SashegDev
37 lines
1.3 KiB
Python
37 lines
1.3 KiB
Python
#!/usr/bin/env python3
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"""sbl_mains.py — кандидаты в sbl_main: плотность BL + близость строк boot-лога.
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Использование: ./tools/sbl_mains.py fw/sbl/img0.elf
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"""
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import struct
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import sys
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d = open(sys.argv[1], "rb").read()
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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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segs = []
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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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segs.append((off, v, fsz))
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# prologues: STMDB sp!,{...,lr} (bit11 set)
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cands = []
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for off, v, sz in segs:
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code = d[off:off + 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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if (x & 0xFFFF0000) == 0xE92D0000: # push ... r11?/lr frame
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# count BLs in next 2KB
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bls = 0
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for q in range(j, min(j + 2048, len(code) - 4), 4):
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y = struct.unpack("<I", code[q:q + 4])[0]
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if (y >> 25) == 0b101 and (y & 0x01000000):
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bls += 1
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if bls >= 8:
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cands.append((bls, v + j))
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cands.sort(reverse=True)
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print("top candidates (bl-count, addr):")
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for bls, a in cands[:15]:
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print(f" {bls:3d} {a:#x}")
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