SSL: Several SSL-backend related fixes

axTLS:

This will make the axTLS backend perform the RFC2818 checks, honoring
the VERIFYHOST setting similar to the OpenSSL backend.

Generic for OpenSSL and axTLS:

Move the hostcheck and cert_hostcheck functions from the lib/ssluse.c
files to make them genericly available for both the OpenSSL, axTLS and
other SSL backends. They are now in the new lib/hostcheck.c file.

CyaSSL:

CyaSSL now also has the RFC2818 checks enabled by default. There is a
limitation that the verifyhost can not be enabled exclusively on the
Subject CN field comparison. This SSL backend will thus behave like the
NSS and the GnuTLS (meaning: RFC2818 ok, or bust). In other words:
setting verifyhost to 0 or 1 will disable the Subject Alt Names checks
too.

Schannel:

Updated the schannel information messages: Split the IP address usage
message from the verifyhost setting and changed the message about
disabling SNI (Server Name Indication, used in HTTP virtual hosting)
into a message stating that the Subject Alternative Names checks are
being disabled when verifyhost is set to 0 or 1. As a side effect of
switching off the RFC2818 related servername checks with
SCH_CRED_NO_SERVERNAME_CHECK
(http://msdn.microsoft.com/en-us/library/aa923430.aspx) the SNI feature
is being disabled. This effect is not documented in MSDN, but Wireshark
output clearly shows the effect (details on the libcurl maillist).

PolarSSL:

Fix the prototype change in PolarSSL of ssl_set_session() and the move
of the peer_cert from the ssl_context to the ssl_session. Found this
change in the PolarSSL SVN between r1316 and r1317 where the
POLARSSL_VERSION_NUMBER was at 0x01010100. But to accommodate the Ubuntu
PolarSSL version 1.1.4 the check is to discriminate between lower then
PolarSSL version 1.2.0 and 1.2.0 and higher. Note: The PolarSSL SVN
trunk jumped from version 1.1.1 to 1.2.0.

Generic:

All the SSL backends are fixed and checked to work with the
ssl.verifyhost as a boolean, which is an internal API change.

1 files changed, 3 insertions, 67 deletions

diff --git a/lib/ssluse.c b/lib/ssluse.c
index 6f0e6bf6b..7c4c9269a 100644
--- a/lib/ssluse.c
+++ b/lib/ssluse.c
@@ -50,6 +50,7 @@
 #include "select.h"
 #include "sslgen.h"
 #include "rawstr.h"
+#include "hostcheck.h"
 
 #define _MPRINTF_REPLACE /* use the internal *printf() functions */
 #include <curl/mprintf.h>
@@ -1039,71 +1040,6 @@ static int asn1_output(const ASN1_UTCTIME *tm,
 
 /* ====================================================== */
 
-/*
- * Match a hostname against a wildcard pattern.
- * E.g.
- *  "foo.host.com" matches "*.host.com".
- *
- * We use the matching rule described in RFC6125, section 6.4.3.
- * http://tools.ietf.org/html/rfc6125#section-6.4.3
- */
-#define HOST_NOMATCH 0
-#define HOST_MATCH   1
-
-static int hostmatch(const char *hostname, const char *pattern)
-{
-  const char *pattern_label_end, *pattern_wildcard, *hostname_label_end;
-  int wildcard_enabled;
-  size_t prefixlen, suffixlen;
-  pattern_wildcard = strchr(pattern, '*');
-  if(pattern_wildcard == NULL) {
-    return Curl_raw_equal(pattern, hostname) ? HOST_MATCH : HOST_NOMATCH;
-  }
-  /* We require at least 2 dots in pattern to avoid too wide wildcard
-     match. */
-  wildcard_enabled = 1;
-  pattern_label_end = strchr(pattern, '.');
-  if(pattern_label_end == NULL || strchr(pattern_label_end+1, '.') == NULL ||
-     pattern_wildcard > pattern_label_end ||
-     Curl_raw_nequal(pattern, "xn--", 4)) {
-    wildcard_enabled = 0;
-  }
-  if(!wildcard_enabled) {
-    return Curl_raw_equal(pattern, hostname) ? HOST_MATCH : HOST_NOMATCH;
-  }
-  hostname_label_end = strchr(hostname, '.');
-  if(hostname_label_end == NULL ||
-     !Curl_raw_equal(pattern_label_end, hostname_label_end)) {
-    return HOST_NOMATCH;
-  }
-  /* The wildcard must match at least one character, so the left-most
-     label of the hostname is at least as large as the left-most label
-     of the pattern. */
-  if(hostname_label_end - hostname < pattern_label_end - pattern) {
-    return HOST_NOMATCH;
-  }
-  prefixlen = pattern_wildcard - pattern;
-  suffixlen = pattern_label_end - (pattern_wildcard+1);
-  return Curl_raw_nequal(pattern, hostname, prefixlen) &&
-    Curl_raw_nequal(pattern_wildcard+1, hostname_label_end - suffixlen,
-                    suffixlen) ?
-    HOST_MATCH : HOST_NOMATCH;
-}
-
-static int
-cert_hostcheck(const char *match_pattern, const char *hostname)
-{
-  if(!match_pattern || !*match_pattern ||
-      !hostname || !*hostname) /* sanity check */
-    return 0;
-
-  if(Curl_raw_equal(hostname, match_pattern)) /* trivial case */
-    return 1;
-
-  if(hostmatch(hostname,match_pattern) == HOST_MATCH)
-    return 1;
-  return 0;
-}
 
 /* Quote from RFC2818 section 3.1 "Server Identity"
 
@@ -1192,7 +1128,7 @@ static CURLcode verifyhost(struct connectdata *conn,
           if((altlen == strlen(altptr)) &&
              /* if this isn't true, there was an embedded zero in the name
                 string and we cannot match it. */
-             cert_hostcheck(altptr, conn->host.name))
+             Curl_cert_hostcheck(altptr, conn->host.name))
             matched = 1;
           else
             matched = 0;
@@ -1291,7 +1227,7 @@ static CURLcode verifyhost(struct connectdata *conn,
             "SSL: unable to obtain common name from peer certificate");
       res = CURLE_PEER_FAILED_VERIFICATION;
     }
-    else if(!cert_hostcheck((const char *)peer_CN, conn->host.name)) {
+    else if(!Curl_cert_hostcheck((const char *)peer_CN, conn->host.name)) {
       failf(data, "SSL: certificate subject name '%s' does not match "
             "target host name '%s'", peer_CN, conn->host.dispname);
       res = CURLE_PEER_FAILED_VERIFICATION;