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authorEric Dumazet <edumazet@google.com>2025-02-05 15:51:10 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-02-21 14:01:40 +0100
commitcb4d7fbc937e37b99082fc76945ae1d4d98435ab (patch)
tree9e78234e1455189db2e8b35ac0956341de35b31e /include
parent56e6976793c0fcf1638aa534242408ab4e4ca705 (diff)
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ipv4: add RCU protection to ip4_dst_hoplimit()
[ 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@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250205155120.1676781-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/net/route.h9
1 files changed, 7 insertions, 2 deletions
diff --git a/include/net/route.h b/include/net/route.h
index 1789f1e6640b..da34b6fa9862 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -363,10 +363,15 @@ 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;
}