Add localauth pluggable interface

Add a new pluggable interface for local authorization, and replace the
existing krb5_aname_to_localname and krb5_kuserok implementations with
implementations based on the pluggable interface.

ticket: 7583 (new)

1 files changed, 139 insertions, 0 deletions

diff --git a/src/include/krb5/localauth_plugin.h b/src/include/krb5/localauth_plugin.h
new file mode 100644
index 0000000000..1c6165b37c
--- /dev/null
+++ b/src/include/krb5/localauth_plugin.h
@@ -0,0 +1,139 @@
+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+ * Copyright (C) 2013 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in
+ *   the documentation and/or other materials provided with the
+ *   distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Declarations for localauth plugin module implementors.
+ *
+ * The localauth pluggable interface currently has only one supported major
+ * version, which is 1.  Major version 1 has a current minor version number of
+ * 1.
+ *
+ * Localauth plugin modules should define a function named
+ * localauth_<modulename>_initvt, matching the signature:
+ *
+ *   krb5_error_code
+ *   localauth_modname_initvt(krb5_context context, int maj_ver, int min_ver,
+ *                            krb5_plugin_vtable vtable);
+ *
+ * The initvt function should:
+ *
+ * - Check that the supplied maj_ver number is supported by the module, or
+ *   return KRB5_PLUGIN_VER_NOTSUPP if it is not.
+ *
+ * - Cast the vtable pointer as appropriate for maj_ver:
+ *     maj_ver == 1: Cast to krb5_localauth_vtable
+ *
+ * - Initialize the methods of the vtable, stopping as appropriate for the
+ *   supplied min_ver.  Optional methods may be left uninitialized.
+ *
+ * Memory for the vtable is allocated by the caller, not by the module.
+ */
+
+#ifndef KRB5_LOCALAUTH_PLUGIN_H
+#define KRB5_LOCALAUTH_PLUGIN_H
+
+#include <krb5/krb5.h>
+#include <krb5/plugin.h>
+#include <kadm5/admin.h>
+
+/* An abstract type for localauth module data. */
+typedef struct krb5_localauth_moddata_st *krb5_localauth_moddata;
+
+/*** Method type declarations ***/
+
+/* Optional: Initialize module data. */
+typedef krb5_error_code
+(*krb5_localauth_init_fn)(krb5_context context,
+                          krb5_localauth_moddata *data);
+
+/* Optional: Release resources used by module data. */
+typedef void
+(*krb5_localauth_fini_fn)(krb5_context context, krb5_localauth_moddata data);
+
+/*
+ * Optional: Determine whether aname is authorized to log in as the local
+ * account lname.  Return 0 if aname is authorized, EPERM if aname is
+ * authoritatively not authorized, KRB5_PLUGIN_NO_HANDLE if the module cannot
+ * determine whether aname is authorized, and any other error code for a
+ * serious failure to process the request.  aname will be considered authorized
+ * if at least one module returns 0 and all other modules return
+ * KRB5_PLUGIN_NO_HANDLE.
+ */
+typedef krb5_error_code
+(*krb5_localauth_userok_fn)(krb5_context context, krb5_localauth_moddata data,
+                            krb5_const_principal aname, const char *lname);
+
+/*
+ * Optional (mandatory if an2ln_types is set): Determine the local account name
+ * corresponding to aname.  Return 0 and set *lname_out if a mapping can be
+ * determined; the contents of *lname_out will later be released with a call to
+ * the module's free_string method.  Return KRB5_LNAME_NOTRANS if no mapping
+ * can be determined.  Return any other error code for a serious failure to
+ * process the request; this will halt the krb5_aname_to_localname operation.
+ *
+ * If the module's an2ln_types field is set, this method will only be invoked
+ * when a profile "auth_to_local" value references one of the module's types.
+ * type and residual will be set to the type and residual of the auth_to_local
+ * value.
+ *
+ * If the module's an2ln_types field is not set but the an2ln method is
+ * implemented, this method will be invoked independently of the profile's
+ * auth_to_local settings, with type and residual set to NULL.  If multiple
+ * modules are registered with an2ln methods but no an2ln_types field, the
+ * order of invocation is not defined, but all such modules will be consulted
+ * before the built-in mechanisms are tried.
+ */
+typedef krb5_error_code
+(*krb5_localauth_an2ln_fn)(krb5_context context, krb5_localauth_moddata data,
+                           const char *type, const char *residual,
+                           krb5_const_principal aname, char **lname_out);
+
+/*
+ * Optional (mandatory if an2ln is implemented): Release the memory returned by
+ * an invocation of an2ln.
+ */
+typedef void
+(*krb5_localauth_free_string_fn)(krb5_context context,
+                                 krb5_localauth_moddata data, char *str);
+
+/* localauth vtable for major version 1. */
+typedef struct krb5_localauth_vtable_st {
+    const char *name;           /* Mandatory: name of module. */
+    const char **an2ln_types;   /* Optional: uppercase auth_to_local types */
+    krb5_localauth_init_fn init;
+    krb5_localauth_fini_fn fini;
+    krb5_localauth_userok_fn userok;
+    krb5_localauth_an2ln_fn an2ln;
+    krb5_localauth_free_string_fn free_string;
+    /* Minor version 1 ends here. */
+} *krb5_localauth_vtable;
+
+#endif /* KRB5_LOCALAUTH_PLUGIN_H */