From de9963f0f2dfad128b26ae7bf6005f5948416a6d Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 14 Feb 2011 17:35:07 +0100 Subject: [PATCH] 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 Acked-by: Eric Dumazet Signed-off-by: Patrick McHardy --- net/netfilter/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 32fcbe290c04..4aa614b8a96a 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -133,6 +133,7 @@ unsigned int nf_iterate(struct list_head *head, /* 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 @@ unsigned int nf_iterate(struct list_head *head, #endif if (verdict != NF_REPEAT) return verdict; - *i = (*i)->prev; + goto repeat; } } return NF_ACCEPT; -- 2.30.2