From d4aa8ee09e2d6e6676ed2dd7144d541e359fef7e Mon Sep 17 00:00:00 2001
From: Michal Nasiadka <mnasiadka@gmail.com>
Date: Wed, 10 Jun 2026 17:27:50 +0100
Subject: kolla-build: Use SandboxedEnvironment to prevent SSTI

Switch from jinja2.Environment to
jinja2.sandbox.SandboxedEnvironment to block Server-Side Template
Injection attacks.

Closes-Bug: #2146056

Change-Id: Iecd1d8dcf99007e3339120961c7c1d0ca12f83d8
Signed-off-by: Michal Nasiadka <mnasiadka@gmail.com>
(cherry picked from commit 0b20ffce09552014fa52c45de574511dc2200ac5)
---
 kolla/tests/test_build.py | 67 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

(limited to 'kolla/tests/test_build.py')

diff --git a/kolla/tests/test_build.py b/kolla/tests/test_build.py
index deb2dfa10..82bcb7d6d 100644
--- a/kolla/tests/test_build.py
+++ b/kolla/tests/test_build.py
@@ -11,6 +11,7 @@
 # limitations under the License.
 
 import fixtures
+import jinja2
 import os
 import requests
 import sys
@@ -579,6 +580,72 @@ class KollaWorkerTest(base.TestCase):
         kolla.setup_working_dir()
         kolla.set_time()
 
+    @mock.patch.dict(os.environ, {'http_proxy': 'http://test-proxy:8080'},
+                     clear=False)
+    @mock.patch(engine_client)
+    def test_create_dockerfiles_env_http_proxy(self, mock_client):
+        tmpdir = self.useFixture(fixtures.TempDir()).path
+        base_dir = os.path.join(tmpdir, 'base')
+        os.makedirs(base_dir)
+        with open(os.path.join(base_dir, 'Dockerfile.j2'), 'w') as f:
+            f.write(
+                '{% if env.http_proxy %}'
+                'ARG http_proxy={{ env.http_proxy }}'
+                '{% endif %}\n'
+            )
+        with mock.patch.object(build.KollaWorker, '_get_images_dir',
+                               return_value=tmpdir):
+            kolla = build.KollaWorker(self.conf)
+        kolla.setup_working_dir()
+        kolla.find_dockerfiles()
+        kolla.create_dockerfiles()
+        dockerfile = os.path.join(kolla.working_dir, 'base', 'Dockerfile')
+        with open(dockerfile) as f:
+            content = f.read()
+        self.assertIn('http://test-proxy:8080', content)
+
+    @mock.patch(engine_client)
+    def test_create_dockerfiles_ssti_blocked(self, mock_client):
+        tmpdir = self.useFixture(fixtures.TempDir()).path
+        base_dir = os.path.join(tmpdir, 'base')
+        os.makedirs(base_dir)
+        with open(os.path.join(base_dir, 'Dockerfile.j2'), 'w') as f:
+            f.write(
+                "{{ self.__init__.__globals__['__builtins__']"
+                "['__import__']('os').popen('id').read() }}\n"
+            )
+        with mock.patch.object(build.KollaWorker, '_get_images_dir',
+                               return_value=tmpdir):
+            kolla = build.KollaWorker(self.conf)
+        kolla.setup_working_dir()
+        kolla.find_dockerfiles()
+        self.assertRaises(jinja2.exceptions.SecurityError,
+                          kolla.create_dockerfiles)
+
+    @mock.patch(engine_client)
+    def test_create_dockerfiles_template_override_ssti_blocked(
+            self, mock_client):
+        tmpdir = self.useFixture(fixtures.TempDir()).path
+        base_dir = os.path.join(tmpdir, 'base')
+        os.makedirs(base_dir)
+        with open(os.path.join(base_dir, 'Dockerfile.j2'), 'w') as f:
+            f.write('FROM {{ base_distro }}:{{ base_distro_tag }}\n')
+        override_file = os.path.join(
+            self.useFixture(fixtures.TempDir()).path, 'template_override.j2')
+        with open(override_file, 'w') as f:
+            f.write(
+                "{{ self.__init__.__globals__['__builtins__']"
+                "['__import__']('os').popen('id').read() }}\n"
+            )
+        self.conf.set_override('template_override', [override_file])
+        with mock.patch.object(build.KollaWorker, '_get_images_dir',
+                               return_value=tmpdir):
+            kolla = build.KollaWorker(self.conf)
+        kolla.setup_working_dir()
+        kolla.find_dockerfiles()
+        self.assertRaises(jinja2.exceptions.SecurityError,
+                          kolla.create_dockerfiles)
+
     def _get_matched_images(self, images):
         return [image for image in images
                 if image.status == utils.Status.MATCHED]
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