From: Liping Zhang <zlpnobody@xxxxxxxxx>
For IPCTNL_MSG_EXP_GET, if the CTA_EXPECT_MASTER attr is specified, then
the NLM_F_DUMP request will dump the expectations related to this
connection tracking.
But we forget to check whether the conntrack has nf_conn_help or not,
so if nfct_help(ct) is NULL, oops will happen:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: ctnetlink_exp_ct_dump_table+0xf9/0x1e0 [nf_conntrack_netlink]
Call Trace:
? ctnetlink_exp_ct_dump_table+0x75/0x1e0 [nf_conntrack_netlink]
netlink_dump+0x124/0x2a0
__netlink_dump_start+0x161/0x190
ctnetlink_dump_exp_ct+0x16c/0x1bc [nf_conntrack_netlink]
? ctnetlink_exp_fill_info.constprop.33+0xf0/0xf0 [nf_conntrack_netlink]
? ctnetlink_glue_seqadj+0x20/0x20 [nf_conntrack_netlink]
ctnetlink_get_expect+0x32e/0x370 [nf_conntrack_netlink]
? debug_lockdep_rcu_enabled+0x1d/0x20
nfnetlink_rcv_msg+0x60a/0x6a9 [nfnetlink]
? nfnetlink_rcv_msg+0x1b9/0x6a9 [nfnetlink]
[...]
Signed-off-by: Liping Zhang <zlpnobody@xxxxxxxxx>
---
net/netfilter/nf_conntrack_netlink.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index f776314..1bb2f27 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -2783,6 +2783,12 @@ static int ctnetlink_dump_exp_ct(struct net *net, struct sock *ctnl,
return -ENOENT;
ct = nf_ct_tuplehash_to_ctrack(h);
+ /* No expectation linked to this connection tracking. */
+ if (!nfct_help(ct)) {
+ nf_ct_put(ct);
+ return 0;
+ }
+
c.data = ct;
err = netlink_dump_start(ctnl, skb, nlh, &c);
--
2.5.5
--
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