alpine 3.8
shell weakness #3


Weakness Breakdown


A shell weakness occurs when a program enables an attacker to execute unexpected commands on the operating system.

Warning code(s):

This causes a new program to execute and is difficult to use safely.

File Name:



The highlighted line of code below is the trigger point of this particular Alpine 3.8 shell weakness.

  /* If we are using --as-pid-1 leak the sync fd into the sandbox.
     --sync-fd will still work unless the container process doesn't close this file.  */
  if (!opt_as_pid_1)
      if (opt_sync_fd != -1)
        close (opt_sync_fd);

  /* We want sigchild in the child */
  unblock_sigchild ();

  /* Optionally bind our lifecycle */
  handle_die_with_parent ();

  if (!is_privileged)
    set_ambient_capabilities ();

  /* Should be the last thing before execve() so that filters don't
   * need to handle anything above */
  if (seccomp_data != NULL &&
      prctl (PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &seccomp_prog) != 0)
    die_with_error ("prctl(PR_SET_SECCOMP)");

  if (execvp (argv[0], argv) == -1)
    die_with_error ("execvp %s", argv[0]);

  return 0;

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