krb5/Allow-deletion-of-require_auth-with-LDAP-KDB.patch

From 59eea8a1977c6039069b3826e5e651582a33fc25 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Tue, 25 Feb 2020 11:32:09 -0500
Subject: [PATCH] Allow deletion of require_auth with LDAP KDB

In update_ldap_mod_auth_ind(), if there is no string attribute value
for require_auth, check for krbPrincipalAuthInd attributes that might
need to be removed.  (This will only work if the entry is loaded and
then modified, but that is the normal case for an existing entry.)

Move the update_ldap_mod_auth_ind() call inside the tl-data
conditional (which should perhaps be a check for KADM5_TL_DATA in the
mask instead).  A modification which did not intend to update tl-data
should not remove the krbPrincipalAuthInd attributes.

Change get_int_from_tl_data() to to zero its output so that it can't
leave a garbage value behind if it returns 0 (as it does if no
KDB_TL_USER_INFO tl-data is present).

Based on a patch by Glenn Machin.

ticket: 8877
tags: pullup
target_version: 1.18-next
target_version: 1.17-next

(cherry picked from commit 6d9da7bb216f96cbdd731aa894714bd84213a9d0)
---
 src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c  |  2 ++
 .../kdb/ldap/libkdb_ldap/ldap_principal2.c    | 31 ++++++++++++-------
 src/tests/t_kdb.py                            | 26 +++++++++++++++-
 3 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c b/src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c
index ec7f32511..6bc20593f 100644
--- a/src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c
+++ b/src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c
@@ -721,6 +721,8 @@ get_int_from_tl_data(krb5_context context, krb5_db_entry *entry, int type,
     void *ptr;
     int *intptr;
 
+    *intval = 0;
+
     tl_data.tl_data_type = KDB_TL_USER_INFO;
     ret = krb5_dbe_lookup_tl_data(context, entry, &tl_data);
     if (ret || tl_data.tl_data_length == 0)
diff --git a/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c b/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c
index 1d0726707..8d97a29b6 100644
--- a/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c
+++ b/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c
@@ -627,12 +627,22 @@ update_ldap_mod_auth_ind(krb5_context context, krb5_db_entry *entry,
     char *auth_ind = NULL;
     char *strval[10] = { 0 };
     char *ai, *ai_save = NULL;
-    int sv_num = sizeof(strval) / sizeof(*strval);
+    int mask, sv_num = sizeof(strval) / sizeof(*strval);
 
     ret = krb5_dbe_get_string(context, entry, KRB5_KDB_SK_REQUIRE_AUTH,
                               &auth_ind);
-    if (ret || auth_ind == NULL)
-        goto cleanup;
+    if (ret)
+        return ret;
+    if (auth_ind == NULL) {
+        /* If we know krbPrincipalAuthInd attributes are present from loading
+         * the entry, delete them. */
+        ret = krb5_get_attributes_mask(context, entry, &mask);
+        if (!ret && (mask & KDB_AUTH_IND_ATTR)) {
+            return krb5_add_str_mem_ldap_mod(mods, "krbPrincipalAuthInd",
+                                             LDAP_MOD_DELETE, NULL);
+        }
+        return 0;
+    }
 
     ai = strtok_r(auth_ind, " ", &ai_save);
     while (ai != NULL && i < sv_num) {
@@ -642,8 +652,6 @@ update_ldap_mod_auth_ind(krb5_context context, krb5_db_entry *entry,
 
     ret = krb5_add_str_mem_ldap_mod(mods, "krbPrincipalAuthInd",
                                     LDAP_MOD_REPLACE, strval);
-
-cleanup:
     krb5_dbe_free_string(context, auth_ind);
     return ret;
 }
@@ -1251,18 +1259,19 @@ krb5_ldap_put_principal(krb5_context context, krb5_db_entry *entry,
 
     } /* Modify Key data ends here */
 
-    /* Auth indicators will also be stored in krbExtraData when processing
-     * tl_data. */
-    st = update_ldap_mod_auth_ind(context, entry, &mods);
-    if (st != 0)
-        goto cleanup;
-
     /* Set tl_data */
     if (entry->tl_data != NULL) {
         int count = 0;
         struct berval **ber_tl_data = NULL;
         krb5_tl_data *ptr;
         krb5_timestamp unlock_time;
+
+        /* Normalize required auth indicators, but also store them as string
+         * attributes within krbExtraData. */
+        st = update_ldap_mod_auth_ind(context, entry, &mods);
+        if (st != 0)
+            goto cleanup;
+
         for (ptr = entry->tl_data; ptr != NULL; ptr = ptr->tl_data_next) {
             if (ptr->tl_data_type == KRB5_TL_LAST_PWD_CHANGE
 #ifdef SECURID
diff --git a/src/tests/t_kdb.py b/src/tests/t_kdb.py
index 03ee70f47..caa7e9d8f 100755
--- a/src/tests/t_kdb.py
+++ b/src/tests/t_kdb.py
@@ -319,19 +319,43 @@ realm.klist(realm.user_princ, realm.host_princ)
 
 mark('LDAP auth indicator')
 
-# Test auth indicator support
+# Test require_auth normalization.
 realm.addprinc('authind', password('authind'))
 realm.run([kadminl, 'setstr', 'authind', 'require_auth', 'otp radius'])
 
+# Check that krbPrincipalAuthInd attributes are set when the string
+# attribute it set.
 out = ldap_search('(krbPrincipalName=authind*)')
 if 'krbPrincipalAuthInd: otp' not in out:
     fail('Expected krbPrincipalAuthInd value not in output')
 if 'krbPrincipalAuthInd: radius' not in out:
     fail('Expected krbPrincipalAuthInd value not in output')
 
+# Check that the string attribute still appears when the principal is
+# loaded.
 realm.run([kadminl, 'getstrs', 'authind'],
           expected_msg='require_auth: otp radius')
 
+# Modify the LDAP attributes and check that the change is reflected in
+# the string attribute.
+ldap_modify('dn: krbPrincipalName=authind@KRBTEST.COM,cn=t1,cn=krb5\n'
+            'changetype: modify\n'
+            'replace: krbPrincipalAuthInd\n'
+            'krbPrincipalAuthInd: radius\n'
+            'krbPrincipalAuthInd: pkinit\n')
+realm.run([kadminl, 'getstrs', 'authind'],
+           expected_msg='require_auth: radius pkinit')
+
+# Regression test for #8877: remove the string attribute and check
+# that it is reflected in the LDAP attributes and by getstrs.
+realm.run([kadminl, 'delstr', 'authind', 'require_auth'])
+out = ldap_search('(krbPrincipalName=authind*)')
+if 'krbPrincipalAuthInd' in out:
+    fail('krbPrincipalAuthInd attribute still present after delstr')
+out = realm.run([kadminl, 'getstrs', 'authind'])
+if 'require_auth' in out:
+    fail('require_auth string attribute still visible after delstr')
+
 mark('LDAP service principal aliases')
 
 # Test service principal aliases.