From 2e0b96d8edc66bf627da29d36344a8f99a76b065 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 5 Feb 2025 15:51:14 +0000
Subject: [PATCH] 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>
---
 net/ipv4/devinet.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 430ca93ba939d..1738cc2bfc7f0 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1320,10 +1320,11 @@ __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;
-- 
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