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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 import hashlib |
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8 |
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9 import bottle |
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10 |
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11 import config |
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12 |
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13 __all__ = ["get_csrf_blob", "check_csrf_blob", "setup_csrf", "get_user_hash"] |
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14 |
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15 HASH=hashlib.sha1 |
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16 |
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17 def get_user_hash(): |
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18 verify = bottle.request.environ.get('SSL_CLIENT_VERIFY', '') |
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19 if not (verify == 'GENEROUS' or verify == 'SUCCESS'): |
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20 return 'FAILVERIFY' |
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21 blob = bottle.request.environ.get('SSL_CLIENT_CERT') |
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22 if not blob: |
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23 return 'NOCERT' |
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24 |
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25 b64 = ''.join(l for l in blob.split('\n') |
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26 if not l.startswith('-')) |
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27 |
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28 return HASH(binascii.a2b_base64(b64)).hexdigest() |
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29 |
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30 def setup_csrf(): |
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31 NONCE_SIZE=16 |
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32 global _csrf_fd, _csrf_key |
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33 _csrf_fd = open('%s/csrf.dat' % config.DATA_PATH, 'r+') |
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34 |
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35 try: |
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36 fcntl.lockf(_csrf_fd, fcntl.LOCK_EX | fcntl.LOCK_NB) |
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37 os.fchmod(_csrf_fd.fileno(), 0600) |
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38 _csrf_fd.write("%d-%s" % (os.getpid(), binascii.hexlify(os.urandom(NONCE_SIZE)))) |
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39 _csrf_fd.flush() |
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40 _csrf_fd.seek(0) |
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41 except IOError: |
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42 pass |
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43 fcntl.lockf(_csrf_fd, fcntl.LOCK_SH) |
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44 _csrf_key = _csrf_fd.read() |
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45 # keep the lock open until we go away |
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46 |
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47 |
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48 def get_csrf_blob(): |
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49 expiry = int(config.CSRF_TIMEOUT + time.time()) |
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50 content = '%s-%s' % (get_user_hash(), expiry) |
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51 mac = hmac.new(_csrf_key, content).hexdigest() |
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52 return "%s-%s" % (content, mac) |
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53 |
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54 def check_csrf_blob(blob): |
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55 toks = blob.split('-') |
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56 if len(toks) != 3: |
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57 print>>sys.stderr, "wrong toks" |
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58 return False |
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59 |
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60 user, expiry, mac = toks |
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61 if user != get_user_hash(): |
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62 print>>sys.stderr, "wrong user" |
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63 return False |
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64 |
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65 try: |
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66 exp = int(expiry) |
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67 except ValueError: |
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68 print>>sys.stderr, "failed exp" |
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69 return False |
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70 |
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71 if exp < 1000000000: |
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72 return False |
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73 |
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74 if exp < time.time(): |
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75 print>>sys.stderr, "expired %d %d" % (exp, time.time()) |
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76 return False |
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77 |
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78 check_content = "%s-%s" % (user, expiry) |
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79 check_mac = hmac.new(_csrf_key, check_content).hexdigest() |
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80 if mac == check_mac: |
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81 print>>sys.stderr, "good hmac" |
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82 return True |
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83 |
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84 print>>sys.stderr, "fail" |
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85 return False |
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86 |
