mailinabox/management/mfa.py

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Python
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import base64
import hmac
import io
import os
import pyotp
import qrcode
from mailconfig import open_database
def get_user_id(email, c):
c.execute('SELECT id FROM users WHERE email=?', (email,))
r = c.fetchone()
if not r: raise ValueError("User does not exist.")
return r[0]
def get_mfa_state(email, env):
c = open_database(env)
c.execute('SELECT id, type, secret, mru_token, label FROM mfa WHERE user_id=?', (get_user_id(email, c),))
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return [
{ "id": r[0], "type": r[1], "secret": r[2], "mru_token": r[3], "label": r[4] }
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for r in c.fetchall()
]
def get_public_mfa_state(email, env):
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mfa_state = get_mfa_state(email, env)
return [
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{ "id": s["id"], "type": s["type"], "label": s["label"] }
for s in mfa_state
]
def get_hash_mfa_state(email, env):
mfa_state = get_mfa_state(email, env)
return [
{ "id": s["id"], "type": s["type"], "secret": s["secret"] }
for s in mfa_state
]
def enable_mfa(email, type, secret, token, label, env):
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if type == "totp":
validate_totp_secret(secret)
# Sanity check with the provide current token.
totp = pyotp.TOTP(secret)
if not totp.verify(token, valid_window=1):
raise ValueError("Invalid token.")
else:
raise ValueError("Invalid MFA type.")
conn, c = open_database(env, with_connection=True)
c.execute('INSERT INTO mfa (user_id, type, secret, label) VALUES (?, ?, ?, ?)', (get_user_id(email, c), type, secret, label))
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conn.commit()
def set_mru_token(email, mfa_id, token, env):
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conn, c = open_database(env, with_connection=True)
c.execute('UPDATE mfa SET mru_token=? WHERE user_id=? AND id=?', (token, get_user_id(email, c), mfa_id))
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conn.commit()
def disable_mfa(email, mfa_id, env):
conn, c = open_database(env, with_connection=True)
if mfa_id is None:
# Disable all MFA for a user.
c.execute('DELETE FROM mfa WHERE user_id=?', (get_user_id(email, c),))
else:
# Disable a particular MFA mode for a user.
c.execute('DELETE FROM mfa WHERE user_id=? AND id=?', (get_user_id(email, c), mfa_id))
conn.commit()
return c.rowcount > 0
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def validate_totp_secret(secret):
if type(secret) != str or secret.strip() == "":
raise ValueError("No secret provided.")
if len(secret) != 32:
raise ValueError("Secret should be a 32 characters base32 string")
def provision_totp(email, env):
# Make a new secret.
secret = base64.b32encode(os.urandom(20)).decode('utf-8')
validate_totp_secret(secret) # sanity check
# Make a URI that we encode within a QR code.
uri = pyotp.TOTP(secret).provisioning_uri(
name=email,
issuer_name=env["PRIMARY_HOSTNAME"] + " Mail-in-a-Box Control Panel"
)
# Generate a QR code as a base64-encode PNG image.
qr = qrcode.make(uri)
byte_arr = io.BytesIO()
qr.save(byte_arr, format='PNG')
png_b64 = base64.b64encode(byte_arr.getvalue()).decode('utf-8')
return {
"type": "totp",
"secret": secret,
"qr_code_base64": png_b64
}
def validate_auth_mfa(email, request, env):
# Validates that a login request satisfies any MFA modes
# that have been enabled for the user's account. Returns
# a tuple (status, [hints]). status is True for a successful
# MFA login, False for a missing token. If status is False,
# hints is an array of codes that indicate what the user
# can try. Possible codes are:
# "missing-totp-token"
# "invalid-totp-token"
mfa_state = get_mfa_state(email, env)
# If no MFA modes are added, return True.
if len(mfa_state) == 0:
return (True, [])
# Try the enabled MFA modes.
hints = set()
for mfa_mode in mfa_state:
if mfa_mode["type"] == "totp":
# Check that a token is present in the X-Auth-Token header.
# If not, give a hint that one can be supplied.
token = request.headers.get('x-auth-token')
if not token:
hints.add("missing-totp-token")
continue
# Check for a replay attack.
if hmac.compare_digest(token, mfa_mode['mru_token'] or ""):
# If the token fails, skip this MFA mode.
hints.add("invalid-totp-token")
continue
# Check the token.
totp = pyotp.TOTP(mfa_mode["secret"])
if not totp.verify(token, valid_window=1):
hints.add("invalid-totp-token")
continue
# On success, record the token to prevent a replay attack.
set_mru_token(email, mfa_mode['id'], token, env)
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return (True, [])
# On a failed login, indicate failure and any hints for what the user can do instead.
return (False, list(hints))