source: server/common/patches/httpd-2.2.8-sni.patch @ 688

httpd-2.2.8-sni.patch - server name indication support for Apache 2.2
(see RFC 4366, "Transport Layer Security (TLS) Extensions")

based on a patch from the EdelKey project
(http://www.edelweb.fr/EdelKey/files/apache-2.2.0+0.9.9+servername.patch)

Needs openssl-SNAP-20060330 / OpenSSL 0.9.8f or later
to work properly (ftp://ftp.openssl.org/snapshot/). The 0.9.8 versions
must be configured explicitly for TLS extension support at compile time
("./config enable-tlsext").

Index: httpd-2.2.x/modules/ssl/ssl_private.h
===================================================================
--- httpd-2.2.x/modules/ssl/ssl_private.h       (revision 627519)
+++ httpd-2.2.x/modules/ssl/ssl_private.h       (working copy)
@@ -35,6 +35,7 @@
 #include "http_connection.h"
 #include "http_request.h"
 #include "http_protocol.h"
+#include "http_vhost.h"
 #include "util_script.h"
 #include "util_filter.h"
 #include "util_ebcdic.h"
@@ -555,6 +556,9 @@
 SSL_SESSION *ssl_callback_GetSessionCacheEntry(SSL *, unsigned char *, int, int *);
 void         ssl_callback_DelSessionCacheEntry(SSL_CTX *, SSL_SESSION *);
 void         ssl_callback_LogTracingState(MODSSL_INFO_CB_ARG_TYPE, int, int);
+#ifndef OPENSSL_NO_TLSEXT
+int          ssl_callback_ServerNameIndication(SSL *, int *, modssl_ctx_t *);
+#endif
 
 /**  Session Cache Support  */
 void         ssl_scache_init(server_rec *, apr_pool_t *);
Index: httpd-2.2.x/modules/ssl/ssl_engine_init.c
===================================================================
--- httpd-2.2.x/modules/ssl/ssl_engine_init.c   (revision 627519)
+++ httpd-2.2.x/modules/ssl/ssl_engine_init.c   (working copy)
@@ -355,6 +355,33 @@
     }
 }
 
+#ifndef OPENSSL_NO_TLSEXT
+static void ssl_init_ctx_tls_extensions(server_rec *s,
+                                        apr_pool_t *p,
+                                        apr_pool_t *ptemp,
+                                        modssl_ctx_t *mctx)
+{
+    /*
+     * Configure TLS extensions support
+     */
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                 "Configuring TLS extension handling");
+
+    /*
+     * Server name indication (SNI)
+     */
+    if (!SSL_CTX_set_tlsext_servername_callback(mctx->ssl_ctx,
+                          ssl_callback_ServerNameIndication) ||
+        !SSL_CTX_set_tlsext_servername_arg(mctx->ssl_ctx, mctx)) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
+                     "Unable to initialize TLS servername extension "
+                     "callback (incompatible 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,
@@ -687,6 +714,9 @@
     if (mctx->pks) {
         /* XXX: proxy support? */
         ssl_init_ctx_cert_chain(s, p, ptemp, mctx);
+#ifndef OPENSSL_NO_TLSEXT
+        ssl_init_ctx_tls_extensions(s, p, ptemp, mctx);
+#endif
     }
 }
 
@@ -1038,7 +1068,11 @@
         if ((ps = (server_rec *)apr_hash_get(table, key, klen))) {
             ap_log_error(APLOG_MARK, APLOG_WARNING, 0,
                          base_server,
+#ifdef OPENSSL_NO_TLSEXT
                          "Init: SSL server IP/port conflict: "
+#else
+                         "Init: SSL server IP/port overlap: "
+#endif
                          "%s (%s:%d) vs. %s (%s:%d)",
                          ssl_util_vhostid(p, s),
                          (s->defn_name ? s->defn_name : "unknown"),
@@ -1055,8 +1089,14 @@
 
     if (conflict) {
         ap_log_error(APLOG_MARK, APLOG_WARNING, 0, base_server,
+#ifdef OPENSSL_NO_TLSEXT
                      "Init: You should not use name-based "
                      "virtual hosts in conjunction with SSL!!");
+#else
+                     "Init: Name-based SSL virtual hosts only "
+                     "work for clients with TLS server name indication "
+                     "support (RFC 4366)");
+#endif
     }
 }
 
Index: httpd-2.2.x/modules/ssl/ssl_engine_vars.c
===================================================================
--- httpd-2.2.x/modules/ssl/ssl_engine_vars.c   (revision 627519)
+++ httpd-2.2.x/modules/ssl/ssl_engine_vars.c   (working copy)
@@ -320,6 +320,12 @@
     else if (ssl != NULL && strcEQ(var, "COMPRESS_METHOD")) {
         result = ssl_var_lookup_ssl_compress_meth(ssl);
     }
+#ifndef OPENSSL_NO_TLSEXT
+    else if (ssl != NULL && strcEQ(var, "TLS_SNI")) {
+        result = apr_pstrdup(p, SSL_get_servername(ssl,
+                                                   TLSEXT_NAMETYPE_host_name));
+    }
+#endif
     return result;
 }
 
Index: httpd-2.2.x/modules/ssl/ssl_engine_kernel.c
===================================================================
--- httpd-2.2.x/modules/ssl/ssl_engine_kernel.c (revision 627519)
+++ httpd-2.2.x/modules/ssl/ssl_engine_kernel.c (working copy)
@@ -31,6 +31,9 @@
 #include "ssl_private.h"
 
 static void ssl_configure_env(request_rec *r, SSLConnRec *sslconn);
+#ifndef OPENSSL_NO_TLSEXT
+static int ssl_find_vhost(void *servername, conn_rec *c, server_rec *s);
+#endif
 
 /*
  *  Post Read Request Handler
@@ -39,6 +42,9 @@
 {
     SSLConnRec *sslconn = myConnConfig(r->connection);
     SSL *ssl;
+#ifndef OPENSSL_NO_TLSEXT
+    const char *servername;
+#endif
 
     if (!sslconn) {
         return DECLINED;
@@ -87,6 +93,14 @@
     if (!ssl) {
         return DECLINED;
     }
+#ifndef OPENSSL_NO_TLSEXT
+    if (!r->hostname &&
+        (servername = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name))) {
+        /* Use the SNI extension as the hostname if no Host: header was sent */
+        r->hostname = apr_pstrdup(r->pool, servername);
+        ap_update_vhost_from_headers(r);
+    }
+#endif
     SSL_set_app_data2(ssl, r);
 
     /*
@@ -997,6 +1011,9 @@
     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;
@@ -1018,6 +1035,13 @@
     /* 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++) {
@@ -1810,3 +1834,136 @@
     }
 }
 
+#ifndef OPENSSL_NO_TLSEXT
+/*
+ * This callback function is executed when OpenSSL encounters an extended
+ * client hello with a server name indication extension ("SNI", cf. RFC 4366).
+ */
+int ssl_callback_ServerNameIndication(SSL *ssl, int *al, modssl_ctx_t *mctx)
+{
+    const char *servername =
+                SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
+
+    if (servername) {
+        conn_rec *c = (conn_rec *)SSL_get_app_data(ssl);
+        if (c) {
+            if (ap_vhost_iterate_given_conn(c, ssl_find_vhost,
+                                            (void *)servername)) {
+                ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c,
+                              "SSL virtual host for servername %s found",
+                              servername);
+                return SSL_TLSEXT_ERR_OK;
+            }
+            else {
+                ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c,
+                              "No matching SSL virtual host for servername "
+                              "%s found (using default/first virtual host)",
+                              servername);
+                return SSL_TLSEXT_ERR_ALERT_WARNING;
+            }
+        }
+    }
+
+    return SSL_TLSEXT_ERR_NOACK;
+}
+
+/*
+ * Find a (name-based) SSL virtual host where either the ServerName
+ * or one of the ServerAliases matches the supplied name (to be used
+ * with ap_vhost_iterate_given_conn())
+ */
+static int ssl_find_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
+     * (adapted from vhost.c:matches_aliases())
+     */
+    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 && (ssl = ((SSLConnRec *)myConnConfig(c))->ssl) &&
+        (sc = mySrvConfig(s))) {
+        SSL_set_SSL_CTX(ssl, sc->server->ssl_ctx);
+        /*
+         * SSL_set_SSL_CTX() only deals with the server cert,
+         * so we need to duplicate a few additional settings
+         * from the ctx by hand
+         */
+        SSL_set_options(ssl, SSL_CTX_get_options(ssl->ctx));
+        if ((SSL_get_verify_mode(ssl) == SSL_VERIFY_NONE) ||
+            (SSL_num_renegotiations(ssl) == 0)) {
+           /*
+            * Only initialize the verification settings from the ctx
+            * if they are not yet set, or if we're called when a new
+            * SSL connection is set up (num_renegotiations == 0).
+            * Otherwise, we would possibly reset a per-directory
+            * configuration which was put into effect by ssl_hook_Access.
+            */
+            SSL_set_verify(ssl, SSL_CTX_get_verify_mode(ssl->ctx),
+                           SSL_CTX_get_verify_callback(ssl->ctx));
+        }
+
+        /*
+         * We also need to make sure that the correct mctx is
+         * assigned to the connection - the CRL callback e.g.
+         * makes use of it for retrieving its store (mctx->crl).
+         * Since logging in callbacks uses c->base_server in many
+         * cases, it also ensures that these messages are routed
+         * to the proper log. And finally, there is one special
+         * filter callback, which is set very early depending on the
+         * base_server's log level. If this is not the first vhost
+         * we're now selecting (and the first vhost doesn't use
+         * APLOG_DEBUG), then we need to set that callback here.
+         */
+        c->base_server = s;
+        if (c->base_server->loglevel >= APLOG_DEBUG) {
+            BIO_set_callback(SSL_get_rbio(ssl), ssl_io_data_cb);
+            BIO_set_callback_arg(SSL_get_rbio(ssl), (void *)ssl);
+        }
+
+        return 1;
+    }
+
+    return 0;
+}
+#endif
Index: httpd-2.2.x/modules/ssl/ssl_toolkit_compat.h
===================================================================
--- httpd-2.2.x/modules/ssl/ssl_toolkit_compat.h        (revision 627519)
+++ httpd-2.2.x/modules/ssl/ssl_toolkit_compat.h        (working copy)
@@ -264,6 +264,12 @@
 #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 */
 
 /** @} */