1 files changed, 39 insertions, 31 deletions

diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
index d7197649dba6..43c926cae9c0 100644
--- a/net/netfilter/nf_log.c
+++ b/net/netfilter/nf_log.c
@@ -19,6 +19,9 @@
 static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;
 static DEFINE_MUTEX(nf_log_mutex);
 
+#define nft_log_dereference(logger) \
+	rcu_dereference_protected(logger, lockdep_is_held(&nf_log_mutex))
+
 static struct nf_logger *__find_logger(int pf, const char *str_logger)
 {
 	struct nf_logger *log;
@@ -28,8 +31,7 @@ static struct nf_logger *__find_logger(int pf, const char *str_logger)
 		if (loggers[pf][i] == NULL)
 			continue;
 
-		log = rcu_dereference_protected(loggers[pf][i],
-						lockdep_is_held(&nf_log_mutex));
+		log = nft_log_dereference(loggers[pf][i]);
 		if (!strncasecmp(str_logger, log->name, strlen(log->name)))
 			return log;
 	}
@@ -45,8 +47,7 @@ void nf_log_set(struct net *net, u_int8_t pf, const struct nf_logger *logger)
 		return;
 
 	mutex_lock(&nf_log_mutex);
-	log = rcu_dereference_protected(net->nf.nf_loggers[pf],
-					lockdep_is_held(&nf_log_mutex));
+	log = nft_log_dereference(net->nf.nf_loggers[pf]);
 	if (log == NULL)
 		rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
 
@@ -61,8 +62,7 @@ void nf_log_unset(struct net *net, const struct nf_logger *logger)
 
 	mutex_lock(&nf_log_mutex);
 	for (i = 0; i < NFPROTO_NUMPROTO; i++) {
-		log = rcu_dereference_protected(net->nf.nf_loggers[i],
-				lockdep_is_held(&nf_log_mutex));
+		log = nft_log_dereference(net->nf.nf_loggers[i]);
 		if (log == logger)
 			RCU_INIT_POINTER(net->nf.nf_loggers[i], NULL);
 	}
@@ -75,6 +75,7 @@ EXPORT_SYMBOL(nf_log_unset);
 int nf_log_register(u_int8_t pf, struct nf_logger *logger)
 {
 	int i;
+	int ret = 0;
 
 	if (pf >= ARRAY_SIZE(init_net.nf.nf_loggers))
 		return -EINVAL;
@@ -82,16 +83,25 @@ int nf_log_register(u_int8_t pf, struct nf_logger *logger)
 	mutex_lock(&nf_log_mutex);
 
 	if (pf == NFPROTO_UNSPEC) {
+		for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
+			if (rcu_access_pointer(loggers[i][logger->type])) {
+				ret = -EEXIST;
+				goto unlock;
+			}
+		}
 		for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
 			rcu_assign_pointer(loggers[i][logger->type], logger);
 	} else {
-		/* register at end of list to honor first register win */
+		if (rcu_access_pointer(loggers[pf][logger->type])) {
+			ret = -EEXIST;
+			goto unlock;
+		}
 		rcu_assign_pointer(loggers[pf][logger->type], logger);
 	}
 
+unlock:
 	mutex_unlock(&nf_log_mutex);
-
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL(nf_log_register);
 
@@ -144,8 +154,7 @@ int nf_logger_find_get(int pf, enum nf_log_type type)
 	struct nf_logger *logger;
 	int ret = -ENOENT;
 
-	logger = loggers[pf][type];
-	if (logger == NULL)
+	if (rcu_access_pointer(loggers[pf][type]) == NULL)
 		request_module("nf-logger-%u-%u", pf, type);
 
 	rcu_read_lock();
@@ -294,37 +303,37 @@ static int seq_show(struct seq_file *s, void *v)
 {
 	loff_t *pos = v;
 	const struct nf_logger *logger;
-	int i, ret;
+	int i;
 	struct net *net = seq_file_net(s);
 
-	logger = rcu_dereference_protected(net->nf.nf_loggers[*pos],
-					   lockdep_is_held(&nf_log_mutex));
+	logger = nft_log_dereference(net->nf.nf_loggers[*pos]);
 
 	if (!logger)
-		ret = seq_printf(s, "%2lld NONE (", *pos);
+		seq_printf(s, "%2lld NONE (", *pos);
 	else
-		ret = seq_printf(s, "%2lld %s (", *pos, logger->name);
+		seq_printf(s, "%2lld %s (", *pos, logger->name);
 
-	if (ret < 0)
-		return ret;
+	if (seq_has_overflowed(s))
+		return -ENOSPC;
 
 	for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
 		if (loggers[*pos][i] == NULL)
 			continue;
 
-		logger = rcu_dereference_protected(loggers[*pos][i],
-					   lockdep_is_held(&nf_log_mutex));
-		ret = seq_printf(s, "%s", logger->name);
-		if (ret < 0)
-			return ret;
-		if (i == 0 && loggers[*pos][i + 1] != NULL) {
-			ret = seq_printf(s, ",");
-			if (ret < 0)
-				return ret;
-		}
+		logger = nft_log_dereference(loggers[*pos][i]);
+		seq_printf(s, "%s", logger->name);
+		if (i == 0 && loggers[*pos][i + 1] != NULL)
+			seq_printf(s, ",");
+
+		if (seq_has_overflowed(s))
+			return -ENOSPC;
 	}
 
-	return seq_printf(s, ")\n");
+	seq_printf(s, ")\n");
+
+	if (seq_has_overflowed(s))
+		return -ENOSPC;
+	return 0;
 }
 
 static const struct seq_operations nflog_seq_ops = {
@@ -385,8 +394,7 @@ static int nf_log_proc_dostring(struct ctl_table *table, int write,
 		mutex_unlock(&nf_log_mutex);
 	} else {
 		mutex_lock(&nf_log_mutex);
-		logger = rcu_dereference_protected(net->nf.nf_loggers[tindex],
-						   lockdep_is_held(&nf_log_mutex));
+		logger = nft_log_dereference(net->nf.nf_loggers[tindex]);
 		if (!logger)
 			table->data = "NONE";
 		else