debian/control

@@ -9,6 +9,7 @@ Uploaders:
 Build-Depends:
  abootimg <!nocheck>,
  androguard <!nocheck>,
+ apksigcopier <!nocheck>,
  apksigner <!nocheck>,
  apktool [!ppc64el !s390x] <!nocheck>,
  bash-completion,

debian/tests/control

@@ -7,7 +7,7 @@
 #   $ mv debian/tests/control.tmp debian/tests/control
 
 Tests: pytest-with-recommends
-Depends: python3-all, diffoscope, black, python3-pytest, python3-h5py, file, linux-image-amd64 [amd64] | linux-image-generic [amd64], abootimg, acl, apksigner, apktool [!ppc64el !s390x], binutils-multiarch, bzip2, caca-utils, colord, coreboot-utils, db-util, default-jdk-headless | default-jdk | java-sdk, device-tree-compiler, docx2txt, e2fsprogs, enjarify, ffmpeg, fontforge-extras, fonttools, fp-utils [!ppc64el !s390x], genisoimage, gettext, ghc, ghostscript, giflib-tools, gnumeric, gnupg, gnupg-utils, hdf5-tools, html2text, imagemagick, jsbeautifier, libarchive-tools, libxmlb-dev, llvm, lz4 | liblz4-tool, lzip, mono-utils, ocaml-nox, odt2txt, oggvideotools [!s390x], openssh-client, openssl, pgpdump, poppler-utils, procyon-decompiler, python3-pdfminer, r-base-core, rpm2cpio, sng, sqlite3, squashfs-tools, tcpdump, u-boot-tools, unzip, wabt, xmlbeans, xxd, xz-utils, zip, zstd, androguard, python3-argcomplete, python3-binwalk, python3-defusedxml, python3-distro, python3-guestfs, python3-jsondiff, python3-progressbar, python3-pypdf2, python3-debian, python3-pyxattr, python3-rpm, python3-tlsh
+Depends: python3-all, diffoscope, black, python3-pytest, python3-h5py, file, linux-image-amd64 [amd64] | linux-image-generic [amd64], abootimg, acl, apksigcopier, apksigner, apktool [!ppc64el !s390x], binutils-multiarch, bzip2, caca-utils, colord, coreboot-utils, db-util, default-jdk-headless | default-jdk | java-sdk, device-tree-compiler, docx2txt, e2fsprogs, enjarify, ffmpeg, fontforge-extras, fonttools, fp-utils [!ppc64el !s390x], genisoimage, gettext, ghc, ghostscript, giflib-tools, gnumeric, gnupg, gnupg-utils, hdf5-tools, html2text, imagemagick, jsbeautifier, libarchive-tools, libxmlb-dev, llvm, lz4 | liblz4-tool, lzip, mono-utils, ocaml-nox, odt2txt, oggvideotools [!s390x], openssh-client, openssl, pgpdump, poppler-utils, procyon-decompiler, python3-pdfminer, r-base-core, rpm2cpio, sng, sqlite3, squashfs-tools, tcpdump, u-boot-tools, unzip, wabt, xmlbeans, xxd, xz-utils, zip, zstd, 
 
 Tests: pytest
 Depends: python3-all, diffoscope, python3-pytest, python3-h5py, file, python3-tlsh

diffoscope/comparators/apk.py

@@ -3,6 +3,7 @@
 #
 # Copyright © 2016 Reiner Herrmann <reiner@reiner-h.de>
 # Copyright © 2016-2021 Chris Lamb <lamby@debian.org>
+# Copyright © 2022 FC Stegerman <flx@obfusk.net>
 #
 # diffoscope is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -230,7 +231,20 @@ class ApkFile(ZipFileBase):
     FILE_EXTENSION_SUFFIX = {".apk"}
     CONTAINER_CLASSES = [ApkContainer, ZipContainer]
 
+    @property
+    def as_container(self):
+        # If we found no differences before the APK Signing Block we return None
+        # here to prevent apktool from being run needlessly (which can take up a
+        # significant amount of extra time) via ApkContainer (since there's no
+        # API that allows us to selectively disable use of container classes in
+        # cases like these).
+        if getattr(self, "_disable_container_compare", False):
+            return None  # don't run apktool
+        return super().as_container
+
     def compare_details(self, other, source=None):
+        self.check_differences_before_signing_block(other)
+
         differences = zipinfo_differences(self, other)
 
         try:
@@ -258,6 +272,42 @@ class ApkFile(ZipFileBase):
 
         return differences
 
+    def check_differences_before_signing_block(self, other):
+        try:
+            self._check_differences_before_signing_block(other)
+        except (RequiredToolNotFound, ImportError):
+            self.add_comment(
+                "'apksigcopier' Python package not installed; unconditionally running 'apktool'."
+            )
+            return
+
+    @tool_required("apksigcopier")
+    def _check_differences_before_signing_block(self, other):
+        import apksigcopier
+
+        try:
+            offset_self, _ = apksigcopier.extract_v2_sig(self.path)
+            offset_other, _ = apksigcopier.extract_v2_sig(other.path)
+        except Exception:
+            return
+
+        if offset_self != offset_other:
+            return
+
+        with open(self.path, "rb") as fh_self:
+            with open(other.path, "rb") as fh_other:
+                while fh_self.tell() < offset_self:
+                    size = min(offset_self - fh_self.tell(), 4096)
+                    if fh_self.read(size) != fh_other.read(size):
+                        return
+
+        self.add_comment(
+            "No differences before APK Signing Block; not running 'apktool'."
+        )
+
+        self._disable_container_compare = True
+        other._disable_container_compare = True
+
 
 def get_v2_signing_keys(path):
     from androguard.core.bytecodes import apk

diffoscope/external_tools.py

@@ -25,6 +25,7 @@ that might resolve to, for example, `/usr/bin/abootimg`.
 EXTERNAL_TOOLS = {
     "abootimg": {"debian": "abootimg", "guix": "abootimg"},
     "androguard": {"debian": "androguard"},
+    "apksigcopier": {"debian": "apksigcopier"},
     "apktool": {"debian": "apktool"},
     "apksigner": {"debian": "apksigner"},
     "db_dump": {"debian": "db-util", "guix": "bdb"},

diffoscope/main.py

@@ -566,18 +566,19 @@ class ListMissingToolsAction(ListToolsAction):
 
 class ListDebianSubstvarsAction(argparse._StoreTrueAction):
     def __call__(self, *args, **kwargs):
+        tools = set()
+
         # Attempt to import all comparators so tool_required.all is as
         # populated as possible...
         ComparatorManager().reload()
+        tools.update(tool_required.all)
 
         # ... however for the generated substvar to be effective/deterministic
         # regardless of the currently installed packages, we special-case some
         # tools (NB. not package names) as their modules may not have been
         # imported by the `ComparatorManager().reload()` call above. (#908072)
-        tools = set(
-            ("gpg", "rpm2cpio")  # comparators/debian.py  # comparators/rpm.py
-        )
-        tools.update(tool_required.all)
+        tools.add("gpg")  # comparators/debian.py
+        tools.add("rpm2cpio")  # comparators/rpm.py
 
         packages = set()
         packages_minimal = set()