linux-kernel - [PATCH AUTOSEL 4.19 019/123] netfilter: nf_conncount: fix unexpected permanent node of list.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181205093555.5386-19-sashal@kernel.org>
Date:   Wed,  5 Dec 2018 04:34:11 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Taehee Yoo <ap420073@...il.com>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Sasha Levin <sashal@...nel.org>,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 019/123] netfilter: nf_conncount: fix unexpected permanent node of list.

From: Taehee Yoo <ap420073@...il.com>

[ Upstream commit 3c5cdb17c3be76714dfd0d03e384f70579545614 ]

When list->count is 0, the list is deleted by GC. But list->count is
never reached 0 because initial count value is 1 and it is increased
when node is inserted. So that initial value of list->count should be 0.

Originally GC always finds zero count list through deleting node and
decreasing count. However, list may be left empty since node insertion
may fail eg.  allocaton problem. In order to solve this problem, GC
routine also finds zero count list without deleting node.

Fixes: cb2b36f5a97d ("netfilter: nf_conncount: Switch to plain list")
Signed-off-by: Taehee Yoo <ap420073@...il.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/netfilter/nf_conncount.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c
index cb33709138df..8acae4a3e4c0 100644
--- a/net/netfilter/nf_conncount.c
+++ b/net/netfilter/nf_conncount.c
@@ -144,8 +144,10 @@ static bool conn_free(struct nf_conncount_list *list,
 	list->count--;
 	conn->dead = true;
 	list_del_rcu(&conn->node);
-	if (list->count == 0)
+	if (list->count == 0) {
+		list->dead = true;
 		free_entry = true;
+	}
 
 	spin_unlock_bh(&list->list_lock);
 	call_rcu(&conn->rcu_head, __conn_free);
@@ -248,7 +250,7 @@ void nf_conncount_list_init(struct nf_conncount_list *list)
 {
 	spin_lock_init(&list->list_lock);
 	INIT_LIST_HEAD(&list->head);
-	list->count = 1;
+	list->count = 0;
 	list->dead = false;
 }
 EXPORT_SYMBOL_GPL(nf_conncount_list_init);
@@ -262,6 +264,7 @@ bool nf_conncount_gc_list(struct net *net,
 	struct nf_conn *found_ct;
 	unsigned int collected = 0;
 	bool free_entry = false;
+	bool ret = false;
 
 	list_for_each_entry_safe(conn, conn_n, &list->head, node) {
 		found = find_or_evict(net, list, conn, &free_entry);
@@ -291,7 +294,15 @@ bool nf_conncount_gc_list(struct net *net,
 		if (collected > CONNCOUNT_GC_MAX_NODES)
 			return false;
 	}
-	return false;
+
+	spin_lock_bh(&list->list_lock);
+	if (!list->count) {
+		list->dead = true;
+		ret = true;
+	}
+	spin_unlock_bh(&list->list_lock);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(nf_conncount_gc_list);
 
@@ -417,6 +428,7 @@ insert_tree(struct net *net,
 	nf_conncount_list_init(&rbconn->list);
 	list_add(&conn->node, &rbconn->list.head);
 	count = 1;
+	rbconn->list.count = count;
 
 	rb_link_node(&rbconn->node, parent, rbnode);
 	rb_insert_color(&rbconn->node, root);
-- 
2.17.1