def test_createChallenge_base64(self):
"""createChallenge() return value should be urlsafe base64-encoded."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
challenge = c.createChallenge('w00t')
decoded = urlsafe_b64decode(challenge)
self.assertTrue(decoded)
def test_check(self):
"""A correct answer and valid challenge should return True."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
self.assertEquals(c.check(challenge, c.answer, c.secretKey, c.hmacKey),
True)
def getCaptchaImage(self, request):
"""Get a random CAPTCHA image from our **captchaDir**.
Creates a :class:`~bridgedb.captcha.GimpCaptcha`, and calls its
:meth:`~bridgedb.captcha.GimpCaptcha.get` method to return a random
CAPTCHA and challenge string.
:type request: :api:`twisted.web.http.Request`
:param request: A client's initial request for some other resource
which is protected by this one (i.e. protected by a CAPTCHA).
:returns: A 2-tuple of ``(image, challenge)``, where::
- ``image`` is a string holding a binary, JPEG-encoded image.
- ``challenge`` is a unique string associated with the request.
"""
# Create a new HMAC key, specific to requests from this client:
clientIP = self.getClientIP(request)
clientHMACKey = crypto.getHMAC(self.hmacKey, clientIP)
capt = captcha.GimpCaptcha(self.publicKey, self.secretKey,
clientHMACKey, self.captchaDir)
try:
capt.get()
except captcha.GimpCaptchaError as error:
logging.error(error)
except Exception as error: # pragma: no cover
logging.error("Unhandled error while retrieving Gimp captcha!")
logging.exception(error)
return (capt.image, capt.challenge)
def test_init(self):
"""Test that __init__ correctly initialised all the values."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
self.assertIsNone(c.answer)
self.assertIsNone(c.image)
self.assertIsNone(c.challenge)
def test_get_emptyCacheDir(self):
"""An empty cacheDir should raise GimpCaptchaError."""
os.makedirs(self.badCacheDir)
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.badCacheDir)
self.assertRaises(captcha.GimpCaptchaError, c.get)
shutil.rmtree(self.badCacheDir)
def test_check_blankAnswer(self):
"""A blank answer and valid challenge should return False."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
self.assertEquals(c.check(challenge, None, c.secretKey, c.hmacKey),
False)
def test_get(self):
"""GimpCaptcha.get() should return image and challenge strings."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
self.assertIsInstance(image, basestring)
self.assertIsInstance(challenge, basestring)
def test_check_badHMACkey(self):
"""A challenge with a bad HMAC key should return False."""
hmacKeyBad = crypto.getKey('test_gimpCaptcha_badHMACkey')
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
self.assertEquals(
c.check(challenge, c.answer, c.secretKey, hmacKeyBad), False)
def test_check_missingAnswerbytes(self):
"""Partial encrypted answers in challenges should return False."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
challengeBadOrig = challenge[:20] + challenge[30:]
self.assertEquals(
c.check(challengeBadOrig, c.answer, c.secretKey, c.hmacKey), False)
def test_check_missingHMACbytes(self):
"""A challenge that is missing part of the HMAC should return False."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
challengeBadHMAC = challenge[:10] + challenge[20:]
self.assertEquals(
c.check(challengeBadHMAC, c.answer, c.secretKey, c.hmacKey), False)
def test_check_encoding_unicode(self):
"""A correct answer in utf-8 lowercase should return True."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
solution = unicode(c.answer)
self.assertEquals(c.check(challenge, solution, c.secretKey, c.hmacKey),
True)
def test_check_caseInsensitive_uppercase(self):
"""A correct answer in uppercase characters should return True."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
solution = c.answer.upper()
self.assertEquals(c.check(challenge, solution, c.secretKey, c.hmacKey),
True)
def test_check_nonBase64(self):
"""Valid answer and challenge with invalid base64 returns False."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
image, challenge = c.get()
challengeBadB64 = challenge.rstrip('==') + "\x42\x42\x42"
self.assertEquals(c.check(challenge, c.answer, c.secretKey, c.hmacKey),
True)
self.assertEquals(
c.check(challengeBadB64, c.answer, c.secretKey, c.hmacKey), False)
def test_createChallenge_hmacValid(self):
"""The HMAC in createChallenge() return value should be valid."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
challenge = c.createChallenge('ShouldHaveAValidHMAC')
decoded = urlsafe_b64decode(challenge)
hmac = decoded[:20]
orig = decoded[20:]
correctHMAC = crypto.getHMAC(self.hmacKey, orig)
self.assertEquals(hmac, correctHMAC)
def test_get_unreadableCaptchaFile(self):
"""An unreadable CAPTCHA file should raise GimpCaptchaError."""
os.makedirs(self.badCacheDir)
badFile = os.path.join(self.badCacheDir, 'uNr34dA81e.jpg')
with open(badFile, 'w') as fh:
fh.write(' ')
fh.flush()
os.chmod(badFile, 0266)
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.badCacheDir)
# This should hit the second `except:` clause in get():
self.assertRaises(captcha.GimpCaptchaError, c.get)
shutil.rmtree(self.badCacheDir)
def test_createChallenge_decryptedAnswerMatches(self):
"""The HMAC in createChallenge() return value should be valid."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
challenge = c.createChallenge('ThisAnswerShouldDecryptToThis')
decoded = urlsafe_b64decode(challenge)
hmac = decoded[:20]
orig = decoded[20:]
correctHMAC = crypto.getHMAC(self.hmacKey, orig)
self.assertEqual(hmac, correctHMAC)
decrypted = self.sekrit.decrypt(orig)
timestamp = int(decrypted[:12].lstrip('0'))
# The timestamp should be within 30 seconds of right now.
self.assertApproximates(timestamp, int(time.time()), 30)
self.assertEqual('ThisAnswerShouldDecryptToThis', decrypted[12:])
def test_createChallenge(self):
"""createChallenge() should return the encrypted CAPTCHA answer."""
c = captcha.GimpCaptcha(self.publik, self.sekrit, self.hmacKey,
self.cacheDir)
challenge = c.createChallenge('w00t')
self.assertIsInstance(challenge, basestring)