From 2eb8dcf26cb37f09cffe26909a646e702dbcab66 Mon Sep 17 00:00:00 2001 From: YAMADA Yasuharu Date: Thu, 11 Apr 2013 00:17:15 +0200 Subject: 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 | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) (limited to 'lib/cookie.c') diff --git a/lib/cookie.c b/lib/cookie.c index 4b9ec0bdd..a67204e6e 100644 --- a/lib/cookie.c +++ b/lib/cookie.c @@ -118,15 +118,29 @@ static void freecookie(struct Cookie *co) 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; } /* -- cgit v1.2.3