1 files changed, 134 insertions, 60 deletions

diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
index 78cf061f8179..310241ca7991 100644
--- a/kernel/bpf/net_namespace.c
+++ b/kernel/bpf/net_namespace.c
@@ -19,18 +19,21 @@ struct bpf_netns_link {
 	 * with netns_bpf_mutex held.
 	 */
 	struct net *net;
+	struct list_head node; /* node in list of links attached to net */
 };
 
 /* Protects updates to netns_bpf */
 DEFINE_MUTEX(netns_bpf_mutex);
 
 /* Must be called with netns_bpf_mutex held. */
-static void __net_exit bpf_netns_link_auto_detach(struct bpf_link *link)
+static void netns_bpf_run_array_detach(struct net *net,
+				       enum netns_bpf_attach_type type)
 {
-	struct bpf_netns_link *net_link =
-		container_of(link, struct bpf_netns_link, link);
+	struct bpf_prog_array *run_array;
 
-	net_link->net = NULL;
+	run_array = rcu_replace_pointer(net->bpf.run_array[type], NULL,
+					lockdep_is_held(&netns_bpf_mutex));
+	bpf_prog_array_free(run_array);
 }
 
 static void bpf_netns_link_release(struct bpf_link *link)
@@ -40,22 +43,18 @@ static void bpf_netns_link_release(struct bpf_link *link)
 	enum netns_bpf_attach_type type = net_link->netns_type;
 	struct net *net;
 
-	/* Link auto-detached by dying netns. */
-	if (!net_link->net)
-		return;
-
 	mutex_lock(&netns_bpf_mutex);
 
-	/* Recheck after potential sleep. We can race with cleanup_net
-	 * here, but if we see a non-NULL struct net pointer pre_exit
-	 * has not happened yet and will block on netns_bpf_mutex.
+	/* We can race with cleanup_net, but if we see a non-NULL
+	 * struct net pointer, pre_exit has not run yet and wait for
+	 * netns_bpf_mutex.
 	 */
 	net = net_link->net;
 	if (!net)
 		goto out_unlock;
 
-	net->bpf.links[type] = NULL;
-	RCU_INIT_POINTER(net->bpf.progs[type], NULL);
+	netns_bpf_run_array_detach(net, type);
+	list_del(&net_link->node);
 
 out_unlock:
 	mutex_unlock(&netns_bpf_mutex);
@@ -76,6 +75,7 @@ static int bpf_netns_link_update_prog(struct bpf_link *link,
 	struct bpf_netns_link *net_link =
 		container_of(link, struct bpf_netns_link, link);
 	enum netns_bpf_attach_type type = net_link->netns_type;
+	struct bpf_prog_array *run_array;
 	struct net *net;
 	int ret = 0;
 
@@ -93,8 +93,11 @@ static int bpf_netns_link_update_prog(struct bpf_link *link,
 		goto out_unlock;
 	}
 
+	run_array = rcu_dereference_protected(net->bpf.run_array[type],
+					      lockdep_is_held(&netns_bpf_mutex));
+	WRITE_ONCE(run_array->items[0].prog, new_prog);
+
 	old_prog = xchg(&link->prog, new_prog);
-	rcu_assign_pointer(net->bpf.progs[type], new_prog);
 	bpf_prog_put(old_prog);
 
 out_unlock:
@@ -142,14 +145,38 @@ static const struct bpf_link_ops bpf_netns_link_ops = {
 	.show_fdinfo = bpf_netns_link_show_fdinfo,
 };
 
+/* Must be called with netns_bpf_mutex held. */
+static int __netns_bpf_prog_query(const union bpf_attr *attr,
+				  union bpf_attr __user *uattr,
+				  struct net *net,
+				  enum netns_bpf_attach_type type)
+{
+	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+	struct bpf_prog_array *run_array;
+	u32 prog_cnt = 0, flags = 0;
+
+	run_array = rcu_dereference_protected(net->bpf.run_array[type],
+					      lockdep_is_held(&netns_bpf_mutex));
+	if (run_array)
+		prog_cnt = bpf_prog_array_length(run_array);
+
+	if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
+		return -EFAULT;
+	if (copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt)))
+		return -EFAULT;
+	if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
+		return 0;
+
+	return bpf_prog_array_copy_to_user(run_array, prog_ids,
+					   attr->query.prog_cnt);
+}
+
 int netns_bpf_prog_query(const union bpf_attr *attr,
 			 union bpf_attr __user *uattr)
 {
-	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
-	u32 prog_id, prog_cnt = 0, flags = 0;
 	enum netns_bpf_attach_type type;
-	struct bpf_prog *attached;
 	struct net *net;
+	int ret;
 
 	if (attr->query.query_flags)
 		return -EINVAL;
@@ -162,36 +189,25 @@ int netns_bpf_prog_query(const union bpf_attr *attr,
 	if (IS_ERR(net))
 		return PTR_ERR(net);
 
-	rcu_read_lock();
-	attached = rcu_dereference(net->bpf.progs[type]);
-	if (attached) {
-		prog_cnt = 1;
-		prog_id = attached->aux->id;
-	}
-	rcu_read_unlock();
+	mutex_lock(&netns_bpf_mutex);
+	ret = __netns_bpf_prog_query(attr, uattr, net, type);
+	mutex_unlock(&netns_bpf_mutex);
 
 	put_net(net);
-
-	if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
-		return -EFAULT;
-	if (copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt)))
-		return -EFAULT;
-
-	if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
-		return 0;
-
-	if (copy_to_user(prog_ids, &prog_id, sizeof(u32)))
-		return -EFAULT;
-
-	return 0;
+	return ret;
 }
 
 int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 {
+	struct bpf_prog_array *run_array;
 	enum netns_bpf_attach_type type;
+	struct bpf_prog *attached;
 	struct net *net;
 	int ret;
 
+	if (attr->target_fd || attr->attach_flags || attr->replace_bpf_fd)
+		return -EINVAL;
+
 	type = to_netns_bpf_attach_type(attr->attach_type);
 	if (type < 0)
 		return -EINVAL;
@@ -200,19 +216,47 @@ int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 	mutex_lock(&netns_bpf_mutex);
 
 	/* Attaching prog directly is not compatible with links */
-	if (net->bpf.links[type]) {
+	if (!list_empty(&net->bpf.links[type])) {
 		ret = -EEXIST;
 		goto out_unlock;
 	}
 
 	switch (type) {
 	case NETNS_BPF_FLOW_DISSECTOR:
-		ret = flow_dissector_bpf_prog_attach(net, prog);
+		ret = flow_dissector_bpf_prog_attach_check(net, prog);
 		break;
 	default:
 		ret = -EINVAL;
 		break;
 	}
+	if (ret)
+		goto out_unlock;
+
+	attached = net->bpf.progs[type];
+	if (attached == prog) {
+		/* The same program cannot be attached twice */
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	run_array = rcu_dereference_protected(net->bpf.run_array[type],
+					      lockdep_is_held(&netns_bpf_mutex));
+	if (run_array) {
+		WRITE_ONCE(run_array->items[0].prog, prog);
+	} else {
+		run_array = bpf_prog_array_alloc(1, GFP_KERNEL);
+		if (!run_array) {
+			ret = -ENOMEM;
+			goto out_unlock;
+		}
+		run_array->items[0].prog = prog;
+		rcu_assign_pointer(net->bpf.run_array[type], run_array);
+	}
+
+	net->bpf.progs[type] = prog;
+	if (attached)
+		bpf_prog_put(attached);
+
 out_unlock:
 	mutex_unlock(&netns_bpf_mutex);
 
@@ -221,63 +265,74 @@ out_unlock:
 
 /* Must be called with netns_bpf_mutex held. */
 static int __netns_bpf_prog_detach(struct net *net,
-				   enum netns_bpf_attach_type type)
+				   enum netns_bpf_attach_type type,
+				   struct bpf_prog *old)
 {
 	struct bpf_prog *attached;
 
 	/* Progs attached via links cannot be detached */
-	if (net->bpf.links[type])
+	if (!list_empty(&net->bpf.links[type]))
 		return -EINVAL;
 
-	attached = rcu_dereference_protected(net->bpf.progs[type],
-					     lockdep_is_held(&netns_bpf_mutex));
-	if (!attached)
+	attached = net->bpf.progs[type];
+	if (!attached || attached != old)
 		return -ENOENT;
-	RCU_INIT_POINTER(net->bpf.progs[type], NULL);
+	netns_bpf_run_array_detach(net, type);
+	net->bpf.progs[type] = NULL;
 	bpf_prog_put(attached);
 	return 0;
 }
 
-int netns_bpf_prog_detach(const union bpf_attr *attr)
+int netns_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
 {
 	enum netns_bpf_attach_type type;
+	struct bpf_prog *prog;
 	int ret;
 
+	if (attr->target_fd)
+		return -EINVAL;
+
 	type = to_netns_bpf_attach_type(attr->attach_type);
 	if (type < 0)
 		return -EINVAL;
 
+	prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
 	mutex_lock(&netns_bpf_mutex);
-	ret = __netns_bpf_prog_detach(current->nsproxy->net_ns, type);
+	ret = __netns_bpf_prog_detach(current->nsproxy->net_ns, type, prog);
 	mutex_unlock(&netns_bpf_mutex);
 
+	bpf_prog_put(prog);
+
 	return ret;
 }
 
 static int netns_bpf_link_attach(struct net *net, struct bpf_link *link,
 				 enum netns_bpf_attach_type type)
 {
-	struct bpf_prog *prog;
+	struct bpf_netns_link *net_link =
+		container_of(link, struct bpf_netns_link, link);
+	struct bpf_prog_array *run_array;
 	int err;
 
 	mutex_lock(&netns_bpf_mutex);
 
 	/* Allow attaching only one prog or link for now */
-	if (net->bpf.links[type]) {
+	if (!list_empty(&net->bpf.links[type])) {
 		err = -E2BIG;
 		goto out_unlock;
 	}
 	/* Links are not compatible with attaching prog directly */
-	prog = rcu_dereference_protected(net->bpf.progs[type],
-					 lockdep_is_held(&netns_bpf_mutex));
-	if (prog) {
+	if (net->bpf.progs[type]) {
 		err = -EEXIST;
 		goto out_unlock;
 	}
 
 	switch (type) {
 	case NETNS_BPF_FLOW_DISSECTOR:
-		err = flow_dissector_bpf_prog_attach(net, link->prog);
+		err = flow_dissector_bpf_prog_attach_check(net, link->prog);
 		break;
 	default:
 		err = -EINVAL;
@@ -286,7 +341,15 @@ static int netns_bpf_link_attach(struct net *net, struct bpf_link *link,
 	if (err)
 		goto out_unlock;
 
-	net->bpf.links[type] = link;
+	run_array = bpf_prog_array_alloc(1, GFP_KERNEL);
+	if (!run_array) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
+	run_array->items[0].prog = link->prog;
+	rcu_assign_pointer(net->bpf.run_array[type], run_array);
+
+	list_add_tail(&net_link->node, &net->bpf.links[type]);
 
 out_unlock:
 	mutex_unlock(&netns_bpf_mutex);
@@ -345,23 +408,34 @@ out_put_net:
 	return err;
 }
 
+static int __net_init netns_bpf_pernet_init(struct net *net)
+{
+	int type;
+
+	for (type = 0; type < MAX_NETNS_BPF_ATTACH_TYPE; type++)
+		INIT_LIST_HEAD(&net->bpf.links[type]);
+
+	return 0;
+}
+
 static void __net_exit netns_bpf_pernet_pre_exit(struct net *net)
 {
 	enum netns_bpf_attach_type type;
-	struct bpf_link *link;
+	struct bpf_netns_link *net_link;
 
 	mutex_lock(&netns_bpf_mutex);
 	for (type = 0; type < MAX_NETNS_BPF_ATTACH_TYPE; type++) {
-		link = net->bpf.links[type];
-		if (link)
-			bpf_netns_link_auto_detach(link);
-		else
-			__netns_bpf_prog_detach(net, type);
+		netns_bpf_run_array_detach(net, type);
+		list_for_each_entry(net_link, &net->bpf.links[type], node)
+			net_link->net = NULL; /* auto-detach link */
+		if (net->bpf.progs[type])
+			bpf_prog_put(net->bpf.progs[type]);
 	}
 	mutex_unlock(&netns_bpf_mutex);
 }
 
 static struct pernet_operations netns_bpf_pernet_ops __net_initdata = {
+	.init = netns_bpf_pernet_init,
 	.pre_exit = netns_bpf_pernet_pre_exit,
 };