feature: add FFI interface to verify SSL client certificate

src/ngx_http_lua_ssl_certby.c

@@ -1294,4 +1294,119 @@ ngx_http_lua_ffi_set_priv_key(ngx_http_request_t *r,
 }
 
 
+static int
+ngx_ssl_verify_callback(int ok, X509_STORE_CTX *x509_store)
+{
+    /*
+     * we never terminate handshake here and user can later use
+     * $ssl_client_verify to check verification result.
+     *
+     * this is consistent with Nginx behavior.
+     */
+    return 1;
+}
+
+
+int
+ngx_http_lua_ffi_ssl_verify_client(ngx_http_request_t *r, void *ca_certs,
+    int depth, char **err)
+{
+    ngx_ssl_conn_t              *ssl_conn;
+    ngx_http_ssl_srv_conf_t     *sscf;
+    STACK_OF(X509)              *chain = ca_certs;
+    STACK_OF(X509_NAME)         *name_chain = NULL;
+    X509                        *x509 = NULL;
+    X509_NAME                   *subject = NULL;
+    X509_STORE                  *ca_store = NULL;
+#ifdef OPENSSL_IS_BORINGSSL
+    size_t                      i;
+#else
+    int                         i;
+#endif
+
+    if (r->connection == NULL || r->connection->ssl == NULL) {
+        *err = "bad request";
+        return NGX_ERROR;
+    }
+
+    ssl_conn = r->connection->ssl->connection;
+    if (ssl_conn == NULL) {
+        *err = "bad ssl conn";
+        return NGX_ERROR;
+    }
+
+    /* enable verify */
+
+    SSL_set_verify(ssl_conn, SSL_VERIFY_PEER, ngx_ssl_verify_callback);
+
+    /* set depth */
+
+    if (depth < 0) {
+        sscf = ngx_http_get_module_srv_conf(r, ngx_http_ssl_module);
+        if (sscf != NULL) {
+            depth = sscf->verify_depth;
+        } else {
+            /* same as the default value of ssl_verify_depth */
+            depth = 1;
+        }
+    }
+    SSL_set_verify_depth(ssl_conn, depth);
+
+    /* set CA chain */
+
+    if (chain != NULL) {
+        ca_store = SSL_CTX_get_cert_store(SSL_get_SSL_CTX(ssl_conn));
+        if (ca_store == NULL) {
+            *err = "SSL_CTX_get_cert_store() failed";
+            return NGX_ERROR;
+        }
+
+        /* construct name chain */
+
+        name_chain = sk_X509_NAME_new_null();
+        if (name_chain == NULL) {
+            *err = "sk_X509_NAME_new_null() failed";
+            return NGX_ERROR;
+        }
+
+        for (i = 0; i < sk_X509_num(chain); i++) {
+            x509 = sk_X509_value(chain, i);
+            if (x509 == NULL) {
+                *err = "sk_X509_value() failed";
+                goto failed;
+            }
+
+            /* add subject to name chain, which will be sent to client */
+            subject = X509_NAME_dup(X509_get_subject_name(x509));
+            if (subject == NULL) {
+                *err = "X509_get_subject_name() failed";
+                goto failed;
+            }
+
+            if (!sk_X509_NAME_push(name_chain, subject)) {
+                *err = "sk_X509_NAME_push() failed";
+                X509_NAME_free(subject);
+                goto failed;
+            }
+
+            /* add to trusted CA store */
+            if (X509_STORE_add_cert(ca_store, x509) == 0) {
+                *err = "X509_STORE_add_cert() failed";
+                goto failed;
+            }
+        }
+
+        SSL_set_client_CA_list(ssl_conn, name_chain);
+    }
+
+    return NGX_OK;
+
+failed:
+
+    sk_X509_NAME_free(name_chain);
+
+    return NGX_ERROR;
+}
+
+
 #endif /* NGX_HTTP_SSL */

t/140-ssl-c-api.t

@@ -63,6 +63,10 @@ ffi.cdef[[
     void ngx_http_lua_ffi_free_priv_key(void *cdata);
 
     int ngx_http_lua_ffi_ssl_clear_certs(void *r, char **err);
+
+    int ngx_http_lua_ffi_ssl_verify_client(void *r, void *cdata,
+        int depth, char **err);
+
 ]]
 _EOC_
     }
@@ -812,3 +816,207 @@ lua ssl server name: "test.com"
 --- no_error_log
 [error]
 [alert]
+
+
+
+=== TEST 6: verify client with CA certificates
+--- http_config
+    server {
+        listen unix:$TEST_NGINX_HTML_DIR/nginx.sock ssl;
+        server_name   test.com;
+
+        ssl_certificate_by_lua_block {
+            collectgarbage()
+
+            require "defines"
+            local ffi = require "ffi"
+
+            local errmsg = ffi.new("char *[1]")
+
+            local r = require "resty.core.base" .get_request()
+            if r == nil then
+                ngx.log(ngx.ERR, "no request found")
+                return
+            end
+
+            local f = assert(io.open("t/cert/test.crt", "rb"))
+            local cert_data = f:read("*all")
+            f:close()
+
+            local cert = ffi.C.ngx_http_lua_ffi_parse_pem_cert(cert_data, #cert_data, errmsg)
+            if not cert then
+                ngx.log(ngx.ERR, "failed to parse PEM cert: ",
+                        ffi.string(errmsg[0]))
+                return
+            end
+
+            local rc = ffi.C.ngx_http_lua_ffi_ssl_verify_client(r, cert, 1, errmsg)
+            if rc ~= 0 then
+                ngx.log(ngx.ERR, "failed to verify client: ",
+                        ffi.string(errmsg[0]))
+                return
+            end
+        }
+
+        ssl_certificate ../../cert/test.crt;
+        ssl_certificate_key ../../cert/test.key;
+
+        server_tokens off;
+        location / {
+            default_type 'text/plain';
+            content_by_lua_block {
+                print('client certificate subject: ', ngx.var.ssl_client_s_dn)
+                ngx.say(ngx.var.ssl_client_verify)
+            }
+            more_clear_headers Date;
+        }
+    }
+--- config
+    server_tokens off;
+    lua_ssl_trusted_certificate ../../cert/test.crt;
+
+    location /t {
+        proxy_pass                  https://unix:$TEST_NGINX_HTML_DIR/nginx.sock;
+        proxy_ssl_certificate       ../../cert/test.crt;
+        proxy_ssl_certificate_key   ../../cert/test.key;
+    }
+
+--- request
+GET /t
+--- response_body
+SUCCESS
+
+--- error_log
+client certificate subject: [email protected],CN=test.com
+
+--- no_error_log
+[error]
+[alert]
+
+
+
+=== TEST 7: verify client without CA certificates
+--- http_config
+    server {
+        listen unix:$TEST_NGINX_HTML_DIR/nginx.sock ssl;
+        server_name   test.com;
+
+        ssl_certificate_by_lua_block {
+            collectgarbage()
+
+            require "defines"
+            local ffi = require "ffi"
+
+            local errmsg = ffi.new("char *[1]")
+
+            local r = require "resty.core.base" .get_request()
+            if r == nil then
+                ngx.log(ngx.ERR, "no request found")
+                return
+            end
+
+            local rc = ffi.C.ngx_http_lua_ffi_ssl_verify_client(r, nil, -1, errmsg)
+            if rc ~= 0 then
+                ngx.log(ngx.ERR, "failed to verify client: ",
+                        ffi.string(errmsg[0]))
+                return
+            end
+        }
+
+        ssl_certificate ../../cert/test.crt;
+        ssl_certificate_key ../../cert/test.key;
+
+        server_tokens off;
+        location / {
+            default_type 'text/plain';
+            content_by_lua_block {
+                print('client certificate subject: ', ngx.var.ssl_client_s_dn)
+                ngx.say(ngx.var.ssl_client_verify)
+            }
+            more_clear_headers Date;
+        }
+    }
+--- config
+    server_tokens off;
+    lua_ssl_trusted_certificate ../../cert/test.crt;
+
+    location /t {
+        proxy_pass                  https://unix:$TEST_NGINX_HTML_DIR/nginx.sock;
+        proxy_ssl_certificate       ../../cert/test.crt;
+        proxy_ssl_certificate_key   ../../cert/test.key;
+    }
+
+--- request
+GET /t
+--- response_body
+FAILED:self signed certificate
+
+--- error_log
+client certificate subject: [email protected],CN=test.com
+
+--- no_error_log
+[error]
+[alert]
+
+
+
+=== TEST 8: verify client but client provides no certificate
+--- http_config
+    server {
+        listen unix:$TEST_NGINX_HTML_DIR/nginx.sock ssl;
+        server_name   test.com;
+
+        ssl_certificate_by_lua_block {
+            collectgarbage()
+
+            require "defines"
+            local ffi = require "ffi"
+
+            local errmsg = ffi.new("char *[1]")
+
+            local r = require "resty.core.base" .get_request()
+            if r == nil then
+                ngx.log(ngx.ERR, "no request found")
+                return
+            end
+
+            local rc = ffi.C.ngx_http_lua_ffi_ssl_verify_client(r, nil, -1, errmsg)
+            if rc ~= 0 then
+                ngx.log(ngx.ERR, "failed to verify client: ",
+                        ffi.string(errmsg[0]))
+                return
+            end
+        }
+
+        ssl_certificate ../../cert/test.crt;
+        ssl_certificate_key ../../cert/test.key;
+
+        server_tokens off;
+        location / {
+            default_type 'text/plain';
+            content_by_lua_block {
+                print('client certificate subject: ', ngx.var.ssl_client_s_dn)
+                ngx.say(ngx.var.ssl_client_verify)
+            }
+            more_clear_headers Date;
+        }
+    }
+--- config
+    server_tokens off;
+    lua_ssl_trusted_certificate ../../cert/test.crt;
+
+    location /t {
+        proxy_pass                  https://unix:$TEST_NGINX_HTML_DIR/nginx.sock;
+    }
+
+--- request
+GET /t
+--- response_body
+NONE
+
+--- error_log
+client certificate subject: nil
+
+--- no_error_log
+[error]
+[alert]