cookies: reject oversized cookies

... instead of truncating them.

There's no fixed limit for acceptable cookie names in RFC 6265, but the
entire cookie is said to be less than 4096 bytes (section 6.1). This is
also what browsers seem to implement.

We now allow max 5000 bytes cookie header. Max 4095 bytes length per
cookie name and value. Name + value together may not exceed 4096 bytes.

Added test 1151 to verify

Bug: https://curl.haxx.se/mail/lib-2017-09/0062.html
Reported-by: Kevin Smith

Closes #1894

1 files changed, 7 insertions, 4 deletions

diff --git a/lib/cookie.h b/lib/cookie.h
index a9a45785c..cb50b71c6 100644
--- a/lib/cookie.h
+++ b/lib/cookie.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -62,13 +62,16 @@ struct CookieInfo {
    that comprise the cookie non-terminal in the syntax description of the
    Set-Cookie header)"
 
+   We allow max 5000 bytes cookie header. Max 4095 bytes length per cookie
+   name and value. Name + value may not exceed 4096 bytes.
+
 */
 #define MAX_COOKIE_LINE 5000
 #define MAX_COOKIE_LINE_TXT "4999"
 
-/* This is the maximum length of a cookie name we deal with: */
-#define MAX_NAME 1024
-#define MAX_NAME_TXT "1023"
+/* This is the maximum length of a cookie name or content we deal with: */
+#define MAX_NAME 4096
+#define MAX_NAME_TXT "4095"
 
 struct Curl_easy;
 /*