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1 import os |
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2 import time |
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3 import fcntl |
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4 import hmac |
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5 import binascii |
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6 import sys |
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7 |
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8 import config |
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9 |
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10 __all__ = ["get_csrf_blob", "check_csrf_blob", "setup_csrf"] |
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11 |
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12 def get_user_hash(): |
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13 return "aaa" |
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14 |
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15 def setup_csrf(): |
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16 NONCE_SIZE=16 |
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17 global _csrf_fd, _csrf_key |
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18 _csrf_fd = open('%s/csrf.dat' % config.DATA_PATH, 'r+') |
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19 |
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20 try: |
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21 fcntl.lockf(_csrf_fd, fcntl.LOCK_EX | fcntl.LOCK_NB) |
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22 os.fchmod(_csrf_fd.fileno(), 0600) |
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23 _csrf_fd.write("%d-%s" % (os.getpid(), binascii.hexlify(os.urandom(NONCE_SIZE)))) |
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24 _csrf_fd.flush() |
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25 _csrf_fd.seek(0) |
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26 except IOError: |
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27 pass |
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28 fcntl.lockf(_csrf_fd, fcntl.LOCK_SH) |
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29 _csrf_key = _csrf_fd.read() |
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30 # keep the lock open until we go away |
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31 |
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32 |
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33 def get_csrf_blob(): |
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34 expiry = int(config.CSRF_TIMEOUT + time.time()) |
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35 content = '%s-%s' % (get_user_hash(), expiry) |
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36 mac = hmac.new(_csrf_key, content).hexdigest() |
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37 return "%s-%s" % (content, mac) |
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38 |
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39 def check_csrf_blob(blob): |
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40 toks = blob.split('-') |
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41 if len(toks) != 3: |
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42 return False |
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43 |
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44 user, expiry, mac = toks |
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45 if user != get_user_hash(): |
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46 return False |
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47 |
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48 try: |
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49 exp = int(expiry) |
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50 except ValueError: |
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51 return False |
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52 |
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53 if exp < 1000000000: |
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54 return False |
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55 |
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56 if exp > time.time(): |
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57 return False |
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58 |
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59 check_content = "%s-%s" % (user, expiry) |
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60 check_mac = hmac.new(_csrf_key, content).hexdigest() |
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61 if mac == check_mac: |
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62 return True |
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63 |
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64 return False |
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65 |
