Revert "Fix cfntools command injection"

This reverts commit e424af2236ed1d6e6d0e11768f873ffe4e696221.

Splitting command strings that were previously assumed to be interpreted
by the shell at whitespace and then passing them as separate args to
execvp will not work.

Change-Id: I7c37b5852ce9b20e63bdbbaddfb852463548aa90

2 files changed, 10 insertions, 65 deletions

diff --git a/heat_cfntools/cfntools/cfn_helper.py b/heat_cfntools/cfntools/cfn_helper.py
index 2351c1d..7e75cf9 100644
--- a/heat_cfntools/cfntools/cfn_helper.py
+++ b/heat_cfntools/cfntools/cfn_helper.py
@@ -180,23 +180,7 @@ class CommandRunner(object):
             self
         """
         LOG.debug("Running command: %s" % self._command)
-
-        cmd = self._command
-        if isinstance(cmd, str):
-            cmd = cmd.split()
-
-        if user != 'root':
-            # lower the privileges
-            try:
-                real = pwd.getpwnam(user)
-                os.setuid(real.pw_uid)
-            except Exception as e:
-                LOG.error("Error setting privileges for user '%s': %s"
-                          % (user, e))
-                # 126: command invoked cannot be executed
-                self._status = 126
-                return
-
+        cmd = ['su', user, '-c', self._command]
         subproc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                                    stderr=subprocess.PIPE, cwd=cwd, env=env)
         output = subproc.communicate()
@@ -576,6 +560,7 @@ class PackagesHandler(object):
           * if a version array is supplied, choose the highest version from the
             array and follow same logic for version string above
         """
+
         cmd = CommandRunner("which yum").run()
         if cmd.status == 1:
             # yum not available, use DNF if available
diff --git a/heat_cfntools/tests/test_cfn_helper.py b/heat_cfntools/tests/test_cfn_helper.py
index 15641bc..59020e2 100644
--- a/heat_cfntools/tests/test_cfn_helper.py
+++ b/heat_cfntools/tests/test_cfn_helper.py
@@ -29,7 +29,7 @@ from heat_cfntools.cfntools import cfn_helper
 def popen_root_calls(calls):
     kwargs = {'env': None, 'cwd': None, 'stderr': -1, 'stdout': -1}
     return [
-        mock.call(call.split(), **kwargs)
+        mock.call(['su', 'root', '-c', call], **kwargs)
         for call in calls
     ]
 
@@ -51,9 +51,9 @@ class TestCommandRunner(testtools.TestCase):
 
     def test_command_runner(self):
         def returns(*args, **kwargs):
-            if args[0][0] == '/bin/command1':
+            if args[0][3] == '/bin/command1':
                 return FakePOpen('All good')
-            elif args[0][0] == '/bin/command2':
+            elif args[0][3] == '/bin/command2':
                 return FakePOpen('Doing something', 'error', -1)
             else:
                 raise Exception('This should never happen')
@@ -73,53 +73,13 @@ class TestCommandRunner(testtools.TestCase):
             calls = popen_root_calls(['/bin/command1', '/bin/command2'])
             mock_popen.assert_has_calls(calls)
 
-    def test_runner_runs_command_as_list(self):
-        with mock.patch('subprocess.Popen') as mock_popen:
-            command = '/bin/command --option=value arg1 arg2'
-            expected_cmd = ['/bin/command', '--option=value', 'arg1', 'arg2']
-            cmd = cfn_helper.CommandRunner(command)
-            cmd.run()
-            self.assertTrue(mock_popen.called)
-            actual_cmd = mock_popen.call_args[0][0]
-            self.assertTrue(isinstance(actual_cmd, list))
-            self.assertItemsEqual(expected_cmd, actual_cmd)
-
-    @mock.patch.object(cfn_helper.pwd, 'getpwnam')
-    @mock.patch.object(cfn_helper.os, 'setuid')
-    def test_privileges_are_lowered_for_non_root_user(self, mock_setuid,
-                                                      mock_getpwnam):
-        pw_entry = mock.MagicMock()
-        pw_entry.pw_uid = 1001
-        mock_getpwnam.return_value = pw_entry
-        with mock.patch('subprocess.Popen') as mock_popen:
-            command = '/bin/command --option=value arg1 arg2'
-            cmd = cfn_helper.CommandRunner(command)
-            cmd.run(user='nonroot')
-            mock_getpwnam.assert_called_once_with('nonroot')
-            mock_setuid.assert_called_once_with(1001)
-            self.assertTrue(mock_popen.called)
-
-    @mock.patch.object(cfn_helper.pwd, 'getpwnam')
-    @mock.patch.object(cfn_helper.os, 'setuid')
-    def test_run_returns_when_cannot_set_privileges(self, mock_setuid,
-                                                    mock_getpwnam):
-        mock_setuid.side_effect = Exception('[Error 1] Permission Denied')
-        with mock.patch('subprocess.Popen') as mock_popen:
-            command = '/bin/command2'
-            cmd = cfn_helper.CommandRunner(command)
-            cmd.run(user='nonroot')
-            self.assertTrue(mock_getpwnam.called)
-            self.assertTrue(mock_setuid.called)
-            self.assertFalse(mock_popen.called)
-            self.assertEqual(126, cmd.status)
-
 
 class TestPackages(testtools.TestCase):
 
     def test_yum_install(self):
 
         def returns(*args, **kwargs):
-            if (args[0][0] == 'rpm' and args[0][1] == '-q'):
+            if args[0][3].startswith('rpm -q '):
                 return FakePOpen(returncode=1)
             else:
                 return FakePOpen(returncode=0)
@@ -146,8 +106,8 @@ class TestPackages(testtools.TestCase):
     def test_dnf_install_yum_unavailable(self):
 
         def returns(*args, **kwargs):
-            if ((args[0][0] == 'rpm' and args[0][1] == '-q')
-                    or (args[0][0] == 'which' and args[0][1] == 'yum')):
+            if args[0][3].startswith('rpm -q ') \
+               or args[0][3] == 'which yum':
                 return FakePOpen(returncode=1)
             else:
                 return FakePOpen(returncode=0)
@@ -174,7 +134,7 @@ class TestPackages(testtools.TestCase):
     def test_dnf_install(self):
 
         def returns(*args, **kwargs):
-            if (args[0][0] == 'rpm' and args[0][1] == '-q'):
+            if args[0][3].startswith('rpm -q '):
                 return FakePOpen(returncode=1)
             else:
                 return FakePOpen(returncode=0)
@@ -201,7 +161,7 @@ class TestPackages(testtools.TestCase):
     def test_zypper_install(self):
 
         def returns(*args, **kwargs):
-            if (args[0][0] == 'rpm' and args[0][1] == '-q'):
+            if args[0][3].startswith('rpm -q '):
                 return FakePOpen(returncode=1)
             else:
                 return FakePOpen(returncode=0)