| 1 | # GNU MediaGoblin -- federated, autonomous media hosting |
| 2 | # Copyright (C) 2011, 2012 MediaGoblin contributors. See AUTHORS. |
| 3 | # |
| 4 | # This program is free software: you can redistribute it and/or modify |
| 5 | # it under the terms of the GNU Affero General Public License as published by |
| 6 | # the Free Software Foundation, either version 3 of the License, or |
| 7 | # (at your option) any later version. |
| 8 | # |
| 9 | # This program is distributed in the hope that it will be useful, |
| 10 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | # GNU Affero General Public License for more details. |
| 13 | # |
| 14 | # You should have received a copy of the GNU Affero General Public License |
| 15 | # along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 16 | import bcrypt |
| 17 | import random |
| 18 | |
| 19 | |
| 20 | def bcrypt_check_password(raw_pass, stored_hash, extra_salt=None): |
| 21 | """ |
| 22 | Check to see if this password matches. |
| 23 | |
| 24 | Args: |
| 25 | - raw_pass: user submitted password to check for authenticity. |
| 26 | - stored_hash: The hash of the raw password (and possibly extra |
| 27 | salt) to check against |
| 28 | - extra_salt: (optional) If this password is with stored with a |
| 29 | non-database extra salt (probably in the config file) for extra |
| 30 | security, factor this into the check. |
| 31 | |
| 32 | Returns: |
| 33 | True or False depending on success. |
| 34 | """ |
| 35 | if extra_salt: |
| 36 | raw_pass = u"%s:%s" % (extra_salt, raw_pass) |
| 37 | |
| 38 | hashed_pass = bcrypt.hashpw(raw_pass.encode('utf-8'), stored_hash) |
| 39 | |
| 40 | # Reduce risk of timing attacks by hashing again with a random |
| 41 | # number (thx to zooko on this advice, which I hopefully |
| 42 | # incorporated right.) |
| 43 | # |
| 44 | # See also: |
| 45 | rand_salt = bcrypt.gensalt(5) |
| 46 | randplus_stored_hash = bcrypt.hashpw(stored_hash, rand_salt) |
| 47 | randplus_hashed_pass = bcrypt.hashpw(hashed_pass, rand_salt) |
| 48 | |
| 49 | return randplus_stored_hash == randplus_hashed_pass |
| 50 | |
| 51 | |
| 52 | def bcrypt_gen_password_hash(raw_pass, extra_salt=None): |
| 53 | """ |
| 54 | Generate a salt for this new password. |
| 55 | |
| 56 | Args: |
| 57 | - raw_pass: user submitted password |
| 58 | - extra_salt: (optional) If this password is with stored with a |
| 59 | non-database extra salt |
| 60 | """ |
| 61 | if extra_salt: |
| 62 | raw_pass = u"%s:%s" % (extra_salt, raw_pass) |
| 63 | |
| 64 | return unicode( |
| 65 | bcrypt.hashpw(raw_pass.encode('utf-8'), bcrypt.gensalt())) |
| 66 | |
| 67 | |
| 68 | def fake_login_attempt(): |
| 69 | """ |
| 70 | Pretend we're trying to login. |
| 71 | |
| 72 | Nothing actually happens here, we're just trying to take up some |
| 73 | time, approximately the same amount of time as |
| 74 | bcrypt_check_password, so as to avoid figuring out what users are |
| 75 | on the system by intentionally faking logins a bunch of times. |
| 76 | """ |
| 77 | rand_salt = bcrypt.gensalt(5) |
| 78 | |
| 79 | hashed_pass = bcrypt.hashpw(str(random.random()), rand_salt) |
| 80 | |
| 81 | randplus_stored_hash = bcrypt.hashpw(str(random.random()), rand_salt) |
| 82 | randplus_hashed_pass = bcrypt.hashpw(hashed_pass, rand_salt) |
| 83 | |
| 84 | randplus_stored_hash == randplus_hashed_pass |