feat(reporting): report meta-data information about chunks.

Allow handlers to provide a dict value as part of a ValidChunk metadata
attribute. That dictionnary can contain any relevant metadata
information from the perspective of the handler, but we advise handler
writers to report parsed information such as header values.

This metadata dict is later reported as part of our ChunkReports and
available in the JSON report file if the user requested one.

The idea is to expose metadata to further analysis steps through the
unblob report. For example, a binary analysis toolkit would read the load
address and architecture from a uImage chunk to analyze the file
extracted from that chunk with the right settings.

A note on the 'as_dict' implementation.

The initial idea was to implement it in dissect.cstruct (see
fox-it/dissect.cstruct#29), but due to expected
changes in the project's API I chose to implement it in unblob so we're
not dependent on another project.

Author: qkaiser

Diff for: tests/test_models.py

@@ -4,7 +4,15 @@
 import pytest
 
 from unblob.file_utils import InvalidInputFormat
-from unblob.models import Chunk, ProcessResult, Task, TaskResult, UnknownChunk, to_json
+from unblob.models import (
+    Chunk,
+    ProcessResult,
+    Task,
+    TaskResult,
+    UnknownChunk,
+    ValidChunk,
+    to_json,
+)
 from unblob.report import (
     ChunkReport,
     ExtractCommandFailedReport,
@@ -170,56 +178,57 @@ def test_process_result_conversion(self):
         decoded_report = json.loads(json_text)
         assert decoded_report == [
             {
-                "__typename__": "TaskResult",
+                "task": {
+                    "path": "/nonexistent",
+                    "depth": 0,
+                    "blob_id": "",
+                    "is_multi_file": False,
+                    "__typename__": "Task",
+                },
                 "reports": [
                     {
-                        "__typename__": "StatReport",
+                        "path": "/nonexistent",
+                        "size": 384,
                         "is_dir": False,
                         "is_file": True,
                         "is_link": False,
                         "link_target": None,
-                        "path": "/nonexistent",
-                        "size": 384,
+                        "__typename__": "StatReport",
                     },
                     {
-                        "__typename__": "FileMagicReport",
                         "magic": "Zip archive data, at least v2.0 to extract",
                         "mime_type": "application/zip",
+                        "__typename__": "FileMagicReport",
                     },
                     {
-                        "__typename__": "HashReport",
                         "md5": "9019fcece2433ad7f12c077e84537a74",
                         "sha1": "36998218d8f43b69ef3adcadf2e8979e81eed166",
                         "sha256": "7d7ca7e1410b702b0f85d18257aebb964ac34f7fad0a0328d72e765bfcb21118",
+                        "__typename__": "HashReport",
                     },
                     {
-                        "__typename__": "ChunkReport",
-                        "end_offset": 384,
-                        "extraction_reports": [],
-                        "handler_name": "zip",
                         "id": "test_basic_conversion:id",
-                        "is_encrypted": False,
-                        "size": 384,
+                        "handler_name": "zip",
                         "start_offset": 0,
+                        "end_offset": 384,
+                        "size": 384,
+                        "is_encrypted": False,
+                        "metadata": {},
+                        "extraction_reports": [],
+                        "__typename__": "ChunkReport",
                     },
                 ],
                 "subtasks": [
                     {
-                        "__typename__": "Task",
-                        "blob_id": "test_basic_conversion:id",
+                        "path": "/extractions/nonexistent_extract",
                         "depth": 314,
+                        "blob_id": "test_basic_conversion:id",
                         "is_multi_file": False,
-                        "path": "/extractions/nonexistent_extract",
+                        "__typename__": "Task",
                     }
                 ],
-                "task": {
-                    "__typename__": "Task",
-                    "blob_id": "",
-                    "depth": 0,
-                    "is_multi_file": False,
-                    "path": "/nonexistent",
-                },
-            },
+                "__typename__": "TaskResult",
+            }
         ]
 
     def test_exotic_command_output(self):
@@ -235,35 +244,44 @@ def test_exotic_command_output(self):
         decoded_report = json.loads(json_text)
 
         assert decoded_report == {
-            "__typename__": "ExtractCommandFailedReport",
-            "command": "dump all bytes",
-            "exit_code": 1,
             "severity": "WARNING",
+            "command": "dump all bytes",
+            "stdout": "\x00\x01\x02\x03\x04\x05\x06\x07\x08"
+            "\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16"
+            "\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,"
+            "-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]"
+            "^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\udc80\udc81"
+            "\udc82\udc83\udc84\udc85\udc86\udc87\udc88\udc89"
+            "\udc8a\udc8b\udc8c\udc8d\udc8e\udc8f\udc90\udc91"
+            "\udc92\udc93\udc94\udc95\udc96\udc97\udc98\udc99"
+            "\udc9a\udc9b\udc9c\udc9d\udc9e\udc9f\udca0\udca1"
+            "\udca2\udca3\udca4\udca5\udca6\udca7\udca8\udca9"
+            "\udcaa\udcab\udcac\udcad\udcae\udcaf\udcb0\udcb1"
+            "\udcb2\udcb3\udcb4\udcb5\udcb6\udcb7\udcb8\udcb9"
+            "\udcba\udcbb\udcbc\udcbd\udcbe\udcbf\udcc0\udcc1"
+            "\udcc2\udcc3\udcc4\udcc5\udcc6\udcc7\udcc8\udcc9"
+            "\udcca\udccb\udccc\udccd\udcce\udccf\udcd0\udcd1"
+            "\udcd2\udcd3\udcd4\udcd5\udcd6\udcd7\udcd8\udcd9"
+            "\udcda\udcdb\udcdc\udcdd\udcde\udcdf\udce0\udce1"
+            "\udce2\udce3\udce4\udce5\udce6\udce7\udce8\udce9"
+            "\udcea\udceb\udcec\udced\udcee\udcef\udcf0\udcf1"
+            "\udcf2\udcf3\udcf4\udcf5\udcf6\udcf7\udcf8\udcf9"
+            "\udcfa\udcfb\udcfc\udcfd\udcfe\udcff",
             "stderr": "stdout is pretty strange ;)",
-            "stdout": (
-                "b'\\x00\\x01\\x02\\x03\\x04\\x05\\x06\\x07"
-                "\\x08\\t\\n\\x0b\\x0c\\r\\x0e\\x0f"
-                "\\x10\\x11\\x12\\x13\\x14\\x15\\x16\\x17"
-                '\\x18\\x19\\x1a\\x1b\\x1c\\x1d\\x1e\\x1f !"#'
-                "$%&\\'()*+,-./0123456789:;<=>?@AB"
-                "CDEFGHIJKLMNOPQRSTUVWXYZ[\\\\]^_`a"
-                "bcdefghijklmnopqrstuvwxyz{|}~\\x7f"
-                "\\x80\\x81\\x82\\x83\\x84\\x85\\x86\\x87"
-                "\\x88\\x89\\x8a\\x8b\\x8c\\x8d\\x8e\\x8f"
-                "\\x90\\x91\\x92\\x93\\x94\\x95\\x96\\x97"
-                "\\x98\\x99\\x9a\\x9b\\x9c\\x9d\\x9e\\x9f"
-                "\\xa0\\xa1\\xa2\\xa3\\xa4\\xa5\\xa6\\xa7"
-                "\\xa8\\xa9\\xaa\\xab\\xac\\xad\\xae\\xaf"
-                "\\xb0\\xb1\\xb2\\xb3\\xb4\\xb5\\xb6\\xb7"
-                "\\xb8\\xb9\\xba\\xbb\\xbc\\xbd\\xbe\\xbf"
-                "\\xc0\\xc1\\xc2\\xc3\\xc4\\xc5\\xc6\\xc7"
-                "\\xc8\\xc9\\xca\\xcb\\xcc\\xcd\\xce\\xcf"
-                "\\xd0\\xd1\\xd2\\xd3\\xd4\\xd5\\xd6\\xd7"
-                "\\xd8\\xd9\\xda\\xdb\\xdc\\xdd\\xde\\xdf"
-                "\\xe0\\xe1\\xe2\\xe3\\xe4\\xe5\\xe6\\xe7"
-                "\\xe8\\xe9\\xea\\xeb\\xec\\xed\\xee\\xef"
-                "\\xf0\\xf1\\xf2\\xf3\\xf4\\xf5\\xf6\\xf7"
-                "\\xf8\\xf9\\xfa\\xfb\\xfc\\xfd\\xfe\\xff"
-                "'"
-            ),
+            "exit_code": 1,
+            "__typename__": "ExtractCommandFailedReport",
         }
+
+    @pytest.mark.parametrize(
+        "metadata",
+        [
+            pytest.param(1, id="metadata_int"),
+            pytest.param(0.2, id="metadata_float"),
+            pytest.param(True, id="metadata_bool"),
+            pytest.param([1, 2], id="metadata_list"),
+            pytest.param((1, 2), id="metadata_tuple"),
+        ],
+    )
+    def test_invalid_metadata(self, metadata):
+        with pytest.raises(ValueError, match="Can only convert dict or Instance"):
+            ValidChunk(start_offset=0, end_offset=100, metadata=metadata)

Diff for: tests/test_report.py

@@ -11,6 +11,7 @@
 from unblob.report import (
     CarveDirectoryReport,
     ChunkReport,
+    ExtractCommandFailedReport,
     FileMagicReport,
     HashReport,
     StatReport,
@@ -48,6 +49,178 @@ def test_process_file_report_output_is_valid_json(
     assert len(report)
 
 
+class Test_ProcessResult_to_json:  # noqa: N801
+    def test_simple_conversion(self):
+        task = Task(path=Path("/nonexistent"), depth=0, blob_id="")
+        task_result = TaskResult(task)
+        chunk_id = "test_basic_conversion:id"
+
+        task_result.add_report(
+            StatReport(
+                path=task.path,
+                size=384,
+                is_dir=False,
+                is_file=True,
+                is_link=False,
+                link_target=None,
+            )
+        )
+        task_result.add_report(
+            FileMagicReport(
+                magic="Zip archive data, at least v2.0 to extract",
+                mime_type="application/zip",
+            )
+        )
+        task_result.add_report(
+            HashReport(
+                md5="9019fcece2433ad7f12c077e84537a74",
+                sha1="36998218d8f43b69ef3adcadf2e8979e81eed166",
+                sha256="7d7ca7e1410b702b0f85d18257aebb964ac34f7fad0a0328d72e765bfcb21118",
+            )
+        )
+        task_result.add_report(
+            ChunkReport(
+                id=chunk_id,
+                handler_name="zip",
+                start_offset=0,
+                end_offset=384,
+                size=384,
+                is_encrypted=False,
+                metadata={},
+                extraction_reports=[],
+            )
+        )
+        task_result.add_subtask(
+            Task(
+                path=Path("/extractions/nonexistent_extract"),
+                depth=314,
+                blob_id=chunk_id,
+            )
+        )
+
+        json_text = ProcessResult(results=[task_result]).to_json()
+
+        # output must be a valid json string
+        assert isinstance(json_text, str)
+
+        # that can be loaded back
+        decoded_report = json.loads(json_text)
+        assert decoded_report == [
+            {
+                "task": {
+                    "path": "/nonexistent",
+                    "depth": 0,
+                    "blob_id": "",
+                    "is_multi_file": False,
+                    "__typename__": "Task",
+                },
+                "reports": [
+                    {
+                        "path": "/nonexistent",
+                        "size": 384,
+                        "is_dir": False,
+                        "is_file": True,
+                        "is_link": False,
+                        "link_target": None,
+                        "__typename__": "StatReport",
+                    },
+                    {
+                        "magic": "Zip archive data, at least v2.0 to extract",
+                        "mime_type": "application/zip",
+                        "__typename__": "FileMagicReport",
+                    },
+                    {
+                        "md5": "9019fcece2433ad7f12c077e84537a74",
+                        "sha1": "36998218d8f43b69ef3adcadf2e8979e81eed166",
+                        "sha256": "7d7ca7e1410b702b0f85d18257aebb964ac34f7fad0a0328d72e765bfcb21118",
+                        "__typename__": "HashReport",
+                    },
+                    {
+                        "id": "test_basic_conversion:id",
+                        "handler_name": "zip",
+                        "start_offset": 0,
+                        "end_offset": 384,
+                        "size": 384,
+                        "is_encrypted": False,
+                        "metadata": {},
+                        "extraction_reports": [],
+                        "__typename__": "ChunkReport",
+                    },
+                ],
+                "subtasks": [
+                    {
+                        "path": "/extractions/nonexistent_extract",
+                        "depth": 314,
+                        "blob_id": "test_basic_conversion:id",
+                        "is_multi_file": False,
+                        "__typename__": "Task",
+                    }
+                ],
+                "__typename__": "TaskResult",
+            }
+        ]
+
+    def test_exotic_command_output(self):
+        task = Task(path=Path("/nonexistent"), depth=0, blob_id="")
+        task_result = TaskResult(task)
+        report = ExtractCommandFailedReport(
+            command="dump all bytes",
+            stdout=bytes(range(256)),
+            stderr=b"stdout is pretty strange ;)",
+            exit_code=1,
+        )
+
+        task_result.add_report(
+            ChunkReport(
+                id="test",
+                handler_name="fail",
+                start_offset=0,
+                end_offset=256,
+                size=256,
+                is_encrypted=False,
+                extraction_reports=[report],
+            )
+        )
+        json_text = ProcessResult(results=[task_result]).to_json()
+
+        decoded_report = json.loads(json_text)
+        assert decoded_report == [
+            {
+                "task": {
+                    "path": "/nonexistent",
+                    "depth": 0,
+                    "blob_id": "",
+                    "is_multi_file": False,
+                    "__typename__": "Task",
+                },
+                "reports": [
+                    {
+                        "id": "test",
+                        "handler_name": "fail",
+                        "start_offset": 0,
+                        "end_offset": 256,
+                        "size": 256,
+                        "is_encrypted": False,
+                        "metadata": {},
+                        "extraction_reports": [
+                            {
+                                "severity": "WARNING",
+                                "command": "dump all bytes",
+                                "stdout": "\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\udc80\udc81\udc82\udc83\udc84\udc85\udc86\udc87\udc88\udc89\udc8a\udc8b\udc8c\udc8d\udc8e\udc8f\udc90\udc91\udc92\udc93\udc94\udc95\udc96\udc97\udc98\udc99\udc9a\udc9b\udc9c\udc9d\udc9e\udc9f\udca0\udca1\udca2\udca3\udca4\udca5\udca6\udca7\udca8\udca9\udcaa\udcab\udcac\udcad\udcae\udcaf\udcb0\udcb1\udcb2\udcb3\udcb4\udcb5\udcb6\udcb7\udcb8\udcb9\udcba\udcbb\udcbc\udcbd\udcbe\udcbf\udcc0\udcc1\udcc2\udcc3\udcc4\udcc5\udcc6\udcc7\udcc8\udcc9\udcca\udccb\udccc\udccd\udcce\udccf\udcd0\udcd1\udcd2\udcd3\udcd4\udcd5\udcd6\udcd7\udcd8\udcd9\udcda\udcdb\udcdc\udcdd\udcde\udcdf\udce0\udce1\udce2\udce3\udce4\udce5\udce6\udce7\udce8\udce9\udcea\udceb\udcec\udced\udcee\udcef\udcf0\udcf1\udcf2\udcf3\udcf4\udcf5\udcf6\udcf7\udcf8\udcf9\udcfa\udcfb\udcfc\udcfd\udcfe\udcff",
+                                "stderr": "stdout is pretty strange ;)",
+                                "exit_code": 1,
+                                "__typename__": "ExtractCommandFailedReport",
+                            }
+                        ],
+                        "__typename__": "ChunkReport",
+                    }
+                ],
+                "subtasks": [],
+                "__typename__": "TaskResult",
+            }
+        ]
+
+
 @pytest.fixture
 def hello_kitty(tmp_path: Path) -> Path:
     """Generate an input file with 3 unknown chunks and 2 zip files."""

Diff for: unblob/handlers/archive/sevenzip.py

@@ -22,6 +22,7 @@
 from pathlib import Path
 from typing import Optional
 
+from dissect.cstruct import Instance
 from structlog import get_logger
 
 from unblob.extractors import Command
@@ -90,14 +91,21 @@ class SevenZipHandler(StructHandler):
     HEADER_STRUCT = HEADER_STRUCT
     EXTRACTOR = Command("7z", "x", "-p", "-y", "{inpath}", "-o{outdir}")
 
+    def get_metadata(self, header: Instance) -> dict:
+        return {"version_maj": header.version_maj, "version_min": header.version_min}
+
     def calculate_chunk(self, file: File, start_offset: int) -> Optional[ValidChunk]:
         header = self.parse_header(file)
 
         check_header_crc(header)
 
         size = calculate_sevenzip_size(header)
 
-        return ValidChunk(start_offset=start_offset, end_offset=start_offset + size)
+        metadata = self.get_metadata(header)
+
+        return ValidChunk(
+            start_offset=start_offset, end_offset=start_offset + size, metadata=metadata
+        )
 
 
 class MultiVolumeSevenZipHandler(DirectoryHandler):