nl80211 : Add support for configuring MFP

NL80211_CMD_ASSOCIATE request must be able to indicate whether
management frame protection (IEEE 802.11w) is being used. mac80211 was
able to use MFP in client mode only with WEXT, but the new
NL80211_ATTR_USE_MFP attribute will allow this to be done with
nl80211, too.

Since we are currently using nl80211 for MFP only with drivers that
use user space SME, only MFP disabled and required values are
used. However, the NL80211_ATTR_USE_MFP attribute is an enum that can
be extended with MFP optional in the future, if that is needed with
some drivers (e.g., if the RSN IE is generated by the driver).

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/nl80211.h

@@ -494,6 +494,11 @@ enum nl80211_commands {
  * @NL80211_ATTR_TIMED_OUT: a flag indicating than an operation timed out; this
  *	is used, e.g., with %NL80211_CMD_AUTHENTICATE event
  *
+ * @NL80211_ATTR_USE_MFP: Whether management frame protection (IEEE 802.11w) is
+ *	used for the association (&enum nl80211_mfp, represented as a u32);
+ *	this attribute can be used
+ *	with %NL80211_CMD_ASSOCIATE request
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -596,6 +601,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_TIMED_OUT,
 
+	NL80211_ATTR_USE_MFP,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -1179,4 +1186,14 @@ enum nl80211_key_type {
 	NL80211_KEYTYPE_PEERKEY,
 };
 
+/**
+ * enum nl80211_mfp - Management frame protection state
+ * @NL80211_MFP_NO: Management frame protection not used
+ * @NL80211_MFP_REQUIRED: Management frame protection required
+ */
+enum nl80211_mfp {
+	NL80211_MFP_NO,
+	NL80211_MFP_REQUIRED,
+};
+
 #endif /* __LINUX_NL80211_H */

include/net/cfg80211.h

@@ -672,6 +672,7 @@ struct cfg80211_auth_request {
  * @ssid_len: Length of ssid in octets
  * @ie: Extra IEs to add to (Re)Association Request frame or %NULL
  * @ie_len: Length of ie buffer in octets
+ * @use_mfp: Use management frame protection (IEEE 802.11w) in this association
  */
 struct cfg80211_assoc_request {
 	struct ieee80211_channel *chan;
@@ -680,6 +681,7 @@ struct cfg80211_assoc_request {
 	size_t ssid_len;
 	const u8 *ie;
 	size_t ie_len;
+	bool use_mfp;
 };
 
 /**

net/mac80211/cfg.c

@@ -1253,6 +1253,14 @@ static int ieee80211_assoc(struct wiphy *wiphy, struct net_device *dev,
 	if (ret)
 		return ret;
 
+	if (req->use_mfp) {
+		sdata->u.mgd.mfp = IEEE80211_MFP_REQUIRED;
+		sdata->u.mgd.flags |= IEEE80211_STA_MFP_ENABLED;
+	} else {
+		sdata->u.mgd.mfp = IEEE80211_MFP_DISABLED;
+		sdata->u.mgd.flags &= ~IEEE80211_STA_MFP_ENABLED;
+	}
+
 	sdata->u.mgd.flags |= IEEE80211_STA_EXT_SME;
 	sdata->u.mgd.state = IEEE80211_STA_MLME_ASSOCIATE;
 	ieee80211_sta_req_auth(sdata);

net/wireless/nl80211.c

@@ -122,6 +122,7 @@ static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
 	[NL80211_ATTR_REASON_CODE] = { .type = NLA_U16 },
 	[NL80211_ATTR_FREQ_FIXED] = { .type = NLA_FLAG },
 	[NL80211_ATTR_TIMED_OUT] = { .type = NLA_FLAG },
+	[NL80211_ATTR_USE_MFP] = { .type = NLA_U32 },
 };
 
 /* IE validation */
@@ -3012,6 +3013,17 @@ static int nl80211_associate(struct sk_buff *skb, struct genl_info *info)
 		req.ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
 	}
 
+	if (info->attrs[NL80211_ATTR_USE_MFP]) {
+		enum nl80211_mfp use_mfp =
+			nla_get_u32(info->attrs[NL80211_ATTR_USE_MFP]);
+		if (use_mfp == NL80211_MFP_REQUIRED)
+			req.use_mfp = true;
+		else if (use_mfp != NL80211_MFP_NO) {
+			err = -EINVAL;
+			goto out;
+		}
+	}
+
 	err = drv->ops->assoc(&drv->wiphy, dev, &req);
 
 out: