[PATCH 1 of 4] OCSP stapling: ssl_trusted_certificate directive

[Maxim Dounin]

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1346840510 -14400
# Node ID ca180646a706288271f411ed65f40ae5a1c26211
# Parent  384fd80c0fe6db6f3f61de47f899567da7b98417
OCSP stapling: ssl_trusted_certificate directive.

The directive allows to specify additional trusted Certificate Authority
certificates to be used during certificate verification.  In contrast to
ssl_client_certificate DNs of these cerificates aren't sent to a client
during handshake.

Trusted certificates are loaded regardless of the fact whether client
certificates verification is enabled as the same certificates will be
used for OCSP stapling, during construction of an OCSP request and for
verification of an OCSP response.

The same applies to a CRL (which is now always loaded).

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -295,6 +295,33 @@ ngx_ssl_client_certificate(ngx_conf_t *c
 
 
 ngx_int_t
+ngx_ssl_trusted_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *cert,
+    ngx_int_t depth)
+{
+    SSL_CTX_set_verify_depth(ssl->ctx, depth);
+
+    if (cert->len == 0) {
+        return NGX_OK;
+    }
+
+    if (ngx_conf_full_name(cf->cycle, cert, 1) != NGX_OK) {
+        return NGX_ERROR;
+    }
+
+    if (SSL_CTX_load_verify_locations(ssl->ctx, (char *) cert->data, NULL)
+        == 0)
+    {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
+                      "SSL_CTX_load_verify_locations(\"%s\") failed",
+                      cert->data);
+        return NGX_ERROR;
+    }
+
+    return NGX_OK;
+}
+
+
+ngx_int_t
 ngx_ssl_crl(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *crl)
 {
     X509_STORE   *store;
diff --git a/src/event/ngx_event_openssl.h b/src/event/ngx_event_openssl.h
--- a/src/event/ngx_event_openssl.h
+++ b/src/event/ngx_event_openssl.h
@@ -101,6 +101,8 @@ ngx_int_t ngx_ssl_certificate(ngx_conf_t
     ngx_str_t *cert, ngx_str_t *key);
 ngx_int_t ngx_ssl_client_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl,
     ngx_str_t *cert, ngx_int_t depth);
+ngx_int_t ngx_ssl_trusted_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl,
+    ngx_str_t *cert, ngx_int_t depth);
 ngx_int_t ngx_ssl_crl(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *crl);
 RSA *ngx_ssl_rsa512_key_callback(SSL *ssl, int is_export, int key_length);
 ngx_int_t ngx_ssl_dhparam(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *file);
diff --git a/src/http/modules/ngx_http_ssl_module.c b/src/http/modules/ngx_http_ssl_module.c
--- a/src/http/modules/ngx_http_ssl_module.c
+++ b/src/http/modules/ngx_http_ssl_module.c
@@ -124,6 +124,13 @@ static ngx_command_t  ngx_http_ssl_comma
       offsetof(ngx_http_ssl_srv_conf_t, client_certificate),
       NULL },
 
+    { ngx_string("ssl_trusted_certificate"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_slot,
+      NGX_HTTP_SRV_CONF_OFFSET,
+      offsetof(ngx_http_ssl_srv_conf_t, trusted_certificate),
+      NULL },
+
     { ngx_string("ssl_prefer_server_ciphers"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
       ngx_conf_set_flag_slot,
@@ -325,6 +332,7 @@ ngx_http_ssl_create_srv_conf(ngx_conf_t 
      *     sscf->dhparam = { 0, NULL };
      *     sscf->ecdh_curve = { 0, NULL };
      *     sscf->client_certificate = { 0, NULL };
+     *     sscf->trusted_certificate = { 0, NULL };
      *     sscf->crl = { 0, NULL };
      *     sscf->ciphers = { 0, NULL };
      *     sscf->shm_zone = NULL;
@@ -380,6 +388,8 @@ ngx_http_ssl_merge_srv_conf(ngx_conf_t *
 
     ngx_conf_merge_str_value(conf->client_certificate, prev->client_certificate,
                          "");
+    ngx_conf_merge_str_value(conf->trusted_certificate,
+                         prev->trusted_certificate, "");
     ngx_conf_merge_str_value(conf->crl, prev->crl, "");
 
     ngx_conf_merge_str_value(conf->ecdh_curve, prev->ecdh_curve,
@@ -479,10 +489,18 @@ ngx_http_ssl_merge_srv_conf(ngx_conf_t *
         {
             return NGX_CONF_ERROR;
         }
+    }
 
-        if (ngx_ssl_crl(cf, &conf->ssl, &conf->crl) != NGX_OK) {
-            return NGX_CONF_ERROR;
-        }
+    if (ngx_ssl_trusted_certificate(cf, &conf->ssl,
+                                    &conf->trusted_certificate,
+                                    conf->verify_depth)
+        != NGX_OK)
+    {
+        return NGX_CONF_ERROR;
+    }
+
+    if (ngx_ssl_crl(cf, &conf->ssl, &conf->crl) != NGX_OK) {
+        return NGX_CONF_ERROR;
     }
 
     if (conf->prefer_server_ciphers) {
diff --git a/src/http/modules/ngx_http_ssl_module.h b/src/http/modules/ngx_http_ssl_module.h
--- a/src/http/modules/ngx_http_ssl_module.h
+++ b/src/http/modules/ngx_http_ssl_module.h
@@ -35,6 +35,7 @@ typedef struct {
     ngx_str_t                       dhparam;
     ngx_str_t                       ecdh_curve;
     ngx_str_t                       client_certificate;
+    ngx_str_t                       trusted_certificate;
     ngx_str_t                       crl;
 
     ngx_str_t                       ciphers;