netfilter: nf_iterate: fix incorrect RCU usage
As noticed by Eric, nf_iterate doesn't use RCU correctly by
accessing the prev pointer of a RCU protected list element when
a verdict of NF_REPEAT is issued.
Fix by jumping backwards to the hook invocation directly instead
of loading the previous list element before continuing the list
iteration.
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 32fcbe2..4aa614b 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -133,6 +133,7 @@
/* Optimization: we don't need to hold module
reference here, since function can't sleep. --RR */
+repeat:
verdict = elem->hook(hook, skb, indev, outdev, okfn);
if (verdict != NF_ACCEPT) {
#ifdef CONFIG_NETFILTER_DEBUG
@@ -145,7 +146,7 @@
#endif
if (verdict != NF_REPEAT)
return verdict;
- *i = (*i)->prev;
+ goto repeat;
}
}
return NF_ACCEPT;