fix(common): prevent injection during jinja templating (#1850)

* fix(common): prevent injection during jinja templating

* refactor: avoid using global jinja_env

Instanciating an env doesn't cost a lot, so it's best to avoid any
globals

tests/test_common.py

@@ -1,6 +1,7 @@
 from datetime import date, datetime, timedelta
 from typing import Any
 
+import jinja2
 import numpy as np
 import pandas as pd
 import pytest
@@ -285,6 +286,25 @@ def test_nosql_apply_parameters_to_query_error_on_params(query: dict, params: di
         nosql_apply_parameters_to_query(query, params, handle_errors=True)
 
 
+def test_nosql_apply_parameters_to_query_unsafe():
+    """
+    It should prevent any code execution, by using Jinja's sandboxed environement
+    """
+    with pytest.raises(jinja2.exceptions.SecurityError):
+        nosql_apply_parameters_to_query(
+            {
+                "test": "{% for x in var.__class__.__base__.__subclasses__() %}"
+                + "{% if 'warning' in x.__name__ %}"
+                + "{{x()._module.__builtins__ ['__import__']"
+                + "('os').popen('ls').read()}}"
+                + "{% endif %}{% endfor %}"
+            },
+            {"var": "plop"},
+        )
+    with pytest.raises(jinja2.exceptions.SecurityError):
+        nosql_apply_parameters_to_query({"test": "{{ var.__class__.mro()[-1] }}"}, {"var": "plop"})
+
+
 def test_nosql_apply_parameters_to_query_dot():
     """It should handle both `x["y"]` and `x.y`"""
     query1 = {"facet": "{{ facet.value }}", "sort": "{{ rank[0] }}", "rows": "{{ bibou[0].value }}"}

toucan_connectors/common.py

@@ -8,8 +8,9 @@
 from copy import deepcopy
 from typing import TYPE_CHECKING, Any, Callable
 
-from jinja2 import Environment, Template, Undefined, UndefinedError, meta
+from jinja2 import Environment, Undefined, UndefinedError, meta
 from jinja2.nativetypes import NativeEnvironment
+from jinja2.sandbox import ImmutableSandboxedEnvironment
 from pydantic import Field
 
 from toucan_connectors.utils.slugify import slugify
@@ -19,6 +20,9 @@
     import sqlalchemy as sa
 
 
+class NativeImmutableSandboxedEnvironment(NativeEnvironment, ImmutableSandboxedEnvironment): ...
+
+
 # Query interpolation
 
 RE_PARAM = r"%\(([^(%\()]*)\)s"
@@ -64,7 +68,7 @@ def is_jinja_alone(s: str) -> bool:
 
 
 def _has_parameters(query: str) -> bool:
-    t = Environment().parse(query)  # noqa: S701
+    t = ImmutableSandboxedEnvironment().parse(query)  # noqa: S701
     return bool(meta.find_undeclared_variables(t) or re.search(RE_PARAM, query))
 
 
@@ -165,9 +169,9 @@ def _render_query(query: dict | list[dict] | tuple | str, parameters: dict | Non
 
         if is_jinja_alone(query):
             clean_p = _prepare_parameters(clean_p)  # type:ignore[assignment]
-            env: Environment | NativeEnvironment = NativeEnvironment()
+            env: Environment | NativeEnvironment = NativeImmutableSandboxedEnvironment()
         else:
-            env = Environment()  # noqa: S701
+            env = ImmutableSandboxedEnvironment()  # noqa: S701
 
         try:
             res = env.from_string(query).render(clean_p)
@@ -237,7 +241,7 @@ def _flatten_dict(p, parent_key=""):
         parameters.update(p_keep_type)
 
     logging.getLogger(__name__).debug(f"Render query: {query} with parameters {parameters}")
-    return Template(query).render(parameters)
+    return ImmutableSandboxedEnvironment().from_string(query).render(parameters)
 
 
 # jq filtering
@@ -476,7 +480,7 @@ def pandas_read_sql(
     if convert_to_printf:
         query = convert_to_printf_templating_style(query)
     if render_user:
-        query = Template(query).render({"user": params.get("user", {})})
+        query = ImmutableSandboxedEnvironment().from_string(query).render({"user": params.get("user", {})})
     if convert_to_qmark:
         query, params = convert_to_qmark_paramstyle(query, params)
     if convert_to_numeric:

toucan_connectors/snowflake/snowflake_connector.py

@@ -29,7 +29,7 @@
     import pandas as pd
     import requests
     import snowflake
-    from jinja2 import Template
+    from jinja2.sandbox import ImmutableSandboxedEnvironment
     from snowflake import connector as sf_connector
     from snowflake.connector import SnowflakeConnection
     from snowflake.connector.cursor import DictCursor as SfDictCursor
@@ -268,7 +268,7 @@ def get_status(self) -> ConnectorStatus:
 
     def get_connection_params(self) -> dict[str, str | int | None]:
         params: dict[str, str | int | None] = {
-            "user": Template(self.user).render(),
+            "user": ImmutableSandboxedEnvironment().from_string(self.user).render(),
             "account": self.account,
             "authenticator": self.authentication_method,
             # hard Snowflake params