nl80211: accept testmode dump with netdev

All nl80211 commands that need only the wiphy
still allow identifying it by giving an interface
index, except, as Kenny pointed out, the testmode
dump support.

Fix this by looking up the wiphy via the ifidx in
this case as well.
Tested-by: Kenny Hsu <kenny.hsu@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/wireless/nl80211.c

@@ -47,22 +47,21 @@ static struct genl_family nl80211_fam = {
 };
 
 /* internal helper: get rdev and dev */
-static int get_rdev_dev_by_info_ifindex(struct genl_info *info,
-				       struct cfg80211_registered_device **rdev,
-				       struct net_device **dev)
+static int get_rdev_dev_by_ifindex(struct net *netns, struct nlattr **attrs,
+				   struct cfg80211_registered_device **rdev,
+				   struct net_device **dev)
 {
-	struct nlattr **attrs = info->attrs;
 	int ifindex;
 
 	if (!attrs[NL80211_ATTR_IFINDEX])
 		return -EINVAL;
 
 	ifindex = nla_get_u32(attrs[NL80211_ATTR_IFINDEX]);
-	*dev = dev_get_by_index(genl_info_net(info), ifindex);
+	*dev = dev_get_by_index(netns, ifindex);
 	if (!*dev)
 		return -ENODEV;
 
-	*rdev = cfg80211_get_dev_from_ifindex(genl_info_net(info), ifindex);
+	*rdev = cfg80211_get_dev_from_ifindex(netns, ifindex);
 	if (IS_ERR(*rdev)) {
 		dev_put(*dev);
 		return PTR_ERR(*rdev);
@@ -4795,7 +4794,7 @@ static int nl80211_testmode_do(struct sk_buff *skb, struct genl_info *info)
 static int nl80211_testmode_dump(struct sk_buff *skb,
 				 struct netlink_callback *cb)
 {
-	struct cfg80211_registered_device *dev;
+	struct cfg80211_registered_device *rdev;
 	int err;
 	long phy_idx;
 	void *data = NULL;
@@ -4813,9 +4812,21 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
 				  nl80211_policy);
 		if (err)
 			return err;
-		if (!nl80211_fam.attrbuf[NL80211_ATTR_WIPHY])
-			return -EINVAL;
-		phy_idx = nla_get_u32(nl80211_fam.attrbuf[NL80211_ATTR_WIPHY]);
+		if (nl80211_fam.attrbuf[NL80211_ATTR_WIPHY]) {
+			phy_idx = nla_get_u32(
+				nl80211_fam.attrbuf[NL80211_ATTR_WIPHY]);
+		} else {
+			struct net_device *netdev;
+
+			err = get_rdev_dev_by_ifindex(sock_net(skb->sk),
+						      nl80211_fam.attrbuf,
+						      &rdev, &netdev);
+			if (err)
+				return err;
+			dev_put(netdev);
+			phy_idx = rdev->wiphy_idx;
+			cfg80211_unlock_rdev(rdev);
+		}
 		if (nl80211_fam.attrbuf[NL80211_ATTR_TESTDATA])
 			cb->args[1] =
 				(long)nl80211_fam.attrbuf[NL80211_ATTR_TESTDATA];
@@ -4827,15 +4838,15 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
 	}
 
 	mutex_lock(&cfg80211_mutex);
-	dev = cfg80211_rdev_by_wiphy_idx(phy_idx);
-	if (!dev) {
+	rdev = cfg80211_rdev_by_wiphy_idx(phy_idx);
+	if (!rdev) {
 		mutex_unlock(&cfg80211_mutex);
 		return -ENOENT;
 	}
-	cfg80211_lock_rdev(dev);
+	cfg80211_lock_rdev(rdev);
 	mutex_unlock(&cfg80211_mutex);
 
-	if (!dev->ops->testmode_dump) {
+	if (!rdev->ops->testmode_dump) {
 		err = -EOPNOTSUPP;
 		goto out_err;
 	}
@@ -4846,7 +4857,7 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
 					   NL80211_CMD_TESTMODE);
 		struct nlattr *tmdata;
 
-		if (nla_put_u32(skb, NL80211_ATTR_WIPHY, dev->wiphy_idx) < 0) {
+		if (nla_put_u32(skb, NL80211_ATTR_WIPHY, phy_idx) < 0) {
 			genlmsg_cancel(skb, hdr);
 			break;
 		}
@@ -4856,8 +4867,8 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
 			genlmsg_cancel(skb, hdr);
 			break;
 		}
-		err = dev->ops->testmode_dump(&dev->wiphy, skb, cb,
-					      data, data_len);
+		err = rdev->ops->testmode_dump(&rdev->wiphy, skb, cb,
+					       data, data_len);
 		nla_nest_end(skb, tmdata);
 
 		if (err == -ENOBUFS || err == -ENOENT) {
@@ -4875,7 +4886,7 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
 	/* see above */
 	cb->args[0] = phy_idx + 1;
  out_err:
-	cfg80211_unlock_rdev(dev);
+	cfg80211_unlock_rdev(rdev);
 	return err;
 }
 
@@ -6110,7 +6121,8 @@ static int nl80211_pre_doit(struct genl_ops *ops, struct sk_buff *skb,
 		}
 		info->user_ptr[0] = rdev;
 	} else if (ops->internal_flags & NL80211_FLAG_NEED_NETDEV) {
-		err = get_rdev_dev_by_info_ifindex(info, &rdev, &dev);
+		err = get_rdev_dev_by_ifindex(genl_info_net(info), info->attrs,
+					      &rdev, &dev);
 		if (err) {
 			if (rtnl)
 				rtnl_unlock();