mac80211: add APIs to allow keeping connections after WoWLAN

In order to be able to (securely) keep connections alive after
the system was suspended for WoWLAN, we need some additional
APIs. We already have API (ieee80211_gtk_rekey_notify) to tell
wpa_supplicant about the new replay counter if GTK rekeying
was done by the device while the host was asleep, but that's
not sufficient.

If GTK rekeying wasn't done, we need to tell the host about
sequence counters for the GTK (and PTK regardless of rekeying)
that was used while asleep, add ieee80211_set_key_rx_seq() for
that.

If GTK rekeying was done, then we need to be able to disable
the old keys (with ieee80211_remove_key()) and allocate the
new GTK key(s) in mac80211 (with ieee80211_gtk_rekey_add()).

If protocol offload (e.g. ARP) is implemented, then also the
TX sequence counter for the PTK must be updated, using the new
ieee80211_set_key_tx_seq() function.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 148 insertions, 8 deletions

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index e39cc91d0cf1..620677e897bd 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -93,6 +93,9 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 
 	might_sleep();
 
+	if (key->flags & KEY_FLAG_TAINTED)
+		return -EINVAL;
+
 	if (!key->local->ops->set_key)
 		goto out_unsupported;
 
@@ -455,6 +458,7 @@ int ieee80211_key_link(struct ieee80211_key *key,
 		       struct ieee80211_sub_if_data *sdata,
 		       struct sta_info *sta)
 {
+	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_key *old_key;
 	int idx, ret;
 	bool pairwise;
@@ -484,10 +488,13 @@ int ieee80211_key_link(struct ieee80211_key *key,
 
 	ieee80211_debugfs_key_add(key);
 
-	ret = ieee80211_key_enable_hw_accel(key);
-
-	if (ret)
-		ieee80211_key_free(key, true);
+	if (!local->wowlan) {
+		ret = ieee80211_key_enable_hw_accel(key);
+		if (ret)
+			ieee80211_key_free(key, true);
+	} else {
+		ret = 0;
+	}
 
 	mutex_unlock(&sdata->local->key_mtx);
 
@@ -540,7 +547,7 @@ void ieee80211_iter_keys(struct ieee80211_hw *hw,
 			 void *iter_data)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
-	struct ieee80211_key *key;
+	struct ieee80211_key *key, *tmp;
 	struct ieee80211_sub_if_data *sdata;
 
 	ASSERT_RTNL();
@@ -548,13 +555,14 @@ void ieee80211_iter_keys(struct ieee80211_hw *hw,
 	mutex_lock(&local->key_mtx);
 	if (vif) {
 		sdata = vif_to_sdata(vif);
-		list_for_each_entry(key, &sdata->key_list, list)
+		list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
 			iter(hw, &sdata->vif,
 			     key->sta ? &key->sta->sta : NULL,
 			     &key->conf, iter_data);
 	} else {
 		list_for_each_entry(sdata, &local->interfaces, list)
-			list_for_each_entry(key, &sdata->key_list, list)
+			list_for_each_entry_safe(key, tmp,
+						 &sdata->key_list, list)
 				iter(hw, &sdata->vif,
 				     key->sta ? &key->sta->sta : NULL,
 				     &key->conf, iter_data);
@@ -751,3 +759,135 @@ void ieee80211_get_key_rx_seq(struct ieee80211_key_conf *keyconf,
 	}
 }
 EXPORT_SYMBOL(ieee80211_get_key_rx_seq);
+
+void ieee80211_set_key_tx_seq(struct ieee80211_key_conf *keyconf,
+			      struct ieee80211_key_seq *seq)
+{
+	struct ieee80211_key *key;
+	u64 pn64;
+
+	key = container_of(keyconf, struct ieee80211_key, conf);
+
+	switch (key->conf.cipher) {
+	case WLAN_CIPHER_SUITE_TKIP:
+		key->u.tkip.tx.iv32 = seq->tkip.iv32;
+		key->u.tkip.tx.iv16 = seq->tkip.iv16;
+		break;
+	case WLAN_CIPHER_SUITE_CCMP:
+		pn64 = (u64)seq->ccmp.pn[5] |
+		       ((u64)seq->ccmp.pn[4] << 8) |
+		       ((u64)seq->ccmp.pn[3] << 16) |
+		       ((u64)seq->ccmp.pn[2] << 24) |
+		       ((u64)seq->ccmp.pn[1] << 32) |
+		       ((u64)seq->ccmp.pn[0] << 40);
+		atomic64_set(&key->u.ccmp.tx_pn, pn64);
+		break;
+	case WLAN_CIPHER_SUITE_AES_CMAC:
+		pn64 = (u64)seq->aes_cmac.pn[5] |
+		       ((u64)seq->aes_cmac.pn[4] << 8) |
+		       ((u64)seq->aes_cmac.pn[3] << 16) |
+		       ((u64)seq->aes_cmac.pn[2] << 24) |
+		       ((u64)seq->aes_cmac.pn[1] << 32) |
+		       ((u64)seq->aes_cmac.pn[0] << 40);
+		atomic64_set(&key->u.aes_cmac.tx_pn, pn64);
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(ieee80211_set_key_tx_seq);
+
+void ieee80211_set_key_rx_seq(struct ieee80211_key_conf *keyconf,
+			      int tid, struct ieee80211_key_seq *seq)
+{
+	struct ieee80211_key *key;
+	u8 *pn;
+
+	key = container_of(keyconf, struct ieee80211_key, conf);
+
+	switch (key->conf.cipher) {
+	case WLAN_CIPHER_SUITE_TKIP:
+		if (WARN_ON(tid < 0 || tid >= IEEE80211_NUM_TIDS))
+			return;
+		key->u.tkip.rx[tid].iv32 = seq->tkip.iv32;
+		key->u.tkip.rx[tid].iv16 = seq->tkip.iv16;
+		break;
+	case WLAN_CIPHER_SUITE_CCMP:
+		if (WARN_ON(tid < -1 || tid >= IEEE80211_NUM_TIDS))
+			return;
+		if (tid < 0)
+			pn = key->u.ccmp.rx_pn[IEEE80211_NUM_TIDS];
+		else
+			pn = key->u.ccmp.rx_pn[tid];
+		memcpy(pn, seq->ccmp.pn, IEEE80211_CCMP_PN_LEN);
+		break;
+	case WLAN_CIPHER_SUITE_AES_CMAC:
+		if (WARN_ON(tid != 0))
+			return;
+		pn = key->u.aes_cmac.rx_pn;
+		memcpy(pn, seq->aes_cmac.pn, IEEE80211_CMAC_PN_LEN);
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(ieee80211_set_key_rx_seq);
+
+void ieee80211_remove_key(struct ieee80211_key_conf *keyconf)
+{
+	struct ieee80211_key *key;
+
+	key = container_of(keyconf, struct ieee80211_key, conf);
+
+	assert_key_lock(key->local);
+
+	/*
+	 * if key was uploaded, we assume the driver will/has remove(d)
+	 * it, so adjust bookkeeping accordingly
+	 */
+	if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
+		key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
+
+		if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
+		      (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
+		      (key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
+			increment_tailroom_need_count(key->sdata);
+	}
+
+	ieee80211_key_free(key, false);
+}
+EXPORT_SYMBOL_GPL(ieee80211_remove_key);
+
+struct ieee80211_key_conf *
+ieee80211_gtk_rekey_add(struct ieee80211_vif *vif,
+			struct ieee80211_key_conf *keyconf)
+{
+	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_key *key;
+	int err;
+
+	if (WARN_ON(!local->wowlan))
+		return ERR_PTR(-EINVAL);
+
+	if (WARN_ON(vif->type != NL80211_IFTYPE_STATION))
+		return ERR_PTR(-EINVAL);
+
+	key = ieee80211_key_alloc(keyconf->cipher, keyconf->keyidx,
+				  keyconf->keylen, keyconf->key,
+				  0, NULL);
+	if (IS_ERR(key))
+		return ERR_PTR(PTR_ERR(key));
+
+	if (sdata->u.mgd.mfp != IEEE80211_MFP_DISABLED)
+		key->conf.flags |= IEEE80211_KEY_FLAG_RX_MGMT;
+
+	err = ieee80211_key_link(key, sdata, NULL);
+	if (err)
+		return ERR_PTR(err);
+
+	return &key->conf;
+}
+EXPORT_SYMBOL_GPL(ieee80211_gtk_rekey_add);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index d23c5a705a68..e1b34a18b243 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1453,8 +1453,8 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 		local->resuming = true;
 
 	if (local->wowlan) {
-		local->wowlan = false;
 		res = drv_resume(local);
+		local->wowlan = false;
 		if (res < 0) {
 			local->resuming = false;
 			return res;