cfg80211/nl80211: add API for MAC address ACLs

Add API to enable drivers to implement MAC address based
access control in AP/P2P GO mode. Capable drivers advertise
this capability by setting the maximum number of MAC
addresses in such a list in wiphy->max_acl_mac_addrs.

An initial ACL may be given to the NL80211_CMD_START_AP
command and/or changed later with NL80211_CMD_SET_MAC_ACL.

Black- and whitelists are supported, but not simultaneously.

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
[rewrite commit log, many cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 116 insertions, 0 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 33de803..b5978ab 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -365,6 +365,8 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
 	[NL80211_ATTR_SCAN_FLAGS] = { .type = NLA_U32 },
 	[NL80211_ATTR_P2P_CTWINDOW] = { .type = NLA_U8 },
 	[NL80211_ATTR_P2P_OPPPS] = { .type = NLA_U8 },
+	[NL80211_ATTR_ACL_POLICY] = {. type = NLA_U32 },
+	[NL80211_ATTR_MAC_ADDRS] = { .type = NLA_NESTED },
 };
 
 /* policy for the key attributes */
@@ -1268,6 +1270,12 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 portid, u32 seq, int flag
 		    dev->wiphy.ht_capa_mod_mask))
 		goto nla_put_failure;
 
+	if (dev->wiphy.flags & WIPHY_FLAG_HAVE_AP_SME &&
+	    dev->wiphy.max_acl_mac_addrs &&
+	    nla_put_u32(msg, NL80211_ATTR_MAC_ACL_MAX,
+			dev->wiphy.max_acl_mac_addrs))
+		goto nla_put_failure;
+
 	return genlmsg_end(msg, hdr);
 
  nla_put_failure:
@@ -2491,6 +2499,97 @@ static int nl80211_del_key(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+/* This function returns an error or the number of nested attributes */
+static int validate_acl_mac_addrs(struct nlattr *nl_attr)
+{
+	struct nlattr *attr;
+	int n_entries = 0, tmp;
+
+	nla_for_each_nested(attr, nl_attr, tmp) {
+		if (nla_len(attr) != ETH_ALEN)
+			return -EINVAL;
+
+		n_entries++;
+	}
+
+	return n_entries;
+}
+
+/*
+ * This function parses ACL information and allocates memory for ACL data.
+ * On successful return, the calling function is responsible to free the
+ * ACL buffer returned by this function.
+ */
+static struct cfg80211_acl_data *parse_acl_data(struct wiphy *wiphy,
+						struct genl_info *info)
+{
+	enum nl80211_acl_policy acl_policy;
+	struct nlattr *attr;
+	struct cfg80211_acl_data *acl;
+	int i = 0, n_entries, tmp;
+
+	if (!wiphy->max_acl_mac_addrs)
+		return ERR_PTR(-EOPNOTSUPP);
+
+	if (!info->attrs[NL80211_ATTR_ACL_POLICY])
+		return ERR_PTR(-EINVAL);
+
+	acl_policy = nla_get_u32(info->attrs[NL80211_ATTR_ACL_POLICY]);
+	if (acl_policy != NL80211_ACL_POLICY_ACCEPT_UNLESS_LISTED &&
+	    acl_policy != NL80211_ACL_POLICY_DENY_UNLESS_LISTED)
+		return ERR_PTR(-EINVAL);
+
+	if (!info->attrs[NL80211_ATTR_MAC_ADDRS])
+		return ERR_PTR(-EINVAL);
+
+	n_entries = validate_acl_mac_addrs(info->attrs[NL80211_ATTR_MAC_ADDRS]);
+	if (n_entries < 0)
+		return ERR_PTR(n_entries);
+
+	if (n_entries > wiphy->max_acl_mac_addrs)
+		return ERR_PTR(-ENOTSUPP);
+
+	acl = kzalloc(sizeof(*acl) + (sizeof(struct mac_address) * n_entries),
+		      GFP_KERNEL);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	nla_for_each_nested(attr, info->attrs[NL80211_ATTR_MAC_ADDRS], tmp) {
+		memcpy(acl->mac_addrs[i].addr, nla_data(attr), ETH_ALEN);
+		i++;
+	}
+
+	acl->n_acl_entries = n_entries;
+	acl->acl_policy = acl_policy;
+
+	return acl;
+}
+
+static int nl80211_set_mac_acl(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	struct cfg80211_acl_data *acl;
+	int err;
+
+	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_AP &&
+	    dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO)
+		return -EOPNOTSUPP;
+
+	if (!dev->ieee80211_ptr->beacon_interval)
+		return -EINVAL;
+
+	acl = parse_acl_data(&rdev->wiphy, info);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+
+	err = rdev_set_mac_acl(rdev, dev, acl);
+
+	kfree(acl);
+
+	return err;
+}
+
 static int nl80211_parse_beacon(struct genl_info *info,
 				struct cfg80211_beacon_data *bcn)
 {
@@ -2734,6 +2833,12 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 	if (err)
 		return err;
 
+	if (info->attrs[NL80211_ATTR_ACL_POLICY]) {
+		params.acl = parse_acl_data(&rdev->wiphy, info);
+		if (IS_ERR(params.acl))
+			return PTR_ERR(params.acl);
+	}
+
 	err = rdev_start_ap(rdev, dev, &params);
 	if (!err) {
 		wdev->preset_chandef = params.chandef;
@@ -2742,6 +2847,9 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 		wdev->ssid_len = params.ssid_len;
 		memcpy(wdev->ssid, params.ssid, wdev->ssid_len);
 	}
+
+	kfree(params.acl);
+
 	return err;
 }
 
@@ -7876,6 +7984,14 @@ static struct genl_ops nl80211_ops[] = {
 		.internal_flags = NL80211_FLAG_NEED_NETDEV |
 				  NL80211_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL80211_CMD_SET_MAC_ACL,
+		.doit = nl80211_set_mac_acl,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV |
+				  NL80211_FLAG_NEED_RTNL,
+	},
 };
 
 static struct genl_multicast_group nl80211_mlme_mcgrp = {