_vif *wvif);
+void wfx_wep_key_work(struct work_struct *work);
+
+#endif /* WFX_STA_H */

drivers/staging/wfx/main.c

@@ -27,6 +27,7 @@
 #include "bus.h"
 #include "bh.h"
 #include "sta.h"
+#include "key.h"
 #include "debug.h"
 #include "data_tx.h"
 #include "secure_link.h"
@@ -56,6 +57,7 @@ static const struct ieee80211_ops wfx_ops = {
 	.remove_interface	= wfx_remove_interface,
 	.tx			= wfx_tx,
 	.hw_scan		= wfx_hw_scan,
+	.set_key		= wfx_set_key,
 };
 
 bool wfx_api_older_than(struct wfx_dev *wdev, int major, int minor)

drivers/staging/wfx/sta.c

@@ -9,6 +9,7 @@
 
 #include "sta.h"
 #include "wfx.h"
+#include "key.h"
 #include "scan.h"
 #include "hif_tx_mib.h"
 
@@ -162,6 +163,9 @@ int wfx_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 	INIT_WORK(&wvif->mcast_stop_work, wfx_mcast_stop_work);
 	timer_setup(&wvif->mcast_timeout, wfx_mcast_timeout, 0);
 
+	wvif->wep_default_key_id = -1;
+	INIT_WORK(&wvif->wep_key_work, wfx_wep_key_work);
+
 	sema_init(&wvif->scan.lock, 1);
 	INIT_WORK(&wvif->scan.work, wfx_scan_work);
 	INIT_DELAYED_WORK(&wvif->scan.timeout, wfx_scan_timeout);

drivers/staging/wfx/wfx.h

@@ -48,6 +48,9 @@ struct wfx_dev {
 	int			tx_burst_idx;
 	atomic_t		tx_lock;
 
+	u32			key_map;
+	struct hif_req_add_key	keys[MAX_KEY_ENTRIES];
+
 	struct hif_rx_stats	rx_stats;
 	struct mutex		rx_stats_lock;
 
@@ -73,6 +76,9 @@ struct wfx_vif {
 	struct work_struct	mcast_start_work;
 	struct work_struct	mcast_stop_work;
 
+	s8			wep_default_key_id;
+	struct sk_buff		*wep_pending_skb;
+	struct work_struct	wep_key_work;
 
 	struct tx_policy_cache	tx_policy_cache;
 	struct work_struct	tx_policy_upload_work;
@@ -120,6 +126,19 @@ static inline struct wfx_vif *wvif_iterate(struct wfx_dev *wdev, struct wfx_vif
 	return NULL;
 }
 
+static inline void memreverse(uint8_t *src, uint8_t length)
+{
+	uint8_t *lo = src;
+	uint8_t *hi = src + length - 1;
+	uint8_t swap;
+
+	while (lo < hi) {
+		swap = *lo;
+		*lo++ = *hi;
+		*hi-- = swap;
+	}
+}
+
 static inline int memzcmp(void *src, unsigned int size)
 {
 	uint8_t *buf = src;