From ce673398c9fcb3371ea67e55544727ab0ca7f334 Mon Sep 17 00:00:00 2001
From: Markus Birth <mbirth@gmail.com>
Date: Fri, 8 May 2020 17:21:28 +0200
Subject: [PATCH] Spiced up kunix's tool a bit.

---
 binbase_kunix.py | 49 +++++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 21 deletions(-)

diff --git a/binbase_kunix.py b/binbase_kunix.py
index f7228a4..2f06452 100644
--- a/binbase_kunix.py
+++ b/binbase_kunix.py
@@ -12,17 +12,18 @@ import os.path
 import sys
 
 FILE = sys.argv[1]
+OFFSET = 0
+if len(sys.argv) > 2:
+  OFFSET = int(sys.argv[2])
 BLOCKSIZE = 4096
 
 END_MARKER = b"\xff\xff\x5a\xa5"
 
 first_block = True
-past_end = False
-trailer = bytes()
-trailer_pos = -1
-
+end_marker_pos = 0xffffffff
 print("Reading {} ...".format(FILE))
 with open(FILE, "rb") as f:
+    f.read(OFFSET)
     while True:
         block = f.read(BLOCKSIZE)
         if first_block:
@@ -30,37 +31,43 @@ with open(FILE, "rb") as f:
             first_block = False
         if END_MARKER in block:
             end_pos = block.find(END_MARKER)
-            marker_end = f.tell() - len(block) + end_pos + 2
-            break
+            found_pos = f.tell() - len(block) + end_pos + 2
+            if found_pos > end_marker_pos:
+                print("Found a second endmarker! Using that one.")
+            end_marker_pos = found_pos
+            #break
         if len(block) < BLOCKSIZE:
             break
     f.close()
 
 size = os.path.getsize(FILE)
 
-print("File is {} Bytes.".format(size))
+print("File is {} (0x{:x}) Bytes.".format(size, size))
 print("First double-words: 0x{:x} / 0x{:x} / 0x{:x} / 0x{:x} / 0x{:x}".format(dw[0], dw[1], dw[2], dw[3], dw[4]))
-print("Found end marker at: 0x{:x}".format(marker_end))
+print("Assuming this is end marker location in memory: 0x{:x}".format(dw[1]))
+print("Found end marker in file at: 0x{:x}".format(end_marker_pos))
 
-base_addr = dw[1] - marker_end
+base_addr = dw[1] - (end_marker_pos - OFFSET)
+if base_addr < 0:
+    base_addr += 0xffffffff
+
+print("This would make Base address probably 0x{:x}".format(base_addr))
 
 if base_addr % 4 != 0:
-    print("Bad alignment. Calculated base address not aligned to doublewords.")
-    #sys.exit(1)
+    print("However, bad alignment. Calculated base address not aligned to doublewords.")
 
 if base_addr + size > 0xffffffff:
-    print("Overflow")
-    sys.exit(1)
+    print("However, base address can't fit whole file.")
 
-if dw[2] % 2 != 0 or dw[2] - base_addr >= marker_end - 3:
-    print("Align & Bounds dw2 wrong.")
-    #sys.exit(1)
+# Assumes second dword points to hwid
+#if dw[2] % 2 != 0 or dw[2] - base_addr >= end_marker_pos - 3:
+#    print("Align & Bounds dw2 wrong.")
+#    sys.exit(1)
 
-if dw[3] % 2 != 0 or dw[3] - base_addr >= marker_end - 3:
-    print("Align & Bounds dw3 wrong.")
-    #sys.exit(1)
-
-print("Base address is probably 0x{:x}".format(base_addr))
+# Assumes third dword points to fwid
+#if dw[3] % 2 != 0 or dw[3] - base_addr >= end_marker_pos - 3:
+#    print("Align & Bounds dw3 wrong.")
+#    sys.exit(1)
 
 # hwid = dw[2] - base_addr
 # fwid = dw[3] - base_addr