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One time passwords (OTP) are a useful adjunct to the standard username/password authentication used by Roundup. The use of a shared secret between Roundup and the user's authentication device such as:

will provide 2-factor authentication.

This has been tested using Python 3.6 and Roundup 2.1.0+ development version as of 12-2021.

This page documents how to add:

to your Roundup tracker.

It was inspired by the article: https://dev.to/jothinkumar/2fa-with-python-4of5.

Other references used during development are:

Also worthy of note is:

Which argues for changing the config.ini setting to use 8 digit OTPs. The login rate limiting (3 in 1 minute) increases the time to break in to 80 or so days if the math is correct. However, implementing an exponentially back-off is also an option. If anybody implements this, please send a message to the mailing list.

Also the onetimepass library was chosen because it supports Python 2 and 3. It has not been changed in some time, which is fine if it is bug free and continues to work as Python 3 evolves. The https://github.com/pyauth/pyotp package supports Python 3.7 and newer and should be a suitable replacement if you need a package under current development. Modifying the code below to work with pyotp is left as an exercise for the reader 8-).

There are a number of steps to add this to your tracker:

  1. Install the onetimepass package

  2. Optionally install the qrcode package to use a QR code for enrolling your tracker. Note this only supports Python3, so Python 2 users will need to type the 32 characters into their device.

  3. Modify the tracker's schema adding 2 fields to the user class
  4. Modify your tracker's page.html template adding a new input field named _otp to the login form.

  5. Modify your tracker's user.item.html template adding a link to the new two factor authentication template.

  6. Install the user.2fa.html template on this page.

  7. Install the 2fa.py extension file

  8. Install the HotpTotp.py detectors file

  9. Restart your tracker.

Changes to existing pages are minor. There is a new page that is used for managing two factor authentication. It looks like (note the colors will be different):

width=75%

You can control the addon using config settings in the extensions/config.ini file in your tracker's home directory.

See the module documentation in the file 2fa.py.

Note that a counter mismatch for the HOTP method may need to be corrected using:

      roundup-admin -i tracker/home set user21 secret_counter=30

with a counter value that brings the generator device and the server back in sync.

Modify schema.py

Find the start of the User class definition in the file schema.py. It looks like:

   1 user = Class(db, "user",
   2                 username=String(required=True),
   3                 password=Password(required=True),

Add the following lines:

   1       secret_2fa=Password(scheme="plaintext", default_value='-'),
   2       secret_counter=Integer(quiet=True, default_value='-1'), # last sequence number seen

alongside the other parameters.

The secret has to be available in plaintext, so it must not be encrypted using a one-way hash. By making the secret_2fa a Password using the plaintext encryption scheme, we meet this requirement. Also, the journal of changes to the field do not expose previous values for the secret.

The user never intentionally changes the secret_counter. It gets changed as a side effect of login or changing the secret_key. So we define it using the quiet setting. Each change of the counter is recorded in the history so it can be used as a login record.

Modify page.html

Add an input field named __otp to the login form. I put it underneath the password entry field. It looks like:

             <input id="__login_password" type="password" size="10"
                    required name="__login_password"><br>
+            <label for="__otp">OTP</label>
+            <input id="__otp" type="text" size="6"
+                   name="__otp"
+                   aria-label="Enter one time password."><br>

where the added lines are marked with a + (remove the plus when inserting them).

The example above shows the password field that you can use to find the right location.

Alternatively, you could tunnel the OTP using the password field. The user would enter a password like: user's_real_Password:<otp here>. You would need to change the login extension below to crack apart the password field to recover the password and OTP. It makes for a cleaner interface if you have some users who are not required to have an OTP (e.g. users with the admin role require OTP but regular users do not). If the OTP was missing, you could return an error ("The password is incomplete.") prompting the user to use an OTP.

Modify user.item.html

Add a link to the user.item.html to allow the user to modify the Two Factor settings. I added it after the password confirmation input element.

   <th metal:use-macro="th_label">Confirm Password</th>
   <td><input metal:use-macro="confirm_input" type="password"></td>
+ </tr>
+ <tr tal:define="name string:; label string:2-factor authentication">
+   <th metal:use-macro="th_label">2-factor auth</th>
+   <td tal:condition="python:context.id and context.secret_2fa == '-'"><a tal:attributes="href
+   python:request.indexargs_url(request.classname+context.id,{'@template':
+   '2fa'})">Two factor authentication is NOT enabled. Click here to change.</a></td>
+   <td tal:condition="python:context.id and context.secret_2fa != '-'"><a tal:attributes="href
+   python:request.indexargs_url(request.classname+context.id,{'@template':
+   '2fa'})">Two factor authentication is enabled. Click here for details.</a></td>
+
  </tr>

again added lines are marked with a + which should be removed.

This change adds the two factor link in the normal user item page which looks like:

width=33%

user.2fa.html add to html directory

Now we need the two factor view by copying this into the file user.2fa.html.

download user.2fa.html

<tal:doc metal:use-macro="templates/page/macros/icing"
define="edit_ok context/is_edit_ok"
>
<title metal:fill-slot="head_title">
<tal:if condition="context/id" i18n:translate=""
 >User <tal:x content="context/id" i18n:name="id"
 />: <tal:x content="context/username" i18n:name="title"
 /> - <tal:x content="config/TRACKER_NAME" i18n:name="tracker"
/></tal:if>
<tal:if condition="not:context/id" i18n:translate=""
 >New User - <span tal:replace="config/TRACKER_NAME" i18n:name="tracker"
/></tal:if>
</title>
<metal:slot fill-slot="more-end-javascript">
<script tal:attributes="nonce request/client/client_nonce"
        metal:use-macro="templates/page/macros/user_utils"></script>
<script tal:attributes="nonce request/client/client_nonce" 
        type="text/javascript" src="@@file/jslibraries/zxcvbn.js"></script>
</metal:slot>
<tal:block metal:fill-slot="body_title"
  define="edit_ok context/is_edit_ok">
 <span tal:omit-tag="python:1" i18n:translate="">Two Factor Authentication</span>
</tal:block>

<div class="content" metal:fill-slot="content">
<p tal:condition="python:not (context.is_view_ok()
 or request.user.hasRole('Anonymous'))" i18n:translate="">
 You are not allowed to view this page.</p>

<p tal:condition="python:not context.is_view_ok()
 and request.user.hasRole('Anonymous')" i18n:translate="">
 Please login with your username and password.</p>

<div tal:condition="context/is_view_ok"
     tal:define="edit_ok context/is_edit_ok">

  <tal:if condition="edit_ok">
  <form method="POST"
        name="twofactor"
        enctype="multipart/form-data"
        tal:attributes="action context/designator;
                        formwins
        python:utils.set_form_wins(request.client, False)">

    <h2>Shared secret passphrase (<small>generate new or remove secret</small>)</h2>
      <details>
        <summary>Toggle visibility by clicking here.</summary>
        <span tal:content="python:utils.chunk_text(context.secret_2fa,
        errormsg='No secret key is set.')">see
        secret here</span>
      <div>
        <label for="__enable_TOTP">Use Time Based OTP</label>
        <input type="checkbox" id="__enable_TOTP"
             name="__enable_TOTP"
             tal:attributes="checked python:context.secret_counter
              == -2">
      </div>
      <input type="submit" value="Generate New Secret"
             i18n:attributes="value">
      <input type="submit"
             tal:condition="python:context.secret_2fa != '-'"
             name="remove_2fa" class="second-button" value="Remove 2FA"
             i18n:attributes="value">
      </details>
      <input type="hidden" name="@template" value="2fa">
      <input type="hidden" name="@action" value="gen2fasecret">
      <input name="@csrf" type="hidden" tal:attributes="value
                                python:utils.anti_csrf_nonce()">
  </form>

    <h2>Shared secret details</h2>
      <div>Current count:
        <span tal:content="python:utils.format_current_count(context.secret_counter)"></span>
      </div>
      <div>Integrity Check Value:
        <span tal:content="python:utils.hotpIntegrityValue(context)"></span>
      </div>
      <h2>Google Authenticator QR Code</h2>
      <details>
        <summary>Toggle visibility by clicking here.</summary>
        <style tal:attributes="nonce request/client/client_nonce"> 
         pre.ascii_otp {line-height: 1em;}</style>

      <svg tal:attributes="width string:40%;height string:40%"
           tal:replace="structure python:utils.qrify(context, output='svg')">
      </svg>
      </details>
  </tal:if>
  <a tal:attributes="href
  python:request.indexargs_url(request.classname+context.id,{})">Return
  to user details page.</a>
</div>
</div>
</tal:doc>

2fa.py add to extensions directory

This adds the template utils needed by the 2fa view, the actions to generate a new secret/remove 2fa, and a new login function/wrapper.

download 2fa.py

   1 """Module to implement two-factor autentication using
   2 rfc4226 HOTP or rfc6238 TOTP on your tracker.
   3 
   4 Templating functions including QR code generator and two
   5 actions:
   6 
   7   * login using TOTP/HOTP
   8   * Manage TOTP/HOTP - enroll using HOTP or TOTP, unenroll 2FA
   9 
  10 
  11 Configuration is done using the extensions/config.ini file.
  12 Settings with default values:
  13 
  14 [HOTP]
  15 
  16 # Presence of the key disables this mechanism.  User will
  17 # not be able to enroll using the mechanism.  They will be
  18 # able to login using the method unless the value is
  19 # 'login_deny' (no quotes). This will tell the user to see
  20 # an administrator.
  21 disable =
  22 
  23 # If the counter on the token generator and the tracker get
  24 # out of sync, increment the counter up to window times to
  25 # try to match the token the user entered.
  26 window = 10
  27 
  28 # Number of digits in the OTP token. 6 or 8 are usually supported by
  29 # authenticators.
  30 length = 6
  31 
  32 # Name for this tracker used for issuer in the QR code.
  33 # If empty, the string before the last / in the TRACKER_WEB
  34 # config.ini setting.
  35 issuer =
  36 
  37 [TOTP]
  38 
  39 # Same as HOTP.
  40 disable =
  41 
  42 # If the time sync on the token generator and this server
  43 # are out of sync calculate the token for window 30 second
  44 # periods before and after now. 0 means the user must
  45 # generate and the server must process the token within the
  46 # current 30 second window.
  47 window = 0
  48 
  49 # Same as HOTP.
  50 length = 6
  51 
  52 # Same as HOTP.
  53 issuer =
  54 
  55 """
  56 
  57 from roundup.anypy.strings import b2s
  58 from roundup.anypy import urllib_
  59 from roundup.i18n import _
  60 
  61 import logging
  62 
  63 # import for generator
  64 from roundup.cgi.actions import EditItemAction
  65 from roundup.configuration import InvalidOptionError
  66 
  67 import random
  68 
  69 # imports for LoginAction replacement
  70 from roundup.cgi.actions import LoginAction
  71 from roundup.cgi.exceptions import Redirect, LoginError
  72 
  73 import cgi
  74 import math
  75 import re
  76 import time
  77 
  78 # If this fails OTP doesn't work at all.
  79 # So fail on import rather than at runtime.
  80 from onetimepass import get_hotp, valid_hotp, valid_totp
  81 
  82 try:
  83     # Hopefully this works for python2
  84     from StringIO import cStringIO as IOBuff
  85 except ImportError:
  86     # python 3
  87     from io import StringIO as IOBuff
  88 
  89 try:
  90     # qrcode only supports python 3
  91     import qrcode
  92     import qrcode.image.svg
  93 except ImportError:
  94     qrcode = None
  95 
  96 logger = logging.getLogger('extension')
  97 
  98 
  99 def chunk_text(text_or_password, chunksize=4, errormsg=None):
 100     """ Template function to chunk text by breaking one of
 101         three types of text source:
 102 
 103            plain text
 104 
 105            HTML form field with _value
 106 
 107            Password hyperdb class with _value.password
 108     """
 109     if not errormsg:
 110         errormsg = _("No value present.")
 111 
 112     if not isinstance(text_or_password, str):
 113         try:
 114             text = text_or_password._value.password
 115         except AttributeError:
 116             text = text_or_password._value
 117     else:
 118         text = text_or_password
 119 
 120     if text == '-':
 121         return errormsg
 122 
 123     return ' '.join([text[x*chunksize:x*chunksize+chunksize] for x in
 124                     range(0, math.ceil(len(text)/chunksize))])
 125 
 126 
 127 def format_current_count(count):
 128     if count == -1:
 129         return _("2FA disabled. No counter.")
 130     if count == -2:
 131         return _("Using time based 2FA. Counter unused.")
 132     return count
 133 
 134 
 135 def hotpIntegrityValue(user_context):
 136     '''Return the OTP for counter value 0. Google Authenticator
 137        uses this as the Integrity Check value for the key.
 138        The first OTP that will be accepted starts at counter
 139        value 1.
 140     '''
 141 
 142     if user_context.secret_counter._value == -2:
 143         return _("Using time based 2FA. Check value not available.")
 144 
 145     try:
 146         key = user_context.secret_2fa._value.password
 147     except AttributeError:
 148         key = user_context.secret_2fa._value
 149 
 150     if key == '-':
 151         return _("2FA disabled. Check value not available.")
 152     value = str(get_hotp(key, 0))
 153     return chunk_text(value.rjust(6, '0'), chunksize=3)
 154 
 155 
 156 def qrify(user_context, output="svg"):
 157     '''Generate a QR code to enroll the user using Google
 158        Authenticator and other client apps.
 159        The QR code is a special url to enroll the user.
 160        We set the following info in the QR:
 161 
 162          identity: issuer:username@TRACKER_NAME
 163          issuer: last element of TRACKER_WEB, HOTP_ISSUER or
 164                  TOTP_ISSUER from extensions/config.ini
 165        All values are url encoded.
 166        Generates an svg or ascii qr code. Default output=svg.
 167        Ascii is useful for text browsers.
 168     '''
 169 
 170     if qrcode is None:
 171         return _("QR code is not available.")
 172 
 173     if user_context.secret_2fa._value == '-':
 174         return _("No secret key is set.")
 175 
 176     def get_ext_setting(setting, default=None):
 177         try:
 178             return user_context._db.config.ext[setting]
 179         except InvalidOptionError:
 180             return default
 181 
 182     counter = int(user_context.secret_counter._value)
 183 
 184     # can be a Password or web text item.
 185     try:
 186         secret = urllib_.quote(user_context.secret_2fa._value.password)
 187     except AttributeError:
 188         secret = urllib_.quote(user_context.secret_2fa._value)
 189 
 190     user = urllib_.quote(user_context.username._value)
 191     web_url = urllib_.quote(user_context._db.config['TRACKER_WEB'])
 192 
 193     if user_context.secret_counter == -2:
 194         # TOTP
 195         issuer = urllib_.quote(get_ext_setting('TOTP_ISSUER', ''))
 196     else:
 197         issuer = urllib_.quote(get_ext_setting('HOTP_ISSUER', ''))
 198 
 199     if not issuer:
 200         # take last component of / terminated web url
 201         issuer = urllib_.quote(web_url.split('/')[-2])
 202     tracker = urllib_.quote(user_context._db.config['TRACKER_NAME'])
 203 
 204     # neither sissuer nor user can have a ':'
 205     issuer.replace(':', '_')
 206     user.replace(':', '_')
 207 
 208     # https://github.com/google/google-authenticator/wiki/Key-Uri-Format
 209     if counter == 0:  # HOTP
 210         url = (("otpauth://hotp/%(issuer)s%%3A%(user)s@%(tracker)s?"
 211                 "secret=%(secret)s&issuer=%(issuer)s&counter=0") %
 212                locals())
 213     else:  # counter = -2 TOTP
 214         url = (("otpauth://totp/%(issuer)s%%3A%(user)s@%(tracker)s?"
 215                 "secret=%(secret)s&issuer=%(issuer)s") % locals())
 216 
 217     if output == "svg":
 218         factory = qrcode.image.svg.SvgPathImage
 219         qr_svg = qrcode.make(url, image_factory=factory)
 220         return b2s(qr_svg.to_string())
 221     elif output == "ascii":
 222         qr = qrcode.QRCode()
 223         qr.add_data(url)
 224         file_mock = IOBuff()
 225         qr.print_ascii(out=file_mock)
 226         file_mock.seek(0)
 227         qr_text = file_mock.read()
 228         # wrap it in pre tags to keep formatting
 229         return '<pre class="ascii_otp">%s</pre>' % qr_text
 230         # The following css is required to make it work on
 231         # browsers that implement css. If the line height is
 232         # not 1, blank space is created between the lines.
 233         # The space makes QR recognition fail. It works fine
 234         # without it on text browsers.
 235         #   pre.ascii_otp {line-height: 1em;}
 236     else:
 237         return "Error generating QR code."
 238 
 239 
 240 def set_form_wins(client, value):
 241     '''set client's form_wins attribute to the boolean value
 242        passed in. If value is False, the templating code displays
 243        values from the database rather than from the current form.
 244 
 245        By default, the value is True so that a rejected form
 246        displays the values the user entered rather than overwriting
 247        them with the values from the database.
 248 
 249        However we want to display the database values on the
 250        user.2fa.html template as there is no user entered data
 251        on the form that changes the secret key.
 252     '''
 253     client.form_wins = value
 254 
 255 
 256 class Generate2faSecret(EditItemAction):
 257     '''Change users HOTP secret or disable 2FA.
 258 
 259        Values for schema properties:
 260        secret_2fa: 32 characters from base32 alphabet or - if disabled
 261        secret_counter:
 262            integer >= 0 2fa HOTP enabled
 263            integer = -1 2fa disabled
 264            integer = -2 reserved for 2fa TOTP enabled (not yet implmented)
 265 
 266        To prevent a user from manually setting the key by submitting
 267           a form, we add a property to the db handle that the detector
 268           looks for. If a web request comes in without that property on
 269           the db, it raises an error.
 270     '''
 271     def handle(self):
 272         ''' Generate new 2FA HOTP secret or remove 2FA enrollment.
 273         '''
 274 
 275         if __debug__:
 276             logger.debug("Generate2faSecret: enter")
 277 
 278         def get_ext_setting(setting, default=None):
 279             try:
 280                 return self.db.config.ext[setting]
 281             except InvalidOptionError:
 282                 return default
 283 
 284         # add property on db object to be used by detector
 285         # so it knows request came from here.
 286         self.db.Generate2faSecret = "Generate2faSecret"
 287 
 288         # Process unenrolling request.
 289 
 290         # 'remove_2fa' is the name of the un-enrolling button
 291         # in web interface.
 292         if 'remove_2fa' in self.form:
 293             # zero out 2FA creds and counter
 294             self.form.list.append(
 295                 cgi.MiniFieldStorage("secret_2fa", "-")
 296             )
 297             # all password changes need confirmation element
 298             self.form.list.append(
 299                 cgi.MiniFieldStorage("@confirm@secret_2fa", "-")
 300             )
 301 
 302             # empty reset counter when removing 2fa
 303             self.form.list.append(
 304                 cgi.MiniFieldStorage("secret_counter", "-1")
 305             )
 306             # call the core EditItemAction to process the edit.
 307             EditItemAction.handle(self)
 308             return
 309 
 310         # Now all we have is to enroll the user.
 311 
 312         # define base32 alphabet for random string generation
 313         alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
 314 
 315         # get available otp methods
 316         otp_methods = []
 317 
 318         if get_ext_setting("HOTP_DISABLE") is None:
 319             otp_methods.append('hotp')
 320         if get_ext_setting("TOTP_DISABLE") is None:
 321             otp_methods.append('totp')
 322 
 323         if not otp_methods:
 324             raise ValueError(_("All two factor methods are disabled."))
 325 
 326         if '__enable_TOTP' in self.form:
 327             if 'totp' in otp_methods:
 328                 use_totp = True
 329             else:
 330                 raise ValueError(_("Time based method disabled"))
 331         else:
 332             if 'hotp' in otp_methods:
 333                 use_totp = False
 334             else:
 335                 raise ValueError(_("Counter based method disabled"))
 336 
 337         # Is this the best we can do?? How random is it?
 338         # 160 bits (32 characters with 5 bits) of entropy.
 339         new_secret = ''.join(
 340             [random.choice(alphabet) for x in range(0, 32)])
 341 
 342         self.form.list.append(
 343             cgi.MiniFieldStorage("secret_2fa", new_secret)
 344         )
 345         self.form.list.append(
 346             cgi.MiniFieldStorage("@confirm@secret_2fa", new_secret)
 347         )
 348 
 349         if use_totp is False:
 350             # always reset counter to 0 when changing HOTP secret
 351             self.form.list.append(
 352                 cgi.MiniFieldStorage("secret_counter", "0")
 353             )
 354         else:
 355             self.form.list.append(
 356                 cgi.MiniFieldStorage("secret_counter", "-2")
 357             )
 358 
 359         # call the core EditItemAction to process the edit.
 360         EditItemAction.handle(self)
 361 
 362 
 363 def make_redirect_url(urlparse_dict):
 364     """As part of 2FA login redirect to new url composed from source
 365        URL plus new query parameters.
 366     """
 367     return urllib_.urlunparse((urlparse_dict['scheme'],
 368                                urlparse_dict['netloc'],
 369                                urlparse_dict['path'],
 370                                urlparse_dict['params'],
 371                                urllib_.urlencode(
 372                                    list(
 373                                        sorted(
 374                                            urlparse_dict['query'].items()
 375                                        )
 376                                    ),
 377                                    doseq=True
 378                                ),
 379                                urlparse_dict['fragment'])
 380                               )
 381 
 382 
 383 def clean_url_dict(self):
 384     """Return a dict with cleaned up components of source URL.
 385 
 386        As part of login code, we need to redirect back to source page
 387        but without @ok_message or @error_message query params.
 388     """
 389 
 390     if '__came_from' in self.form:
 391         # On valid or invalid login, redirect the user back to the page
 392         # they started on. Searches, issue, and other pages
 393         # are all preserved in __came_from. Clean out any old feedback
 394         # @error_message, @ok_message from the __came_from url.
 395         #
 396         # 1. Split the url into components.
 397         # 2. Split the query string into parts.
 398         # 3. Delete @error_message and @ok_message if present.
 399         # 4. Define a new redirect_url missing the @...message entries.
 400         #    This will be redefined if there is a login error to include
 401         #      a new error message
 402 
 403         clean_url = self.examine_url(self.form['__came_from'].value)
 404         redirect_url_tuple = urllib_.urlparse(clean_url)
 405         # now I have a tuple form for the __came_from url
 406         try:
 407             query = urllib_.parse_qs(redirect_url_tuple.query)
 408             if "@error_message" in query:
 409                 del query["@error_message"]
 410             if "@ok_message" in query:
 411                 del query["@ok_message"]
 412             if "@action" in query:
 413                 # also remove the action from the redirect
 414                 # there is only ever one @action value.
 415                 if query['@action'] == ["logout"]:
 416                     del query["@action"]
 417         except AttributeError:
 418             # no query param so nothing to remove. Just define.
 419             query = {}
 420             pass
 421 
 422         urlparse_dict = {"scheme": redirect_url_tuple.scheme,
 423                          "netloc": redirect_url_tuple.netloc,
 424                          "path":   redirect_url_tuple.path,
 425                          "params": redirect_url_tuple.params,
 426                          "query":  query,
 427                          "fragment": redirect_url_tuple.fragment
 428                          }
 429         return urlparse_dict
 430     else:
 431         return None
 432 
 433 
 434 class OtpLoginAction(LoginAction):
 435     '''Login Action requiring one time password (HOTP/TOTP)
 436        to successfully log in.
 437     '''
 438 
 439     # Calculate TOTP for an interval of this many seconds
 440     # Changing this INVALIDATES all TOTP's.
 441     # Some authenticators won't allow a value other than 30.
 442     # Read the rfc before changing this.
 443     totp_interval_in_sec = 30
 444 
 445     def handle(self):
 446 
 447         if __debug__:
 448             logger.debug("OtpLoginAction: enter")
 449 
 450         redirect_url_dict = clean_url_dict(self)
 451 
 452         def get_ext_setting(setting, default=None):
 453             try:
 454                 return self.db.config.ext[setting]
 455             except InvalidOptionError:
 456                 return default
 457 
 458         # store exceptions thrown by verifyLogin to expose
 459         # error message later
 460         verifyLoginException = None
 461 
 462         # Find enabled methods.
 463         otp_methods = []
 464         if get_ext_setting("HOTP_DISABLE") is None:
 465             otp_methods.append('hotp')
 466         if get_ext_setting("TOTP_DISABLE") is None:
 467             otp_methods.append('totp')
 468 
 469         if '__login_name' in self.form:
 470             username = self.form['__login_name'].value
 471             try:
 472                 # get the info for the user
 473                 userid = self.db.user.lookup(username)
 474 
 475                 try:
 476                     secret = self.db.user.get(userid, 'secret_2fa',
 477                                               "").password
 478                 except AttributeError:
 479                     # thrown if secret is empty
 480                     secret = '-'
 481 
 482                 last = self.db.user.get(userid, 'secret_counter')
 483 
 484                 if __debug__:
 485                     logger.debug("Login username %s is valid", username)
 486             except KeyError:
 487                 # No such user so login will fail.
 488                 # Set variables as though OTP is disabled.
 489                 # Don't return here as a timing attack can find
 490                 # valid usernames.
 491                 secret = "-"  # user's TOTP/HOTP secret
 492                 last = -1    # sequence number of last used HOTP -1 invalid
 493 
 494         try:
 495             last = int(last)
 496         except (ValueError, TypeError):
 497             # string but not an int or non-string
 498             last = -1  # sentinal value - indicates OTP disabled
 499 
 500         # sanity check
 501         if (secret == "-" and last != -1) or \
 502            (secret != "-" and last == -1):
 503             # somebody is playing games. This should never happen.
 504             # abort immediately.
 505             errormsg = _("Internal error. Secret key and counter mismatch.")
 506             # keep user on original page and report error.
 507             if redirect_url_dict is None:
 508                 self.client.add_error_message(errormsg)
 509                 return
 510             else:
 511                 redirect_url_dict['query']['@error_message'] = errormsg
 512                 raise Redirect(make_redirect_url(redirect_url_dict))
 513 
 514         if '__login_password' in self.form:
 515             password = self.form['__login_password'].value
 516         else:
 517             password = ""
 518 
 519         if '__otp' in self.form:
 520             token = self.form['__otp'].value
 521             # remove spaces/tabs. Some auth generators
 522             # chunk the token, copy/paste includes the spaces
 523             token = re.sub(r'\s', '', token)
 524         else:
 525             if secret == '-':
 526                 # 2fa not enabled, do a normal login
 527                 LoginAction.handle(self)
 528                 # LoginAction "returns" an exception
 529                 # so the return below should not be reached
 530                 return
 531             else:
 532                 token = ""
 533 
 534         if last == -2:
 535             # TOTP - window is the number of 30 second
 536             # (interval) periods before/after the current 30
 537             # second period. 0 only matches the code for
 538             # this (30) second period.
 539             windows = int(get_ext_setting('TOTP_WINDOW', 0))
 540         else:
 541             # HOTP - window we will search for a match so
 542             # up to 10 keys past the last used one can be valid.
 543             windows = int(get_ext_setting('HOTP_WINDOW', 10))
 544 
 545         if last == -2:
 546             # TOTP - token length number of numbers in token
 547             # 6 or 8 are usually supported
 548             token_length = int(get_ext_setting('TOTP_LENGTH', 6))
 549         else:
 550             token_length = int(get_ext_setting('HOTP_LENGTH', 6))
 551 
 552         # Verify TOTP/HOTP and prevent replay
 553         if last >= 0:
 554             # uppercase because it's used for retreiving a config setting.
 555             otp_method = "HOTP"
 556 
 557             # valid_hotp returns: integer > 0 (match sequence number) or False
 558             otp_ok = valid_hotp(token,
 559                                 secret,
 560                                 token_length=token_length,
 561                                 trials=windows,
 562                                 last=last)
 563 
 564             # FIXME: should the TOTP stuff be done here to prevent
 565             # leaking that the user is using HOTP and not TOTP. TOTP
 566             # validation will take longer. Try sleeping
 567             # random.random()/10 seconds.
 568             time.sleep(random.random()/10)
 569 
 570             # invalidate an exposed HOTP to make it single
 571             # use even if username/password fails.
 572             if otp_ok:
 573                 self.db.user.set(userid, secret_counter=otp_ok)
 574             self.db.commit()
 575 
 576         elif last == -2:
 577             # uppercase because it's used for retreiving a config setting.
 578             otp_method = "TOTP"
 579 
 580             interval = self.totp_interval_in_sec
 581 
 582             # FIXME: consider setting clock argument for
 583             #  valid_otp to (now - interval) and then None.
 584             #  Allow one interval look back to account for
 585             #  entry delay and network transmission between
 586             #  synchronized clocks. This is a look back
 587             #  window only. Note setting windows=1 looks
 588             #  forward and back one interval.
 589 
 590             # valid_totp returns: True or False
 591             otp_ok = valid_totp(token,
 592                                 secret,
 593                                 token_length=token_length,
 594                                 window=windows,
 595                                 interval_length=interval)
 596 
 597             # verify that token has not been used
 598             # check against last TOTP to prevent replay
 599             #   Use session db so multiple tokens
 600             #   (TOTP_used-<user>-<token>) with lifetime of
 601             #       now + (window * 30 seconds or (interval))
 602             #       can be saved and expired by usual method?
 603             otk = self.client.db.Otk
 604 
 605             totp_key = "TOTP_used-%s-%s" % (username, token)
 606 
 607             try:
 608                 _discard = otk.getall(totp_key)
 609                 # token has been seen before, login must fail.
 610                 otp_ok = False
 611             except KeyError:
 612                 # ignore if key not found
 613                 pass
 614 
 615             # Calculate a timestamp that will make OTK.clean()
 616             # expire the entry 1.1 x interval plus windows * interval
 617             # after the current time. 1.1 is just to make sure we record
 618             # the TOTP through it's entire interval.
 619             #  (FYI expiration is 1 week, so we subtract a week first)
 620             ts = time.time() - (60 * 60 * 24 * 7) \
 621                  + (interval * windows) + 1.1*interval
 622 
 623             if otp_ok:
 624                 # this is the only code that depends on a valid otp
 625                 otk.set(totp_key, token=token, __timestamp=ts)
 626 
 627             # The time spent cleaning the OTK db depends on
 628             # on number of records in database. Attempts to
 629             # determine if the TOTP was correct via timing attack
 630             # may be made more difficult by doing housekeeping.
 631             otk.clean()
 632             otk.commit()
 633 
 634         else:
 635             # process the token so we take the same amount of
 636             # time as when 2fa is enabled but the token is wrong.
 637             _discard = valid_hotp(token, 'A'*32, last=0, trials=windows)
 638             time.sleep(random.random()/10)  # combat timing attack
 639 
 640             # Since 2fa not enabled: set otp_ok False
 641             otp_ok = False
 642 
 643         login_ok = False
 644         try:
 645             LoginAction.verifyLogin(self, username, password)
 646             login_ok = True
 647         except LoginError as e:
 648             # store for later use
 649             verifyLoginException = e
 650 
 651         # If user supplied the next OTP in the HOTP sequence
 652         # or if it passes with a TOTP, call core LoginAction.
 653         if otp_ok and ((otp_ok == last + 1) or (last == -2)):
 654             # if otp method is not supported and logins disabled
 655             # using it, reject with a suitable error.
 656 
 657             if get_ext_setting(otp_method + "_DISABLE") == 'login_deny':
 658                 # implement part of workflow from core LoginAction.handle
 659                 self.client.make_user_anonymous()
 660                 self.client.session_api.destroy()
 661 
 662                 errormsg = _('Login disabled please see Administrator')
 663                 if redirect_url_dict is None:
 664                     self.client.add_error_message(errormsg)
 665                     return
 666                 else:
 667                     redirect_url_dict['query']['@error_message'] = errormsg
 668                     raise Redirect(make_redirect_url(redirect_url_dict))
 669 
 670             # perform normal user login
 671             LoginAction.handle(self)
 672             return  # just in case control returns here
 673 
 674         if (last != -2) and otp_ok and login_ok:
 675             # User has skipped one or more HOTP's save the sequence
 676             # number and reject the login. Request they enter the next
 677             # number in the sequence.
 678             #
 679             # FIXME how to detect hotp and not login_ok to force two
 680             #       hotp keys in a row. Maybe a new field secret_missing
 681             #       to store state between login attempts?
 682 
 683             # implement part of workflow from core LoginAction.handle
 684             self.client.make_user_anonymous()
 685             self.client.session_api.destroy()
 686 
 687             errormsg = _(
 688                 'Multiple One Time Passwords were skipped. '
 689                 'Please log in again with your next One Time Password.')
 690 
 691             if redirect_url_dict is None:
 692                 self.client.add_error_message(errormsg)
 693                 return
 694             else:
 695                 redirect_url_dict['query']['@error_message'] = errormsg
 696                 raise Redirect(make_redirect_url(redirect_url_dict))
 697 
 698         if not login_ok:
 699             # implement part of workflow from core LoginAction.handle
 700             self.client.make_user_anonymous()
 701 
 702             # keep user on same page, report error from verifyLogin.
 703             if redirect_url_dict is None:
 704                 for arg in verifyLoginException.args:
 705                     self.client.add_error_message(arg)
 706                 return
 707             else:
 708                 redirect_url_dict['query']['@error_message'] = \
 709                               verifyLoginException.args
 710                 raise Redirect(make_redirect_url(redirect_url_dict))
 711 
 712         # If hotp/totp was not matched, fail login.
 713         if otp_ok is False:
 714             # implement part of workflow from core LoginAction.handle
 715             self.client.make_user_anonymous()
 716             self.client.session_api.destroy()
 717             # Match LoginAction.handle error so we don't give away info
 718             errormsg = _('Invalid login')
 719 
 720             # keep user on original page and report error.
 721             if redirect_url_dict is None:
 722                 self.client.add_error_message(errormsg)
 723                 return
 724             else:
 725                 redirect_url_dict['query']['@error_message'] = errormsg
 726                 raise Redirect(make_redirect_url(redirect_url_dict))
 727 
 728 
 729 def init(instance):
 730     instance.registerUtil('chunk_text', chunk_text)
 731     instance.registerUtil('format_current_count', format_current_count)
 732     instance.registerUtil('hotpIntegrityValue', hotpIntegrityValue)
 733     instance.registerUtil('qrify', qrify)
 734     if 'set_form_wins' not in instance.templating_utils:
 735         instance.registerUtil('set_form_wins', set_form_wins)
 736 
 737     instance.registerAction('gen2fasecret', Generate2faSecret)
 738     instance.registerAction('login', OtpLoginAction)
2fa.py

HotpTotp.py add to detectors directory

Since a user can modify the fields directly by posting a form to roundup, this implements some simple safeguards to prevent invalid changes.

  1. The secret must be 32 characters from the base-32 character set or

    the - sentinel used when 2-factor is disabled.

  2. When the secret is set the counter must be set to 0, -1 if disabled, or -2 for TOTP.
  3. The counter must always increase if the secret is not being set.

download HotpTotp.py

   1 import logging
   2 import re
   3 
   4 from roundup.exceptions import Reject
   5 
   6 logger = logging.getLogger('detector')
   7 
   8 
   9 def audit_2fa(db, cl, nodeid, newvalues):
  10     '''Cases:
  11 
  12         secret_2fa must be 32 characters from base32 alphabet [A-Z2-7]
  13            or must be '-' (disabled).
  14 
  15         If secret_2fa is '-' secret_counter must be set to -1 in same
  16            transacation.
  17         Any other secret_2fa change must set secret_counter to 0 in same
  18            transacation.
  19            (Note this may change if TOTP used. Value of -2 reserved for
  20             counter value in TOTP mode.)
  21 
  22         If the secret_counter is changed without secret_2fa change, counter
  23            must only be increased. It must not go backwards (to avoid
  24            replay attacks).
  25     '''
  26 
  27     if __debug__:
  28         logger.debug("in auditor: user%s and newvalues: %r", nodeid, newvalues)
  29 
  30     if ('secret_2fa' not in newvalues and
  31             'secret_counter' not in newvalues):
  32         # nothing to do
  33         return
  34 
  35     secret_counter = 0
  36 
  37     if 'secret_2fa' in newvalues:
  38 
  39         # verify that the secret is changed via the gen2fasecret
  40         # action. This prevents the user from submitting a form
  41         # that changes the secret to something simple like 32 A's.
  42         #
  43         # dbhandle has a creator property added by Generate2faSecret
  44         # continue if:
  45         #    db has the Generate2faSecret property. Generate2faSecret action
  46         #    tx_Source is cli (command line)
  47         # otherwise abort change.
  48         if not (hasattr(db, 'Generate2faSecret') or (db.tx_Source in ['cli'])):
  49             logger.error("Unauthorized path for two factor auth: "
  50                          "user id %s method %s" % (db.getuid(), db.tx_Source))
  51             raise Reject("Found unauthorized path for changing "
  52                          "Two Factor Auth.")
  53 
  54         secret_2fa = newvalues['secret_2fa']
  55 
  56         logger.debug("processing secret_2fa change")
  57         if 'secret_counter' not in newvalues:
  58             # make sure it's not set to 0 or -2 in db
  59             if db.user.get(nodeid, 'secret_counter') not in [0, -2]:
  60                 raise Reject("Two Factor Auth secret changed without "
  61                              "resetting counter.")
  62         else:
  63             secret_counter = newvalues['secret_counter']
  64 
  65         if secret_2fa.password == '-':
  66             if secret_counter != -1:
  67                 raise Reject("Disabling Two Factor Auth missing proper "
  68                              "counter value.")
  69             else:
  70                 return
  71 
  72         if re.match(r'^[A-Z2-7]{32}$', secret_2fa.password):
  73             # -2 is TOTP sentinal
  74             if secret_counter not in [0, -2]:
  75                 raise Reject("Resetting Two Factor Auth missing proper "
  76                              "counter value.")
  77             else:
  78                 return
  79         else:
  80             raise Reject("Invalid secret value for Two Factor Auth")
  81 
  82     # all cases where we are changing the secret_2fa are accounted for.
  83     vals = {'new': newvalues['secret_counter'],
  84             'old': db.user.get(nodeid, 'secret_counter')}
  85 
  86     if vals['old'] >= 0:
  87         if vals['new'] <= vals['old']:
  88             # if it stays the same it hasn't changed so we won't be called.
  89             raise Reject("Two Factor Auth secret count must not decrease: "
  90                          "new: %(new)s, old: %(old)s." % vals)
  91     else:
  92         raise Reject("Two Factor Auth is disabled. You must set "
  93                      "both secret and count at the same time "
  94                      "to enable it")
  95 
  96 
  97 def init(db):
  98     # fire before changes are made
  99     db.user.audit('set', audit_2fa)
 100     db.user.audit('create', audit_2fa)
 101 
 102 # vim: sts=4 sw=4 et si
HotpTotp.py


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