CVE-2022-37966 param: let "kdc default domain supportedenctypes = 0" mean the default

In order to allow better upgrades we need the default value for smb.conf to the
same even if the effective default value of the software changes in future.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15237

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
(cherry picked from commit fa64f8fa8d92167ed15d1109af65bbb4daab4bad)

diff --git a/docs-xml/smbdotconf/security/kdcdefaultdomainsupportedenctypes.xml b/docs-xml/smbdotconf/security/kdcdefaultdomainsupportedenctypes.xml
index e93650ac3e078496b168c2996217209ac71e002b..984611167b595e977fb9bf32439c0f904779d70c 100644 (file)
--- a/docs-xml/smbdotconf/security/kdcdefaultdomainsupportedenctypes.xml
+++ b/docs-xml/smbdotconf/security/kdcdefaultdomainsupportedenctypes.xml
@@ -38,5 +38,5 @@
 
 </description>
 
-<value type="default">36<comment>equivalent to: rc4-hmac aes256-cts-hmac-sha1-96-sk</comment></value>
+<value type="default">0<comment>maps to what the software supports currently: arcfour-hmac-md5 aes256-cts-hmac-sha1-96-sk</comment></value>
 </samba:parameter>

diff --git a/lib/param/loadparm.c b/lib/param/loadparm.c
index e810fa564d68eec10e658d5a0252e15495f9d480..71f08c77bbf2a9293a567cf04132b13f5f1d46e6 100644 (file)
--- a/lib/param/loadparm.c
+++ b/lib/param/loadparm.c
@@ -3083,10 +3083,6 @@ struct loadparm_context *loadparm_init(TALLOC_CTX *mem_ctx)
                                  "rpc start on demand helpers",
                                  "yes");
 
-       lpcfg_do_global_parameter(lp_ctx,
-                                 "kdc default domain supported enctypes",
-                                 "rc4-hmac aes256-cts-hmac-sha1-96-sk");
-
        for (i = 0; parm_table[i].label; i++) {
                if (!(lp_ctx->flags[i] & FLAG_CMDLINE)) {
                        lp_ctx->flags[i] |= FLAG_DEFAULT;

diff --git a/python/samba/tests/krb5/etype_tests.py b/python/samba/tests/krb5/etype_tests.py
index 1a16518df94e682c32c59cca71c4e9f71b7c0ebe..9725d544c2ac5ac4a983a3f51da13d5ca6c809ad 100755 (executable)
--- a/python/samba/tests/krb5/etype_tests.py
+++ b/python/samba/tests/krb5/etype_tests.py
@@ -63,6 +63,8 @@ class EtypeTests(KdcTgsBaseTests):
             lp = self.get_lp()
             self.default_supported_enctypes = lp.get(
                 'kdc default domain supported enctypes')
+            if self.default_supported_enctypes == 0:
+                self.default_supported_enctypes = rc4_bit | aes256_sk_bit
 
     def _server_creds(self, supported=None, force_nt4_hash=False,
                       account_type=None):

diff --git a/python/samba/tests/krb5/kdc_base_test.py b/python/samba/tests/krb5/kdc_base_test.py
index 801d69ca43a584c8edfee35c050cd857e850c78f..ace756ab0d262aae28118fffaa1e0436af66af58 100644 (file)
--- a/python/samba/tests/krb5/kdc_base_test.py
+++ b/python/samba/tests/krb5/kdc_base_test.py
@@ -58,6 +58,9 @@ from samba.ndr import ndr_pack, ndr_unpack
 from samba import net
 from samba.samdb import SamDB, dsdb_Dn
 
+rc4_bit = security.KERB_ENCTYPE_RC4_HMAC_MD5
+aes256_sk_bit = security.KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96_SK
+
 from samba.tests import delete_force
 import samba.tests.krb5.kcrypto as kcrypto
 from samba.tests.krb5.raw_testcase import (
@@ -635,7 +638,8 @@ class KDCBaseTest(RawKerberosTest):
         if supported_enctypes is None:
             lp = self.get_lp()
             supported_enctypes = lp.get('kdc default domain supported enctypes')
-
+            if supported_enctypes == 0:
+                supported_enctypes = rc4_bit | aes256_sk_bit
         supported_enctypes = int(supported_enctypes)
 
         if extra_bits is not None:

diff --git a/source3/param/loadparm.c b/source3/param/loadparm.c
index c33b0cd3fea58fb177044f6fe18ccb163e073b0e..6d567a9e7e54bf45a29dcdebfb267869ac133f48 100644 (file)
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -991,9 +991,6 @@ static void init_globals(struct loadparm_context *lp_ctx, bool reinit_globals)
         */
        Globals.rpc_start_on_demand_helpers = true;
 
-       Globals.kdc_default_domain_supported_enctypes =
-               KERB_ENCTYPE_RC4_HMAC_MD5 | KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96_SK;
-
        /* Now put back the settings that were set with lp_set_cmdline() */
        apply_lp_set_cmdline();
 }

diff --git a/source4/kdc/db-glue.c b/source4/kdc/db-glue.c
index cf3a731926e397012232cb0308ef5fad7ec323a8..0b07961f838d2632fac553bbf3bb725f992f5653 100644 (file)
--- a/source4/kdc/db-glue.c
+++ b/source4/kdc/db-glue.c
@@ -991,7 +991,11 @@ static krb5_error_code samba_kdc_message2entry(krb5_context context,
        bool force_rc4 = lpcfg_kdc_force_enable_rc4_weak_session_keys(lp_ctx);
        struct ldb_message_element *objectclasses;
        struct ldb_val computer_val;
-       uint32_t default_supported_enctypes = lpcfg_kdc_default_domain_supported_enctypes(lp_ctx);
+       uint32_t config_default_supported_enctypes = lpcfg_kdc_default_domain_supported_enctypes(lp_ctx);
+       uint32_t default_supported_enctypes =
+               config_default_supported_enctypes != 0 ?
+               config_default_supported_enctypes :
+               ENC_RC4_HMAC_MD5 | ENC_HMAC_SHA1_96_AES256_SK;
        uint32_t supported_enctypes
                = ldb_msg_find_attr_as_uint(msg,
                                            "msDS-SupportedEncryptionTypes",