SSL: the "ssl_verify_client" directive parameter "optional_no_ca".

This parameter allows to don't require certificate to be signed by
a trusted CA, e.g. if CA certificate isn't known in advance, like in
WebID protocol.

Note that it doesn't add any security unless the certificate is actually
checked to be trusted by some external means (e.g. by a backend).

Patch by Mike Kazantsev, Eric O'Connor.

diff --git a/src/event/ngx_event_openssl.h b/src/event/ngx_event_openssl.h
index d1fb5739fe50564bcd4ca7aabbd8a80cf3f417ad..bf81d2529c9a5dad253b325f29bb8ab921fc6a2a 100644 (file)
--- a/src/event/ngx_event_openssl.h
+++ b/src/event/ngx_event_openssl.h
@@ -127,6 +127,13 @@ ngx_int_t ngx_ssl_set_session(ngx_connection_t *c, ngx_ssl_session_t *session);
 #define ngx_ssl_get_server_conf(ssl_ctx)                                      \
     SSL_CTX_get_ex_data(ssl_ctx, ngx_ssl_server_conf_index)
 
+#define ngx_ssl_verify_error_optional(n)                                      \
+    (n == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT                              \
+     || n == X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN                             \
+     || n == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY                     \
+     || n == X509_V_ERR_CERT_UNTRUSTED                                        \
+     || n == X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE)
+
 
 ngx_int_t ngx_ssl_get_protocol(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);

diff --git a/src/http/modules/ngx_http_ssl_module.c b/src/http/modules/ngx_http_ssl_module.c
index 0073dba3c222308cf4b44b5418010068aed1a0f3..284edd0029ad3982879f69d5e1c0b93d2f2818b0 100644 (file)
--- a/src/http/modules/ngx_http_ssl_module.c
+++ b/src/http/modules/ngx_http_ssl_module.c
@@ -50,6 +50,7 @@ static ngx_conf_enum_t  ngx_http_ssl_verify[] = {
     { ngx_string("off"), 0 },
     { ngx_string("on"), 1 },
     { ngx_string("optional"), 2 },
+    { ngx_string("optional_no_ca"), 3 },
     { ngx_null_string, 0 }
 };
 
@@ -515,7 +516,7 @@ ngx_http_ssl_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
 
     if (conf->verify) {
 
-        if (conf->client_certificate.len == 0) {
+        if (conf->client_certificate.len == 0 && conf->verify != 3) {
             ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                           "no ssl_client_certificate for ssl_client_verify");
             return NGX_CONF_ERROR;

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index cb970c5c20286e3a555a2f20824cb3d704dda192..ec9d4a1c36397a26c5450972be1611f9ff49f9b7 100644 (file)
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -1642,7 +1642,9 @@ ngx_http_process_request(ngx_http_request_t *r)
         if (sscf->verify) {
             rc = SSL_get_verify_result(c->ssl->connection);
 
-            if (rc != X509_V_OK) {
+            if (rc != X509_V_OK
+                && (sscf->verify != 3 || !ngx_ssl_verify_error_optional(rc)))
+            {
                 ngx_log_error(NGX_LOG_INFO, c->log, 0,
                               "client SSL certificate verify error: (%l:%s)",
                               rc, X509_verify_cert_error_string(rc));