applied patch to disable SSLv2 by default; discussion:

http://sourceforge.net/tracker/index.php?func=detail&aid=1767276&group_id=976&atid=350976
Submitted by Kaspar Brand.

docs/libcurl/curl_easy_setopt.3

@@ -1379,10 +1379,9 @@ Pass a long as parameter to control what version of SSL/TLS to attempt to use.
 The available options are:
 .RS
 .IP CURL_SSLVERSION_DEFAULT
-The default action. When libcurl built with OpenSSL or NSS, this will attempt
-to figure out the remote SSL protocol version. Unfortunately there are a lot of
-ancient and broken servers in use which cannot handle this technique and will
-fail to connect. When libcurl is built with GnuTLS, this will mean SSLv3.
+The default action. This will attempt to figure out the remote SSL protocol
+version, i.e. either SSLv3 or TLSv1 (but not SSLv2, which became disabled
+by default with 7.18.1).
 .IP CURL_SSLVERSION_TLSv1
 Force TLSv1
 .IP CURL_SSLVERSION_SSLv2

lib/nss.c

@@ -873,7 +873,7 @@ CURLcode Curl_nss_connect(struct connectdata * conn, int sockindex)
   switch (data->set.ssl.version) {
   default:
   case CURL_SSLVERSION_DEFAULT:
-    ssl2 = ssl3 = tlsv1 = PR_TRUE;
+    ssl3 = tlsv1 = PR_TRUE;
     break;
   case CURL_SSLVERSION_TLSv1:
     tlsv1 = PR_TRUE;
@@ -893,6 +893,9 @@ CURLcode Curl_nss_connect(struct connectdata * conn, int sockindex)
   if(SSL_OptionSet(model, SSL_ENABLE_TLS, tlsv1) != SECSuccess)
     goto error;
 
+  if(SSL_OptionSet(model, SSL_V2_COMPATIBLE_HELLO, ssl2) != SECSuccess)
+    goto error;
+
   if(data->set.ssl.cipher_list) {
     if(set_ciphers(data, model, data->set.ssl.cipher_list) != SECSuccess) {
       curlerr = CURLE_SSL_CIPHER;

lib/qssl.c

@@ -90,7 +90,7 @@ static CURLcode Curl_qsossl_init_session(struct SessionHandle * data)
   memset((char *) &initappstr, 0, sizeof initappstr);
   initappstr.applicationID = certname;
   initappstr.applicationIDLen = strlen(certname);
-  initappstr.protocol = SSL_VERSION_CURRENT;
+  initappstr.protocol = TLSV1_SSLV3;
   initappstr.sessionType = SSL_REGISTERED_AS_CLIENT;
   rc = SSL_Init_Application(&initappstr);
 
@@ -190,7 +190,7 @@ static CURLcode Curl_qsossl_handshake(struct connectdata * conn, int sockindex)
 
   default:
   case CURL_SSLVERSION_DEFAULT:
-    h->protocol = SSL_VERSION_CURRENT;
+    h->protocol = TLSV1_SSLV3;
     break;
 
   case CURL_SSLVERSION_TLSv1:

lib/ssluse.c

@@ -1324,6 +1324,10 @@ ossl_connect_step1(struct connectdata *conn,
   */
   SSL_CTX_set_options(connssl->ctx, SSL_OP_ALL);
 
+  /* disable SSLv2 in the default case (i.e. allow SSLv3 and TLSv1) */
+  if(data->set.ssl.version == CURL_SSLVERSION_DEFAULT)
+    SSL_CTX_set_options(connssl->ctx, SSL_OP_NO_SSLv2);
+
 #if 0
   /*
    * Not sure it's needed to tell SSL_connect() that socket is