[PATCH nf 1/2] netfilter: WARN about wrong usage of sequence number adju

To: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Subject: [PATCH nf 1/2] netfilter: WARN about wrong usage of sequence number adjustments
Cc: lvs-devel@xxxxxxxxxxxxxxx, netdev@xxxxxxxxxxxxxxx, netfilter-devel@xxxxxxxxxxxxxxx, Wensong Zhang <wensong@xxxxxxxxxxxx>, Julian Anastasov <ja@xxxxxx>, Jesper Dangaard Brouer <brouer@xxxxxxxxxx>, Simon Horman <horms@xxxxxxxxxxxx>
From: Simon Horman <horms@xxxxxxxxxxxx>
Date: Fri, 27 Dec 2013 12:37:36 +0900
From: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>

Since commit 41d73ec053d2 (netfilter: nf_conntrack: make sequence
number adjustments usuable without NAT), the sequence number extension
is dynamically allocated.

Instead of dying, give a WARN splash, in case of wrong usage of the
seqadj code, e.g. when forgetting to allocate via nfct_seqadj_ext_add().

Wrong usage have been seen in the IPVS code path.

Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Acked-by: Julian Anastasov <ja@xxxxxx>
Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
 net/netfilter/nf_conntrack_seqadj.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/netfilter/nf_conntrack_seqadj.c 
index 17c1bcb..b2d38da 100644
--- a/net/netfilter/nf_conntrack_seqadj.c
+++ b/net/netfilter/nf_conntrack_seqadj.c
@@ -36,6 +36,11 @@ int nf_ct_seqadj_set(struct nf_conn *ct, enum 
ip_conntrack_info ctinfo,
        if (off == 0)
                return 0;
+       if (unlikely(!seqadj)) {
+               WARN(1, "Wrong seqadj usage, missing nfct_seqadj_ext_add()\n");
+               return 0;
+       }
        set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);

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