kadm5_hook: new plugin interface

Implement http://k5wiki.kerberos.org/wiki/Projects/Kadmin_hook_interface

This provides an interface that allows a plugin to track kadmin
operations. This can be used for projects like the krb5-sync project.

ticket: 6791

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@24375 dc483132-0cff-0310-8789-dd5450dbe970

2 files changed, 128 insertions, 1 deletions

diff --git a/src/include/k5-int.h b/src/include/k5-int.h
index efffa3b5e..750f989c9 100644
--- a/src/include/k5-int.h
+++ b/src/include/k5-int.h
@@ -1517,7 +1517,8 @@ struct plugin_interface {
 /* A list of plugin interface IDs.  Make sure to increment
  * PLUGIN_NUM_INTERFACES when a new interface is added. */
 #define PLUGIN_INTERFACE_PWQUAL 0
-#define PLUGIN_NUM_INTERFACES   1
+#define PLUGIN_INTERFACE_KADM5_HOOK 1
+#define PLUGIN_NUM_INTERFACES   2
 
 /* Retrieve the plugin module of type interface_id and name modname,
  * storing the result into module. */
diff --git a/src/include/krb5/kadm5_hook_plugin.h b/src/include/krb5/kadm5_hook_plugin.h
new file mode 100644
index 000000000..7e23a249d
--- /dev/null
+++ b/src/include/krb5/kadm5_hook_plugin.h
@@ -0,0 +1,126 @@
+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+ * include/krb5/kadm5_hook_plugin.h
+ */
+/*
+ * Copyright (C) 2010 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Export of this software from the United States of America may
+ *   require a specific license from the United States Government.
+ *   It is the responsibility of any person or organization contemplating
+ *   export to obtain such a license before exporting.
+ *
+ * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
+ * distribute this software and its documentation for any purpose and
+ * without fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright notice and
+ * this permission notice appear in supporting documentation, and that
+ * the name of M.I.T. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission.  Furthermore if you modify this software you must label
+ * your software as modified software and not distribute it in such a
+ * fashion that it might be confused with the original M.I.T. software.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is" without express
+ * or implied warranty.
+ */
+
+#ifndef H_KRB5_KADM5_HOOK_PLUGIN
+#define H_KRB5_KADM5_HOOK_PLUGIN
+
+/**
+ * @file krb5/krb5_kadm5_hook_plugin.h
+ * Provide a plugin interface for kadm5 operations. This interface
+ * permits a plugin to intercept principal modification, creation and
+ * change password operations. Operations run at two stages: a
+ * precommit stage that runs before the operation is committed to the
+ * database and a postcommit operation that runs after the database
+ * is updated; see #kadm5_hook_stage for details on semantics.
+ *
+ * This interface is based on a proposed extension to Heimdal by Russ
+ * Allbery; it is likely that Heimdal will adopt an approach based on
+ * stacked kdb modules rather than this interface. For MIT, writing a
+ * plugin to this interface is significantly easier than stacking kdb
+ * modules. Also, the kadm5 interface is significantly more stable
+ * than the kdb interface, so this approach is more desirable than
+ * stacked kdb modules.
+ *
+ * This interface depends on kadm5/admin.h. As such, the interface
+ * does not provide strong guarantees of ABI stability.
+ */
+
+#include <krb5/krb5.h>
+#include <krb5/plugin.h>
+#include <kadm5/admin.h>
+
+/**
+ * Whether the operation is being run before or after the database
+ * update
+ */
+enum kadm5_hook_stage {
+    /** In this stage, any plugin failure prevents following plugins from
+     *         running and aborts the operation.*/
+    KADM5_HOOK_STAGE_PRECOMMIT,
+    /** In this stage, plugin failures are logged but otherwise ignored.*/
+    KADM5_HOOK_STAGE_POSTCOMMIT
+};
+
+/** Opaque module data pointer*/
+typedef struct kadm5_hook_modinfo_st kadm5_hook_modinfo;
+
+/**
+ * Interface for the v1 virtual table for the kadm5_hook plugin
+ * All entry points are optional. The name field must be provided.
+ */
+typedef struct kadm5_hook_vtable_1_st {
+
+    /** A text string identifying the plugin for logging messages*/
+    char *name;
+
+    /** Initialize a plugin module
+     * @param modinfo returns newly allocated module info for future
+     * calls. Cleaned up by the fini() function.
+     */
+    kadm5_ret_t (*init)(krb5_context, kadm5_hook_modinfo **modinfo);
+
+    /** Clean up a module and free @a modinfo*/
+    void (*fini)(krb5_context, kadm5_hook_modinfo *modinfo);
+
+    /** Indicates that the password is being changed.
+     * @param stage is an integer from #kadm5_hook_stage enumeration
+     * @param keepold is true if existing keys are being kept.
+     * */
+    kadm5_ret_t (*chpass)(krb5_context,
+                          kadm5_hook_modinfo *modinfo,
+                          int stage,
+                          krb5_principal, krb5_boolean keepold,
+                          int n_ks_tuple,
+                          krb5_key_salt_tuple *ks_tuple,
+                          const char *newpass);
+
+    /** Indicate a principal is created*/
+    kadm5_ret_t (*create)(krb5_context,
+                          kadm5_hook_modinfo *,
+                          int stage,
+                          kadm5_principal_ent_t, long mask,
+                          int n_ks_tuple,
+                          krb5_key_salt_tuple *ks_tuple,
+                          const char *password);
+    /** Modify a principal*/
+    kadm5_ret_t (*modify)(krb5_context,
+                          kadm5_hook_modinfo *,
+                          int stage,
+                          kadm5_principal_ent_t, long mask);
+
+
+    /** Indicate a principal is deleted*/
+    kadm5_ret_t (* remove) (krb5_context,
+                            kadm5_hook_modinfo *modinfo,
+                            int stage, krb5_principal
+    );
+
+    /*End of minor version 1*/
+}kadm5_hook_vftable_1;
+
+#endif /*H_KRB5_KADM5_HOOK_PLUGIN*/