Always use S4U2Proxy second ticket parsed authdata

When the KDC handles an S4U2Proxy request, if the KDB module returned
parsed authdata for the header ticket and not for the second ticket,
we could erroneously pass the header ticket's parsed authdata to
handle_authdata().  Make sure we always pass the parsed authdata for
the second ticket.

[ghudson@mit.edu: added comment; rewrote commit message]

(cherry picked from commit 21d823991a81d64af460ec62a98585c85534850b)

ticket: 8874
version_fixed: 1.18

diff --git a/src/kdc/do_tgs_req.c b/src/kdc/do_tgs_req.c
index dfb5205795ed9f4062e4d641ade8ac469640f004..241f34e2a8d274d05c5cce11c6c0651672e7a82b 100644 (file)
--- a/src/kdc/do_tgs_req.c
+++ b/src/kdc/do_tgs_req.c
@@ -331,7 +331,7 @@ process_tgs_req(krb5_kdc_req *request, krb5_data *pkt,
         goto cleanup;
 
     if (isflagset(request->kdc_options, KDC_OPT_CNAME_IN_ADDL_TKT)) {
-        /* Do constrained delegation protocol and authorization checks */
+        /* Do constrained delegation protocol and authorization checks. */
         setflag(c_flags, KRB5_KDB_FLAG_CONSTRAINED_DELEGATION);
 
         errcode = kdc_process_s4u2proxy_req(kdc_active_realm, c_flags, request,
@@ -359,6 +359,12 @@ process_tgs_req(krb5_kdc_req *request, krb5_data *pkt,
             goto cleanup;
 
         assert(krb5_is_tgs_principal(header_ticket->server));
+
+        /* Use the parsed authdata from the second ticket during authdata
+         * handling. */
+        krb5_db_free_authdata_info(kdc_context, ad_info);
+        ad_info = stkt_ad_info;
+        stkt_ad_info = NULL;
     }
 
     au_state->stage = ISSUE_TKT;
@@ -636,8 +642,8 @@ process_tgs_req(krb5_kdc_req *request, krb5_data *pkt,
                               subkey != NULL ? subkey :
                               header_ticket->enc_part2->session,
                               encrypting_key, subject_key, pkt, request,
-                              altcprinc, stkt_ad_info ? stkt_ad_info : ad_info,
-                              subject_tkt, &auth_indicators, &enc_tkt_reply);
+                              altcprinc, ad_info, subject_tkt,
+                              &auth_indicators, &enc_tkt_reply);
     if (errcode) {
         krb5_klog_syslog(LOG_INFO, _("TGS_REQ : handle_authdata (%d)"),
                          errcode);