From: Isaac Boukris Date: Fri, 17 Aug 2018 21:40:30 +0000 (+0300) Subject: CVE-2018-16853: The ticket in check_policy_as can actually be a TGS X-Git-Tag: tdb-1.3.17~596 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6c453aeb0c771d14fe501e9a37d9f51b9403872b;p=thirdparty%2Fsamba.git CVE-2018-16853: The ticket in check_policy_as can actually be a TGS This happens when we are called from S4U2Self flow, and in that case kdcreq->client is NULL. Use the name from client entry instead. BUG: https://bugzilla.samba.org/show_bug.cgi?id=13571 Signed-off-by: Isaac Boukris Reviewed-by: Andreas Schneider Reviewed-by: Stefan Metzmacher --- diff --git a/source4/kdc/mit-kdb/kdb_samba_policies.c b/source4/kdc/mit-kdb/kdb_samba_policies.c index de5813bde2f..81ac73582e0 100644 --- a/source4/kdc/mit-kdb/kdb_samba_policies.c +++ b/source4/kdc/mit-kdb/kdb_samba_policies.c @@ -81,6 +81,7 @@ krb5_error_code kdb_samba_db_check_policy_as(krb5_context context, char *netbios_name = NULL; char *realm = NULL; bool password_change = false; + krb5_const_principal client_princ; DATA_BLOB int_data = { NULL, 0 }; krb5_data d; krb5_pa_data **e_data; @@ -90,7 +91,10 @@ krb5_error_code kdb_samba_db_check_policy_as(krb5_context context, return KRB5_KDB_DBNOTINITED; } - if (ks_is_kadmin(context, kdcreq->client)) { + /* Prefer canonicalised name from client entry */ + client_princ = client ? client->princ : kdcreq->client; + + if (client_princ == NULL || ks_is_kadmin(context, client_princ)) { return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN; } @@ -111,7 +115,7 @@ krb5_error_code kdb_samba_db_check_policy_as(krb5_context context, goto done; } - code = krb5_unparse_name(context, kdcreq->client, &client_name); + code = krb5_unparse_name(context, client_princ, &client_name); if (code) { goto done; }