diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index cf45555..eccec53 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2470,7 +2470,7 @@
 		/* Values greater than interface MTU won't take effect. However
 		 * at the point when this call is done we typically don't yet
 		 * know which interface is going to be used */
-		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
+		if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) {
 			err = -EINVAL;
 			break;
 		}