From 1aa628768d05e158a251daeaf2742982e770d26d Mon Sep 17 00:00:00 2001
From: Dual Tachyon <N/A>
Date: Tue, 5 Sep 2023 22:16:42 +0100
Subject: [PATCH] Support for packed firmware.

---
 .github/workflows/main.yaml    |  5 ++++-
 .github/workflows/release.yaml |  7 ++++--
 Makefile                       |  1 +
 fw-pack.py                     | 40 ++++++++++++++++++++++++++++++++++
 4 files changed, 50 insertions(+), 3 deletions(-)
 create mode 100755 fw-pack.py

diff --git a/.github/workflows/main.yaml b/.github/workflows/main.yaml
index 2aeba2b..4a24b3c 100644
--- a/.github/workflows/main.yaml
+++ b/.github/workflows/main.yaml
@@ -11,6 +11,9 @@ jobs:
       with:
         release: '10.3-2021.10'
 
+    - name: Install Python dependencies
+      run: python -m pip install --upgrade pip crcmod
+
     - name: Checkout
       uses: actions/checkout@v3
 
@@ -27,5 +30,5 @@ jobs:
       uses: actions/upload-artifact@v3
       with:
         name: firmware
-        path: firmware.bin
+        path: firmware*.bin
 
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index edcf1dd..86b9241 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -13,6 +13,9 @@ jobs:
       with:
         release: '10.3-2021.10'
 
+    - name: Install Python dependencies
+      run: python3 -m pip install --upgrade pip crcmod
+
     - name: Checkout
       uses: actions/checkout@v3
 
@@ -29,10 +32,10 @@ jobs:
       uses: actions/upload-artifact@v3
       with:
         name: firmware
-        path: firmware.bin
+        path: firmware*.bin
 
     - name: 'Create Release'
       uses: ncipollo/release-action@v1
       with:
-        artifacts: "firmware.bin"
+        artifacts: "firmware*.bin"
 
diff --git a/Makefile b/Makefile
index f00c9fb..5ef092e 100755
--- a/Makefile
+++ b/Makefile
@@ -107,6 +107,7 @@ DEPS = $(OBJS:.o=.d)
 
 all: $(TARGET)
 	$(OBJCOPY) -O binary $< $<.bin
+	./fw-pack.py $<.bin $(GIT_HASH) $<.packed.bin
 	$(SIZE) $<
 
 debug:
diff --git a/fw-pack.py b/fw-pack.py
new file mode 100755
index 0000000..a3e6127
--- /dev/null
+++ b/fw-pack.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+
+import crcmod
+import sys
+
+from itertools import cycle
+from binascii import hexlify
+
+OBFUSCATION = [
+        0x47, 0x22, 0xC0, 0x52, 0x5D, 0x57, 0x48, 0x94, 0xB1, 0x60, 0x60, 0xDB, 0x6F, 0xE3, 0x4C, 0x7C,
+        0xD8, 0x4A, 0xD6, 0x8B, 0x30, 0xEC, 0x25, 0xE0, 0x4C, 0xD9, 0x00, 0x7F, 0xBF, 0xE3, 0x54, 0x05,
+        0xE9, 0x3A, 0x97, 0x6B, 0xB0, 0x6E, 0x0C, 0xFB, 0xB1, 0x1A, 0xE2, 0xC9, 0xC1, 0x56, 0x47, 0xE9,
+        0xBA, 0xF1, 0x42, 0xB6, 0x67, 0x5F, 0x0F, 0x96, 0xF7, 0xC9, 0x3C, 0x84, 0x1B, 0x26, 0xE1, 0x4E,
+        0x3B, 0x6F, 0x66, 0xE6, 0xA0, 0x6A, 0xB0, 0xBF, 0xC6, 0xA5, 0x70, 0x3A, 0xBA, 0x18, 0x9E, 0x27,
+        0x1A, 0x53, 0x5B, 0x71, 0xB1, 0x94, 0x1E, 0x18, 0xF2, 0xD6, 0x81, 0x02, 0x22, 0xFD, 0x5A, 0x28,
+        0x91, 0xDB, 0xBA, 0x5D, 0x64, 0xC6, 0xFE, 0x86, 0x83, 0x9C, 0x50, 0x1C, 0x73, 0x03, 0x11, 0xD6,
+        0xAF, 0x30, 0xF4, 0x2C, 0x77, 0xB2, 0x7D, 0xBB, 0x3F, 0x29, 0x28, 0x57, 0x22, 0xD6, 0x92, 0x8B,
+    ]
+
+def obfuscate(fw):
+    return bytes([a^b for a, b in zip(fw, cycle(OBFUSCATION))])
+
+plain = open(sys.argv[1], 'rb').read()
+if len(sys.argv[2]) > 10:
+    print('Version suffix is too big!')
+    sys.exit(1)
+
+version = b'*OEFW-' + bytes(sys.argv[2], 'ascii')
+if len(version) < 16:
+    version += b'\x00' * (16 - len(version))
+
+packed = obfuscate(plain[:0x2000] + version + plain[0x2000:])
+
+crc = crcmod.predefined.Crc('xmodem')
+crc.update(packed)
+digest = crc.digest()
+digest = bytes([digest[1], digest[0]])
+
+open(sys.argv[3], 'wb').write(packed + digest)
+