1 files changed, 50 insertions, 26 deletions

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index e2d13cd18875..d8d33ef52ce0 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -506,9 +506,45 @@ nla_put_failure:
 	return -1;
 }
 
+/* all these functions access ct->ext. Caller must either hold a reference
+ * on ct or prevent its deletion by holding either the bucket spinlock or
+ * pcpu dying list lock.
+ */
+static int ctnetlink_dump_extinfo(struct sk_buff *skb,
+				  struct nf_conn *ct, u32 type)
+{
+	if (ctnetlink_dump_acct(skb, ct, type) < 0 ||
+	    ctnetlink_dump_timestamp(skb, ct) < 0 ||
+	    ctnetlink_dump_helpinfo(skb, ct) < 0 ||
+	    ctnetlink_dump_labels(skb, ct) < 0 ||
+	    ctnetlink_dump_ct_seq_adj(skb, ct) < 0 ||
+	    ctnetlink_dump_ct_synproxy(skb, ct) < 0)
+		return -1;
+
+	return 0;
+}
+
+static int ctnetlink_dump_info(struct sk_buff *skb, struct nf_conn *ct)
+{
+	if (ctnetlink_dump_status(skb, ct) < 0 ||
+	    ctnetlink_dump_mark(skb, ct) < 0 ||
+	    ctnetlink_dump_secctx(skb, ct) < 0 ||
+	    ctnetlink_dump_id(skb, ct) < 0 ||
+	    ctnetlink_dump_use(skb, ct) < 0 ||
+	    ctnetlink_dump_master(skb, ct) < 0)
+		return -1;
+
+	if (!test_bit(IPS_OFFLOAD_BIT, &ct->status) &&
+	    (ctnetlink_dump_timeout(skb, ct) < 0 ||
+	     ctnetlink_dump_protoinfo(skb, ct) < 0))
+		return -1;
+
+	return 0;
+}
+
 static int
 ctnetlink_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
-		    struct nf_conn *ct)
+		    struct nf_conn *ct, bool extinfo)
 {
 	const struct nf_conntrack_zone *zone;
 	struct nlmsghdr *nlh;
@@ -552,23 +588,9 @@ ctnetlink_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 				   NF_CT_DEFAULT_ZONE_DIR) < 0)
 		goto nla_put_failure;
 
-	if (ctnetlink_dump_status(skb, ct) < 0 ||
-	    ctnetlink_dump_acct(skb, ct, type) < 0 ||
-	    ctnetlink_dump_timestamp(skb, ct) < 0 ||
-	    ctnetlink_dump_helpinfo(skb, ct) < 0 ||
-	    ctnetlink_dump_mark(skb, ct) < 0 ||
-	    ctnetlink_dump_secctx(skb, ct) < 0 ||
-	    ctnetlink_dump_labels(skb, ct) < 0 ||
-	    ctnetlink_dump_id(skb, ct) < 0 ||
-	    ctnetlink_dump_use(skb, ct) < 0 ||
-	    ctnetlink_dump_master(skb, ct) < 0 ||
-	    ctnetlink_dump_ct_seq_adj(skb, ct) < 0 ||
-	    ctnetlink_dump_ct_synproxy(skb, ct) < 0)
+	if (ctnetlink_dump_info(skb, ct) < 0)
 		goto nla_put_failure;
-
-	if (!test_bit(IPS_OFFLOAD_BIT, &ct->status) &&
-	    (ctnetlink_dump_timeout(skb, ct) < 0 ||
-	     ctnetlink_dump_protoinfo(skb, ct) < 0))
+	if (extinfo && ctnetlink_dump_extinfo(skb, ct, type) < 0)
 		goto nla_put_failure;
 
 	nlmsg_end(skb, nlh);
@@ -953,13 +975,11 @@ restart:
 			if (!ctnetlink_filter_match(ct, cb->data))
 				continue;
 
-			rcu_read_lock();
 			res =
 			ctnetlink_fill_info(skb, NETLINK_CB(cb->skb).portid,
 					    cb->nlh->nlmsg_seq,
 					    NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
-					    ct);
-			rcu_read_unlock();
+					    ct, true);
 			if (res < 0) {
 				nf_conntrack_get(&ct->ct_general);
 				cb->args[1] = (unsigned long)ct;
@@ -1364,10 +1384,8 @@ static int ctnetlink_get_conntrack(struct net *net, struct sock *ctnl,
 		return -ENOMEM;
 	}
 
-	rcu_read_lock();
 	err = ctnetlink_fill_info(skb2, NETLINK_CB(skb).portid, nlh->nlmsg_seq,
-				  NFNL_MSG_TYPE(nlh->nlmsg_type), ct);
-	rcu_read_unlock();
+				  NFNL_MSG_TYPE(nlh->nlmsg_type), ct, true);
 	nf_ct_put(ct);
 	if (err <= 0)
 		goto free;
@@ -1429,12 +1447,18 @@ restart:
 					continue;
 				cb->args[1] = 0;
 			}
-			rcu_read_lock();
+
+			/* We can't dump extension info for the unconfirmed
+			 * list because unconfirmed conntracks can have
+			 * ct->ext reallocated (and thus freed).
+			 *
+			 * In the dying list case ct->ext can't be free'd
+			 * until after we drop pcpu->lock.
+			 */
 			res = ctnetlink_fill_info(skb, NETLINK_CB(cb->skb).portid,
 						  cb->nlh->nlmsg_seq,
 						  NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
-						  ct);
-			rcu_read_unlock();
+						  ct, dying ? true : false);
 			if (res < 0) {
 				if (!atomic_inc_not_zero(&ct->ct_general.use))
 					continue;