jailed tasks can not share files

* Permission changes in bubblewrap shared directories persist when the
jailed tasks finish execution. Effectively, this allows playbooks
executing as awx to share files with lower privileged users on the
system.
* To prevent this, we wrap the directory that we intend to share with
bubblewrap in another directory that is owned by awx with permissions
700. The wrapped directory permissions can be changed by the jailed task
while the wrapper directory can not.
* Given `/tmp/bwrap_3_abcd/awx_3_1234/` `bwrap_3_abcd` is the wrapper
directory and `awx_3_1234` is the wrapped directory.

awx/main/tasks.py

@@ -893,10 +893,19 @@ def build_private_data_dir(self, instance):
         '''
         Create a temporary directory for job-related files.
         '''
-        path = tempfile.mkdtemp(prefix='awx_%s_' % instance.pk, dir=settings.AWX_PROOT_BASE_PATH)
-        os.chmod(path, stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR)
+        bwrap_path = tempfile.mkdtemp(
+            prefix=f'bwrap_{instance.pk}_',
+            dir=settings.AWX_PROOT_BASE_PATH
+        )
+        os.chmod(bwrap_path, stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR)
         if settings.AWX_CLEANUP_PATHS:
-            self.cleanup_paths.append(path)
+            self.cleanup_paths.append(bwrap_path)
+
+        path = tempfile.mkdtemp(
+            prefix='awx_%s_' % instance.pk,
+            dir=bwrap_path,
+        )
+        os.chmod(path, stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR)
         runner_project_folder = os.path.join(path, 'project')
         if not os.path.exists(runner_project_folder):
             # Ansible Runner requires that this directory exists.
@@ -1008,6 +1017,8 @@ def build_params_process_isolation(self, instance, private_data_dir, cwd):
                     '/etc/ssh',
                     '/var/lib/awx',
                     '/var/log',
+                    '/home',
+                    '/var/tmp',
                     settings.PROJECTS_ROOT,
                     settings.JOBOUTPUT_ROOT,
                 ] + getattr(settings, 'AWX_PROOT_HIDE_PATHS', None) or [],

awx/main/utils/common.py

@@ -863,7 +863,7 @@ def wrap_args_with_proot(args, cwd, **kwargs):
     new_args = [getattr(settings, 'AWX_PROOT_CMD', 'bwrap'), '--unshare-pid', '--dev-bind', '/', '/', '--proc', '/proc']
     hide_paths = [settings.AWX_PROOT_BASE_PATH]
     if not kwargs.get('isolated'):
-        hide_paths.extend(['/etc/tower', '/var/lib/awx', '/var/log', '/etc/ssh',
+        hide_paths.extend(['/etc/tower', '/var/lib/awx', '/var/log', '/etc/ssh', '/var/tmp', '/home',
                            settings.PROJECTS_ROOT, settings.JOBOUTPUT_ROOT])
     hide_paths.extend(getattr(settings, 'AWX_PROOT_HIDE_PATHS', None) or [])
     for path in sorted(set(hide_paths)):