Remove untrusted progress parsing (stderr instead)

Now that only the second container can send JSON-encoded progress
information, we can the untrusted JSON parsing. The parse_progress was
also renamed to `parse_progress_trusted` to ensure future developers
don't mistake this as a safe method.

The old methods for sending untrusted JSON were repurposed to send the
progress instead to stderr for troubleshooting in development mode.

Fixes #456

dangerzone/conversion/common.py

@@ -192,5 +192,6 @@ def calculate_timeout(
     async def convert(self) -> None:
         pass
 
-    def update_progress(self, text: str, *, error: bool = False) -> None:
+    @abstractmethod
+    def update_progress(self, text: str) -> None:
         pass

dangerzone/conversion/doc_to_pixels.py

@@ -35,6 +35,9 @@ async def write_page_height(self, height: int) -> None:
     async def write_page_data(self, data: bytes) -> None:
         return await self.write_bytes(data)
 
+    def update_progress(self, text: str, *, error: bool = False) -> None:
+        print(text, file=sys.stderr)
+
     async def convert(self) -> None:
         conversions: Dict[str, Dict[str, Optional[str]]] = {
             # .pdf

dangerzone/conversion/pixels_to_pdf.py

@@ -93,11 +93,11 @@ async def convert(
     def update_progress(self, text: str, *, error: bool = False) -> None:
         if running_on_qubes():
             if self.progress_callback:
-                self.progress_callback(error, text, int(self.percentage))
+                self.progress_callback(error, text, self.percentage)
         else:
             print(
                 json.dumps(
-                    {"error": error, "text": text, "percentage": int(self.percentage)}
+                    {"error": error, "text": text, "percentage": self.percentage}
                 )
             )
             sys.stdout.flush()

dangerzone/isolation_provider/base.py

@@ -83,13 +83,13 @@ def convert(
             exception = errors.exception_from_error_code(error_code)
             document.mark_as_failed()
         except errors.ConversionException as e:
-            self.print_progress_trusted(document, True, str(e), 0)
+            self.print_progress(document, True, str(e), 0)
             document.mark_as_failed()
         except Exception as e:
             log.exception(
                 f"An exception occurred while converting document '{document.id}'"
             )
-            self.print_progress_trusted(document, True, str(e), 0)
+            self.print_progress(document, True, str(e), 0)
             document.mark_as_failed()
 
     def doc_to_pixels(self, document: Document, tempdir: str) -> None:
@@ -120,7 +120,7 @@ def doc_to_pixels(self, document: Document, tempdir: str) -> None:
             sw.start()
             for page in range(1, n_pages + 1):
                 text = f"Converting page {page}/{n_pages} to pixels"
-                self.print_progress_trusted(document, False, text, self.percentage)
+                self.print_progress(document, False, text, self.percentage)
 
                 width = read_int(self.proc.stdout, timeout=sw.remaining)
                 height = read_int(self.proc.stdout, timeout=sw.remaining)
@@ -151,7 +151,7 @@ def doc_to_pixels(self, document: Document, tempdir: str) -> None:
 
         # TODO handle leftover code input
         text = "Converted document to pixels"
-        self.print_progress_trusted(document, False, text, self.percentage)
+        self.print_progress(document, False, text, self.percentage)
 
         if getattr(sys, "dangerzone_dev", False):
             assert self.proc.stderr is not None
@@ -168,11 +168,11 @@ def pixels_to_pdf(
     ) -> None:
         pass
 
-    def _print_progress(
+    def print_progress(
         self, document: Document, error: bool, text: str, percentage: float
     ) -> None:
         s = Style.BRIGHT + Fore.YELLOW + f"[doc {document.id}] "
-        s += Fore.CYAN + f"{percentage}% " + Style.RESET_ALL
+        s += Fore.CYAN + f"{int(percentage)}% " + Style.RESET_ALL
         if error:
             s += Fore.RED + text + Style.RESET_ALL
             log.error(s)
@@ -183,19 +183,6 @@ def _print_progress(
         if self.progress_callback:
             self.progress_callback(error, text, percentage)
 
-    def print_progress_trusted(
-        self, document: Document, error: bool, text: str, percentage: float
-    ) -> None:
-        return self._print_progress(document, error, text, int(percentage))
-
-    def print_progress(
-        self, document: Document, error: bool, untrusted_text: str, percentage: float
-    ) -> None:
-        text = replace_control_chars(untrusted_text)
-        return self.print_progress_trusted(
-            document, error, "UNTRUSTED> " + text, percentage
-        )
-
     @abstractmethod
     def get_max_parallel_conversions(self) -> int:
         pass

dangerzone/isolation_provider/container.py

@@ -11,12 +11,7 @@
 
 from ..conversion import errors
 from ..document import Document
-from ..util import (
-    get_resource_path,
-    get_subprocess_startupinfo,
-    get_tmp_dir,
-    replace_control_chars,
-)
+from ..util import get_resource_path, get_subprocess_startupinfo, get_tmp_dir
 from .base import IsolationProvider
 
 # Define startupinfo for subprocesses
@@ -147,29 +142,22 @@ def assert_field_type(self, val: Any, _type: object) -> None:
         if not type(val) == _type:
             raise ValueError("Status field has incorrect type")
 
-    def parse_progress(self, document: Document, untrusted_line: str) -> None:
+    def parse_progress_trusted(self, document: Document, line: str) -> None:
         """
         Parses a line returned by the container.
         """
         try:
-            untrusted_status = json.loads(untrusted_line)
-
-            text = untrusted_status["text"]
+            status = json.loads(line)
+            text = status["text"]
             self.assert_field_type(text, str)
-
-            error = untrusted_status["error"]
+            error = status["error"]
             self.assert_field_type(error, bool)
-
-            percentage = untrusted_status["percentage"]
-            self.assert_field_type(percentage, int)
-
+            percentage = status["percentage"]
+            self.assert_field_type(percentage, float)
             self.print_progress(document, error, text, percentage)
         except Exception:
-            line = replace_control_chars(untrusted_line)
-            error_message = (
-                f"Invalid JSON returned from container:\n\n\tUNTRUSTED> {line}"
-            )
-            self.print_progress_trusted(document, True, error_message, -1)
+            error_message = f"Invalid JSON returned from container:\n\n\t {line}"
+            self.print_progress(document, True, error_message, -1)
 
     def exec(
         self,
@@ -249,8 +237,9 @@ def pixels_to_pdf(
         ]
 
         pixels_to_pdf_proc = self.exec_container(command, extra_args)
-        for line in pixels_to_pdf_proc.stdout:
-            self.parse_progress(document, line)
+        if pixels_to_pdf_proc.stdout:
+            for line in pixels_to_pdf_proc.stdout:
+                self.parse_progress_trusted(document, line.decode())
         error_code = pixels_to_pdf_proc.wait()
         if error_code != 0:
             log.error("pixels-to-pdf failed")

dangerzone/isolation_provider/qubes.py

@@ -36,7 +36,7 @@ def pixels_to_pdf(
         self, document: Document, tempdir: str, ocr_lang: Optional[str]
     ) -> None:
         def print_progress_wrapper(error: bool, text: str, percentage: float) -> None:
-            self.print_progress_trusted(document, error, text, percentage)
+            self.print_progress(document, error, text, percentage)
 
         converter = PixelsToPDF(progress_callback=print_progress_wrapper)
         try:

tests/isolation_provider/base.py

@@ -18,46 +18,6 @@
 )
 @pytest.mark.skipif(not running_on_qubes(), reason="Not on a Qubes system")
 class IsolationProviderTest:
-    def test_print_progress(
-        self,
-        provider: base.IsolationProvider,
-        uncommon_text: str,
-        sanitized_text: str,
-        mocker: MockerFixture,
-    ) -> None:
-        """Test that the print_progress() method of our isolation providers sanitizes text.
-
-        Iterate our isolation providers and make sure that their print_progress() methods
-        sanitizes the provided text, before passing it to the logging functions and other
-        callbacks.
-        """
-        d = Document()
-        provider.progress_callback = mocker.MagicMock()
-        log_info_spy = mocker.spy(base.log, "info")
-        log_error_spy = mocker.spy(base.log, "error")
-        _print_progress_spy = mocker.spy(provider, "_print_progress")
-
-        for error, untrusted_text, sanitized_text in [
-            (True, "normal text", "UNTRUSTED> normal text"),
-            (False, "normal text", "UNTRUSTED> normal text"),
-            (True, uncommon_text, "UNTRUSTED> " + sanitized_text),
-            (False, uncommon_text, "UNTRUSTED> " + sanitized_text),
-        ]:
-            log_info_spy.reset_mock()
-            log_error_spy.reset_mock()
-
-            provider.print_progress(d, error, untrusted_text, 0)
-            provider.progress_callback.assert_called_with(error, sanitized_text, 0)  # type: ignore [union-attr]
-            _print_progress_spy.assert_called_with(d, error, sanitized_text, 0)
-            if error:
-                assert log_error_spy.call_args[0][0].endswith(
-                    sanitized_text + Style.RESET_ALL
-                )
-                log_info_spy.assert_not_called()
-            else:
-                assert log_info_spy.call_args[0][0].endswith(sanitized_text)
-                log_error_spy.assert_not_called()
-
     def test_max_pages_received(
         self,
         pdf_11k_pages: str,

tests/isolation_provider/test_container.py

@@ -19,77 +19,4 @@ def provider() -> Container:
 
 
 class TestContainer(IsolationProviderTest):
-    def test_parse_progress(
-        self,
-        provider: Container,
-        uncommon_text: str,
-        sanitized_text: str,
-        mocker: MockerFixture,
-    ) -> None:
-        """Test that the `parse_progress()` function handles escape sequences properly."""
-        container = Container(enable_timeouts=False)
-        container.progress_callback = mocker.MagicMock()
-        print_progress_mock = mocker.patch.object(container, "_print_progress")
-        d = Document()
-
-        # Test 1 - Check that normal JSON values are printed as is.
-        simple_json = json.dumps({"text": "text", "error": False, "percentage": 0})
-        container.parse_progress(d, simple_json)
-        print_progress_mock.assert_called_with(d, False, "UNTRUSTED> text", 0)
-
-        # Test 2 - Check that a totally invalid string is reported as a failure. If this
-        # string contains escape characters, they should be sanitized as well.
-        def assert_invalid_json(text: str) -> None:
-            print_progress_mock.assert_called_with(
-                d,
-                True,
-                f"Invalid JSON returned from container:\n\n\tUNTRUSTED> {text}",
-                -1,
-            )
-
-        # Try first with a trivially invalid string.
-        invalid_json = "()"
-        container.parse_progress(d, invalid_json)
-        assert_invalid_json(invalid_json)
-
-        # Try next with an invalid string that contains uncommon text.
-        container.parse_progress(d, uncommon_text)
-        assert_invalid_json(sanitized_text)
-
-        # Test 3 - Check that a structurally valid JSON value with escape characters in it
-        # is sanitized.
-        valid_json = json.dumps(
-            {"text": uncommon_text, "error": False, "percentage": 0}
-        )
-        sanitized_json = json.dumps(
-            {"text": sanitized_text, "error": False, "percentage": 0}
-        )
-        container.parse_progress(d, valid_json)
-        print_progress_mock.assert_called_with(
-            d, False, "UNTRUSTED> " + sanitized_text, 0
-        )
-
-        # Test 4 - Check that a structurally valid JSON, that otherwise does not have the
-        # expected keys, or the expected value types, is reported as an error, and any
-        # escape sequences are sanitized.
-
-        keys = ["text", "error", "percentage", uncommon_text]
-        values = [uncommon_text, False, 0, None]
-        possible_kvs = list(itertools.product(keys, values, repeat=1))
-
-        # Based on the above keys and values, create any combination possible, from 0 to 3
-        # elements. Take extra care to:
-        #
-        # * Remove combinations with non-unique keys.
-        # * Ignore the sole valid combination (see `valid_json`), since we have already
-        #   tested it above.
-        for i in range(len(keys)):
-            for combo in itertools.combinations(possible_kvs, i):
-                dict_combo: Dict[str, Any] = dict(combo)  # type: ignore [arg-type]
-                if len(combo) == len(dict_combo.keys()):
-                    bad_json = json.dumps(dict_combo)
-                    sanitized_json = bad_json.replace(uncommon_text, sanitized_text)
-                    if bad_json == valid_json:
-                        continue
-                    container.parse_progress(d, bad_json)
-                    assert_invalid_json(sanitized_json)
+    pass