pyr0ball
27174a1c79
Diagnosed and fixed the crash that killed HAVOC_NOCD.EXE ~1s after launch
(dgVoodoo window appears black, then the process exits). It was not a clean
exit: an ACCESS_VIOLATION (null-pointer read at VA 0x444E6A) during init.
Root cause is a copy-protection check in the WORLDS\ data-file loader
(0x42a480). It opens each file (GRAFIX/LAND/MAP/STUF) from both a local
"WORLDS\<name>" path and a CD-drive path (HAVOC.INI [SETUP] DRIVE=D:\), and
returns a valid stream only when the local open fails and the CD-drive open
succeeds. With files present locally and no D: drive it returned NULL, and the
GRAFIX loader (0x444db0) dereferenced that NULL without checking.
Fix: 14-byte patch at FO 0x29a2b rewrites the return decision to hand back the
successfully-opened local object. The game now boots to the title screen
("HAVOC(tm) by Reality Bytes"), responsive, main loop running.
- docs/PATCHES.md: full patch table (28 patches) + crash write-up
- tools/: RE + patching scripts (r2pipe disasm, minidump parser, ctypes
debugger, PE/IAT/import analysis)
- run_probe.bat / run_and_log.bat: reliable native launch for repro
- .gitignore: exclude CD images, Ghidra install/project, dgVoodoo, *.ini
Diagnosed via WER minidumps (%LOCALAPPDATA%\CrashDumps) parsed in pure Python
(no cdb/windbg available).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TN4Ytn3gdWRonNmHpisWQv
50 lines
2.2 KiB
Python
50 lines
2.2 KiB
Python
import struct, sys, io
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sys.stdout = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-8', errors='replace')
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data = open('HAVOC_NOCD.EXE','rb').read()
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FO2VA = lambda fo: fo + 0x400C00
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def show(start, length):
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for row in range(start, start + length, 16):
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chunk = data[row:row+16]
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ann = []
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for j in range(len(chunk)):
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f = row + j
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try:
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if data[f] == 0xe8 and f+5 <= len(data):
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rel = struct.unpack_from('<i', data, f+1)[0]
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tgt = (FO2VA(f+5) + rel) & 0xFFFFFFFF
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ann.append('+%d:CALL_0x%x' % (j, tgt))
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if data[f] == 0xff and data[f+1] == 0x15 and f+6 <= len(data):
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iat = struct.unpack_from('<I', data, f+2)[0]
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d = {
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0x4822f4:'DirectDrawCreate', 0x4822fc:'DirectSoundCreate',
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0x48240c:'ExitProcess', 0x48248c:'MessageBoxA',
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0x4823cc:'LocalAlloc', 0x482370:'VirtualAlloc',
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0x482390:'CreateFileA',
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}
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ann.append('+%d:[%s]' % (j, d.get(iat, 'iat_0x%x' % iat)))
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if data[f] == 0xc3: ann.append('+%d:RET' % j)
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if data[f] == 0xc2 and f+3 <= len(data):
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n = struct.unpack_from('<H', data, f+1)[0]
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ann.append('+%d:RET%d' % (j, n))
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if data[f] == 0xc7 and data[f+1] in (0x01,0x06,0x07) and f+6 <= len(data):
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val = struct.unpack_from('<I', data, f+2)[0]
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if 0x479000 <= val <= 0x47BFFF:
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ann.append('+%d:VTABLE=0x%x' % (j, val))
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except Exception:
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pass
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line = 'FO 0x%05x VA 0x%07x: %s' % (row, FO2VA(row), ' '.join('%02x' % b for b in chunk))
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if ann:
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line += ' [%s]' % ','.join(ann)
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print(line)
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print("=== context around caller FO 0x17A8A (pool allocator caller) ===")
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show(0x17A60, 192)
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print()
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print("=== what's at FO 0x17A60 parent function start ===")
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# find function start
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fo = 0x17A60
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while fo > 0 and data[fo-1] != 0xCC:
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fo -= 1
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print("Function start: FO 0x%05x VA 0x%07x" % (fo, FO2VA(fo)))
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show(fo, min(32, 0x17A60 - fo + 32))
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