Allow usage of enterprise principals

Enterprise principals are currently most useful for the AD provider and
hence enabled here by default while for the other Kerberos based
authentication providers they are disabled by default.

If additional UPN suffixes are configured for the AD domain the user
principal stored in the AD LDAP server might not contain the real
Kerberos realm of the AD domain but one of the additional suffixes which
might be completely randomly chooses, e.g. are not related to any
existing DNS domain. This make it hard for a client to figure out the
right KDC to send requests to.

To get around this enterprise principals (see
http://tools.ietf.org/html/rfc6806 for details) were introduced.
Basically a default realm is added to the principal so that the Kerberos
client libraries at least know where to send the request to. It is not
in the responsibility of the KDC to either handle the request itself,
return a client referral if he thinks a different KDC can handle the
request or return and error. This feature is also use to allow
authentication in AD environments with cross forest trusts.

Fixes https://fedorahosted.org/sssd/ticket/1842

2 files changed, 28 insertions, 0 deletions

diff --git a/src/util/sss_krb5.c b/src/util/sss_krb5.c
index ab0344c8..674e9fcd 100644
--- a/src/util/sss_krb5.c
+++ b/src/util/sss_krb5.c
@@ -766,6 +766,25 @@ sss_krb5_component_length_quoted(const krb5_data *src, int flags)
 
 
 krb5_error_code
+sss_krb5_parse_name_flags(krb5_context context, const char *name, int flags,
+                          krb5_principal *principal)
+{
+#ifdef HAVE_KRB5_PARSE_NAME_FLAGS
+    return krb5_parse_name_flags(context, name, flags, principal);
+#else
+    if (flags != 0) {
+        DEBUG(SSSDBG_MINOR_FAILURE, ("krb5_parse_name_flags not available on " \
+                                     "this plattform, names are parsed " \
+                                     "without flags. Some features like " \
+                                     "enterprise principals might not work " \
+                                     "as expected.\n"));
+    }
+
+    return krb5_parse_name(context, name, principal);
+#endif
+}
+
+krb5_error_code
 sss_krb5_unparse_name_flags(krb5_context context, krb5_const_principal principal,
                         int flags, char **name)
 {
diff --git a/src/util/sss_krb5.h b/src/util/sss_krb5.h
index deb0cbff..5fe7178c 100644
--- a/src/util/sss_krb5.h
+++ b/src/util/sss_krb5.h
@@ -122,6 +122,15 @@ krb5_error_code KRB5_CALLCONV sss_krb5_get_init_creds_opt_set_fast_flags(
 #endif
 
 
+#ifndef HAVE_KRB5_PARSE_NAME_FLAGS
+#define KRB5_PRINCIPAL_PARSE_NO_REALM           0x1
+#define KRB5_PRINCIPAL_PARSE_REQUIRE_REALM      0x2
+#define KRB5_PRINCIPAL_PARSE_ENTERPRISE         0x4
+#endif
+krb5_error_code
+sss_krb5_parse_name_flags(krb5_context context, const char *name, int flags,
+                          krb5_principal *principal);
+
 #ifndef HAVE_KRB5_UNPARSE_NAME_FLAGS
 #define KRB5_PRINCIPAL_UNPARSE_SHORT 0x1
 #define KRB5_PRINCIPAL_UNPARSE_NO_REALM 0x2