Add warning for big-endian squashfs filesystems

.gitattributes

@@ -0,0 +1 @@
+tests/_data/** filter=lfs diff=lfs merge=lfs -text

.gitignore

@@ -1,11 +1,12 @@
 coverage.xml
 .coverage
+build/
 dist/
 .eggs/
 *.egg-info/
 *.pyc
 __pycache__/
 .pytest_cache/
-tests/docs/api
-tests/docs/build
+tests/_docs/api
+tests/_docs/build
 .tox/

pyproject.toml

@@ -98,7 +98,7 @@ select = [
 ignore = ["E203", "B904", "UP024", "ANN002", "ANN003", "ANN204", "ANN401", "SIM105", "TRY003"]
 
 [tool.ruff.lint.per-file-ignores]
-"tests/docs/**" = ["INP001"]
+"tests/_docs/**" = ["INP001"]
 
 [tool.ruff.lint.isort]
 known-first-party = ["dissect.squashfs"]

tests/conftest.py

@@ -26,34 +26,34 @@ def open_file_gz(name: str, mode: str = "rb") -> Iterator[BinaryIO]:
 
 @pytest.fixture
 def gzip_sqfs() -> Iterator[BinaryIO]:
-    yield from open_file("data/gzip.sqfs")
+    yield from open_file("_data/gzip.sqfs")
 
 
 @pytest.fixture
 def gzip_opts_sqfs() -> Iterator[BinaryIO]:
-    yield from open_file("data/gzip-opts.sqfs")
+    yield from open_file("_data/gzip-opts.sqfs")
 
 
 @pytest.fixture
 def lz4_sqfs() -> Iterator[BinaryIO]:
-    yield from open_file("data/lz4.sqfs")
+    yield from open_file("_data/lz4.sqfs")
 
 
 @pytest.fixture
 def lzma_sqfs() -> Iterator[BinaryIO]:
-    yield from open_file("data/lzma.sqfs")
+    yield from open_file("_data/lzma.sqfs")
 
 
 @pytest.fixture
 def lzo_sqfs() -> Iterator[BinaryIO]:
-    yield from open_file("data/lzo.sqfs")
+    yield from open_file("_data/lzo.sqfs")
 
 
 @pytest.fixture
 def xz_sqfs() -> Iterator[BinaryIO]:
-    yield from open_file("data/xz.sqfs")
+    yield from open_file("_data/xz.sqfs")
 
 
 @pytest.fixture
 def zstd_sqfs() -> Iterator[BinaryIO]:
-    yield from open_file("data/zstd.sqfs")
+    yield from open_file("_data/zstd.sqfs")

tests/test_squashfs.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from io import BytesIO
+
 import pytest
 
 from dissect.squashfs.c_squashfs import c_squashfs
@@ -75,3 +77,20 @@ def test_squashfs(sqfs: str, compression_id: int, request: pytest.FixtureRequest
     sqfs = SquashFS(request.getfixturevalue(sqfs))
     assert sqfs.sb.compression == compression_id
     _verify_filesystem(sqfs)
+
+
+def test_squashfs_unsupported_bigendian_3_0() -> None:
+    """Test if we correctly detect a SquashFS 3.0 big-endian filesystem."""
+
+    # Random SquashFS version 3.0 big-endian header found on binwalk GitHub issue tracker.
+    buf = bytes.fromhex(
+        "73717368000000b60000002042010d364200bc844200339440016800000300006b0400104003004ae64f330000000000"
+        "001623000100000000001177ff8e0800000000000e303100000000000e3025000000000000000000000000000e234c00"
+    )
+
+    sb = c_squashfs.squashfs_super_block(buf)
+    assert sb.s_magic == c_squashfs.SQUASHFS_MAGIC_SWAP
+    assert sb.s_major == 0x300
+
+    with pytest.raises(NotImplementedError, match="Unsupported squashfs pre-4.0 big-endian filesystem"):
+        SquashFS(BytesIO(buf))

tox.ini

@@ -55,12 +55,12 @@ deps =
     sphinx-design
     furo
 commands =
-    make -C tests/docs clean
-    make -C tests/docs html
+    make -C tests/_docs clean
+    make -C tests/_docs html
 
 [testenv:docs-linkcheck]
 allowlist_externals = make
 deps = {[testenv:docs-build]deps}
 commands =
-    make -C tests/docs clean
-    make -C tests/docs linkcheck
+    make -C tests/_docs clean
+    make -C tests/_docs linkcheck