CONC-724: Added TLS verification callback support

For testing purposes (the python3 dummy server can't handle
further communication after TLS handshake succeeded) support
for verification callback was added.

my_bool callback(MYSQL *mysql, unsigned int *flags, my_bool verified)

Parameter:
  - mysql     connection handle for current connection
  - flags     verification flags
  - verified  true if callback was called after verification,
              otherwise false

Return value:
  - False (0) to continue
  - True  (1) to abort tls connection

The callback function can be registered via
mysql_optionsv(mysql, MARIADB_OPT_TLS_VERIFICATION_CALLBACK, callback);

include/ma_common.h

@@ -88,6 +88,7 @@ struct st_mysql_options_extension {
   void (*status_callback)(void *ptr, enum enum_mariadb_status_info type, ...);
   void *status_data;
   my_bool tls_allow_invalid_server_cert;
+  my_bool (*tls_verification_callback)(MYSQL *mysql, unsigned int *verification_flags, my_bool verified);
 };
 
 typedef struct st_connection_handler

include/mariadb_com.h

@@ -297,7 +297,7 @@ typedef struct st_net {
   unsigned char reading_or_writing;
   char save_char;
   char unused_1;
-  my_bool tls_verify_status;
+  unsigned char tls_verify_status;
   my_bool compress;
   my_bool unused_2;
   char *unused_3;

include/mysql.h

@@ -259,7 +259,8 @@ extern const char *SQLSTATE_UNKNOWN;
     MARIADB_OPT_RPL_REGISTER_REPLICA,
     MARIADB_OPT_STATUS_CALLBACK,
     MARIADB_OPT_SERVER_PLUGINS,
-    MARIADB_OPT_BULK_UNIT_RESULTS
+    MARIADB_OPT_BULK_UNIT_RESULTS,
+    MARIADB_OPT_TLS_VERIFICATION_CALLBACK
   };
 
   enum mariadb_value {

libmariadb/ma_tls.c

@@ -119,7 +119,17 @@ int ma_pvio_tls_verify_server_cert(MARIADB_TLS *ctls, unsigned int flags)
     return 0;
   }
 
-  rc= ma_tls_verify_server_cert(ctls, flags);
+  if (mysql->options.extension->tls_verification_callback &&
+      mysql->options.extension->tls_verification_callback(mysql, &flags, 0))
+    rc= 1;
+  else {
+    rc= ma_tls_verify_server_cert(ctls, flags);
+    if (mysql->options.extension->tls_verification_callback &&
+        mysql->options.extension->tls_verification_callback(mysql, &flags, 1))
+    {
+      rc= 1;
+    }
+  }
 
   /* Set error messages */
   if (!mysql->net.last_errno)

libmariadb/mariadb_lib.c

@@ -3853,6 +3853,9 @@ mysql_optionsv(MYSQL *mysql,enum mysql_option option, ...)
   case MARIADB_OPT_BULK_UNIT_RESULTS:
     OPT_SET_EXTENDED_VALUE_INT(&mysql->options, bulk_unit_results, *(my_bool *)arg1);
     break;
+  case MARIADB_OPT_TLS_VERIFICATION_CALLBACK:
+    OPT_SET_EXTENDED_VALUE(&mysql->options, tls_verification_callback, arg1);
+    break;
   default:
     va_end(ap);
     SET_CLIENT_ERROR(mysql, CR_NOT_IMPLEMENTED, SQLSTATE_UNKNOWN, 0);

unittest/libmariadb/tls.c.in

@@ -42,11 +42,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
   FAIL_IF(!(status & (flag)), (text));\
 }
 
-#define CHECK_NO_TLS_FLAGS(m)\
+#define CHECK_NO_TLS_FLAG(m, flag, text)\
 {\
   unsigned int status;\
   mariadb_get_infov(mysql, MARIADB_TLS_VERIFY_STATUS, &status);\
-  FAIL_IF(status), "Expected MARIADB_TLS_VERIFY_OK");\
+  FAIL_IF((status & (flag)), (text));\
 }
 
 my_bool auto_generated_cert= 0;
@@ -141,7 +141,7 @@ static int test_start_tls_server(MYSQL *my __attribute__((unused)))
 
     snprintf(hostname, sizeof(hostname), "--host=%s", tls_dummy_host);
     snprintf(port, sizeof(port), "--port=%d", tls_dummy_port);
-    execlp("@Python3_EXECUTABLE@", "@Python3_EXECUTABLE@", "tls_server.py", hostname, port, NULL);
+    execlp("@Python3_EXECUTABLE@", "@Python3_EXECUTABLE@", "@CC_SOURCE_DIR@/unittest/libmariadb/tls_server.py", hostname, port, NULL);
   }
   
 #endif
@@ -658,11 +658,72 @@ static int stop_tls_server(MYSQL *my __attribute__((unused)))
   return OK;
 }
 
+my_bool tls_wildcard_callback(MYSQL *mysql, unsigned int *flags, my_bool verified)
+{
+  if (!verified)
+  {
+    free(mysql->host);
+    mysql->host= strdup("test.example.com");
+    *flags= MARIADB_TLS_VERIFY_HOST;
+    return 0;
+  }
+  /* Indicate error, since the dummy server can't handle further client server
+     communication after TLS handshake */
+  mysql->net.tls_verify_status|= MARIADB_TLS_VERIFY_ERROR;
+  my_set_error(mysql, CR_SSL_CONNECTION_ERROR, SQLSTATE_UNKNOWN,
+               ER(CR_SSL_CONNECTION_ERROR),
+               "Certificate verification aborted by callback");
+  return 1;
+}
+
+static int test_cert_wildcard(MYSQL *my __attribute((unused)))
+{
+  MYSQL *mysql= mysql_init(NULL);
+  if (set_tls_dummy_options("CMD:create_new=True commonName='*.example.com'"))
+  {
+    diag("Error when setting TLS options");
+    return FAIL;
+  }
+  mysql_ssl_set(mysql, NULL, NULL, NULL, NULL, NULL);
+  mysql_optionsv(mysql, MARIADB_OPT_TLS_VERIFICATION_CALLBACK, tls_wildcard_callback);
+
+  if (!my_test_connect(mysql, tls_dummy_host, "tlsuser", "foo", NULL, tls_dummy_port, NULL, 0, 0))
+  {
+    CHECK_NO_TLS_FLAG(mysql, MARIADB_TLS_VERIFY_HOST, "Hostname verification didn't pass");
+    CHECK_TLS_FLAGS(mysql, MARIADB_TLS_VERIFY_TRUST, "Self signed certificate expected");
+    mysql_close(mysql);
+  } else {
+    mysql_close(mysql);
+    return FAIL;
+  }
+
+  mysql= mysql_init(NULL);
+  if (set_tls_dummy_options("CMD:create_new=True commonName='*.noexample.com'"))
+  {
+    diag("Error when setting TLS options");
+    return FAIL;
+  }
+  mysql_ssl_set(mysql, NULL, NULL, NULL, NULL, NULL);
+  mysql_optionsv(mysql, MARIADB_OPT_TLS_VERIFICATION_CALLBACK, tls_wildcard_callback);
+
+  if (!my_test_connect(mysql, tls_dummy_host, "tlsuser", "foo", NULL, tls_dummy_port, NULL, 0, 0))
+  {
+    CHECK_TLS_FLAGS(mysql, MARIADB_TLS_VERIFY_HOST, "Hostname verification passed with wrong wildcard");
+    mysql_close(mysql);
+  } else {
+    mysql_close(mysql);
+    return FAIL;
+  }
+  return OK;
+}
+
+
 struct my_tests_st my_tests[] = {
   /* Don't add test above, test_init needs to be run first */
   {"test_start_tls_server", test_start_tls_server, TEST_CONNECTION_NONE, 0, NULL, NULL},
   {"test_init", test_init, TEST_CONNECTION_NONE, 0, NULL, NULL},
   /* Here you can add more tests */
+  {"test_cert_wildcard", test_cert_wildcard, TEST_CONNECTION_NEW, 0, NULL, NULL},
   {"test_cert_expired", test_cert_expired, TEST_CONNECTION_NEW, 0, NULL, NULL},
   {"test_pw_check", test_pw_check, TEST_CONNECTION_NEW, 0, NULL, NULL},
   {"test_ca_cert_check", test_ca_cert_check, TEST_CONNECTION_NONE, 0, NULL, NULL},