389-ds-base/0024-Issue-4817-BUG-locked-crypt-accounts-on-import-may-a.patch

122 lines
4.4 KiB
Diff

From 2f0218f91d35c83a2aaecb71849a54b2481390ab Mon Sep 17 00:00:00 2001
From: Firstyear <william@blackhats.net.au>
Date: Fri, 9 Jul 2021 11:53:35 +1000
Subject: [PATCH] Issue 4817 - BUG - locked crypt accounts on import may allow
all passwords (#4819)
Bug Description: Due to mishanding of short dbpwd hashes, the
crypt_r algorithm was misused and was only comparing salts
in some cases, rather than checking the actual content
of the password.
Fix Description: Stricter checks on dbpwd lengths to ensure
that content passed to crypt_r has at least 2 salt bytes and
1 hash byte, as well as stricter checks on ct_memcmp to ensure
that compared values are the same length, rather than potentially
allowing overruns/short comparisons.
fixes: https://github.com/389ds/389-ds-base/issues/4817
Author: William Brown <william@blackhats.net.au>
Review by: @mreynolds389
---
.../password/pwd_crypt_asterisk_test.py | 50 +++++++++++++++++++
ldap/servers/plugins/pwdstorage/crypt_pwd.c | 20 +++++---
2 files changed, 64 insertions(+), 6 deletions(-)
create mode 100644 dirsrvtests/tests/suites/password/pwd_crypt_asterisk_test.py
diff --git a/dirsrvtests/tests/suites/password/pwd_crypt_asterisk_test.py b/dirsrvtests/tests/suites/password/pwd_crypt_asterisk_test.py
new file mode 100644
index 000000000..d76614db1
--- /dev/null
+++ b/dirsrvtests/tests/suites/password/pwd_crypt_asterisk_test.py
@@ -0,0 +1,50 @@
+# --- BEGIN COPYRIGHT BLOCK ---
+# Copyright (C) 2021 William Brown <william@blackhats.net.au>
+# All rights reserved.
+#
+# License: GPL (version 3 or any later version).
+# See LICENSE for details.
+# --- END COPYRIGHT BLOCK ---
+#
+import ldap
+import pytest
+from lib389.topologies import topology_st
+from lib389.idm.user import UserAccounts
+from lib389._constants import (DEFAULT_SUFFIX, PASSWORD)
+
+pytestmark = pytest.mark.tier1
+
+def test_password_crypt_asterisk_is_rejected(topology_st):
+ """It was reported that {CRYPT}* was allowing all passwords to be
+ valid in the bind process. This checks that we should be rejecting
+ these as they should represent locked accounts. Similar, {CRYPT}!
+
+ :id: 0b8f1a6a-f3eb-4443-985e-da14d0939dc3
+ :setup: Single instance
+ :steps: 1. Set a password hash in with CRYPT and the content *
+ 2. Test a bind
+ 3. Set a password hash in with CRYPT and the content !
+ 4. Test a bind
+ :expectedresults:
+ 1. Successfully set the values
+ 2. The bind fails
+ 3. Successfully set the values
+ 4. The bind fails
+ """
+ topology_st.standalone.config.set('nsslapd-allow-hashed-passwords', 'on')
+ topology_st.standalone.config.set('nsslapd-enable-upgrade-hash', 'off')
+
+ users = UserAccounts(topology_st.standalone, DEFAULT_SUFFIX)
+ user = users.create_test_user()
+
+ user.set('userPassword', "{CRYPT}*")
+
+ # Attempt to bind with incorrect password.
+ with pytest.raises(ldap.INVALID_CREDENTIALS):
+ badconn = user.bind('badpassword')
+
+ user.set('userPassword', "{CRYPT}!")
+ # Attempt to bind with incorrect password.
+ with pytest.raises(ldap.INVALID_CREDENTIALS):
+ badconn = user.bind('badpassword')
+
diff --git a/ldap/servers/plugins/pwdstorage/crypt_pwd.c b/ldap/servers/plugins/pwdstorage/crypt_pwd.c
index 9031b2199..1b37d41ed 100644
--- a/ldap/servers/plugins/pwdstorage/crypt_pwd.c
+++ b/ldap/servers/plugins/pwdstorage/crypt_pwd.c
@@ -48,15 +48,23 @@ static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */
int
crypt_pw_cmp(const char *userpwd, const char *dbpwd)
{
- int rc;
- char *cp;
+ int rc = -1;
+ char *cp = NULL;
+ size_t dbpwd_len = strlen(dbpwd);
struct crypt_data data;
data.initialized = 0;
- /* we use salt (first 2 chars) of encoded password in call to crypt_r() */
- cp = crypt_r(userpwd, dbpwd, &data);
- if (cp) {
- rc = slapi_ct_memcmp(dbpwd, cp, strlen(dbpwd));
+ /*
+ * there MUST be at least 2 chars of salt and some pw bytes, else this is INVALID and will
+ * allow any password to bind as we then only compare SALTS.
+ */
+ if (dbpwd_len >= 3) {
+ /* we use salt (first 2 chars) of encoded password in call to crypt_r() */
+ cp = crypt_r(userpwd, dbpwd, &data);
+ }
+ /* If these are not the same length, we can not proceed safely with memcmp. */
+ if (cp && dbpwd_len == strlen(cp)) {
+ rc = slapi_ct_memcmp(dbpwd, cp, dbpwd_len);
} else {
rc = -1;
}
--
2.31.1