rps: flow_dissector: Fix uninitialized flow_keys used in __skb_get_hash possibly
The original codes depend on that the function parameters are evaluated from
left to right. But the parameter's evaluation order is not defined in C
standard actually.
When flow_keys_have_l4(&keys) is invoked before ___skb_get_hash(skb, &keys,
hashrnd) with some compilers or environment, the keys passed to
flow_keys_have_l4 is not initialized.
Fixes: 6db61d79c1e1 ("flow_dissector: Ignore flow dissector return value from ___skb_get_hash")
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 61ad43f..52742a0 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -680,11 +680,13 @@
void __skb_get_hash(struct sk_buff *skb)
{
struct flow_keys keys;
+ u32 hash;
__flow_hash_secret_init();
- __skb_set_sw_hash(skb, ___skb_get_hash(skb, &keys, hashrnd),
- flow_keys_have_l4(&keys));
+ hash = ___skb_get_hash(skb, &keys, hashrnd);
+
+ __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
}
EXPORT_SYMBOL(__skb_get_hash);