62 lines
2.7 KiB
Plaintext
62 lines
2.7 KiB
Plaintext
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macro calldatachar($x):
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div(calldataload($x), 2**248)
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# sum([2**x for x in [0x31, 0x32, 0x33, 0x3a, 0x3b, 0x3c, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x54, 0x55, 0xf0, 0xff])
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mask = 57897811465722876096115075801844696845150819816717215668290421542284681019392
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data approved_addrs[]
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def submit(addr: address):
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# Copy external contract code
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extcode = string(~extcodesize(addr))
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~extcodecopy(addr, extcode, 0, ~extcodesize(addr))
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ops = array(~extcodesize(addr))
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pushargs = array(~extcodesize(addr))
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# Loop through the code
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with i = 0:
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with op = 0:
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while i < len(extcode):
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with c = ~mod(~mload(extcode + i - 31), 256):
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# Banned opcode
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if ~and(2**c, mask):
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~invalid()
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# PUSH
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if 0x60 <= c and c <= 0x7f:
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pushargs[op] = ~div(~mload(extcode + i + 1), 256 ** (0x7f - c))
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i += c - 0x5e
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# Call, callcode, delegatecall
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elif c == 0xf1 or c == 0xf2 or c == 0xf4:
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# Pattern-match two ways of setting the gas parameter:
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#
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# 1. PUSH<value>
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# 2. sub(gas, PUSH<value>)
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if op >= 2 and ops[op - 1] >= 0x60 and ops[op - 1] <= 0x7f:
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address_entry = op - 2
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elif op >= 4 and ops[op - 1] == 0x03 and ops[op - 2] == 0x5a and ops[op - 3] >= 0x60 and ops[op - 3] <= 0x7f:
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address_entry = op - 4
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else:
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~invalid()
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# Operation before the gas parameter must satisfy one of three conditions:
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#
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# 1. It is a PUSH of an already approved address
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# 2. It is the address itself, through the ADDRESS opcode (ie. self-calling is permitted)
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# 3. It is a PUSH1, ie. less than 256 (ie. a present or future precompile)
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if self.approved_addrs[pushargs[address_entry]]:
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success = 1
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elif ops[address_entry] == 0x30:
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success = 1
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elif ops[address_entry] == 0x60:
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success = 1
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if not success:
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~invalid()
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i += 1
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else:
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i += 1
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ops[op] = c
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op += 1
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self.approved_addrs[addr] = 1
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return(1: bool)
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def check(addr: address):
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return(self.approved_addrs[addr]:bool)
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