diff --git a/Mailman/CSRFcheck.py b/Mailman/CSRFcheck.py
index a3b6885..73b003a 100644
--- a/Mailman/CSRFcheck.py
+++ b/Mailman/CSRFcheck.py
@@ -18,11 +18,13 @@
""" Cross-Site Request Forgery checker """
import time
+import urllib
import marshal
import binascii
from Mailman import mm_cfg
-from Mailman.Utils import sha_new
+from Mailman.Logging.Syslog import syslog
+from Mailman.Utils import UnobscureEmail, sha_new
keydict = {
'user': mm_cfg.AuthUser,
@@ -37,6 +39,10 @@ keydict = {
def csrf_token(mlist, contexts, user=None):
""" create token by mailman cookie generation algorithm """
+ if user:
+ # Unmunge a munged email address.
+ user = UnobscureEmail(urllib.unquote(user))
+
for context in contexts:
key, secret = mlist.AuthContextInfo(context, user)
if key:
@@ -49,9 +55,8 @@ def csrf_token(mlist, contexts, user=None):
token = binascii.hexlify(marshal.dumps((issued, keymac)))
return token
-def csrf_check(mlist, token):
+def csrf_check(mlist, token, options_user=None):
""" check token by mailman cookie validation algorithm """
-
try:
issued, keymac = marshal.loads(binascii.unhexlify(token))
key, received_mac = keymac.split(':', 1)
@@ -61,6 +66,17 @@ def csrf_check(mlist, token):
key, user = key.split('+', 1)
else:
user = None
+ if user:
+ # This is for CVE-2021-42097. The token is a user token because
+ # of the fix for CVE-2021-42096 but it must match the user for
+ # whom the options page is requested.
+ raw_user = UnobscureEmail(urllib.unquote(user))
+ if options_user and options_user != raw_user:
+ syslog('mischief',
+ 'Form for user %s submitted with CSRF token '
+ 'issued for %s.',
+ options_user, raw_user)
+ return False
context = keydict.get(key)
key, secret = mlist.AuthContextInfo(context, user)
assert key
diff --git a/Mailman/Cgi/options.py b/Mailman/Cgi/options.py
index 328d9d5..51c06b6 100644
--- a/Mailman/Cgi/options.py
+++ b/Mailman/Cgi/options.py
@@ -48,9 +48,6 @@ except NameError:
True = 1
False = 0
-AUTH_CONTEXTS = (mm_cfg.AuthListAdmin, mm_cfg.AuthSiteAdmin,
- mm_cfg.AuthListModerator, mm_cfg.AuthUser)
-
def main():
doc = Document()
@@ -95,14 +92,6 @@ def main():
safe_params = ['displang-button', 'language', 'email', 'password', 'login',
'login-unsub', 'login-remind', 'VARHELP', 'UserOptions']
params = cgidata.keys()
- if set(params) - set(safe_params):
- csrf_checked = csrf_check(mlist, cgidata.getvalue('csrf_token'))
- else:
- csrf_checked = True
- # if password is present, void cookie to force password authentication.
- if cgidata.getvalue('password'):
- os.environ['HTTP_COOKIE'] = ''
- csrf_checked = True
# Set the language for the page. If we're coming from the listinfo cgi,
# we might have a 'language' key in the cgi data. That was an explicit
@@ -131,6 +120,16 @@ def main():
user = Utils.LCDomain(Utils.UnobscureEmail(SLASH.join(parts[1:])))
# Avoid cross-site scripting attacks
+ if set(params) - set(safe_params):
+ csrf_checked = csrf_check(mlist, cgidata.getfirst('csrf_token'),
+ Utils.UnobscureEmail(urllib.unquote(user)))
+ else:
+ csrf_checked = True
+ # if password is present, void cookie to force password authentication.
+ if cgidata.getfirst('password'):
+ os.environ['HTTP_COOKIE'] = ''
+ csrf_checked = True
+
safeuser = Utils.websafe(user)
try:
Utils.ValidateEmail(user)
@@ -804,8 +803,9 @@ def options_page(mlist, doc, user, cpuser, userlang, message=''):
mlist.FormatButton('othersubs',
_('List my other subscriptions')))
replacements['<mm-form-start>'] = (
+ # Always make the CSRF token for the user. CVE-2021-42096
mlist.FormatFormStart('options', user, mlist=mlist,
- contexts=AUTH_CONTEXTS, user=user))
+ contexts=[mm_cfg.AuthUser], user=user))
replacements['<mm-user>'] = user
replacements['<mm-presentable-user>'] = presentable_user
replacements['<mm-email-my-pw>'] = mlist.FormatButton(
diff --git a/Mailman/SecurityManager.py b/Mailman/SecurityManager.py
index 4f6aa34..74b7a67 100644
--- a/Mailman/SecurityManager.py
+++ b/Mailman/SecurityManager.py
@@ -104,6 +104,7 @@ class SecurityManager:
if user is None:
# A bad system error
raise TypeError, 'No user supplied for AuthUser context'
+ user = Utils.UnobscureEmail(urllib.unquote(user))
secret = self.getMemberPassword(user)
userdata = urllib.quote(Utils.ObscureEmail(user), safe='')
key += 'user+%s' % userdata