mirror of
https://github.com/mandiant/capa.git
synced 2026-06-12 19:11:32 -07:00
Willi Ballenthin
113 lines
4.1 KiB
Python
113 lines
4.1 KiB
Python
# Copyright 2022 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from pathlib import Path
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import dnfile
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import pytest
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import fixtures
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from dncil.clr.token import Token
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from capa.features.common import Format
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from capa.features.extractors.dnfile.insn import get_callee
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from capa.features.extractors.dnfile.helpers import get_dotnet_table_row, calculate_dotnet_token_value
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from capa.features.extractors.dnfile.extractor import (
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DnfileFeatureExtractor,
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DnFileFeatureExtractorCache,
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)
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CD = Path(__file__).resolve().parent
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DOTNET_DIR = Path(__file__).resolve().parent / "data" / "dotnet"
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BACKEND = fixtures.BackendFeaturePolicy(
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name="dnfile",
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get_extractor=fixtures.get_dnfile_extractor,
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include_tags={"dotnet"},
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)
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@fixtures.parametrize_backend_feature_fixtures(BACKEND)
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def test_dnfile_features(feature_fixture):
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fixtures.run_feature_fixture(BACKEND, feature_fixture)
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def test_get_dotnet_table_row_first_row():
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"""row_index=1 is the first valid .NET metadata row; it must not be rejected."""
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pe = dnfile.dnPE(DOTNET_DIR / "dd9098ff91717f4906afe9dafdfa2f52.exe_")
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row = get_dotnet_table_row(pe, dnfile.mdtable.TypeDef.number, 1)
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assert row is not None
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assert str(row.TypeName) == "<Module>"
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def test_get_dotnet_table_row_invalid_zero():
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"""row_index=0 is the null token; the function must return None."""
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pe = dnfile.dnPE(DOTNET_DIR / "dd9098ff91717f4906afe9dafdfa2f52.exe_")
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assert get_dotnet_table_row(pe, dnfile.mdtable.TypeDef.number, 0) is None
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def test_get_dotnet_table_row_valid_rows():
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"""All valid row indices 1..N return a row from the real PE."""
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pe = dnfile.dnPE(DOTNET_DIR / "dd9098ff91717f4906afe9dafdfa2f52.exe_")
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assert pe.net is not None
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assert pe.net.mdtables is not None
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table = pe.net.mdtables.tables.get(dnfile.mdtable.TypeDef.number)
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assert table is not None
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for row_index in range(1, len(table.rows) + 1):
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assert get_dotnet_table_row(pe, dnfile.mdtable.TypeDef.number, row_index) is not None
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def test_get_dotnet_table_row_out_of_bounds():
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"""row_index beyond the table size returns None."""
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pe = dnfile.dnPE(DOTNET_DIR / "dd9098ff91717f4906afe9dafdfa2f52.exe_")
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assert pe.net is not None
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assert pe.net.mdtables is not None
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table = pe.net.mdtables.tables.get(dnfile.mdtable.TypeDef.number)
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assert table is not None
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assert get_dotnet_table_row(pe, dnfile.mdtable.TypeDef.number, len(table.rows) + 1) is None
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def test_no_duplicate_format_feature_in_dnfile_extractor():
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path = fixtures.DNFILE_TESTFILES / "hello-world" / "hello-world.exe"
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if not path.exists():
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pytest.skip("test data not available")
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extractor = DnfileFeatureExtractor(path)
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format_values = [
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f.value
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for f, _ in list(extractor.extract_file_features()) + list(extractor.extract_global_features())
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if isinstance(f, Format)
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]
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assert len(format_values) == len(set(format_values)), f"duplicate Format features: {format_values}"
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def test_get_callee_invalid_methodspec_token_returns_none():
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path = CD / "data" / "2dae11cc5f86f5399b560b8837c26274b7e09431deed669b0844fef44e917915.exe_"
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pe = dnfile.dnPE(str(path))
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cache = DnFileFeatureExtractorCache(pe)
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assert pe.net is not None
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assert pe.net.mdtables is not None
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ms_table = pe.net.mdtables.tables.get(dnfile.mdtable.MethodSpec.number)
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assert ms_table is not None and len(ms_table.rows) > 0
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out_of_range_rid = len(ms_table.rows) + 999
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token_value = calculate_dotnet_token_value(dnfile.mdtable.MethodSpec.number, out_of_range_rid)
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token = Token(token_value)
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result = get_callee(pe, cache, token)
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assert result is None
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