Merge branch 'tipc-a-batch-of-uninit-value-fixes-for-netlink_compat'

Xin Long says:

====================
tipc: a batch of uninit-value fixes for netlink_compat

These issues were all reported by syzbot, and exist since very beginning.
See the details on each patch.
====================
Acked-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/tipc/netlink_compat.c

@@ -267,8 +267,14 @@ static int tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd,
 	if (msg->rep_type)
 		tipc_tlv_init(msg->rep, msg->rep_type);
 
-	if (cmd->header)
-		(*cmd->header)(msg);
+	if (cmd->header) {
+		err = (*cmd->header)(msg);
+		if (err) {
+			kfree_skb(msg->rep);
+			msg->rep = NULL;
+			return err;
+		}
+	}
 
 	arg = nlmsg_new(0, GFP_KERNEL);
 	if (!arg) {
@@ -397,7 +403,12 @@ static int tipc_nl_compat_bearer_enable(struct tipc_nl_compat_cmd_doit *cmd,
 	if (!bearer)
 		return -EMSGSIZE;
 
-	len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_BEARER_NAME);
+	len = TLV_GET_DATA_LEN(msg->req);
+	len -= offsetof(struct tipc_bearer_config, name);
+	if (len <= 0)
+		return -EINVAL;
+
+	len = min_t(int, len, TIPC_MAX_BEARER_NAME);
 	if (!string_is_valid(b->name, len))
 		return -EINVAL;
 
@@ -766,7 +777,12 @@ static int tipc_nl_compat_link_set(struct tipc_nl_compat_cmd_doit *cmd,
 
 	lc = (struct tipc_link_config *)TLV_DATA(msg->req);
 
-	len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_LINK_NAME);
+	len = TLV_GET_DATA_LEN(msg->req);
+	len -= offsetof(struct tipc_link_config, name);
+	if (len <= 0)
+		return -EINVAL;
+
+	len = min_t(int, len, TIPC_MAX_LINK_NAME);
 	if (!string_is_valid(lc->name, len))
 		return -EINVAL;