deblob

commit: 1b5b4e32509df0c7c55fe198b04f571f82390842
parent 615d91e277233e4c1492874ed9d4078304906ca3
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Fri, 30 Sep 2022 06:54:54 +0200

Add support for All Portable Executable (aka .exe) files

Diffstat:
M
deblob.1
1
-
M
main.ha
17
+++++++++++++++--
A
test/fixtures/monodx.dll
0

A
test/fixtures/monodx.dll.license
2
++

4 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/deblob.1 b/deblob.1
@@ -54,7 +54,6 @@ Portable Executable files, typically
 .Sq *.exe
 and
 .Sq *.dll .
-Supported variants: ECMA-335 aka .Net
 .It
 Lua bytecode
 .It
diff --git a/main.ha b/main.ha
@@ -1,6 +1,7 @@
 // Copyright © 2019-2022 deblob Authors <https://hacktivis.me/projects/deblob>
 // SPDX-License-Identifier: BSD-3-Clause
 use bytes;
+use endian;
 use errors;
 use fmt;
 use fnmatch;
@@ -30,6 +31,8 @@ const magic: [_][]u8 = [
 	[0x61, 0x0D, '\r', '\n'], // (3425i litte-endian) Python 3.9
 	[0x6F, 0x0D, '\r', '\n'], // (3439i litte-endian) Python 3.10
 ];
+const dos_magic: []u8 = ['M', 'Z'];
+const pe_magic: []u8 = ['P', 'E', 0x00, 0x00];
 
 fn is_blob(filename: str) (bool | fs::error | io::error) = {
 	static let buffer: [512]u8 = [0...];
@@ -49,6 +52,15 @@ fn is_blob(filename: str) (bool | fs::error | io::error) = {
 		};
 	};
 
+	// Special check to detect *all* Microsoft Portable Executable files
+	if (bytes::hasprefix(buffer, dos_magic)) {
+		const pe_offset = endian::legetu32(buffer[60..64]);
+
+		if ((pe_offset < 512+4) && bytes::hasprefix(buffer[pe_offset..pe_offset+4], pe_magic)) {
+			return true;
+		};
+	};
+
 	return false;
 };
 
@@ -65,6 +77,7 @@ fn is_blob(filename: str) (bool | fs::error | io::error) = {
 		("test/fixtures/hello.o", true),
 		("test/fixtures/hello.a", true),
 		("test/fixtures/hello.exe", true),
+		("test/fixtures/monodx.dll", true),
 		("test/fixtures/hello.wasm", true),
 		("test/fixtures/Elixir.Hex.API.Auth.beam", true),
 		//("test/fixtures/option.rom", true),
@@ -170,7 +183,7 @@ fn check_dir(dirname: str) (void | errors::invalid) = {
 	case let e: fs::error =>
 		fmt::fatalf("os::readdir({}): {}", dirname, fs::strerror(e));
 	};
-	assert(len(files_before) == 22);
+	assert(len(files_before) == 24);
 
 	const ret = check_dir(dirname);
 	assert(ret is void);
@@ -181,7 +194,7 @@ fn check_dir(dirname: str) (void | errors::invalid) = {
 	case let e: fs::error =>
 		fmt::fatalf("os::readdir({}): {}", dirname, fs::strerror(e));
 	};
-	assert(len(files_after) == 13);
+	assert(len(files_after) == 14);
 };
 
 export fn main() void = {
diff --git a/test/fixtures/monodx.dll b/test/fixtures/monodx.dll
Binary files differ.
diff --git a/test/fixtures/monodx.dll.license b/test/fixtures/monodx.dll.license
@@ -0,0 +1,2 @@
+SPDX-FileCopyrightText: 2013 Alistair Leslie-Hughes
+SPDX-License-Identifier: MIT