1 files changed, 44 insertions, 19 deletions

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index cb54a8a3c273..d64b83e85642 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -1,11 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	ip6_flowlabel.c		IPv6 flowlabel manager.
  *
- *	This program is free software; you can redistribute it and/or
- *      modify it under the terms of the GNU General Public License
- *      as published by the Free Software Foundation; either version
- *      2 of the License, or (at your option) any later version.
- *
  *	Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  */
 
@@ -21,6 +17,7 @@
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <linux/pid_namespace.h>
+#include <linux/jump_label_ratelimit.h>
 
 #include <net/net_namespace.h>
 #include <net/sock.h>
@@ -57,6 +54,9 @@ static DEFINE_SPINLOCK(ip6_fl_lock);
 
 static DEFINE_SPINLOCK(ip6_sk_fl_lock);
 
+DEFINE_STATIC_KEY_DEFERRED_FALSE(ipv6_flowlabel_exclusive, HZ);
+EXPORT_SYMBOL(ipv6_flowlabel_exclusive);
+
 #define for_each_fl_rcu(hash, fl)				\
 	for (fl = rcu_dereference_bh(fl_ht[(hash)]);		\
 	     fl != NULL;					\
@@ -94,15 +94,33 @@ static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
 	return fl;
 }
 
+static bool fl_shared_exclusive(struct ip6_flowlabel *fl)
+{
+	return fl->share == IPV6_FL_S_EXCL ||
+	       fl->share == IPV6_FL_S_PROCESS ||
+	       fl->share == IPV6_FL_S_USER;
+}
+
+static void fl_free_rcu(struct rcu_head *head)
+{
+	struct ip6_flowlabel *fl = container_of(head, struct ip6_flowlabel, rcu);
+
+	if (fl->share == IPV6_FL_S_PROCESS)
+		put_pid(fl->owner.pid);
+	kfree(fl->opt);
+	kfree(fl);
+}
+
 
 static void fl_free(struct ip6_flowlabel *fl)
 {
-	if (fl) {
-		if (fl->share == IPV6_FL_S_PROCESS)
-			put_pid(fl->owner.pid);
-		kfree(fl->opt);
-		kfree_rcu(fl, rcu);
-	}
+	if (!fl)
+		return;
+
+	if (fl_shared_exclusive(fl) || fl->opt)
+		static_branch_slow_dec_deferred(&ipv6_flowlabel_exclusive);
+
+	call_rcu(&fl->rcu, fl_free_rcu);
 }
 
 static void fl_release(struct ip6_flowlabel *fl)
@@ -238,7 +256,7 @@ static struct ip6_flowlabel *fl_intern(struct net *net,
 
 /* Socket flowlabel lists */
 
-struct ip6_flowlabel *fl6_sock_lookup(struct sock *sk, __be32 label)
+struct ip6_flowlabel *__fl6_sock_lookup(struct sock *sk, __be32 label)
 {
 	struct ipv6_fl_socklist *sfl;
 	struct ipv6_pinfo *np = inet6_sk(sk);
@@ -248,9 +266,9 @@ struct ip6_flowlabel *fl6_sock_lookup(struct sock *sk, __be32 label)
 	rcu_read_lock_bh();
 	for_each_sk_fl_rcu(np, sfl) {
 		struct ip6_flowlabel *fl = sfl->fl;
-		if (fl->label == label) {
+
+		if (fl->label == label && atomic_inc_not_zero(&fl->users)) {
 			fl->lastuse = jiffies;
-			atomic_inc(&fl->users);
 			rcu_read_unlock_bh();
 			return fl;
 		}
@@ -258,7 +276,7 @@ struct ip6_flowlabel *fl6_sock_lookup(struct sock *sk, __be32 label)
 	rcu_read_unlock_bh();
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(fl6_sock_lookup);
+EXPORT_SYMBOL_GPL(__fl6_sock_lookup);
 
 void fl6_free_socklist(struct sock *sk)
 {
@@ -431,10 +449,15 @@ fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
 		err = -EINVAL;
 		goto done;
 	}
+	if (fl_shared_exclusive(fl) || fl->opt)
+		static_branch_deferred_inc(&ipv6_flowlabel_exclusive);
 	return fl;
 
 done:
-	fl_free(fl);
+	if (fl) {
+		kfree(fl->opt);
+		kfree(fl);
+	}
 	*err_p = err;
 	return NULL;
 }
@@ -616,7 +639,8 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 						goto done;
 					}
 					fl1 = sfl->fl;
-					atomic_inc(&fl1->users);
+					if (!atomic_inc_not_zero(&fl1->users))
+						fl1 = NULL;
 					break;
 				}
 			}
@@ -633,9 +657,9 @@ recheck:
 				if (fl1->share == IPV6_FL_S_EXCL ||
 				    fl1->share != fl->share ||
 				    ((fl1->share == IPV6_FL_S_PROCESS) &&
-				     (fl1->owner.pid == fl->owner.pid)) ||
+				     (fl1->owner.pid != fl->owner.pid)) ||
 				    ((fl1->share == IPV6_FL_S_USER) &&
-				     uid_eq(fl1->owner.uid, fl->owner.uid)))
+				     !uid_eq(fl1->owner.uid, fl->owner.uid)))
 					goto release;
 
 				err = -ENOMEM;
@@ -851,6 +875,7 @@ int ip6_flowlabel_init(void)
 
 void ip6_flowlabel_cleanup(void)
 {
+	static_key_deferred_flush(&ipv6_flowlabel_exclusive);
 	del_timer(&ip6_fl_gc_timer);
 	unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 }