Added server name indication (RFC 4366) support (PR 34607).

Submitted by: Kaspar Brand <asfbugz velox.ch>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@606190 13f79535-47bb-0310-9956-ffa450edef68

CHANGES

@@ -2,6 +2,9 @@
 Changes with Apache 2.3.0
 [ When backported to 2.2.x, remove entry from this file ]
 
+  *) mod_ssl: Added server name indication support (RFC 4366).
+     PR 34607. [Kaspar Brand <asfbugz velox.ch>]
+
   *) ApacheMonitor.exe: Introduce --kill argument for use by the
      installer.  This will permit the installation tool to remove
      all running instances before attempting to remove the .exe.

modules/ssl/ssl_engine_init.c

@@ -135,6 +135,87 @@ static int ssl_tmp_keys_init(server_rec *s)
     return OK;
 }
 
+#ifndef OPENSSL_NO_TLSEXT
+static int set_ssl_vhost(void *servername, conn_rec *c, server_rec *s) 
+{
+    SSLSrvConfigRec *sc;
+    SSL *ssl;
+    BOOL found = FALSE;
+    apr_array_header_t *names;
+    int i;
+
+    /* check ServerName */
+    if (!strcasecmp(servername, s->server_hostname))
+        found = TRUE;
+
+    /* if not matched yet, check ServerAlias entries */
+    if (!found) {
+        names = s->names;
+        if (names) {
+            char **name = (char **) names->elts;
+            for (i = 0; i < names->nelts; ++i) {
+                if(!name[i]) continue;
+                if (!strcasecmp(servername, name[i])) {
+                    found = TRUE;
+                    break;
+                }
+            }
+        }
+    }
+
+    /* if still no match, check ServerAlias entries with wildcards */
+    if (!found) {
+        names = s->wild_names;
+        if (names) {
+            char **name = (char **) names->elts;
+            for (i = 0; i < names->nelts; ++i) {
+                if(!name[i]) continue;
+                if (!ap_strcasecmp_match(servername, name[i])) {
+                    found = TRUE;
+                    break;
+                }
+            }
+        }
+    }
+
+    /* set SSL_CTX (if matched) */
+    if (found) {
+        if ((ssl = ((SSLConnRec *)myConnConfig(c))->ssl) == NULL) 
+            return 0;
+        if (!(sc = mySrvConfig(s)))
+            return 0;	
+        SSL_set_SSL_CTX(ssl,sc->server->ssl_ctx);
+        return 1;
+    }
+    return 0;
+}
+
+int ssl_set_vhost_ctx(SSL *ssl, const char *servername) 
+{
+    conn_rec *c;
+
+    if (servername == NULL)   /* should not occur. */
+        return 0;
+
+    SSL_set_SSL_CTX(ssl,NULL);
+
+    if (!(c = (conn_rec *)SSL_get_app_data(ssl))) 
+        return 0;
+
+    return ap_vhost_iterate_given_conn(c,set_ssl_vhost,servername);
+}
+
+int ssl_servername_cb(SSL *s, int *al, modssl_ctx_t *mctx)
+{
+    const char *servername = SSL_get_servername(s,TLSEXT_NAMETYPE_host_name);
+
+    if (servername) {
+        return ssl_set_vhost_ctx(s,servername)?SSL_TLSEXT_ERR_OK:SSL_TLSEXT_ERR_ALERT_FATAL;
+    }
+    return SSL_TLSEXT_ERR_NOACK;
+}
+#endif
+
 /*
  *  Per-module initialization
  */
@@ -355,6 +436,29 @@ static void ssl_init_server_check(server_rec *s,
     }
 }
 
+static void ssl_init_server_extensions(server_rec *s,
+                             apr_pool_t *p,
+                             apr_pool_t *ptemp,
+                             modssl_ctx_t *mctx)
+{
+    /*
+     * Configure TLS extensions support
+     */
+
+#ifndef OPENSSL_NO_TLSEXT
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                 "Configuring TLS extensions facility");
+
+    if (!SSL_CTX_set_tlsext_servername_callback(mctx->ssl_ctx, ssl_servername_cb) ||
+        !SSL_CTX_set_tlsext_servername_arg(mctx->ssl_ctx, mctx)) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
+                "Unable to initialize servername callback, bad openssl version.");
+        ssl_log_ssl_error(APLOG_MARK, APLOG_ERR, s);
+        ssl_die();
+    }
+#endif
+}
+
 static void ssl_init_ctx_protocol(server_rec *s,
                                   apr_pool_t *p,
                                   apr_pool_t *ptemp,
@@ -712,6 +816,8 @@ static void ssl_init_ctx(server_rec *s,
         /* XXX: proxy support? */
         ssl_init_ctx_cert_chain(s, p, ptemp, mctx);
     }
+
+    ssl_init_server_extensions(s, p, ptemp, mctx);
 }
 
 static int ssl_server_import_cert(server_rec *s,
@@ -1038,6 +1144,7 @@ void ssl_init_CheckServers(server_rec *base_server, apr_pool_t *p)
         }
     }
 
+#ifdef OPENSSL_NO_TLSEXT
     /*
      * Give out warnings when more than one SSL-aware virtual server uses the
      * same IP:port. This doesn't work because mod_ssl then will always use
@@ -1082,6 +1189,7 @@ void ssl_init_CheckServers(server_rec *base_server, apr_pool_t *p)
                      "Init: You should not use name-based "
                      "virtual hosts in conjunction with SSL!!");
     }
+#endif
 }
 
 #ifdef SSLC_VERSION_NUMBER

modules/ssl/ssl_engine_kernel.c

@@ -297,6 +297,19 @@ int ssl_hook_Access(request_rec *r)
      * the currently active one.
      */
 
+#ifndef OPENSSL_NO_TLSEXT
+    /*
+     * We will switch to another virtualhost and to its ssl_ctx
+     * if changed, we will force a renegotiation.
+     */
+    if (r->hostname && !SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name)) {
+        SSL_CTX *ctx = SSL_get_SSL_CTX(ssl);
+        if (ssl_set_vhost_ctx(ssl,(char *)r->hostname) &&
+                      ctx != SSL_get_SSL_CTX(ssl))
+            renegotiate = TRUE;
+    }
+#endif
+
     /*
      * Override of SSLCipherSuite
      *
@@ -1063,6 +1076,9 @@ int ssl_hook_Fixup(request_rec *r)
     SSLDirConfigRec *dc = myDirConfig(r);
     apr_table_t *env = r->subprocess_env;
     char *var, *val = "";
+#ifndef OPENSSL_NO_TLSEXT
+    const char* servername;
+#endif
     STACK_OF(X509) *peer_certs;
     SSL *ssl;
     int i;
@@ -1089,6 +1105,13 @@ int ssl_hook_Fixup(request_rec *r)
     /* the always present HTTPS (=HTTP over SSL) flag! */
     apr_table_setn(env, "HTTPS", "on");
 
+#ifndef OPENSSL_NO_TLSEXT
+    /* add content of SNI TLS extension (if supplied with ClientHello) */
+    if (servername = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name)) {
+        apr_table_set(env, "SSL_TLS_SNI", servername);
+    }
+#endif
+
     /* standard SSL environment variables */
     if (dc->nOptions & SSL_OPT_STDENVVARS) {
         for (i = 0; ssl_hook_Fixup_vars[i]; i++) {

modules/ssl/ssl_toolkit_compat.h

@@ -270,6 +270,12 @@ typedef void (*modssl_popfree_fn)(char *data);
 #define SSL_SESS_CACHE_NO_INTERNAL  SSL_SESS_CACHE_NO_INTERNAL_LOOKUP
 #endif
 
+#ifndef OPENSSL_NO_TLSEXT
+#ifndef SSL_CTRL_SET_TLSEXT_HOSTNAME
+#define OPENSSL_NO_TLSEXT
+#endif
+#endif
+
 #endif /* SSL_TOOLKIT_COMPAT_H */
 
 /** @} */