[PATCH v5 01/11] netlink: check for CAP_NET_ADMIN manually

[Julian Orth <ju.orth@gmail.com>]

---
 src/netlink.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/netlink.c b/src/netlink.c
index 18bebb8..364d4d8 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -163,6 +163,7 @@ err:
 static int wg_get_device_start(struct netlink_callback *cb)
 {
 	struct nlattr **attrs = genl_family_attrbuf(&genl_family);
+	struct net *dev_net = sock_net(cb->skb->sk);
 	struct wg_device *wg;
 	int ret;
 
@@ -170,6 +171,8 @@ static int wg_get_device_start(struct netlink_callback *cb)
 			  genl_family.maxattr, device_policy, NULL);
 	if (ret < 0)
 		return ret;
+	if (!netlink_ns_capable(cb->skb, dev_net->user_ns, CAP_NET_ADMIN))
+		return -EPERM;
 	cb->args[2] = (long)kzalloc(sizeof(struct allowedips_cursor),
 				    GFP_KERNEL);
 	if (unlikely(!cb->args[2]))
@@ -470,9 +473,17 @@ out:
 
 static int wg_set_device(struct sk_buff *skb, struct genl_info *info)
 {
-	struct wg_device *wg = lookup_interface(info->attrs, skb);
+	struct net *dev_net = sock_net(skb->sk);
+	struct wg_device *wg;
 	int ret;
 
+	if (!netlink_ns_capable(skb, dev_net->user_ns, CAP_NET_ADMIN)) {
+		ret = -EPERM;
+		goto out_nodev;
+	}
+
+	wg = lookup_interface(info->attrs, skb);
+
 	if (IS_ERR(wg)) {
 		ret = PTR_ERR(wg);
 		goto out_nodev;
@@ -574,12 +585,10 @@ struct genl_ops genl_ops[] = {
 		.dumpit = wg_get_device_dump,
 		.done = wg_get_device_done,
 		.policy = device_policy,
-		.flags = GENL_UNS_ADMIN_PERM
 	}, {
 		.cmd = WG_CMD_SET_DEVICE,
 		.doit = wg_set_device,
 		.policy = device_policy,
-		.flags = GENL_UNS_ADMIN_PERM
 	}
 };
 
-- 
2.19.2

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