cfg80211: Support key configuration for Beacon protection (BIGTK)

IEEE P802.11-REVmd/D3.0 adds support for protecting Beacon frames using
a new set of keys (BIGTK; key index 6..7) similarly to the way
group-addressed Robust Management frames are protected (IGTK; key index
4..5). Extend cfg80211 and nl80211 to allow the new BIGTK to be
configured. Add an extended feature flag to indicate driver support for
the new key index values to avoid array overflows in driver
implementations and also to indicate to user space when this
functionality is available.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Link: https://lore.kernel.org/r/20200222132548.20835-2-jouni@codeaurora.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 45 insertions, 11 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index ce55a2c05fe9..a75f72288139 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -368,7 +368,7 @@ const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_KEY] = { .type = NLA_NESTED, },
 	[NL80211_ATTR_KEY_DATA] = { .type = NLA_BINARY,
 				    .len = WLAN_MAX_KEY_LEN },
-	[NL80211_ATTR_KEY_IDX] = NLA_POLICY_MAX(NLA_U8, 5),
+	[NL80211_ATTR_KEY_IDX] = NLA_POLICY_MAX(NLA_U8, 7),
 	[NL80211_ATTR_KEY_CIPHER] = { .type = NLA_U32 },
 	[NL80211_ATTR_KEY_DEFAULT] = { .type = NLA_FLAG },
 	[NL80211_ATTR_KEY_SEQ] = { .type = NLA_BINARY, .len = 16 },
@@ -1037,7 +1037,7 @@ struct key_parse {
 	struct key_params p;
 	int idx;
 	int type;
-	bool def, defmgmt;
+	bool def, defmgmt, defbeacon;
 	bool def_uni, def_multi;
 };
 
@@ -1053,12 +1053,13 @@ static int nl80211_parse_key_new(struct genl_info *info, struct nlattr *key,
 
 	k->def = !!tb[NL80211_KEY_DEFAULT];
 	k->defmgmt = !!tb[NL80211_KEY_DEFAULT_MGMT];
+	k->defbeacon = !!tb[NL80211_KEY_DEFAULT_BEACON];
 
 	if (k->def) {
 		k->def_uni = true;
 		k->def_multi = true;
 	}
-	if (k->defmgmt)
+	if (k->defmgmt || k->defbeacon)
 		k->def_multi = true;
 
 	if (tb[NL80211_KEY_IDX])
@@ -1165,14 +1166,17 @@ static int nl80211_parse_key(struct genl_info *info, struct key_parse *k)
 	if (err)
 		return err;
 
-	if (k->def && k->defmgmt) {
-		GENL_SET_ERR_MSG(info, "key with def && defmgmt is invalid");
+	if ((k->def ? 1 : 0) + (k->defmgmt ? 1 : 0) +
+	    (k->defbeacon ? 1 : 0) > 1) {
+		GENL_SET_ERR_MSG(info,
+				 "key with multiple default flags is invalid");
 		return -EINVAL;
 	}
 
-	if (k->defmgmt) {
+	if (k->defmgmt || k->defbeacon) {
 		if (k->def_uni || !k->def_multi) {
-			GENL_SET_ERR_MSG(info, "defmgmt key must be mcast");
+			GENL_SET_ERR_MSG(info,
+					 "defmgmt/defbeacon key must be mcast");
 			return -EINVAL;
 		}
 	}
@@ -1184,14 +1188,20 @@ static int nl80211_parse_key(struct genl_info *info, struct key_parse *k)
 						 "defmgmt key idx not 4 or 5");
 				return -EINVAL;
 			}
+		} else if (k->defbeacon) {
+			if (k->idx < 6 || k->idx > 7) {
+				GENL_SET_ERR_MSG(info,
+						 "defbeacon key idx not 6 or 7");
+				return -EINVAL;
+			}
 		} else if (k->def) {
 			if (k->idx < 0 || k->idx > 3) {
 				GENL_SET_ERR_MSG(info, "def key idx not 0-3");
 				return -EINVAL;
 			}
 		} else {
-			if (k->idx < 0 || k->idx > 5) {
-				GENL_SET_ERR_MSG(info, "key idx not 0-5");
+			if (k->idx < 0 || k->idx > 7) {
+				GENL_SET_ERR_MSG(info, "key idx not 0-7");
 				return -EINVAL;
 			}
 		}
@@ -3817,8 +3827,14 @@ static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info)
 	void *hdr;
 	struct sk_buff *msg;
 
-	if (info->attrs[NL80211_ATTR_KEY_IDX])
+	if (info->attrs[NL80211_ATTR_KEY_IDX]) {
 		key_idx = nla_get_u8(info->attrs[NL80211_ATTR_KEY_IDX]);
+		if (key_idx > 5 &&
+		    !wiphy_ext_feature_isset(
+			    &rdev->wiphy,
+			    NL80211_EXT_FEATURE_BEACON_PROTECTION))
+			return -EINVAL;
+	}
 
 	if (info->attrs[NL80211_ATTR_MAC])
 		mac_addr = nla_data(info->attrs[NL80211_ATTR_MAC]);
@@ -3894,7 +3910,7 @@ static int nl80211_set_key(struct sk_buff *skb, struct genl_info *info)
 	/* Only support setting default key and
 	 * Extended Key ID action NL80211_KEY_SET_TX.
 	 */
-	if (!key.def && !key.defmgmt &&
+	if (!key.def && !key.defmgmt && !key.defbeacon &&
 	    !(key.p.mode == NL80211_KEY_SET_TX))
 		return -EINVAL;
 
@@ -3941,6 +3957,24 @@ static int nl80211_set_key(struct sk_buff *skb, struct genl_info *info)
 #ifdef CONFIG_CFG80211_WEXT
 		dev->ieee80211_ptr->wext.default_mgmt_key = key.idx;
 #endif
+	} else if (key.defbeacon) {
+		if (key.def_uni || !key.def_multi) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (!rdev->ops->set_default_beacon_key) {
+			err = -EOPNOTSUPP;
+			goto out;
+		}
+
+		err = nl80211_key_allowed(dev->ieee80211_ptr);
+		if (err)
+			goto out;
+
+		err = rdev_set_default_beacon_key(rdev, dev, key.idx);
+		if (err)
+			goto out;
 	} else if (key.p.mode == NL80211_KEY_SET_TX &&
 		   wiphy_ext_feature_isset(&rdev->wiphy,
 					   NL80211_EXT_FEATURE_EXT_KEY_ID)) {