Merge tag 'ipvs-fixes-for-v5.4' of https://git.kernel.org/pub/scm/linux/kernel/git/horms/ipvs

Simon Horman says:

====================
IPVS fixes for v5.4

* Eric Dumazet resolves a race condition in switching the defense level
* Davide Caratti resolves a race condition in module removal
====================

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/ip_vs.h

@@ -889,6 +889,7 @@ struct netns_ipvs {
 	struct delayed_work	defense_work;   /* Work handler */
 	int			drop_rate;
 	int			drop_counter;
+	int			old_secure_tcp;
 	atomic_t		dropentry;
 	/* locks in ctl.c */
 	spinlock_t		dropentry_lock;  /* drop entry handling */

net/netfilter/ipvs/ip_vs_app.c

@@ -193,21 +193,29 @@ struct ip_vs_app *register_ip_vs_app(struct netns_ipvs *ipvs, struct ip_vs_app *
 
 	mutex_lock(&__ip_vs_app_mutex);
 
+	/* increase the module use count */
+	if (!ip_vs_use_count_inc()) {
+		err = -ENOENT;
+		goto out_unlock;
+	}
+
 	list_for_each_entry(a, &ipvs->app_list, a_list) {
 		if (!strcmp(app->name, a->name)) {
 			err = -EEXIST;
+			/* decrease the module use count */
+			ip_vs_use_count_dec();
 			goto out_unlock;
 		}
 	}
 	a = kmemdup(app, sizeof(*app), GFP_KERNEL);
 	if (!a) {
 		err = -ENOMEM;
+		/* decrease the module use count */
+		ip_vs_use_count_dec();
 		goto out_unlock;
 	}
 	INIT_LIST_HEAD(&a->incs_list);
 	list_add(&a->a_list, &ipvs->app_list);
-	/* increase the module use count */
-	ip_vs_use_count_inc();
 
 out_unlock:
 	mutex_unlock(&__ip_vs_app_mutex);

net/netfilter/ipvs/ip_vs_ctl.c

@@ -93,7 +93,6 @@ static bool __ip_vs_addr_is_local_v6(struct net *net,
 static void update_defense_level(struct netns_ipvs *ipvs)
 {
 	struct sysinfo i;
-	static int old_secure_tcp = 0;
 	int availmem;
 	int nomem;
 	int to_change = -1;
@@ -174,35 +173,35 @@ static void update_defense_level(struct netns_ipvs *ipvs)
 	spin_lock(&ipvs->securetcp_lock);
 	switch (ipvs->sysctl_secure_tcp) {
 	case 0:
-		if (old_secure_tcp >= 2)
+		if (ipvs->old_secure_tcp >= 2)
 			to_change = 0;
 		break;
 	case 1:
 		if (nomem) {
-			if (old_secure_tcp < 2)
+			if (ipvs->old_secure_tcp < 2)
 				to_change = 1;
 			ipvs->sysctl_secure_tcp = 2;
 		} else {
-			if (old_secure_tcp >= 2)
+			if (ipvs->old_secure_tcp >= 2)
 				to_change = 0;
 		}
 		break;
 	case 2:
 		if (nomem) {
-			if (old_secure_tcp < 2)
+			if (ipvs->old_secure_tcp < 2)
 				to_change = 1;
 		} else {
-			if (old_secure_tcp >= 2)
+			if (ipvs->old_secure_tcp >= 2)
 				to_change = 0;
 			ipvs->sysctl_secure_tcp = 1;
 		}
 		break;
 	case 3:
-		if (old_secure_tcp < 2)
+		if (ipvs->old_secure_tcp < 2)
 			to_change = 1;
 		break;
 	}
-	old_secure_tcp = ipvs->sysctl_secure_tcp;
+	ipvs->old_secure_tcp = ipvs->sysctl_secure_tcp;
 	if (to_change >= 0)
 		ip_vs_protocol_timeout_change(ipvs,
 					      ipvs->sysctl_secure_tcp > 1);
@@ -1275,7 +1274,8 @@ ip_vs_add_service(struct netns_ipvs *ipvs, struct ip_vs_service_user_kern *u,
 	struct ip_vs_service *svc = NULL;
 
 	/* increase the module use count */
-	ip_vs_use_count_inc();
+	if (!ip_vs_use_count_inc())
+		return -ENOPROTOOPT;
 
 	/* Lookup the scheduler by 'u->sched_name' */
 	if (strcmp(u->sched_name, "none")) {
@@ -2435,9 +2435,6 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
 	if (copy_from_user(arg, user, len) != 0)
 		return -EFAULT;
 
-	/* increase the module use count */
-	ip_vs_use_count_inc();
-
 	/* Handle daemons since they have another lock */
 	if (cmd == IP_VS_SO_SET_STARTDAEMON ||
 	    cmd == IP_VS_SO_SET_STOPDAEMON) {
@@ -2450,13 +2447,13 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
 			ret = -EINVAL;
 			if (strscpy(cfg.mcast_ifn, dm->mcast_ifn,
 				    sizeof(cfg.mcast_ifn)) <= 0)
-				goto out_dec;
+				return ret;
 			cfg.syncid = dm->syncid;
 			ret = start_sync_thread(ipvs, &cfg, dm->state);
 		} else {
 			ret = stop_sync_thread(ipvs, dm->state);
 		}
-		goto out_dec;
+		return ret;
 	}
 
 	mutex_lock(&__ip_vs_mutex);
@@ -2551,10 +2548,6 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
 
   out_unlock:
 	mutex_unlock(&__ip_vs_mutex);
-  out_dec:
-	/* decrease the module use count */
-	ip_vs_use_count_dec();
-
 	return ret;
 }
 

net/netfilter/ipvs/ip_vs_pe.c

@@ -68,7 +68,8 @@ int register_ip_vs_pe(struct ip_vs_pe *pe)
 	struct ip_vs_pe *tmp;
 
 	/* increase the module use count */
-	ip_vs_use_count_inc();
+	if (!ip_vs_use_count_inc())
+		return -ENOENT;
 
 	mutex_lock(&ip_vs_pe_mutex);
 	/* Make sure that the pe with this name doesn't exist

net/netfilter/ipvs/ip_vs_sched.c

@@ -179,7 +179,8 @@ int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
 	}
 
 	/* increase the module use count */
-	ip_vs_use_count_inc();
+	if (!ip_vs_use_count_inc())
+		return -ENOENT;
 
 	mutex_lock(&ip_vs_sched_mutex);
 

net/netfilter/ipvs/ip_vs_sync.c

@@ -1762,6 +1762,10 @@ int start_sync_thread(struct netns_ipvs *ipvs, struct ipvs_sync_daemon_cfg *c,
 	IP_VS_DBG(7, "Each ip_vs_sync_conn entry needs %zd bytes\n",
 		  sizeof(struct ip_vs_sync_conn_v0));
 
+	/* increase the module use count */
+	if (!ip_vs_use_count_inc())
+		return -ENOPROTOOPT;
+
 	/* Do not hold one mutex and then to block on another */
 	for (;;) {
 		rtnl_lock();
@@ -1892,9 +1896,6 @@ int start_sync_thread(struct netns_ipvs *ipvs, struct ipvs_sync_daemon_cfg *c,
 	mutex_unlock(&ipvs->sync_mutex);
 	rtnl_unlock();
 
-	/* increase the module use count */
-	ip_vs_use_count_inc();
-
 	return 0;
 
 out:
@@ -1924,11 +1925,17 @@ out:
 		}
 		kfree(ti);
 	}
+
+	/* decrease the module use count */
+	ip_vs_use_count_dec();
 	return result;
 
 out_early:
 	mutex_unlock(&ipvs->sync_mutex);
 	rtnl_unlock();
+
+	/* decrease the module use count */
+	ip_vs_use_count_dec();
 	return result;
 }