Started parsing for hwid / version.

grmn/rgnbin.py

@@ -18,7 +18,9 @@ class ParseException(Exception):
 class RgnBin:
     def __init__(self, filename: str=None):
         self.filename = filename
-        self.struct = []
+        self.hwid = None
+        self.version = None
+        self.payload = None
         if filename is not None:
             self.load()
 
@@ -30,14 +32,95 @@ class RgnBin:
             f.close()
         self.load_from_bytes(rawdata)
 
+    def find_metadata(self):
+        try:
+            end_loc = self.payload.rindex(END_PATTERN)
+            #print("end_loc: {}".format(end_loc))
+        except ValueError:
+            # No END_PATTERN found
+            end_loc = None
+        jmp = unpack("<L", self.payload[0:4])[0]
+        print("JMP: 0x{:08x}".format(jmp))
+        hwid_addr = None
+        swver_addr = None
+        if jmp == 0xe59ff008:
+            # Variant 1a or 1b (end > hwid > swver > entry OR hwid > swver > end > entry)
+            (x1, x2, x3, entry_addr) = unpack("<LLLL", self.payload[4:20])
+            print("{:04x} / {:04x} / {:04x} / {:04x}".format(x1, x2, x3, entry_addr))
+            # HWID and SWVER are near each other
+            if abs(x2 - x1) == 2:
+                # Assume 1b: x1 = hw_id, x2 = swver
+                delta = 20 - entry_addr
+                hwid_addr = x1 + delta
+                swver_addr = x2 + delta
+            else:
+                # Assume 1a: x2 = hw_id, x3 = swver
+                delta = 20 - entry_addr
+                hwid_addr = x2 + delta
+                swver_addr = x3 + delta
+        if jmp == 0xe59ff00c:
+            print(RED + "Checking for 2" + RESET)
+            # Variant 2 (end > hwid > swver > lend > entry)
+            (end_addr, hwid_addr, swver_addr, lend_addr, entry_addr) = unpack("<LLLlL", self.payload[4:24])
+            print("hwid_addr: {} / swver_addr: {}".format(hwid_addr, swver_addr))
+            print("end_addr: {} / lend_addr: {} / entry_addr: {}".format(end_addr, lend_addr, entry_addr))
+            if lend_addr < 0:
+                load_addr = -lend_addr
+                print("load_addr: {}".format(load_addr))
+                delta = 24 - load_addr
+            else:
+                delta = 24 - entry_addr
+            print("delta: {}".format(delta))
+            hwid_addr += delta
+            swver_addr += delta
+            print("hwaddr: {} / swveraddr: {}".format(hwid_addr, swver_addr))
+            # expected hw_addr: 0x4b5e = 19294 / swver: 0x4b60 = 19296
+        if end_loc and jmp == 0xea000002:
+            # Variant 3 (end > hwid > swver)
+            (end_addr, hwid_addr, swver_addr) = unpack("<LLL", self.payload[4:16])
+            delta = end_loc + 2 - end_addr
+            hwid_addr += delta
+            swver_addr += delta
+        if jmp == 0xea000003:
+            print(RED + "Checking for 4" + RESET)
+            # Variant 4 (end > hwid > swver > ???)
+
+        if jmp == 0xea000004:
+            print(RED + "checking for 5" + RESET)
+            # Variant 5
+
+        if hwid_addr:
+            if hwid_addr < 0 or hwid_addr > len(self.payload)-2:
+                print(RED + "HWID OFFSET {:04x} OUT OF BOUNDS {:04x}".format(hwid_addr, len(self.payload)) + RESET)
+            else:
+                self.hwid = unpack("<H", self.payload[hwid_addr:hwid_addr+2])[0]
+        if swver_addr:
+            if swver_addr < 0 or swver_addr > len(self.payload)-2:
+                print(RED + "SWVER OFFSET {:04x} OUT OF BOUNDS {:04x}".format(swver_addr, len(self.payload)) + RESET)
+            else:
+                self.version = unpack("<H", self.payload[swver_addr:swver_addr+2])[0]
+
+        # Try EOF-4
+        if not self.hwid and not self.version:
+            print("Checking for EOF-4")
+            (hwid, version) = unpack("<HH", self.payload[-6:-2])
+            if hwid < 0xffff and version < 0xffff:
+                print("EOF-4 matches")
+                self.hwid = hwid
+                self.version = version
+
+        return None
+
     def load_from_bytes(self, payload: bytes):
         self.payload = payload
-        print(repr(payload[0:10]))
-        jmp = unpack("<L", payload[0:4])[0]
-        print("{:08x}".format(jmp))
+        self.find_metadata()
 
     def __str__(self):
         txt = "Binary payload, {} Bytes".format(len(self.payload))
+        if self.hwid:
+            txt += "\n  -    hw_id: 0x{:04x} / {:d} ({})".format(self.hwid, self.hwid, devices.DEVICES.get(self.hwid, RED + "Unknown device" + RESET))
+        if self.version:
+            txt += "\n  -  Version: 0x{:04x} / {:d}".format(self.version, self.version)
         cksum = ChkSum()
         cksum.add(self.payload)
         exp_byte = cksum.get_expected()