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authorStefan Metzmacher <metze@samba.org>2011-06-21 11:05:15 +0200
committerStefan Metzmacher <metze@samba.org>2011-06-22 17:05:14 +0200
commit033f3376a834c1078b377647069b7e30aef59667 (patch)
tree96106cb06d9b3e5e1061e1d6328ee03bf216f25e
parentb9e095fdfb684005f9bb5c1d943b2a0705308500 (diff)
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s4:auth/kerberos: protect kerberos_kinit_password_cc() against old KDCs
If the KDC does not support S4U2Proxy, it might return a ticket for the TGT client principal. metze
-rw-r--r--source4/auth/kerberos/kerberos.c49
1 files changed, 48 insertions, 1 deletions
diff --git a/source4/auth/kerberos/kerberos.c b/source4/auth/kerberos/kerberos.c
index d32559ed81..0fc9d143ab 100644
--- a/source4/auth/kerberos/kerberos.c
+++ b/source4/auth/kerberos/kerberos.c
@@ -109,6 +109,7 @@
krb5_ccache tmp_cc;
const char *self_realm;
krb5_principal blacklist_principal = NULL;
+ krb5_principal whitelist_principal = NULL;
if (impersonate_principal && self_service == NULL) {
return EINVAL;
@@ -282,14 +283,24 @@
s4u2self_creds->ticket.length,
&s4u2self_ticket,
&s4u2self_ticketlen);
- krb5_free_creds(ctx, s4u2self_creds);
if (code != 0) {
+ krb5_free_creds(ctx, s4u2self_creds);
krb5_free_principal(ctx, blacklist_principal);
krb5_cc_destroy(ctx, tmp_cc);
return code;
}
/*
+ * we need to remember the client principal of the
+ * S4U2Self stage and as it needs to match the one we
+ * will get for the S4U2Proxy stage. We need this
+ * in order to detect KDCs which does not support S4U2Proxy.
+ */
+ whitelist_principal = s4u2self_creds->client;
+ s4u2self_creds->client = NULL;
+ krb5_free_creds(ctx, s4u2self_creds);
+
+ /*
* For S4U2Proxy we also got a target service principal,
* which also belongs to our own realm (available on
* our client principal).
@@ -297,6 +308,7 @@
code = krb5_parse_name(ctx, target_service, &target_princ);
if (code != 0) {
free_Ticket(&s4u2self_ticket);
+ krb5_free_principal(ctx, whitelist_principal);
krb5_free_principal(ctx, blacklist_principal);
krb5_cc_destroy(ctx, tmp_cc);
return code;
@@ -306,6 +318,7 @@
if (code != 0) {
free_Ticket(&s4u2self_ticket);
krb5_free_principal(ctx, target_princ);
+ krb5_free_principal(ctx, whitelist_principal);
krb5_free_principal(ctx, blacklist_principal);
krb5_cc_destroy(ctx, tmp_cc);
return code;
@@ -315,6 +328,7 @@
if (code != 0) {
free_Ticket(&s4u2self_ticket);
krb5_free_principal(ctx, target_princ);
+ krb5_free_principal(ctx, whitelist_principal);
krb5_free_principal(ctx, blacklist_principal);
krb5_cc_destroy(ctx, tmp_cc);
return code;
@@ -328,6 +342,7 @@
if (code != 0) {
krb5_get_creds_opt_free(ctx, options);
krb5_free_principal(ctx, target_princ);
+ krb5_free_principal(ctx, whitelist_principal);
krb5_free_principal(ctx, blacklist_principal);
krb5_cc_destroy(ctx, tmp_cc);
return code;
@@ -339,6 +354,7 @@
krb5_free_principal(ctx, target_princ);
krb5_cc_destroy(ctx, tmp_cc);
if (code != 0) {
+ krb5_free_principal(ctx, whitelist_principal);
krb5_free_principal(ctx, blacklist_principal);
return code;
}
@@ -352,6 +368,7 @@
&store_creds);
krb5_free_creds(ctx, s4u2proxy_creds);
if (code != 0) {
+ krb5_free_principal(ctx, whitelist_principal);
krb5_free_principal(ctx, blacklist_principal);
return code;
}
@@ -385,6 +402,7 @@
SAFE_FREE(sp);
SAFE_FREE(ip);
+ krb5_free_principal(ctx, whitelist_principal);
krb5_free_principal(ctx, blacklist_principal);
krb5_free_cred_contents(ctx, &store_creds);
return KRB5_FWD_BAD_PRINCIPAL;
@@ -393,6 +411,35 @@
krb5_free_principal(ctx, blacklist_principal);
}
+ if (whitelist_principal &&
+ !krb5_principal_compare(ctx, store_creds.client, whitelist_principal)) {
+ char *sp = NULL;
+ char *ep = NULL;
+
+ code = krb5_unparse_name(ctx, store_creds.client, &sp);
+ if (code != 0) {
+ sp = NULL;
+ }
+ code = krb5_unparse_name(ctx, whitelist_principal, &ep);
+ if (code != 0) {
+ ep = NULL;
+ }
+ DEBUG(1, ("kerberos_kinit_password_cc: "
+ "KDC returned wrong principal[%s] we expected [%s]\n",
+ sp?sp:"<no memory>",
+ ep?ep:"<no memory>"));
+
+ SAFE_FREE(sp);
+ SAFE_FREE(ep);
+
+ krb5_free_principal(ctx, whitelist_principal);
+ krb5_free_cred_contents(ctx, &store_creds);
+ return KRB5_FWD_BAD_PRINCIPAL;
+ }
+ if (whitelist_principal) {
+ krb5_free_principal(ctx, whitelist_principal);
+ }
+
code = krb5_cc_initialize(ctx, store_cc, store_principal);
if (code != 0) {
krb5_free_cred_contents(ctx, &store_creds);