Python os.setuid() Examples

def drop_privileges(uid_name='nobody', gid_name='nogroup'):
    try: import pwd, grp
    except ImportError: return False # Windows

    # Get the uid/gid from the name
    running_uid = pwd.getpwnam(uid_name).pw_uid
    running_uid_home = pwd.getpwnam(uid_name).pw_dir
    running_gid = grp.getgrnam(gid_name).gr_gid

    # Remove group privileges
    os.setgroups([])

    # Try setting the new uid/gid
    os.setgid(running_gid)
    os.setuid(running_uid)

    # Ensure a very conservative umask
    old_umask = os.umask(int('077', 8))
    value = (os.getuid() == running_uid and os.getgid() == running_gid)
    if value:  # could be useful
       os.environ['HOME'] = running_uid_home
       logger.info('Changed permissions to: %s: %i, %s, %i' % (uid_name, running_uid, gid_name, running_gid))
    return value 

def switch(self):
        """
        Switch the current process's user/group to ``self.user``, and
        ``self.group``.  Change directory to ``self.dir``, and write the
        current pid out to ``self.pid_file``.
        """
        # set the running uid/gid
        LOG.debug('setting process uid(%s) and gid(%s)' %
                  (self.user.pw_uid, self.group.gr_gid))
        os.setgid(self.group.gr_gid)
        os.setuid(self.user.pw_uid)
        os.environ['HOME'] = self.user.pw_dir
        os.chdir(self.dir)
        if self.pid_file and os.path.exists(self.pid_file):
            raise exc.FrameworkError("Process already running (%s)" %
                                     self.pid_file)
        else:
            self._write_pid_file() 

def _execChild(self, path, uid, gid, executable, args, environment):
        """
        The exec() which is done in the forked child.
        """
        if path:
            os.chdir(path)
        if uid is not None or gid is not None:
            if uid is None:
                uid = os.geteuid()
            if gid is None:
                gid = os.getegid()
            # set the UID before I actually exec the process
            os.setuid(0)
            os.setgid(0)
            switchUID(uid, gid)
        os.execvpe(executable, args, environment) 

def test_mockPTYSetUid(self):
        """
        Try creating a PTY process with setting its uid: it's almost the same
        path as the standard path, but with a C{switchUID} call before the
        exec.
        """
        cmd = b'/mock/ouch'

        d = defer.Deferred()
        p = TrivialProcessProtocol(d)
        try:
            reactor.spawnProcess(p, cmd, [b'ouch'], env=None,
                                 usePTY=True, uid=8081)
        except SystemError:
            self.assertTrue(self.mockos.exited)
            self.assertEqual(
                self.mockos.actions,
                [('fork', False), 'setsid', ('setuid', 0), ('setgid', 0),
                 ('switchuid', 8081, 1234), 'exec', ('exit', 1)])
        else:
            self.fail("Should not be here") 

def createDirs(self):
        uid_change = pwd.getpwnam(self.user).pw_uid
        gid_change = pwd.getpwnam(self.user).pw_gid
        pidx = os.fork()
        if pidx == 0:
            try:
                os.setgid(gid_change)
                os.setuid(uid_change)
                if not os.path.exists(self.directory):
                    os.makedirs(self.directory)
                os.chdir(self.directory)
                man_dir = os.path.abspath("manifests")
                userlists_dir = os.path.abspath("userlists")
                self.copy(self.manifests, man_dir)
                self.copy(self.userlists, userlists_dir)
            finally:
                os._exit(0)
        os.waitpid(pidx, 0) 

def _setuser(user):
    ''' Normalizes user to a uid and sets the current uid, or does 
    nothing if user is None.
    '''
    if user is None:
        return
        
    # Normalize group to gid
    elif isinstance(user, str):
        uid = pwd.getpwnam(user).pw_uid
    # The group is already a gid.
    else:
        uid = user
        
    try:
        os.setuid(uid)
    except OSError:
        self.logger.error('Unable to change user.')
        sys.exit(1) 

def test_mockSetUid(self):
        """
        Try creating a process with setting its uid: it's almost the same path
        as the standard path, but with a C{switchUID} call before the exec.
        """
        cmd = b'/mock/ouch'

        d = defer.Deferred()
        p = TrivialProcessProtocol(d)
        try:
            reactor.spawnProcess(p, cmd, [b'ouch'], env=None,
                                 usePTY=False, uid=8080)
        except SystemError:
            self.assertTrue(self.mockos.exited)
            self.assertEqual(
                self.mockos.actions,
                [('fork', False), ('setuid', 0), ('setgid', 0),
                 ('switchuid', 8080, 1234), 'exec', ('exit', 1)])
        else:
            self.fail("Should not be here") 

def change_process_owner(uid, gid):
    """ Change the owning UID and GID of this process.

        Sets the GID then the UID of the process (in that order, to
        avoid permission errors) to the specified `gid` and `uid`
        values. Requires appropriate OS privileges for this process.

        """
    try:
        os.setgid(gid)
        os.setuid(uid)
    except Exception, exc:
        error = DaemonOSEnvironmentError(
            "Unable to change file creation mask (%(exc)s)"
            % vars())
        raise error 

def shutil_setuid(user = None, group = None):
    """ set fork-child uid/gid (returns pw-info env-settings)"""
    if group:
        import grp
        gid = grp.getgrnam(group).gr_gid
        os.setgid(gid)
        logg.debug("setgid %s '%s'", gid, group)
    if user:
        import pwd
        pw = pwd.getpwnam(user)
        if not group:
            gid = pw.pw_gid
            os.setgid(gid)
            logg.debug("setgid %s", gid)
        uid = pw.pw_uid
        os.setuid(uid)
        logg.debug("setuid %s '%s'", uid, user)
        home = pw.pw_dir
        shell = pw.pw_shell
        logname = pw.pw_name
        return { "USER": user, "LOGNAME": logname, "HOME": home, "SHELL": shell }
    return {} 

def test_mockSetUid(self):
        """
        Try creating a process with setting its uid: it's almost the same path
        as the standard path, but with a C{switchUID} call before the exec.
        """
        cmd = b'/mock/ouch'

        d = defer.Deferred()
        p = TrivialProcessProtocol(d)
        try:
            reactor.spawnProcess(p, cmd, [b'ouch'], env=None,
                                 usePTY=False, uid=8080)
        except SystemError:
            self.assertTrue(self.mockos.exited)
            self.assertEqual(
                self.mockos.actions,
                [('fork', False), ('setuid', 0), ('setgid', 0),
                 ('switchuid', 8080, 1234), 'exec', ('exit', 1)])
        else:
            self.fail("Should not be here") 

def run_as(pwent, umask=0o22):
    """Drop privileges to given user's password entry, and set up
    environment. Assumes the parent process has root privileges.
    """
    os.umask(umask)
    home = pwent.home
    try:
      os.chdir(home)
    except OSError:
      os.chdir("/")
    # drop privs to user
    os.setgroups(pwent.groups)
    os.setgid(pwent.gid)
    os.setegid(pwent.gid)
    os.setuid(pwent.uid)
    os.seteuid(pwent.uid)
    os.environ["HOME"] = home
    os.environ["USER"] = pwent.name
    os.environ["LOGNAME"] = pwent.name
    os.environ["SHELL"] = pwent.shell
    os.environ["PATH"] = "/bin:/usr/bin:/usr/local/bin"
    return None 

def _execChild(self, path, uid, gid, executable, args, environment):
        """
        The exec() which is done in the forked child.
        """
        if path:
            os.chdir(path)
        if uid is not None or gid is not None:
            if uid is None:
                uid = os.geteuid()
            if gid is None:
                gid = os.getegid()
            # set the UID before I actually exec the process
            os.setuid(0)
            os.setgid(0)
            switchUID(uid, gid)
        os.execvpe(executable, args, environment) 

def drop_privileges(user):
    """
    Change the system user of the current python process.

    It will only work if called as root or as the target user.

    :param string user: target user
    :raise KeyError: if the target user doesn't exists
    :raise OSError: when the user change fails
    """
    pw = pwd.getpwnam(user)
    if pw.pw_uid == os.getuid():
        return
    groups = [e.gr_gid for e in grp.getgrall() if pw.pw_name in e.gr_mem]
    groups.append(pw.pw_gid)
    os.setgroups(groups)
    os.setgid(pw.pw_gid)
    os.setuid(pw.pw_uid)
    os.environ['HOME'] = pw.pw_dir 

def demote(self, uid, gid):
        def fn_uid_gid():
            os.setgid(gid)
            os.setuid(uid)

        def fn_uid():
            os.setuid(uid)

        def fn_gid():
            os.setgid(gid)

        def fn_nop():
            pass

        if uid and gid:
            return fn_uid_gid
        elif uid:
            return fn_uid
        elif gid:
            return fn_gid
        return fn_nop 

def switch(self):
        """
        Switch the current process's user/group to ``self.user``, and
        ``self.group``.  Change directory to ``self.dir``, and write the
        current pid out to ``self.pid_file``.
        """
        # set the running uid/gid
        LOG.debug('setting process uid(%s) and gid(%s)' %
                  (self.user.pw_uid, self.group.gr_gid))
        os.setgid(self.group.gr_gid)
        os.setuid(self.user.pw_uid)
        os.environ['HOME'] = self.user.pw_dir
        os.chdir(self.dir)
        if self.pid_file and os.path.exists(self.pid_file):
            raise exc.FrameworkError("Process already running (%s)" %
                                     self.pid_file)
        else:
            self._write_pid_file() 

def testEINTR(self):
    m1 = self.content("testEINTR", 0)
    m2 = self.content("testEINTR", 1)

    self.snd.send(m1, timeout=self.timeout())
    try:
      os.setuid(500)
      assert False, "setuid should fail"
    except:
      pass
    self.snd.send(m2, timeout=self.timeout()) 

def drop_privileges(self, uid_name='nobody', gid_name='nogroup'):
        if self.args.debug:
            print("Init: Running as {0}/{1}.".format(pwd.getpwuid(os.getuid())[0], grp.getgrgid(os.getgid())[0]))
        wanted_uid = pwd.getpwnam(uid_name)[2]
        wanted_gid = grp.getgrnam(gid_name)[2]

        pid = gevent.fork()
        # print "root_fork : drop_privil  :  pid   ",pid
        if pid == 0:
            # child
            # print  ('starting child process')
            child_process = gevent.spawn(self.root_process)
            child_process.join()
            # print  ('Child done:', child_process.successful())
            flush_tables()
            # print  ('Child exit')
        else:
            # parent
            os.setgid(wanted_gid)
            os.setuid(wanted_uid)
            new_uid_name = pwd.getpwuid(os.getuid())[0]
            new_gid_name = grp.getgrgid(os.getgid())[0]
            if self.args.debug:
                print("Parent: Privileges dropped, running as {0}/{1}.".format(new_uid_name, new_gid_name))
            while True:
                try:
                    gevent.sleep(1)
                    # print ('Parent: ping')
                except KeyboardInterrupt:
                    break 

def drop_privileges(uid_name='nobody', gid_name='nogroup'):
    print("Init: Running as {0}/{1}.".format(pwd.getpwuid(os.getuid())[0], grp.getgrgid(os.getgid())[0]))
    wanted_uid = pwd.getpwnam(uid_name)[2]
    wanted_gid = grp.getgrnam(gid_name)[2]

    pid = gevent.fork()
    # print "root_fork : drop_privil  :  pid   ",pid
    if pid == 0:
        # child
        print ('starting child process')
        child_process = gevent.spawn(root_process)
        child_process.join()
        print ('Child done:', child_process.successful())
        flush_tables()
        print ('Child exit')
    else:
        # parent
        os.setgid(wanted_gid)
        os.setuid(wanted_uid)
        new_uid_name = pwd.getpwuid(os.getuid())[0]
        new_gid_name = grp.getgrgid(os.getgid())[0]
        print("Parent: Privileges dropped, running as {0}/{1}.".format(new_uid_name, new_gid_name))
        while True:
            try:
                gevent.sleep(1)
                print ('Parent: ping')
            except KeyboardInterrupt:
                break 

def set_user(username):
    if username is None:
        return

    import pwd
    import grp

    try:
        pwrec = pwd.getpwnam(username)
    except KeyError:
        logging.error('user not found: %s' % username)
        raise
    user = pwrec[0]
    uid = pwrec[2]
    gid = pwrec[3]

    cur_uid = os.getuid()
    if uid == cur_uid:
        return
    if cur_uid != 0:
        logging.error('can not set user as nonroot user')
        # will raise later

    # inspired by supervisor
    if hasattr(os, 'setgroups'):
        groups = [grprec[2] for grprec in grp.getgrall() if user in grprec[3]]
        groups.insert(0, gid)
        os.setgroups(groups)
    os.setgid(gid)
    os.setuid(uid) 

def _demo_posix():
    #
    # Example 1: Simple redirection: Get process list
    #
    plist = Popen(["ps"], stdout=PIPE).communicate()[0]
    print "Process list:"
    print plist

    #
    # Example 2: Change uid before executing child
    #
    if os.getuid() == 0:
        p = Popen(["id"], preexec_fn=lambda: os.setuid(100))
        p.wait()

    #
    # Example 3: Connecting several subprocesses
    #
    print "Looking for 'hda'..."
    p1 = Popen(["dmesg"], stdout=PIPE)
    p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
    print repr(p2.communicate()[0])

    #
    # Example 4: Catch execution error
    #
    print
    print "Trying a weird file..."
    try:
        print Popen(["/this/path/does/not/exist"]).communicate()
    except OSError, e:
        if e.errno == errno.ENOENT:
            print "The file didn't exist.  I thought so..."
            print "Child traceback:"
            print e.child_traceback
        else:
            print "Error", e.errno 

def set_user(username):
    if username is None:
        return

    import pwd
    import grp

    try:
        pwrec = pwd.getpwnam(username)
    except KeyError:
        logging.error('user not found: %s' % username)
        raise
    user = pwrec[0]
    uid = pwrec[2]
    gid = pwrec[3]

    cur_uid = os.getuid()
    if uid == cur_uid:
        return
    if cur_uid != 0:
        logging.error('can not set user as nonroot user')
        # will raise later

    # inspired by supervisor
    if hasattr(os, 'setgroups'):
        groups = [grprec[2] for grprec in grp.getgrall() if user in grprec[3]]
        groups.insert(0, gid)
        os.setgroups(groups)
    os.setgid(gid)
    os.setuid(uid) 

def set_user(username):
    if username is None:
        return

    import pwd
    import grp

    try:
        pwrec = pwd.getpwnam(username)
    except KeyError:
        logging.error('user not found: %s' % username)
        raise
    user = pwrec[0]
    uid = pwrec[2]
    gid = pwrec[3]

    cur_uid = os.getuid()
    if uid == cur_uid:
        return
    if cur_uid != 0:
        logging.error('can not set user as nonroot user')
        # will raise later

    # inspired by supervisor
    if hasattr(os, 'setgroups'):
        groups = [grprec[2] for grprec in grp.getgrall() if user in grprec[3]]
        groups.insert(0, gid)
        os.setgroups(groups)
    os.setgid(gid)
    os.setuid(uid) 

def _demo_posix():
    #
    # Example 1: Simple redirection: Get process list
    #
    plist = Popen(["ps"], stdout=PIPE).communicate()[0]
    print "Process list:"
    print plist

    #
    # Example 2: Change uid before executing child
    #
    if os.getuid() == 0:
        p = Popen(["id"], preexec_fn=lambda: os.setuid(100))
        p.wait()

    #
    # Example 3: Connecting several subprocesses
    #
    print "Looking for 'hda'..."
    p1 = Popen(["dmesg"], stdout=PIPE)
    p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
    print repr(p2.communicate()[0])

    #
    # Example 4: Catch execution error
    #
    print
    print "Trying a weird file..."
    try:
        print Popen(["/this/path/does/not/exist"]).communicate()
    except OSError, e:
        if e.errno == errno.ENOENT:
            print "The file didn't exist.  I thought so..."
            print "Child traceback:"
            print e.child_traceback
        else:
            print "Error", e.errno 

def drop_privileges():
    """Drops privileges if running as root."""
    try:
        ent = pwd.getpwnam(USER)
    except KeyError:
        return

    if os.getuid() != 0:
        return

    os.setgid(ent.pw_gid)
    os.setuid(ent.pw_uid) 

def test_setuid(self):
        if os.getuid() != 0:
            self.assertRaises(OSError, os.setuid, 0)
        self.assertRaises(OverflowError, os.setuid, 1<<32) 

def test_setuid(self):
        if os.getuid() != 0:
            self.assertRaises(OSError, os.setuid, 0)
        self.assertRaises(OverflowError, os.setuid, 1<<32) 

def _demo_posix():
    #
    # Example 1: Simple redirection: Get process list
    #
    plist = Popen(["ps"], stdout=PIPE).communicate()[0]
    print "Process list:"
    print plist

    #
    # Example 2: Change uid before executing child
    #
    if os.getuid() == 0:
        p = Popen(["id"], preexec_fn=lambda: os.setuid(100))
        p.wait()

    #
    # Example 3: Connecting several subprocesses
    #
    print "Looking for 'hda'..."
    p1 = Popen(["dmesg"], stdout=PIPE)
    p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
    print repr(p2.communicate()[0])

    #
    # Example 4: Catch execution error
    #
    print
    print "Trying a weird file..."
    try:
        print Popen(["/this/path/does/not/exist"]).communicate()
    except OSError, e:
        if e.errno == errno.ENOENT:
            print "The file didn't exist.  I thought so..."
            print "Child traceback:"
            print e.child_traceback
        else:
            print "Error", e.errno 

def enable_sudo(master,command):
	'''
	ssh_command(master,"echo \"import os\" > setuid.py ")
	ssh_command(master,"echo \"import sys\" >> setuid.py")
	ssh_command(master,"echo \"import commands\" >> setuid.py")
	ssh_command(master,"echo \"command=sys.argv[1]\" >> setuid.py")
	ssh_command(master,"echo \"os.setuid(os.geteuid())\" >> setuid.py")
	ssh_command(master,"echo \"print commands.getstatusoutput(\"command\")\" >> setuid.py")
	'''
	os.system("ssh -i " + identity_file + " -t -o 'UserKnownHostsFile=/dev/null' -o 'CheckHostIP=no' -o 'StrictHostKeyChecking no' "+ username + "@" + master + " '" + command + "'") 

def set_user(username):
    if username is None:
        return

    import pwd
    import grp

    try:
        pwrec = pwd.getpwnam(username)
    except KeyError:
        logging.error('user not found: %s' % username)
        raise
    user = pwrec[0]
    uid = pwrec[2]
    gid = pwrec[3]

    cur_uid = os.getuid()
    if uid == cur_uid:
        return
    if cur_uid != 0:
        logging.error('can not set user as nonroot user')
        # will raise later

    # inspired by supervisor
    if hasattr(os, 'setgroups'):
        groups = [grprec[2] for grprec in grp.getgrall() if user in grprec[3]]
        groups.insert(0, gid)
        os.setgroups(groups)
    os.setgid(gid)
    os.setuid(uid) 

def setuid(self, val):
        """
        Override C{os.setuid}. Do nothing.
        """
        self.actions.append(('setuid', val))