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patch: bounds #218

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Merged
SweetVishnya merged 4 commits into from
Oct 14, 2025
Merged

patch: bounds #218

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f8351fa
patch: bounds
0xf00sec Oct 9, 2025
d9aa336
Add removed comments
0xf00sec Oct 11, 2025
67cc563
redundant change
0xf00sec Oct 12, 2025
0a0f954
clean redundant
0xf00sec Oct 14, 2025
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63 changes: 35 additions & 28 deletions ropgadget/gadgets.py
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Original file line number Diff line number Diff line change
Expand Up @@ -43,48 +43,55 @@ def __passCleanX86(self, decodes):
return False

def __gadgetsFinding(self, section, gadgets, arch, mode):

PREV_BYTES = 9 # Number of bytes prior to the gadget to store.

opcodes = section["opcodes"]
sec_vaddr = section["vaddr"]

ret = []
md = Cs(arch, mode)
op_len = len(opcodes)

for gad_op, gad_size, gad_align in gadgets:
if self.__options.align:
gad_align = self.__options.align
allRefRet = [m.start() for m in re.finditer(gad_op, opcodes)]
for ref in allRefRet:
end = ref + gad_size
if ref < 0 or end > op_len:
continue
for i in range(self.__options.depth):
start = ref - (i * gad_align)
if (sec_vaddr + start) % gad_align == 0:
code = opcodes[start:end]
decodes = md.disasm_lite(code, sec_vaddr + start)
decodes = list(decodes)
if sum(size for _, size, _, _ in decodes) != i * gad_align + gad_size:
# We've read less instructions than planned so something went wrong
continue
if arch == CS_ARCH_RISCV and decodes[-1][1] != gad_size:
# Last disassembled instruction has wrong size! This happens
# e.g. if gad_align == 2 and the last two bytes of a 4-byte
# instruction are also a valid 2-byte instruction.
continue
if self.passClean(decodes):
continue
off = self.__offset
vaddr = off + sec_vaddr + start
g = {"vaddr": vaddr}
if not self.__options.noinstr:
g["gadget"] = " ; ".join("{}{}{}".format(mnemonic, " " if op_str else "", op_str)
for _, _, mnemonic, op_str in decodes).replace(" ", " ")
if self.__options.callPreceded:
prevBytesAddr = max(sec_vaddr, vaddr - PREV_BYTES)
g["prev"] = opcodes[prevBytesAddr - sec_vaddr:vaddr - sec_vaddr]
if self.__options.dump:
g["bytes"] = code
ret.append(g)
if start < 0 or (sec_vaddr + start) % gad_align != 0 or start >= op_len or end > op_len:
continue
code = opcodes[start:end]
try:
decodes = list(md.disasm_lite(code, sec_vaddr + start))
except Exception:
continue
if not decodes:
continue
total_size = sum(size for _, size, _, _ in decodes)
expected_size = i * gad_align + gad_size
if total_size != expected_size:
continue
if arch == CS_ARCH_RISCV and decodes[-1][1] != gad_size:
continue
if self.passClean(decodes):
continue
vaddr = self.__offset + sec_vaddr + start
g = {"vaddr": vaddr}
if not self.__options.noinstr:
g["gadget"] = " ; ".join("{}{}{}".format(mnemonic, " " if op_str else "", op_str)
for _, _, mnemonic, op_str in decodes).replace(" ", " ")
if self.__options.callPreceded:
prevBytesAddr = max(sec_vaddr, vaddr - PREV_BYTES)
pstart = max(prevBytesAddr - sec_vaddr, 0)
pend = min(vaddr - sec_vaddr, op_len)
g["prev"] = opcodes[pstart:pend]
if self.__options.dump:
g["bytes"] = code
ret.append(g)
return ret

def addROPGadgets(self, section):
Expand Down