154 lines
5.7 KiB
Diff
154 lines
5.7 KiB
Diff
Origin: https://bazaar.launchpad.net/~mailman-coders/mailman/2.1/revision/1873
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Author: Mark Sapiro
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Bug: https://bugs.launchpad.net/mailman/+bug/1947639,
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https://bugs.launchpad.net/mailman/+bug/1947640
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Subject: Fixes for CVEs 2021-42096 and 2021-42097.
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Security
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- A potential for a list member to carry out an off-line brute force
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attack to obtain the list admin password has been reported by Andre
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Protas, Richard Cloke and Andy Nuttall of Apple. This is fixed.
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CVE-2021-42096 (LP:#1947639)
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- A CSRF attack via the user options page could allow takeover of a users
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account. This is fixed. CVE-2021-42097 (LP:#1947640)
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=== modified file 'Mailman/CSRFcheck.py'
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---
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Mailman/CSRFcheck.py | 22 +++++++++++++++++++---
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Mailman/Cgi/options.py | 25 ++++++++++++-------------
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Mailman/SecurityManager.py | 1 +
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3 files changed, 32 insertions(+), 16 deletions(-)
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diff --git a/Mailman/CSRFcheck.py b/Mailman/CSRFcheck.py
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index a1e78d9..0940b7e 100644
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--- a/Mailman/CSRFcheck.py
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+++ b/Mailman/CSRFcheck.py
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@@ -18,11 +18,13 @@
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""" Cross-Site Request Forgery checker """
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import time
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+import urllib
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import marshal
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import binascii
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from Mailman import mm_cfg
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-from Mailman.Utils import sha_new
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+from Mailman.Logging.Syslog import syslog
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+from Mailman.Utils import UnobscureEmail, sha_new
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keydict = {
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'user': mm_cfg.AuthUser,
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@@ -37,6 +39,10 @@ keydict = {
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def csrf_token(mlist, contexts, user=None):
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""" create token by mailman cookie generation algorithm """
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+ if user:
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+ # Unmunge a munged email address.
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+ user = UnobscureEmail(urllib.unquote(user))
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+
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for context in contexts:
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key, secret = mlist.AuthContextInfo(context, user)
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if key:
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@@ -49,9 +55,8 @@ def csrf_token(mlist, contexts, user=None):
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token = binascii.hexlify(marshal.dumps((issued, keymac)))
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return token
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-def csrf_check(mlist, token):
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+def csrf_check(mlist, token, options_user=None):
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""" check token by mailman cookie validation algorithm """
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-
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try:
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issued, keymac = marshal.loads(binascii.unhexlify(token))
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key, received_mac = keymac.split(':', 1)
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@@ -62,6 +67,17 @@ def csrf_check(mlist, token):
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key, user = key.split('+', 1)
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else:
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user = None
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+ if user:
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+ # This is for CVE-2021-42097. The token is a user token because
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+ # of the fix for CVE-2021-42096 but it must match the user for
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+ # whom the options page is requested.
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+ raw_user = UnobscureEmail(urllib.unquote(user))
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+ if options_user and options_user != raw_user:
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+ syslog('mischief',
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+ 'Form for user %s submitted with CSRF token '
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+ 'issued for %s.',
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+ options_user, raw_user)
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+ return False
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context = keydict.get(key)
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key, secret = mlist.AuthContextInfo(context, user)
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assert key
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diff --git a/Mailman/Cgi/options.py b/Mailman/Cgi/options.py
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index 386b308..980fc09 100644
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--- a/Mailman/Cgi/options.py
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+++ b/Mailman/Cgi/options.py
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@@ -54,9 +54,6 @@ except NameError:
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True = 1
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False = 0
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-AUTH_CONTEXTS = (mm_cfg.AuthListAdmin, mm_cfg.AuthSiteAdmin,
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- mm_cfg.AuthListModerator, mm_cfg.AuthUser)
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-
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def main():
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global _
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@@ -124,15 +121,6 @@ def main():
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print doc.Format()
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return
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- if set(params) - set(safe_params):
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- csrf_checked = csrf_check(mlist, cgidata.getfirst('csrf_token'))
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- else:
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- csrf_checked = True
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- # if password is present, void cookie to force password authentication.
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- if cgidata.getfirst('password'):
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- os.environ['HTTP_COOKIE'] = ''
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- csrf_checked = True
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-
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# Set the language for the page. If we're coming from the listinfo cgi,
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# we might have a 'language' key in the cgi data. That was an explicit
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# preference to view the page in, so we should honor that here. If that's
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@@ -168,6 +156,16 @@ def main():
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user = user[-1]
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# Avoid cross-site scripting attacks
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+ if set(params) - set(safe_params):
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+ csrf_checked = csrf_check(mlist, cgidata.getfirst('csrf_token'),
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+ Utils.UnobscureEmail(urllib.unquote(user)))
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+ else:
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+ csrf_checked = True
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+ # if password is present, void cookie to force password authentication.
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+ if cgidata.getfirst('password'):
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+ os.environ['HTTP_COOKIE'] = ''
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+ csrf_checked = True
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+
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safeuser = Utils.websafe(user)
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try:
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Utils.ValidateEmail(user)
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@@ -867,8 +865,9 @@ def options_page(mlist, doc, user, cpuser, userlang, message=''):
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mlist.FormatButton('othersubs',
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_('List my other subscriptions')))
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replacements['<mm-form-start>'] = (
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+ # Always make the CSRF token for the user. CVE-2021-42096
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mlist.FormatFormStart('options', user, mlist=mlist,
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- contexts=AUTH_CONTEXTS, user=user))
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+ contexts=[mm_cfg.AuthUser], user=user))
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replacements['<mm-user>'] = user
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replacements['<mm-presentable-user>'] = presentable_user
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replacements['<mm-email-my-pw>'] = mlist.FormatButton(
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diff --git a/Mailman/SecurityManager.py b/Mailman/SecurityManager.py
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index 9b7f03f..e9e5ce5 100644
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--- a/Mailman/SecurityManager.py
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+++ b/Mailman/SecurityManager.py
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@@ -104,6 +104,7 @@ class SecurityManager:
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if user is None:
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# A bad system error
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raise TypeError, 'No user supplied for AuthUser context'
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+ user = Utils.UnobscureEmail(urllib.unquote(user))
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secret = self.getMemberPassword(user)
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userdata = urllib.quote(Utils.ObscureEmail(user), safe='')
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key += 'user+%s' % userdata
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--
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2.23.0
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