From: Eric Dumazet <edumazet@xxxxxxxxxx>
Setting rt variable to NULL at the beginning of ip_tunnel_xmit()
missed possible use of this variable as a scratch value.
Also fixes a possible dst leak in tunnel_dst_check() :
If we had to call tunnel_dst_reset(), we forgot to
release the reference on dst.
Merges tunnel_dst_get()/tunnel_dst_check() into
a single tunnel_rtable_get() function for clarity.
Many thanks to Tommi for his report and tests.
Fixes: 7d442fab0a67 ("ipv4: Cache dst in tunnels)"
Reported-by: Tommi Rantala <tt.rantala@xxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Tested-by: Tommi Rantala <tt.rantala@xxxxxxxxx>
Cc: Tom Herbert <therbert@xxxxxxxxxx>
Cc: Maciej Żenczykowski <maze@xxxxxxxxxx>
---
net/ipv4/ip_tunnel.c | 29 +++++++++++------------------
1 file changed, 11 insertions(+), 18 deletions(-)
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index bd28f386bd02..50228be5c17b 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -101,28 +101,22 @@ static void tunnel_dst_reset_all(struct ip_tunnel *t)
__tunnel_dst_set(per_cpu_ptr(t->dst_cache, i), NULL);
}
-static struct dst_entry *tunnel_dst_get(struct ip_tunnel *t)
+static struct rtable *tunnel_rtable_get(struct ip_tunnel *t, u32 cookie)
{
struct dst_entry *dst;
rcu_read_lock();
dst = rcu_dereference(this_cpu_ptr(t->dst_cache)->dst);
- if (dst)
+ if (dst) {
+ if (dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
+ rcu_read_unlock();
+ tunnel_dst_reset(t);
+ return NULL;
+ }
dst_hold(dst);
- rcu_read_unlock();
- return dst;
-}
-
-static struct dst_entry *tunnel_dst_check(struct ip_tunnel *t, u32 cookie)
-{
- struct dst_entry *dst = tunnel_dst_get(t);
-
- if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
- tunnel_dst_reset(t);
- return NULL;
}
-
- return dst;
+ rcu_read_unlock();
+ return (struct rtable *)dst;
}
/* Often modified stats are per cpu, other are shared (netdev->stats) */
@@ -584,7 +578,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
struct flowi4 fl4;
u8 tos, ttl;
__be16 df;
- struct rtable *rt = NULL; /* Route to the other host */
+ struct rtable *rt; /* Route to the other host */
unsigned int max_headroom; /* The extra header space needed */
__be32 dst;
int err;
@@ -657,8 +651,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
init_tunnel_flow(&fl4, protocol, dst, tnl_params->saddr,
tunnel->parms.o_key, RT_TOS(tos), tunnel->parms.link);
- if (connected)
- rt = (struct rtable *)tunnel_dst_check(tunnel, 0);
+ rt = connected ? tunnel_rtable_get(tunnel, 0) : NULL;
if (!rt) {
rt = ip_route_output_key(tunnel->net, &fl4);
--
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