160 lines
3.6 KiB
Python
Executable File
160 lines
3.6 KiB
Python
Executable File
#!/usr/bin/env python3
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# synacor.py - An implementation of the Synacor Challenge
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# Copyright © 2017 RunasSudo
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import struct # for bytes<-->word handling
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import sys # for args
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# Read code into memory
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SYN_MEM = [0] * 32768
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with open(sys.argv[1], 'rb') as data:
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i = 0
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while True:
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byteData = data.read(2)
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if len(byteData) < 2:
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break
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SYN_MEM[i] = struct.unpack('<H', byteData)[0]
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i += 1
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# Emulate 06bb
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for R1 in range(0x17b4, 0x7562):
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R0 = SYN_MEM[R1]
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R0 ^= pow(R1, 2, 32768)
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R0 ^= 0x4154
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SYN_MEM[R1] = R0
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class OpLiteral:
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def __init__(self, value):
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self.value = value;
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def get(self):
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return '{:04x}'.format(self.value);
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def set(self):
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return '{:04x}'.format(self.value);
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class OpRegister:
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def __init__(self, register):
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self.register = register;
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def get(self):
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return 'R{}'.format(self.register + 1);
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def set(self):
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return 'R{}'.format(self.register + 1);
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def readWord():
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global SYN_PTR
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word = SYN_MEM[SYN_PTR]
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SYN_PTR += 1
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return word
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def readOp():
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word = readWord()
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if 0 <= word <= 32767:
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return OpLiteral(word)
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if 32768 <= word <= 32775:
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return OpRegister(word - 32768)
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raise Exception('Invalid word {} at {}'.format(word, SYN_PTR))
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def escapeChar(char):
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return char.replace('\\', '\\\\').replace('\n', '\\n').replace('"', '\\"')
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SYN_PTR = 0
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while SYN_PTR < len(SYN_MEM):
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word = readWord()
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if word == 21: #NOP
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pass
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elif word == 0: #HALT
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pass
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elif word == 1: #SET
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readOp()
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readOp()
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elif word == 2: #PUSH
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readOp()
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elif word == 3: #POP
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readOp()
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elif word == 4: #EQ
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readOp()
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readOp()
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readOp()
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elif word == 5: #GT
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readOp()
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readOp()
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readOp()
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elif word == 6: #JMP
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readOp()
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elif word == 7: #JT (jump if not zero)
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readOp()
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readOp()
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elif word == 8: #JF (jump if zero)
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readOp()
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readOp()
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elif word == 9: #ADD
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readOp()
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readOp()
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readOp()
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elif word == 10: #MULT
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readOp()
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readOp()
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readOp()
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elif word == 11: #MOD
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readOp()
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readOp()
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readOp()
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elif word == 12: #AND
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readOp()
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readOp()
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readOp()
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elif word == 13: #OR
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readOp()
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readOp()
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readOp()
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elif word == 14: #NOT
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readOp()
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readOp()
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elif word == 15: #RMEM
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readOp()
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readOp()
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elif word == 16: #WMEM
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readOp()
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readOp()
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elif word == 17: #CALL
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if readWord() == 0x05b2:
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if (SYN_MEM[SYN_PTR-9:SYN_PTR-6] == [1, 32769, 0x05fb] # set R1 05fb
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and SYN_MEM[SYN_PTR-12:SYN_PTR-10] == [1, 32768] # set R0 XXXX
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and SYN_MEM[SYN_PTR-6:SYN_PTR-4] == [9, 32770]): # add R2 XXXX XXXX
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# Got an encrypted string!
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R0 = SYN_MEM[SYN_PTR-10]
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R2 = (SYN_MEM[SYN_PTR-4] + SYN_MEM[SYN_PTR-3]) % 32768
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#print('{:04x} {:04x}'.format(R0, R2))
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strlen = SYN_MEM[R0]
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strbuf = ''
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for i in range(strlen):
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encrypted = SYN_MEM[R0 + 1 + i]
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decrypted = encrypted ^ R2
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strbuf += escapeChar(chr(decrypted))
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print('{:04x}: "{}"'.format(R0, strbuf))
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elif word == 18: #RET
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pass
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elif word == 19: #OUT
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readOp()
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elif word == 20: #IN
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readOp()
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else: #data
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pass
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