[PATCH nf 4/4] netfilter: ctnetlink: acquire ct->lock before operating nf_ct_seqadj

[Liping Zhang]

From: Liping Zhang <zlpnob...@gmail.com>

We should acquire the ct->lock before accessing or modifying the
nf_ct_seqadj, as another CPU may modify the nf_ct_seqadj at the same
time during its packet proccessing.

Signed-off-by: Liping Zhang <zlpnob...@gmail.com>
---
 net/netfilter/nf_conntrack_netlink.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c 
b/net/netfilter/nf_conntrack_netlink.c
index 86deed6..78f8c9a 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -417,8 +417,7 @@ dump_ct_seq_adj(struct sk_buff *skb, const struct 
nf_ct_seqadj *seq, int type)
        return -1;
 }
 
-static int ctnetlink_dump_ct_seq_adj(struct sk_buff *skb,
-                                    const struct nf_conn *ct)
+static int ctnetlink_dump_ct_seq_adj(struct sk_buff *skb, struct nf_conn *ct)
 {
        struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
        struct nf_ct_seqadj *seq;
@@ -426,15 +425,20 @@ static int ctnetlink_dump_ct_seq_adj(struct sk_buff *skb,
        if (!(ct->status & IPS_SEQ_ADJUST) || !seqadj)
                return 0;
 
+       spin_lock_bh(&ct->lock);
        seq = &seqadj->seq[IP_CT_DIR_ORIGINAL];
        if (dump_ct_seq_adj(skb, seq, CTA_SEQ_ADJ_ORIG) == -1)
-               return -1;
+               goto err;
 
        seq = &seqadj->seq[IP_CT_DIR_REPLY];
        if (dump_ct_seq_adj(skb, seq, CTA_SEQ_ADJ_REPLY) == -1)
-               return -1;
+               goto err;
 
+       spin_unlock_bh(&ct->lock);
        return 0;
+err:
+       spin_unlock_bh(&ct->lock);
+       return -1;
 }
 
 static int ctnetlink_dump_id(struct sk_buff *skb, const struct nf_conn *ct)
@@ -1637,11 +1641,12 @@ ctnetlink_change_seq_adj(struct nf_conn *ct,
        if (!seqadj)
                return 0;
 
+       spin_lock_bh(&ct->lock);
        if (cda[CTA_SEQ_ADJ_ORIG]) {
                ret = change_seq_adj(&seqadj->seq[IP_CT_DIR_ORIGINAL],
                                     cda[CTA_SEQ_ADJ_ORIG]);
                if (ret < 0)
-                       return ret;
+                       goto err;
 
                set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
        }
@@ -1650,12 +1655,16 @@ ctnetlink_change_seq_adj(struct nf_conn *ct,
                ret = change_seq_adj(&seqadj->seq[IP_CT_DIR_REPLY],
                                     cda[CTA_SEQ_ADJ_REPLY]);
                if (ret < 0)
-                       return ret;
+                       goto err;
 
                set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
        }
 
+       spin_unlock_bh(&ct->lock);
        return 0;
+err:
+       spin_unlock_bh(&ct->lock);
+       return ret;
 }
 
 static int
-- 
2.5.5


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