SashegDev
39 lines
1.4 KiB
Python
39 lines
1.4 KiB
Python
#!/usr/bin/env python3
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"""sbl_refs.py — поиск кодовых ссылок на строку в SBL1 (img0.elf, seg 0x8005800).
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Использование: ./tools/sbl_refs.py fw/sbl/img0.elf 'SBL1, Start'
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"""
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import struct
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import sys
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path, needle = sys.argv[1], sys.argv[2].encode()
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d = open(path, "rb").read()
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i = d.find(needle)
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print("str fileoff:", hex(i))
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SEG_OFF, SEG_VA, SEG_SZ = 0x3000, 0x8005800, 0x33A54
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va = SEG_VA + (i - SEG_OFF)
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print("str VA:", hex(va))
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# search ALL segments for pc-relative loads to it
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import re
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def segs(d):
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phoff = struct.unpack("<I", d[28:32])[0]
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phnum = struct.unpack("<H", d[44:46])[0]
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out = []
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for k in range(phnum):
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p = d[phoff + k * 32:phoff + (k + 1) * 32]
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t, off, v, pa, fsz, msz, fl, al = struct.unpack("<IIIIIIII", p)
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if t == 1 and fsz:
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out.append((off, v, fsz))
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return out
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for soff, v, sz in segs(d):
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code = d[soff:soff + sz]
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for j in range(0, len(code) - 4, 4):
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x = struct.unpack("<I", code[j:j + 4])[0]
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# LDR Rd,[pc,#imm] (0x059Fxxxx) or LDR Rd,[pc,#-imm] (0x051Fxxxx)
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if (x & 0x0FF00000) in (0x05900000, 0x05100000) and (x & 0xF0000) == 0xF0000:
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o = x & 0xFFF
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tgt = v + j + 8 + (-o if x & 0x800000 == 0 else o)
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if abs(tgt - va) < 0x200:
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print(hex(v + j), "LDR r%d" % ((x >> 12) & 15), "->", hex(tgt))
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