From 1a82b407a41f9d2e59e9cc408fe3be80e1f4b9fa Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Sun, 24 Mar 2019 08:26:14 -0700
Subject: [PATCH] sept-sign: remove += for compatibility

---
 sept/sept-secondary/sept_sign.py | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/sept/sept-secondary/sept_sign.py b/sept/sept-secondary/sept_sign.py
index a4dd83a87..ba108c1fc 100644
--- a/sept/sept-secondary/sept_sign.py
+++ b/sept/sept-secondary/sept_sign.py
@@ -32,8 +32,8 @@ def get_last_block_for_desired_mac(key, data, desired_mac):
     k1 = shift_left_xor_rb(AES.new(key, AES.MODE_ECB).encrypt(bytearray(0x10)))
     if len(data) & 0xF:
         k1 = shift_left_xor_rb(k1)
-        data += b'\x80'
-        data += bytearray((0x10 - (len(data) & 0xF)) & 0xF)
+        data = data + b'\x80'
+        data = data + bytearray((0x10 - (len(data) & 0xF)) & 0xF)
     num_blocks = (len(data) + 0xF) >> 4
     last_block = sxor(bytearray(AES.new(key, AES.MODE_ECB).decrypt(desired_mac)), bytearray(k1))
     if len(data) > 0x0:
@@ -43,20 +43,20 @@ def get_last_block_for_desired_mac(key, data, desired_mac):
 
 def sign_encrypt_code(code, sig_key, enc_key, iv, desired_mac):
     # Pad with 0x20 of zeroes.
-    code += bytearray(0x20)
+    code = code + bytearray(0x20)
     code_len = len(code)
     code_len += 0xFFF
     code_len &= ~0xFFF
-    code += bytearray(code_len - len(code))
+    code = code + bytearray(code_len - len(code))
 
     # Add empty trustzone, warmboot segments.
-    code += bytearray(0x1FE0 - 0x10)
+    code = code + bytearray(0x1FE0 - 0x10)
     pk11_hdr = b'PK11' + pk('<IIIIIII', 0x1000, 0, 0, code_len - 0x20, 0, 0x1000, 0)
     pk11 = pk11_hdr + code
     enc_pk11 = AES.new(enc_key, AES.MODE_CBC, iv).encrypt(pk11)
     enc_pk11 = pk('<IIII', len(pk11) + 0x10, 0, 0, 0) + iv + enc_pk11
-    enc_pk11 += get_last_block_for_desired_mac(sig_key, enc_pk11, desired_mac)
-    enc_pk11 += CMAC.new(sig_key, enc_pk11, AES).digest()
+    enc_pk11 = enc_pk11 + get_last_block_for_desired_mac(sig_key, enc_pk11, desired_mac)
+    enc_pk11 = enc_pk11 + CMAC.new(sig_key, enc_pk11, AES).digest()
     return enc_pk11
 
 
@@ -67,7 +67,7 @@ def main(argc, argv):
     with open(argv[1], 'rb') as f:
         code = f.read()
     if len(code) & 0xF:
-        code += bytearray(0x10 - (len(code) & 0xF))
+        code = code + bytearray(0x10 - (len(code) & 0xF))
     # TODO: Support dev unit crypto
     with open(argv[2], 'wb') as f:
         f.write(sign_encrypt_code(code, KEYS.HOVI_SIG_KEY_PRD, KEYS.HOVI_ENC_KEY_PRD, KEYS.IV, b'THANKS_NVIDIA_<3'))