From fa5d09798a56960c34f28296726ed4525e6950d9 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Mon, 23 Mar 2020 19:10:03 -0400
Subject: [PATCH] Eliminate redundant PKINIT responder invocation

In pkinit_client_prep_questions(), only act if the input padata type
is KRB5_PADATA_PK_AS_REQ.  Otherwise we will ask questions again when
the KDC issues a ticket.

Commit 7621d2f9a87214327ca3b2594e34dc7cea84596b (ticket 8242)
unintentionally changed the behavior of pkinit_load_fs_cert_and_key(),
causing pkinit_client_prep_questions() to do nothing on its first
call.  Restore the original behavior of returning 0 when prompting is
deferred.

Modify the existing "FILE identity, password on key (responder)"
PKINIT test to check that the responder is only invoked once.

ticket: 8885
(cherry picked from commit f1286842ce7b9e507a4ce0a47f44ab361a98be63)
(cherry picked from commit 4a05805eb39ba088c07f782fb52a6538ec3f2db6)
---
 src/plugins/preauth/pkinit/pkinit_clnt.c           |  5 +++++
 src/plugins/preauth/pkinit/pkinit_crypto_openssl.c | 13 +++++++------
 src/tests/t_pkinit.py                              | 11 +++++++----
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/src/plugins/preauth/pkinit/pkinit_clnt.c b/src/plugins/preauth/pkinit/pkinit_clnt.c
index 2f0431991..9b991ffe0 100644
--- a/src/plugins/preauth/pkinit/pkinit_clnt.c
+++ b/src/plugins/preauth/pkinit/pkinit_clnt.c
@@ -897,6 +897,11 @@ pkinit_client_prep_questions(krb5_context context,
     k5_json_object jval = NULL;
     k5_json_number jflag = NULL;
 
+    /* Don't ask questions for the informational padata items or when the
+     * ticket is issued. */
+    if (pa_data->pa_type != KRB5_PADATA_PK_AS_REQ)
+        return 0;
+
     if (!reqctx->identity_initialized) {
         pkinit_client_profile(context, plgctx, reqctx, cb, rock,
                               &request->server->realm);
diff --git a/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c b/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
index dd718c2be..dbb054378 100644
--- a/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
+++ b/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
@@ -4362,17 +4362,18 @@ pkinit_load_fs_cert_and_key(krb5_context context,
 
     /* Load the certificate. */
     retval = get_cert(certname, &x);
-    if (retval != 0 || x == NULL) {
-        retval = oerr(context, 0, _("Cannot read certificate file '%s'"),
+    if (retval) {
+        retval = oerr(context, retval, _("Cannot read certificate file '%s'"),
                       certname);
-        goto cleanup;
     }
+    if (retval || x == NULL)
+        goto cleanup;
     /* Load the key. */
     retval = get_key(context, id_cryptoctx, keyname, fsname, &y, password);
-    if (retval != 0 || y == NULL) {
-        retval = oerr(context, 0, _("Cannot read key file '%s'"), fsname);
+    if (retval)
+        retval = oerr(context, retval, _("Cannot read key file '%s'"), fsname);
+    if (retval || y == NULL)
         goto cleanup;
-    }
 
     id_cryptoctx->creds[cindex] = malloc(sizeof(struct _pkinit_cred_info));
     if (id_cryptoctx->creds[cindex] == NULL) {
diff --git a/src/tests/t_pkinit.py b/src/tests/t_pkinit.py
index 69daf4987..ecd450e8a 100755
--- a/src/tests/t_pkinit.py
+++ b/src/tests/t_pkinit.py
@@ -248,10 +248,13 @@ realm.run(['./adata', realm.host_princ],
 # supplied by the responder.
 # Supply the response in raw form.
 mark('FILE identity, password on key (responder)')
-realm.run(['./responder', '-x', 'pkinit={"%s": 0}' % file_enc_identity,
-           '-r', 'pkinit={"%s": "encrypted"}' % file_enc_identity,
-           '-X', 'X509_user_identity=%s' % file_enc_identity,
-           realm.user_princ])
+out = realm.run(['./responder', '-x', 'pkinit={"%s": 0}' % file_enc_identity,
+                 '-r', 'pkinit={"%s": "encrypted"}' % file_enc_identity,
+                 '-X', 'X509_user_identity=%s' % file_enc_identity,
+                 realm.user_princ])
+# Regression test for #8885 (password question asked twice).
+if out.count('OK: ') != 1:
+    fail('Wrong number of responder calls')
 # Supply the response through the convenience API.
 realm.run(['./responder', '-X', 'X509_user_identity=%s' % file_enc_identity,
            '-p', '%s=%s' % (file_enc_identity, 'encrypted'), realm.user_princ])