From 3648ba7db833d318269daba2a8d6be42660c5b60 Mon Sep 17 00:00:00 2001
From: Maxim Dounin <mdounin@mdounin.ru>
Date: Mon, 1 Oct 2012 12:39:36 +0000
Subject: [PATCH] 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).
---
 src/event/ngx_event_openssl.c          | 27 ++++++++++++++++++++++++++
 src/event/ngx_event_openssl.h          |  2 ++
 src/http/modules/ngx_http_ssl_module.c | 24 ++++++++++++++++++++---
 src/http/modules/ngx_http_ssl_module.h |  1 +
 4 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index 5e25b0156..5c451675e 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -296,6 +296,33 @@ ngx_ssl_client_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *cert,
 }
 
 
+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)
 {
diff --git a/src/event/ngx_event_openssl.h b/src/event/ngx_event_openssl.h
index cd6d88518..81f0a8b8e 100644
--- 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 *cf, ngx_ssl_t *ssl,
     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
index d759489a6..aa0a4b4e1 100644
--- 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_commands[] = {
       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 *cf)
      *     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 *cf, void *parent, void *child)
 
     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 *cf, void *parent, void *child)
         {
             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
index 58659ab95..1fb891b17 100644
--- 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;