Merge remote-tracking branch 'origin/pakjoy' into pakjoy

4 files changed, 364 insertions, 24 deletions

diff --git a/qutebrowser/browser/webengine/webenginesettings.py b/qutebrowser/browser/webengine/webenginesettings.py
index d0b6b5beb..168fb8280 100644
--- a/qutebrowser/browser/webengine/webenginesettings.py
+++ b/qutebrowser/browser/webengine/webenginesettings.py
@@ -24,6 +24,7 @@ from qutebrowser.browser.webengine import (spell, webenginequtescheme, cookies,
                                            webenginedownloads, notification)
 from qutebrowser.config import config, websettings
 from qutebrowser.config.websettings import AttributeInfo as Attr
+from qutebrowser.misc import pakjoy
 from qutebrowser.utils import (standarddir, qtutils, message, log,
                                urlmatch, usertypes, objreg, version)
 if TYPE_CHECKING:
@@ -546,6 +547,10 @@ def init():
     _global_settings = WebEngineSettings(_SettingsWrapper())
 
     log.init.debug("Initializing profiles...")
+
+    # Apply potential resource patches before initializing profiles.
+    pakjoy.patch()
+
     _init_default_profile()
     init_private_profile()
     config.instance.changed.connect(_update_settings)
diff --git a/qutebrowser/misc/binparsing.py b/qutebrowser/misc/binparsing.py
index 7627ef6cf..81e2e6dbb 100644
--- a/qutebrowser/misc/binparsing.py
+++ b/qutebrowser/misc/binparsing.py
@@ -41,4 +41,3 @@ def safe_seek(fobj: IO[bytes], pos: int) -> None:
         fobj.seek(pos)
     except (OSError, OverflowError) as e:
         raise ParseError(e)
-
diff --git a/qutebrowser/misc/pakjoy.py b/qutebrowser/misc/pakjoy.py
index 57d85b482..78d02550a 100644
--- a/qutebrowser/misc/pakjoy.py
+++ b/qutebrowser/misc/pakjoy.py
@@ -1,4 +1,3 @@
-
 # SPDX-FileCopyrightText: Florian Bruhin (The-Compiler) <mail@qutebrowser.org>
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
@@ -26,10 +25,14 @@ This is a "best effort" parser. If it errors out, we don't apply the workaround
 instead of crashing.
 """
 
+import os
+import shutil
+import pathlib
 import dataclasses
 from typing import ClassVar, IO, Optional, Dict, Tuple
 
 from qutebrowser.misc import binparsing
+from qutebrowser.utils import qtutils, standarddir, version, utils, log
 
 HANGOUTS_MARKER = b"// Extension ID: nkeimhogjdpnpccoofpliimaahmaaome"
 HANGOUTS_ID = 36197  # as found by toofar
@@ -47,7 +50,7 @@ class PakHeader:
 
     encoding: int  # uint32
     resource_count: int  # uint16
-    alias_count: int  # uint16
+    _alias_count: int  # uint16
 
     _FORMAT: ClassVar[str] = '<IHH'
 
@@ -60,7 +63,7 @@ class PakHeader:
 @dataclasses.dataclass
 class PakEntry:
 
-    """Entry description in a .pak file"""
+    """Entry description in a .pak file."""
 
     resource_id: int  # uint16
     file_offset: int  # uint32
@@ -75,18 +78,20 @@ class PakEntry:
 
 
 class PakParser:
+    """Parse webengine pak and find patch location to disable Google Meet extension."""
 
     def __init__(self, fobj: IO[bytes]) -> None:
         """Parse the .pak file from the given file object."""
-        version = binparsing.unpack("<I", fobj)[0]
-        if version != PAK_VERSION:
-            raise binparsing.ParseError(f"Unsupported .pak version {version}")
+        pak_version = binparsing.unpack("<I", fobj)[0]
+        if pak_version != PAK_VERSION:
+            raise binparsing.ParseError(f"Unsupported .pak version {pak_version}")
 
         self.fobj = fobj
         entries = self._read_header()
         self.manifest_entry, self.manifest = self._find_manifest(entries)
 
     def find_patch_offset(self) -> int:
+        """Return byte offset of TARGET_URL into the pak file."""
         try:
             return self.manifest_entry.file_offset + self.manifest.index(TARGET_URL)
         except ValueError:
@@ -135,25 +140,79 @@ class PakParser:
         for entry in entries.values():
             manifest = self._maybe_get_hangouts_manifest(entry)
             if manifest is not None:
-                return entry, manifest
+                return entries[id_], manifest
 
         raise binparsing.ParseError("Couldn't find hangouts manifest")
 
 
+def copy_webengine_resources() -> pathlib.Path:
+    """Copy qtwebengine resources to local dir for patching."""
+    resources_dir = qtutils.library_path(qtutils.LibraryPath.data)
+    if utils.is_mac:
+        # I'm not sure how to arrive at this path without hardcoding it
+        # ourselves. importlib_resources("PyQt6.Qt6") can serve as a
+        # replacement for the qtutils bit but it doesn't seem to help find the
+        # actually Resources folder.
+        resources_dir /= pathlib.Path("lib", "QtWebEngineCore.framework", "Resources")
+    else:
+        resources_dir /= "resources"
+    work_dir = pathlib.Path(standarddir.cache()) / "webengine_resources_pak_quirk"
+
+    log.misc.debug(
+        "Copying webengine resources for quirk patching: "
+        f"{resources_dir} -> {work_dir}"
+    )
+
+    if work_dir.exists():
+        # TODO: make backup?
+        shutil.rmtree(work_dir)
+
+    shutil.copytree(resources_dir, work_dir)
+
+    os.environ["QTWEBENGINE_RESOURCES_PATH"] = str(work_dir)
+
+    return work_dir
+
+
+def patch(file_to_patch: pathlib.Path = None) -> None:
+    """Apply any patches to webengine resource pak files."""
+    versions = version.qtwebengine_versions(avoid_init=True)
+    if versions.webengine != utils.VersionNumber(6, 6):
+        return
+
+    if not file_to_patch:
+        try:
+            file_to_patch = copy_webengine_resources() / "qtwebengine_resources.pak"
+        except OSError:
+            log.misc.exception("Failed to copy webengine resources, not applying quirk")
+            return
+
+    if not file_to_patch.exists():
+        log.misc.error(
+            "Resource pak doesn't exist at expected location! "
+            f"Not applying quirks. Expected location: {file_to_patch}"
+        )
+        return
+
+    with open(file_to_patch, "r+b") as f:
+        try:
+            parser = PakParser(f)
+            log.misc.debug(f"Patching pak entry: {parser.manifest_entry}")
+            offset = parser.find_patch_offset()
+            binparsing.safe_seek(f, offset)
+            f.write(REPLACEMENT_URL)
+        except binparsing.ParseError:
+            log.misc.exception("Failed to apply quirk to resources pak.")
+
+
 if __name__ == "__main__":
-    import shutil
-    shutil.copy("/usr/share/qt6/resources/qtwebengine_resources.pak", "/tmp/test.pak")
-
-    with open("/tmp/test.pak", "r+b") as f:
-        parser = PakParser(f)
-        print(parser.manifest_entry)
-        print(parser.manifest)
-        offset = parser.find_patch_offset()
-        f.seek(offset)
-        f.write(REPLACEMENT_URL)
-
-    with open("/tmp/test.pak", "rb") as f:
-        parser = PakParser(f)
-
-    print(parser.manifest_entry)
-    print(parser.manifest)
+    output_test_file = pathlib.Path("/tmp/test.pak")
+    #shutil.copy("/opt/google/chrome/resources.pak", output_test_file)
+    shutil.copy("/usr/share/qt6/resources/qtwebengine_resources.pak", output_test_file)
+    patch(output_test_file)
+
+    with open(output_test_file, "rb") as fd:
+        reparsed = PakParser(fd)
+
+    print(reparsed.manifest_entry)
+    print(reparsed.manifest)
diff --git a/tests/unit/misc/test_pakjoy.py b/tests/unit/misc/test_pakjoy.py
new file mode 100644
index 000000000..5c35d0111
--- /dev/null
+++ b/tests/unit/misc/test_pakjoy.py
@@ -0,0 +1,277 @@
+# SPDX-FileCopyrightText: Florian Bruhin (The-Compiler) <mail@qutebrowser.org>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+import os
+import io
+import json
+import struct
+import pathlib
+import logging
+
+import pytest
+
+from qutebrowser.misc import pakjoy, binparsing
+from qutebrowser.utils import utils, version, standarddir
+
+
+pytest.importorskip("qutebrowser.qt.webenginecore")
+
+
+versions = version.qtwebengine_versions(avoid_init=True)
+
+
+@pytest.fixture
+def skipifneeded():
+    """Used to skip happy path tests with the real resources file.
+
+    Since we don't know how reliably the Google Meet hangouts extensions is
+    reliably in the resource files, and this quirk is only targeting 6.6
+    anyway.
+    """
+    if versions.webengine != utils.VersionNumber(6, 6):
+        raise pytest.skip("Code under test only runs on 6.6")
+
+
+@pytest.fixture(autouse=True)
+def clean_env():
+    yield
+    if "QTWEBENGINE_RESOURCES_PATH" in os.environ:
+        del os.environ["QTWEBENGINE_RESOURCES_PATH"]
+
+
+def patch_version(monkeypatch, *args):
+    monkeypatch.setattr(
+        pakjoy.version,
+        "qtwebengine_versions",
+        lambda **kwargs: version.WebEngineVersions(
+            webengine=utils.VersionNumber(*args),
+            chromium=None,
+            source="unittest",
+        )
+    )
+
+
+@pytest.fixture
+def unaffected_version(monkeypatch):
+    patch_version(monkeypatch, 6, 6, 1)
+
+
+@pytest.fixture
+def affected_version(monkeypatch):
+    patch_version(monkeypatch, 6, 6)
+
+
+def test_version_gate(unaffected_version, mocker):
+
+    fake_open = mocker.patch("qutebrowser.misc.pakjoy.open")
+    pakjoy.patch()
+    assert not fake_open.called
+
+
+@pytest.fixture(autouse=True)
+def tmp_cache(tmp_path, monkeypatch):
+    monkeypatch.setattr(pakjoy.standarddir, "cache", lambda: tmp_path)
+    return str(tmp_path)
+
+
+def json_without_comments(bytestring):
+    str_without_comments = "\n".join(
+        [
+            line
+            for line in
+            bytestring.decode("utf-8").split("\n")
+            if not line.strip().startswith("//")
+        ]
+    )
+    return json.loads(str_without_comments)
+
+
+@pytest.mark.usefixtures("affected_version")
+class TestWithRealResourcesFile:
+    """Tests that use the real pak file form the Qt installation."""
+
+    def test_happy_path(self, skipifneeded):
+        # Go through the full patching processes with the real resources file from
+        # the current installation. Make sure our replacement string is in it
+        # afterwards.
+        pakjoy.patch()
+
+        patched_resources = pathlib.Path(os.environ["QTWEBENGINE_RESOURCES_PATH"])
+
+        with open(patched_resources / "qtwebengine_resources.pak", "rb") as fd:
+            reparsed = pakjoy.PakParser(fd)
+
+        json_manifest = json_without_comments(reparsed.manifest)
+
+        assert pakjoy.REPLACEMENT_URL.decode("utf-8") in json_manifest[
+            "externally_connectable"
+        ]["matches"]
+
+    def test_copying_resources(self):
+        # Test we managed to copy some files over
+        work_dir = pakjoy.copy_webengine_resources()
+
+        assert work_dir.exists()
+        assert work_dir == standarddir.cache() / "webengine_resources_pak_quirk"
+        assert (work_dir / "qtwebengine_resources.pak").exists()
+        assert len(list(work_dir.glob("*"))) > 1
+
+    def test_copying_resources_overwrites(self):
+        work_dir = pakjoy.copy_webengine_resources()
+        tmpfile = work_dir / "tmp.txt"
+        tmpfile.touch()
+
+        pakjoy.copy_webengine_resources()
+        assert not tmpfile.exists()
+
+    @pytest.mark.parametrize("osfunc", ["copytree", "rmtree"])
+    def test_copying_resources_oserror(self, monkeypatch, caplog, osfunc):
+        # Test errors from the calls to shutil are handled
+        pakjoy.copy_webengine_resources()  # run twice so we hit rmtree too
+        caplog.clear()
+
+        def raiseme(err):
+            raise err
+
+        monkeypatch.setattr(pakjoy.shutil, osfunc, lambda *_args: raiseme(PermissionError(osfunc)))
+        with caplog.at_level(logging.ERROR, "misc"):
+            pakjoy.patch()
+        assert caplog.messages == ["Failed to copy webengine resources, not applying quirk"]
+
+    def test_expected_file_not_found(self, tmp_cache, monkeypatch, caplog):
+        with caplog.at_level(logging.ERROR, "misc"):
+            pakjoy.patch(pathlib.Path(tmp_cache) / "doesntexist")
+        assert caplog.messages[-1].startswith(
+            "Resource pak doesn't exist at expected location! "
+            "Not applying quirks. Expected location: "
+        )
+
+
+def json_manifest_factory(extension_id=pakjoy.HANGOUTS_MARKER, url=pakjoy.TARGET_URL):
+    assert isinstance(extension_id, bytes)
+    assert isinstance(url, bytes)
+
+    return f"""
+    {{
+      {extension_id.decode("utf-8")}
+      "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDAQt2ZDdPfoSe/JI6ID5bgLHRCnCu9T36aYczmhw/tnv6QZB2I6WnOCMZXJZlRdqWc7w9jo4BWhYS50Vb4weMfh/I0On7VcRwJUgfAxW2cHB+EkmtI1v4v/OU24OqIa1Nmv9uRVeX0GjhQukdLNhAE6ACWooaf5kqKlCeK+1GOkQIDAQAB",
+      "name": "Google Hangouts",
+      // Note: Always update the version number when this file is updated. Chrome
+      // triggers extension preferences update on the version increase.
+      "version": "1.3.21",
+      "manifest_version": 2,
+      "externally_connectable": {{
+        "matches": [
+          "{url.decode("utf-8")}",
+          "http://localhost:*/*"
+        ]
+        }}
+    }}
+    """.strip().encode("utf-8")
+
+
+def pak_factory(version=5, entries=None, encoding=1, sentinel_position=-1):
+    if entries is None:
+        entries = [json_manifest_factory()]
+
+    buffer = io.BytesIO()
+    buffer.write(struct.pack("<I", version))
+    buffer.write(struct.pack(pakjoy.Pak5Header._FORMAT, encoding, len(entries), 0))
+
+    entry_headers_size = (len(entries) + 1) * 6
+    start_of_data = buffer.tell() + entry_headers_size
+
+    # Normally the sentinel sits between the headers and the data. But to get
+    # full coverage we want to insert it in other positions.
+    with_indices = list(enumerate(entries, 1))
+    if sentinel_position == -1:
+        with_indices.append((0, b""))
+    elif sentinel_position is not None:
+        with_indices.insert(sentinel_position, (0, b""))
+
+    accumulated_data_offset = start_of_data
+    for idx, entry in with_indices:
+        buffer.write(struct.pack(pakjoy.PakEntry._FORMAT, idx, accumulated_data_offset))
+        accumulated_data_offset += len(entry)
+
+    for entry in entries:
+        assert isinstance(entry, bytes)
+        buffer.write(entry)
+
+    buffer.seek(0)
+    return buffer
+
+
+@pytest.mark.usefixtures("affected_version")
+class TestWithConstructedResourcesFile:
+    """Tests that use a constructed pak file to give us more control over it."""
+
+    def test_happy_path(self):
+        buffer = pak_factory()
+
+        parser = pakjoy.PakParser(buffer)
+
+        json_manifest = json_without_comments(parser.manifest)
+
+        assert pakjoy.TARGET_URL.decode("utf-8") in json_manifest[
+            "externally_connectable"
+        ]["matches"]
+
+    def test_bad_version(self):
+        buffer = pak_factory(version=99)
+
+        with pytest.raises(
+            binparsing.ParseError,
+            match="Unsupported .pak version 99",
+        ):
+            pakjoy.PakParser(buffer)
+
+    @pytest.mark.parametrize("position, error", [
+        (0, "Unexpected sentinel entry"),
+        (None, "Missing sentinel entry"),
+    ])
+    def test_bad_sentinal_position(self, position, error):
+        buffer = pak_factory(sentinel_position=position)
+
+        with pytest.raises(binparsing.ParseError):
+            pakjoy.PakParser(buffer)
+
+    @pytest.mark.parametrize("entry", [
+        b"{foo}",
+        b"V2VsbCBoZWxsbyB0aGVyZQo=",
+    ])
+    def test_marker_not_found(self, entry):
+        buffer = pak_factory(entries=[entry])
+
+        with pytest.raises(
+            binparsing.ParseError,
+            match="Couldn't find hangouts manifest",
+        ):
+            pakjoy.PakParser(buffer)
+
+    def test_url_not_found(self):
+        buffer = pak_factory(entries=[json_manifest_factory(url=b"example.com")])
+
+        parser = pakjoy.PakParser(buffer)
+        with pytest.raises(
+            binparsing.ParseError,
+            match="Couldn't find URL in manifest",
+        ):
+            parser.find_patch_offset()
+
+    def test_url_not_found_high_level(self, tmp_cache, caplog,
+                                      affected_version):
+        buffer = pak_factory(entries=[json_manifest_factory(url=b"example.com")])
+
+        # Write bytes to file so we can test pakjoy.patch()
+        tmpfile = pathlib.Path(tmp_cache) / "bad.pak"
+        with open(tmpfile, "wb") as fd:
+            fd.write(buffer.read())
+
+        with caplog.at_level(logging.ERROR, "misc"):
+            pakjoy.patch(tmpfile)
+
+        assert caplog.messages == [
+            "Failed to apply quirk to resources pak."
+        ]