From: Eric Dumazet <edumazet@google.com>
Date: Wed, 5 Feb 2025 15:51:14 +0000 (+0000)
Subject: ipv4: use RCU protection in inet_select_addr()
X-Git-Tag: v5.10.235~181
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c7665524a6b1f21a79ac56fe5ad48fcd3fcdbc25;p=thirdparty%2Fkernel%2Fstable.git

ipv4: use RCU protection in inet_select_addr()

[ Upstream commit 719817cd293e4fa389e1f69c396f3f816ed5aa41 ]

inet_select_addr() must use RCU protection to make
sure the net structure it reads does not disappear.

Fixes: c4544c724322 ("[NETNS]: Process inet_select_addr inside a namespace.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250205155120.1676781-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 6918b3ced6713..2dc94109fc0ea 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1317,10 +1317,11 @@ __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope)
 	__be32 addr = 0;
 	unsigned char localnet_scope = RT_SCOPE_HOST;
 	struct in_device *in_dev;
-	struct net *net = dev_net(dev);
+	struct net *net;
 	int master_idx;
 
 	rcu_read_lock();
+	net = dev_net_rcu(dev);
 	in_dev = __in_dev_get_rcu(dev);
 	if (!in_dev)
 		goto no_in_dev;