Alexander Hansen Færøy · b5099682 · b5099682
--- a/src/test/test_switch_id.c
+++ b/src/test/test_switch_id.c
+ * permissions. Usually this function returns 1024. */
+static uint16_t
+unprivileged_port_range_start(void)
+{
+  uint16_t result = 1024;
+
+#if defined(__linux__)
+  char *content = NULL;
+
+  content = read_file_to_str(
+              "/proc/sys/net/ipv4/ip_unprivileged_port_start",
+              0,
+              NULL);
+
+  if (content != NULL)
+    result = (uint16_t)atoi(content);
--- a/src/test/test_switch_id.c
+++ b/src/test/test_switch_id.c
       * does not make us lose the ability to bind low ports */
    {
-      int keepcaps = (test_id == TEST_SETUID_KEEPCAPS);
+      const int keepcaps = (test_id == TEST_SETUID_KEEPCAPS);
      okay = switch_id(username, keepcaps ? SWITCH_ID_KEEP_BINDLOW : 0) == 0;
+
      if (okay) {
-        okay = check_can_bind_low_ports() == keepcaps;
+        /* Only run this check if there are ports we may not be able to bind
+         * to. */
+        const uint16_t min_port = unprivileged_port_range_start();
+
+        if (min_port >= PORT_TEST_RANGE_START &&
+            min_port < PORT_TEST_RANGE_END) {
+          okay = check_can_bind_low_ports() == keepcaps;
+        }