From 3604fde3d3c9b0d0e389e079aecf470d123ba180 Mon Sep 17 00:00:00 2001

From: YAMADA Yasuharu <[email protected]>

Date: Thu, 11 Apr 2013 00:17:15 +0200

Subject: [PATCH] cookie: fix tailmatching to prevent cross-domain leakage

Cookies set for 'example.com' could accidentaly also be sent by libcurl

to the 'bexample.com' (ie with a prefix to the first domain name).

This is a security vulnerabilty, CVE-2013-1944.

Bug: http://curl.haxx.se/docs/adv_20130412.html

--- lib/cookie.c	2013-04-12 13:42:43.099608542 -0700

+++ lib/cookie.c	2013-04-12 13:51:27.701845050 -0700

@@ -118,15 +118,29 @@

   free(co);

 }

-static bool tailmatch(const char *little, const char *bigone)

+static bool tailmatch(const char *cooke_domain, const char *hostname)

 {

-  size_t littlelen = strlen(little);

-  size_t biglen = strlen(bigone);

+  size_t cookie_domain_len = strlen(cooke_domain);

+  size_t hostname_len = strlen(hostname);

-  if(littlelen > biglen)

+  if(hostname_len < cookie_domain_len)

     return FALSE;

-  return Curl_raw_equal(little, bigone+biglen-littlelen) ? TRUE : FALSE;

+  if(!Curl_raw_equal(cooke_domain, hostname+hostname_len-cookie_domain_len))

+    return FALSE;

+

+  /* A lead char of cookie_domain is not '.'.

+     RFC6265 4.1.2.3. The Domain Attribute says:

+       For example, if the value of the Domain attribute is

+       "example.com", the user agent will include the cookie in the Cookie

+       header when making HTTP requests to example.com, www.example.com, and

+       www.corp.example.com.

+   */

+  if(hostname_len == cookie_domain_len)

+    return TRUE;

+  if('.' == *(hostname + hostname_len - cookie_domain_len - 1))

+    return TRUE;

+  return FALSE;

 }

 /*