alpine 3.6
access weakness #449


Weakness Breakdown


An access weakness occurs when software does not properly implement permissions that could have unintended consequences if exploited by malicious actors. An example of this weakness is when a default username and password are set by the developer but do not get changed by the system administrator.

Warning code(s):

Ensure that umask is given most restrictive possible setting.

File Name:



The highlighted line of code below is the trigger point of this particular Alpine 3.6 access weakness.

   redirecting_stderr = isatty (STDERR_FILENO);

  /* If standard input is a tty, replace it with /dev/null if possible.
     Note that it is deliberately opened for *writing*,
     to ensure any read evokes an error.  */
  if (ignoring_input)
      if (fd_reopen (STDIN_FILENO, "/dev/null", O_WRONLY, 0) < 0)
        error (exit_internal_failure, errno,
               _("failed to render standard input unusable"));
      if (!redirecting_stdout && !redirecting_stderr)
        error (0, 0, _("ignoring input"));

  /* If standard output is a tty, redirect it (appending) to a file.
     First try nohup.out, then $ HOME/nohup.out.  If standard error is
     a tty and standard output is closed, open nohup.out or
     $ HOME/nohup.out without redirecting anything.  */
  if (redirecting_stdout || (redirecting_stderr && stdout_is_closed))
      char *in_home = NULL;
      char const *file = "nohup.out";
      int flags = O_CREAT | O_WRONLY | O_APPEND;
      mode_t mode = S_IRUSR | S_IWUSR;
      mode_t umask_value = umask (~mode);
      out_fd = (redirecting_stdout
                ? fd_reopen (STDOUT_FILENO, file, flags, mode)
                : open (file, flags, mode));

      if (out_fd < 0)
          int saved_errno = errno;
          char const *home = getenv ("HOME");
          if (home)
              in_home = file_name_concat (home, file, NULL);
              out_fd = (redirecting_stdout
                        ? fd_reopen (STDOUT_FILENO, in_home, flags, mode)
                        : open (in_home, flags, mode));
          if (out_fd < 0)
              int saved_errno2 = errno;
              error (0, saved_errno, _("failed to open %s"), quoteaf (file));
              if (in_home)
                error (0, saved_errno2, _("failed to open %s"),
                       quoteaf (in_home));
              return exit_internal_failure;
          file = in_home; 

The registered trademark Linux® is used pursuant to a sublicense from the Linux Foundation, the exclusive licensee of Linus Torvalds, owner of the mark on a world­wide basis.