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fstat13
2a58cbcb43
- docs/REVERSE_ENGINEERING.md: library extraction, scan-out ring, pan, chroma plane (V-first words), kernel-side notes, PLD delivery, timeline - tools/: dumplib payload + sprx/xref hunters + frame renderers (own code only)
94 lines
3.2 KiB
Python
94 lines
3.2 KiB
Python
#!/usr/bin/env python3
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# -*- coding: latin-1 -*-
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# Scanner grezzo di riferimenti in un ELF64 LE x86-64: trova chi materializza un
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# indirizzo (stringa/rodata/vtable) via:
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# - lea reg,[rip+disp32] (48/4C 8d, o 8d senza REX)
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# - mov reg,[rip+disp32] (48 8b / 48 8d)
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# - valore assoluto u64 nei dati (tabelle/vtable)
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#
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# python -I scan_refs.py <elf> <hexaddr> [<hexaddr> ...]
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#
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import struct
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import sys
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def load(path):
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data = open(path, 'rb').read()
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e_phoff = struct.unpack_from('<Q', data, 0x20)[0]
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e_phentsize = struct.unpack_from('<H', data, 0x36)[0]
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e_phnum = struct.unpack_from('<H', data, 0x38)[0]
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segs = []
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for i in range(e_phnum):
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off = e_phoff + i * e_phentsize
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p_type, p_flags = struct.unpack_from('<II', data, off)
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if p_type != 1:
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continue
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p_offset, p_vaddr, p_paddr, p_filesz, p_memsz, p_align = \
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struct.unpack_from('<QQQQQQ', data, off + 8)
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segs.append([p_vaddr, p_offset, p_filesz, p_flags])
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return data, segs
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def scan(elf, targets):
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data, segs = load(elf)
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tset = set(targets)
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# pass 1: valori assoluti u64 nei dati (vtable/tabelle con reloc pre-applicate)
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abs_hits = set()
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for vaddr, off, sz, fl in segs:
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if fl & 1: # solo segmenti dati
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continue
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end = min(off + sz, len(data))
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for i in range(off, end - 8, 8):
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v64 = struct.unpack_from('<Q', data, i)[0]
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if v64 in tset:
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print('ABS64 @ %x = %x' % (vaddr + (i - off), v64))
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abs_hits.add(vaddr + (i - off))
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# pass 2: istruzioni x86-64 con displacement RIP-relativo
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hits = set()
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for vaddr, off, sz, fl in segs:
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if not (fl & 1):
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continue
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end = min(off + sz, len(data))
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buf = data[off:end]
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base = vaddr
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n = len(buf)
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for i in range(n - 8):
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# candidati: [REX] [8d|8b] modrm(rip)
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j = i
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rex = 0
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if buf[j] in (0x48, 0x4c, 0x49, 0x4d, 0x44, 0x41, 0x40, 0x42, 0x43, 0x45, 0x46, 0x47):
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rex = buf[j]
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j += 1
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if j >= n:
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break
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op = buf[j]
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if op not in (0x8d, 0x8b, 0x89):
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continue
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if j + 6 > n:
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continue
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modrm = buf[j + 1]
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if (modrm & 0xC7) != 0x05: # mod=00, rm=101 -> RIP+disp32
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continue
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# con 0x41/0x44 ecc. (REX.R/X/B) e' comunque RIP-rel se mod=00 rm=101
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disp = struct.unpack_from('<i', buf, j + 2)[0]
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ilen = (j - i) + 1 + 1 + 4
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tgt = base + i + ilen + disp
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if tgt in tset:
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reg = (modrm >> 3) & 7
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if rex & 4:
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reg += 8
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kind = {0x8d: 'lea', 0x8b: 'mov-r', 0x89: 'mov-w'}.get(op, hex(op))
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print('CODE %s @ %x (r%d) -> %x' % (kind, base + i, reg, tgt))
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hits.add(base + i)
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print('abs hits: %d code hits: %d' % (len(abs_hits), len(hits)))
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return hits
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if __name__ == '__main__':
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elf = sys.argv[1]
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tgts = [int(x, 16) for x in sys.argv[2:]]
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print('targets: %s' % [hex(t) for t in tgts])
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scan(elf, tgts)
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