fix overflow if more data on stream than content-length indicates

src/request.zig

@@ -854,6 +854,9 @@ pub const State = struct {
             self.pos = len;
             return true;
         }
+        if  (read > cl) {
+            return error.InvalidContentLength;
+        }
 
         // how much of the body are we missing
         const missing = cl - read;
@@ -1203,6 +1206,11 @@ test "request: query & body" {
     try t.expectString("keemun tea", (try r.query()).get("search").?);
 }
 
+test "request: invalid content-length" {
+    defer t.reset();
+    try expectParseError(error.InvalidContentLength, "GET / HTTP/1.0\r\nContent-Length: 1\r\n\r\nabc", .{ });
+}
+
 test "body: json" {
     defer t.reset();
     const Tea = struct {