diff --git a/changes/bug40317 b/changes/bug40317
new file mode 100644
index 0000000000..18ec499a51
--- /dev/null
+++ b/changes/bug40317
@@ -0,0 +1,5 @@
+  o Minor bugfixes (control, sandbox):
+    - Allows the control command SAVECONF to succeed when the seccomp
+      sandbox is enabled. Makes SAVECONF keep only one backup file to
+      simplify implementation. Fixes bug 40317; bugfix on 0.2.5.4-alpha.
+      Patch by Daniel Pinto.
diff --git a/src/app/config/config.c b/src/app/config/config.c
index fa74907b3d..abc64ee92d 100644
--- a/src/app/config/config.c
+++ b/src/app/config/config.c
@@ -6827,7 +6827,7 @@ validate_data_directories(or_options_t *options)
 /** This string can change; it tries to give the reader an idea
  * that editing this file by hand is not a good plan. */
 #define GENERATED_FILE_COMMENT "# The old torrc file was renamed " \
-  "to torrc.orig.1 or similar, and Tor will ignore it"
+  "to torrc.orig.1, and Tor will ignore it"
 
 /** Save a configuration file for the configuration in <b>options</b>
  * into the file <b>fname</b>.  If the file already exists, and
@@ -6871,17 +6871,18 @@ write_configuration_file(const char *fname, const or_options_t *options)
                GENERATED_FILE_PREFIX, GENERATED_FILE_COMMENT, new_conf);
 
   if (rename_old) {
-    int i = 1;
     char *fn_tmp = NULL;
-    while (1) {
-      tor_asprintf(&fn_tmp, "%s.orig.%d", fname, i);
-      if (file_status(fn_tmp) == FN_NOENT)
-        break;
+    tor_asprintf(&fn_tmp, CONFIG_BACKUP_PATTERN, fname);
+    file_status_t fn_tmp_status = file_status(fn_tmp);
+    if (fn_tmp_status == FN_DIR || fn_tmp_status == FN_ERROR) {
+      log_warn(LD_CONFIG,
+               "Config backup file \"%s\" is not a file? Failing.", fn_tmp);
       tor_free(fn_tmp);
-      ++i;
+      goto err;
     }
+
     log_notice(LD_CONFIG, "Renaming old configuration file to \"%s\"", fn_tmp);
-    if (tor_rename(fname, fn_tmp) < 0) {//XXXX sandbox doesn't allow
+    if (replace_file(fname, fn_tmp) < 0) {
       log_warn(LD_FS,
                "Couldn't rename configuration file \"%s\" to \"%s\": %s",
                fname, fn_tmp, strerror(errno));
diff --git a/src/app/config/config.h b/src/app/config/config.h
index e95ef4a728..ee78d1e0f7 100644
--- a/src/app/config/config.h
+++ b/src/app/config/config.h
@@ -44,6 +44,9 @@ int get_protocol_warning_severity_level(void);
 
 #define LOG_PROTOCOL_WARN (get_protocol_warning_severity_level())
 
+/** Pattern for backing up configuration files */
+#define CONFIG_BACKUP_PATTERN "%s.orig.1"
+
 /** An error from options_trial_assign() or options_init_from_string(). */
 typedef enum setopt_err_t {
   SETOPT_OK = 0,
diff --git a/src/app/main/main.c b/src/app/main/main.c
index 56478a0f71..7c6feb77fe 100644
--- a/src/app/main/main.c
+++ b/src/app/main/main.c
@@ -831,7 +831,6 @@ sandbox_init_filter(void)
 {
   const or_options_t *options = get_options();
   sandbox_cfg_t *cfg = sandbox_cfg_new();
-  int i;
 
   sandbox_cfg_allow_openat_filename(&cfg,
       get_cachedir_fname("cached-status"));
@@ -917,10 +916,23 @@ sandbox_init_filter(void)
   else
     sandbox_cfg_allow_open_filename(&cfg, tor_strdup("/etc/resolv.conf"));
 
-  for (i = 0; i < 2; ++i) {
-    if (get_torrc_fname(i)) {
-      sandbox_cfg_allow_open_filename(&cfg, tor_strdup(get_torrc_fname(i)));
-    }
+  const char *torrc_defaults_fname = get_torrc_fname(1);
+  if (torrc_defaults_fname) {
+    sandbox_cfg_allow_open_filename(&cfg, tor_strdup(torrc_defaults_fname));
+  }
+  const char *torrc_fname = get_torrc_fname(0);
+  if (torrc_fname) {
+    sandbox_cfg_allow_open_filename(&cfg, tor_strdup(torrc_fname));
+    // allow torrc backup and torrc.tmp to make SAVECONF work
+    char *torrc_bck = NULL;
+    tor_asprintf(&torrc_bck, CONFIG_BACKUP_PATTERN, torrc_fname);
+    sandbox_cfg_allow_rename(&cfg, tor_strdup(torrc_fname), torrc_bck);
+    char *torrc_tmp = NULL;
+    tor_asprintf(&torrc_tmp, "%s.tmp", torrc_fname);
+    sandbox_cfg_allow_rename(&cfg, torrc_tmp, tor_strdup(torrc_fname));
+    sandbox_cfg_allow_open_filename(&cfg, tor_strdup(torrc_tmp));
+    // we need to stat the existing backup file
+    sandbox_cfg_allow_stat_filename(&cfg, tor_strdup(torrc_bck));
   }
 
   SMARTLIST_FOREACH(options->FilesOpenedByIncludes, char *, f, {