1 files changed, 22 insertions, 26 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index b93148e8e9fb..b9e0ee4e22f5 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -128,7 +128,6 @@ static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
 };
 
 static int netlink_dump(struct sock *sk);
-static void netlink_skb_destructor(struct sk_buff *skb);
 
 /* nl_table locking explained:
  * Lookup and traversal are protected with an RCU read-side lock. Insertion
@@ -2136,7 +2135,7 @@ static int netlink_dump(struct sock *sk)
 	struct sk_buff *skb = NULL;
 	struct nlmsghdr *nlh;
 	struct module *module;
-	int len, err = -ENOBUFS;
+	int err = -ENOBUFS;
 	int alloc_min_size;
 	int alloc_size;
 
@@ -2183,9 +2182,11 @@ static int netlink_dump(struct sock *sk)
 	skb_reserve(skb, skb_tailroom(skb) - alloc_size);
 	netlink_skb_set_owner_r(skb, sk);
 
-	len = cb->dump(skb, cb);
+	if (nlk->dump_done_errno > 0)
+		nlk->dump_done_errno = cb->dump(skb, cb);
 
-	if (len > 0) {
+	if (nlk->dump_done_errno > 0 ||
+	    skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
 		mutex_unlock(nlk->cb_mutex);
 
 		if (sk_filter(sk, skb))
@@ -2195,13 +2196,15 @@ static int netlink_dump(struct sock *sk)
 		return 0;
 	}
 
-	nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
-	if (!nlh)
+	nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE,
+			       sizeof(nlk->dump_done_errno), NLM_F_MULTI);
+	if (WARN_ON(!nlh))
 		goto errout_skb;
 
 	nl_dump_check_consistent(cb, nlh);
 
-	memcpy(nlmsg_data(nlh), &len, sizeof(len));
+	memcpy(nlmsg_data(nlh), &nlk->dump_done_errno,
+	       sizeof(nlk->dump_done_errno));
 
 	if (sk_filter(sk, skb))
 		kfree_skb(skb);
@@ -2273,6 +2276,7 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 	}
 
 	nlk->cb_running = true;
+	nlk->dump_done_errno = INT_MAX;
 
 	mutex_unlock(nlk->cb_mutex);
 
@@ -2313,17 +2317,16 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
 	 * requests to cap the error message, and get extra error data if
 	 * requested.
 	 */
+	if (nlk_has_extack && extack && extack->_msg)
+		tlvlen += nla_total_size(strlen(extack->_msg) + 1);
+
 	if (err) {
 		if (!(nlk->flags & NETLINK_F_CAP_ACK))
 			payload += nlmsg_len(nlh);
 		else
 			flags |= NLM_F_CAPPED;
-		if (nlk_has_extack && extack) {
-			if (extack->_msg)
-				tlvlen += nla_total_size(strlen(extack->_msg) + 1);
-			if (extack->bad_attr)
-				tlvlen += nla_total_size(sizeof(u32));
-		}
+		if (nlk_has_extack && extack && extack->bad_attr)
+			tlvlen += nla_total_size(sizeof(u32));
 	} else {
 		flags |= NLM_F_CAPPED;
 
@@ -2336,16 +2339,8 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
 
 	skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
 	if (!skb) {
-		struct sock *sk;
-
-		sk = netlink_lookup(sock_net(in_skb->sk),
-				    in_skb->sk->sk_protocol,
-				    NETLINK_CB(in_skb).portid);
-		if (sk) {
-			sk->sk_err = ENOBUFS;
-			sk->sk_error_report(sk);
-			sock_put(sk);
-		}
+		NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
+		NETLINK_CB(in_skb).sk->sk_error_report(NETLINK_CB(in_skb).sk);
 		return;
 	}
 
@@ -2356,10 +2351,11 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
 	memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
 
 	if (nlk_has_extack && extack) {
+		if (extack->_msg) {
+			WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
+					       extack->_msg));
+		}
 		if (err) {
-			if (extack->_msg)
-				WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
-						       extack->_msg));
 			if (extack->bad_attr &&
 			    !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
 				     (u8 *)extack->bad_attr >= in_skb->data +