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
51 lines
2.4 KiB
Python
51 lines
2.4 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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VA2FO = lambda va: va - 0x400C00
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IAT = {
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0x482370:'VirtualAlloc', 0x4823cc:'LocalAlloc', 0x48240c:'ExitProcess',
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0x482390:'CreateFileA', 0x4822f4:'DirectDrawCreate', 0x4822fc:'DirectSoundCreate',
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0x48248c:'MessageBoxA', 0x48243c:'GetVersion', 0x48242c:'GetStartupInfoA',
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}
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def show(start, length, label=''):
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if label: print("=== %s ===" % label)
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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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ann.append('+%d:[%s]' % (j, IAT.get(iat, 'iat_0x%x' % iat)))
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if data[f] == 0xa3 and f+5 <= len(data):
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va = struct.unpack_from('<I', data, f+1)[0]
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if 0x47C000 <= va <= 0x482000:
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ann.append('+%d:MOV[0x%x],EAX' % (j, va))
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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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ann.append('+%d:RET%d' % (j, struct.unpack_from('<H', data, f+1)[0]))
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if data[f] == 0xe9 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:JMP_0x%x' % (j, tgt))
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except Exception: 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: line += ' [%s]' % ','.join(ann)
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print(line)
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# 0x464F52 = the "both free lists at sentinel" path in 0x464E77
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show(VA2FO(0x464F52), 64, "0x464F52 (empty-lists fallback in 0x464E77)")
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print()
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# 0x464F67 = second alloc helper called from 0x4633D1 when 0x464E77 returns NULL
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show(VA2FO(0x464F67), 96, "0x464F67 (second alloc helper)")
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print()
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# 0x4633D1 full - 0x60 bytes to see what it does after 0x464E77 returns
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show(VA2FO(0x4633D1), 96, "0x4633D1 (real allocator, full body)")
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