Pytorch Load / Save Plugin (#1114)

* Pytorch Load / Save Plugin

This plugin checks for the use of `torch.load` and `torch.save`.
Using `torch.load` with untrusted data can lead to arbitrary code
execution, and improper use of `torch.save` might expose sensitive
data or lead to data corruption.

Signed-off-by: Luke Hinds <[email protected]>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Add missing save check

Signed-off-by: Luke Hinds <[email protected]>

* Review fixes from 8b92a02

Signed-off-by: Luke Hinds <[email protected]>

* Fix tox issues

Signed-off-by: Luke Hinds <[email protected]>

* Review fixes

Signed-off-by: Luke Hinds <[email protected]>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Update test_functional.py

* Update bandit/plugins/pytorch_load_save.py

Co-authored-by: Eric Brown <[email protected]>

* Update bandit/plugins/pytorch_load_save.py

Co-authored-by: Eric Brown <[email protected]>

* Update doc/source/plugins/b704_pytorch_load_save.rst

Co-authored-by: Eric Brown <[email protected]>

* Update bandit/plugins/pytorch_load_save.py

Co-authored-by: Eric Brown <[email protected]>

---------

Signed-off-by: Luke Hinds <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Eric Brown <[email protected]>

bandit/plugins/pytorch_load_save.py

@@ -0,0 +1,72 @@
+# Copyright (c) 2024 Stacklok, Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+r"""
+==========================================
+B614: Test for unsafe PyTorch load or save
+==========================================
+
+This plugin checks for the use of `torch.load` and `torch.save`. Using
+`torch.load` with untrusted data can lead to arbitrary code execution, and
+improper use of `torch.save` might expose sensitive data or lead to data
+corruption. A safe alternative is to use `torch.load` with the `safetensors`
+library from hugingface, which provides a safe deserialization mechanism.
+
+:Example:
+
+.. code-block:: none
+
+        >> Issue: Use of unsafe PyTorch load or save
+        Severity: Medium   Confidence: High
+        CWE: CWE-94 (https://cwe.mitre.org/data/definitions/94.html)
+        Location: examples/pytorch_load_save.py:8
+        7    loaded_model.load_state_dict(torch.load('model_weights.pth'))
+        8    another_model.load_state_dict(torch.load('model_weights.pth',
+                map_location='cpu'))
+        9
+        10   print("Model loaded successfully!")
+
+.. seealso::
+
+     - https://cwe.mitre.org/data/definitions/94.html
+     - https://pytorch.org/docs/stable/generated/torch.load.html#torch.load
+     - https://github.com/huggingface/safetensors
+
+.. versionadded:: 1.7.10
+
+"""
+import bandit
+from bandit.core import issue
+from bandit.core import test_properties as test
+
+
+@test.checks("Call")
+@test.test_id("B614")
+def pytorch_load_save(context):
+    """
+    This plugin checks for the use of `torch.load` and `torch.save`. Using
+    `torch.load` with untrusted data can lead to arbitrary code execution,
+    and improper use of `torch.save` might expose sensitive data or lead
+    to data corruption.
+    """
+    imported = context.is_module_imported_exact("torch")
+    qualname = context.call_function_name_qual
+    if not imported and isinstance(qualname, str):
+        return
+
+    qualname_list = qualname.split(".")
+    func = qualname_list[-1]
+    if all(
+        [
+            "torch" in qualname_list,
+            func in ["load", "save"],
+            not context.check_call_arg_value("map_location", "cpu"),
+        ]
+    ):
+        return bandit.Issue(
+            severity=bandit.MEDIUM,
+            confidence=bandit.HIGH,
+            text="Use of unsafe PyTorch load or save",
+            cwe=issue.Cwe.DESERIALIZATION_OF_UNTRUSTED_DATA,
+            lineno=context.get_lineno_for_call_arg("load"),
+        )

doc/source/plugins/b704_pytorch_load_save.rst

@@ -0,0 +1,5 @@
+-----------------------
+B614: pytorch_load_save
+-----------------------
+
+.. automodule:: bandit.plugins.pytorch_load_save

examples/pytorch_load_save.py

@@ -0,0 +1,21 @@
+import torch
+import torchvision.models as models
+
+# Example of saving a model
+model = models.resnet18(pretrained=True)
+torch.save(model.state_dict(), 'model_weights.pth')
+
+# Example of loading the model weights in an insecure way
+loaded_model = models.resnet18()
+loaded_model.load_state_dict(torch.load('model_weights.pth'))
+
+# Save the model
+torch.save(loaded_model.state_dict(), 'model_weights.pth')
+
+# Another example using torch.load with more parameters
+another_model = models.resnet18()
+another_model.load_state_dict(torch.load('model_weights.pth', map_location='cpu'))
+
+# Save the model
+torch.save(another_model.state_dict(), 'model_weights.pth')
+

setup.cfg

@@ -152,6 +152,9 @@ bandit.plugins =
     #bandit/plugins/tarfile_unsafe_members.py
     tarfile_unsafe_members = bandit.plugins.tarfile_unsafe_members:tarfile_unsafe_members
 
+    #bandit/plugins/pytorch_load_save.py
+    pytorch_load_save = bandit.plugins.pytorch_load_save:pytorch_load_save
+
     # bandit/plugins/trojansource.py
     trojansource = bandit.plugins.trojansource:trojansource
 

tests/functional/test_functional.py

@@ -930,6 +930,14 @@ def test_tarfile_unsafe_members(self):
         }
         self.check_example("tarfile_extractall.py", expect)
 
+    def test_pytorch_load_save(self):
+        """Test insecure usage of torch.load and torch.save."""
+        expect = {
+            "SEVERITY": {"UNDEFINED": 0, "LOW": 0, "MEDIUM": 4, "HIGH": 0},
+            "CONFIDENCE": {"UNDEFINED": 0, "LOW": 0, "MEDIUM": 0, "HIGH": 4},
+        }
+        self.check_example("pytorch_load_save.py", expect)
+
     def test_trojansource(self):
         expect = {
             "SEVERITY": {"UNDEFINED": 0, "LOW": 0, "MEDIUM": 0, "HIGH": 1},