chore: initial commit — recon artifacts + design spec + Phase 1 plan

recon/scripts/unpack_xaba.py

@@ -0,0 +1,49 @@
+"""
+Distill XABA/XALZ assemblies.blob into individual .NET assemblies.
+Format ref (reverse-engineered): https://github.com/dotnet/android/blob/main/src/Xamarin.Android.Build.Tasks/Utilities/AssemblyStore.cs
+"""
+import struct, sys, pathlib, lz4.block
+
+if len(sys.argv) != 3:
+    print("Usage: unpack_xaba.py <assemblies.blob> <out_dir>")
+    sys.exit(1)
+
+blob_path = pathlib.Path(sys.argv[1])
+out_dir = pathlib.Path(sys.argv[2])
+out_dir.mkdir(parents=True, exist_ok=True)
+
+data = blob_path.read_bytes()
+assert data[:4] == b"XABA", f"not a XABA blob, got {data[:4]!r}"
+
+# Scan for XALZ markers (each = one compressed assembly)
+i = 0
+extracted = 0
+while True:
+    idx = data.find(b"XALZ", i)
+    if idx == -1:
+        break
+    # XALZ: 4 magic + 4 descriptor_index + 4 uncompressed_size + N lz4_data
+    desc_idx = struct.unpack_from("<I", data, idx + 4)[0]
+    uncompressed = struct.unpack_from("<I", data, idx + 8)[0]
+    payload_start = idx + 12
+    # Find next XALZ to bound payload (or EOF)
+    next_idx = data.find(b"XALZ", payload_start)
+    payload_end = next_idx if next_idx != -1 else len(data)
+    compressed = data[payload_start:payload_end]
+    try:
+        decompressed = lz4.block.decompress(compressed, uncompressed_size=uncompressed)
+    except Exception as e:
+        # Try without explicit size as fallback
+        try:
+            decompressed = lz4.block.decompress(compressed)
+        except Exception as e2:
+            print(f"[skip] desc={desc_idx} decompress failed: {e2}")
+            i = payload_start
+            continue
+    out_file = out_dir / f"{desc_idx:03d}.dll"
+    out_file.write_bytes(decompressed)
+    extracted += 1
+    print(f"[ok]   desc={desc_idx:03d}  size={len(decompressed)}  -> {out_file.name}")
+    i = payload_start
+
+print(f"\nExtracted {extracted} assemblies into {out_dir}")