6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 469308552ca4560176cfc100e7ca84add1bebd7c ]
ip4_dst_hoplimit() must use RCU protection to make
sure the net structure it reads does not disappear.
Fixes: fa50d974d104 ("ipv4: Namespaceify ip_default_ttl sysctl knob")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Link: https://patch.msgid.link/20250205155120.1676781-3-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/net/route.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/net/route.h b/include/net/route.h
index 51a45b1887b56..0171e9e1bbea3 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -357,10 +357,15 @@ static inline int inet_iif(const struct sk_buff *skb)
static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
{
int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
- struct net *net = dev_net(dst->dev);
- if (hoplimit == 0)
+ if (hoplimit == 0) {
+ const struct net *net;
+
+ rcu_read_lock();
+ net = dev_net_rcu(dst->dev);
hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
+ rcu_read_unlock();
+ }
return hoplimit;
}
--
2.39.5
