Files
heimdal/lib/kadm5/context_s.c
Luke Howard 62c1790bf5 kadm5: pre/post-commit plugin hook for kadm5 update operations (#397)
This change adds plugin support to the kadmin libraries for performing
actions before and after a password change is committed to the KDC database
and after a change is made to the attributes of a principal (specifically,
a change to DISALLOW_ALL_TIX).

This change adds a hook_libraries configuration option to the [kadmin]
section of krb5.conf (or kdc.conf if you use that file) that must be set
to load the module. That configuration option is in the form:

[kadmin]
  hook_libraries = /usr/local/lib/krb5/plugins/kadm5_hook/krb5_sync.so

where the value is the full path to the plugin that you want to load. If
this option is not present, kadmind will not load a plugin and the changes
from the patch will be inactive. If this option is given and the plugin
cannot be loaded, kadmind startup will abort with a (hopefully useful)
error message in syslog.

Any plugin used with this patch must expose a public function named
kadm5_hook_init of type kadm5_hook_init_t that returns a kadm5_hook structure.
See sample_hook.c for an example of this initialization function.

typedef struct kadm5_hook {
    const char *name;
    uint32_t version;
    const char *vendor;
    void (KRB5_CALLCONV *fini)(krb5_context, void *data);

    krb5_error_code (KRB5_CALLCONV *chpass)(krb5_context context,
					    void *data,
					    enum kadm5_hook_stage stage,
                                            krb5_error_code code,
                                            krb5_const_principal princ,
                                            uint32_t flags,
                                            size_t n_ks_tuple,
                                            krb5_key_salt_tuple *ks_tuple,
                                            const char *password,
                                            char **error_msg);
    ...
};

where enum kadm5_hook_stage is:

enum kadm5_hook_stage {
    KADM5_HOOK_STAGE_PRECOMMIT,
    KADM5_HOOK_STAGE_POSTCOMMIT
};

init creates a hook context that is passed into all subsequent calls.
chpass is called for password changes, create is called for principal
creation (with the newly-created principal in the kadm5_principal_ent_t
argument), and modify is called when a principal is modified. The purpose of
the remaining functions should be self-explanatory.

returning 0 on success and a Kerberos error code on failure, setting the
Kerberos error message in the provided context. The error code passed in is
valid for post-commit hooks and contains the result of the update operation.

This change is submitted under the following license

Copyright 2012, 2013
The Board of Trustees of the Leland Stanford Junior University

Portions Copyright 2018 AuriStor Inc.

Copying and distribution of this file, with or without modification, are
permitted in any medium without royalty provided the copyright notice and
this notice are preserved. This file is offered as-is, without any
warranty.
2018-12-26 11:04:05 -06:00

304 lines
8.4 KiB
C

/*
* Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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.
*/
#include "kadm5_locl.h"
RCSID("$Id$");
static kadm5_ret_t
kadm5_s_lock(void *server_handle)
{
kadm5_server_context *context = server_handle;
kadm5_ret_t ret;
if (context->keep_open) {
/*
* We open/close around every operation, but we retain the DB
* open if the DB was locked with a prior call to kadm5_lock(),
* so if it's open here that must be because the DB is locked.
*/
heim_assert(context->db->lock_count > 0,
"Internal error in tracking HDB locks");
return KADM5_ALREADY_LOCKED;
}
ret = context->db->hdb_open(context->context, context->db, O_RDWR, 0);
if (ret)
return ret;
ret = context->db->hdb_lock(context->context, context->db, HDB_WLOCK);
if (ret) {
(void) context->db->hdb_close(context->context, context->db);
return ret;
}
/*
* Attempt to recover the log. This will generally fail on slaves,
* and we can't tell if we're on a slave here.
*
* Perhaps we could set a flag in the kadm5_server_context to
* indicate whether a read has been done without recovering the log,
* in which case we could fail any subsequent writes.
*/
if (kadm5_log_init(context) == 0)
(void) kadm5_log_end(context);
context->keep_open = 1;
return 0;
}
static kadm5_ret_t
kadm5_s_unlock(void *server_handle)
{
kadm5_server_context *context = server_handle;
kadm5_ret_t ret;
if (!context->keep_open)
return KADM5_NOT_LOCKED;
context->keep_open = 0;
ret = context->db->hdb_unlock(context->context, context->db);
(void) context->db->hdb_close(context->context, context->db);
return ret;
}
static void
set_funcs(kadm5_server_context *c)
{
#define SET(C, F) (C)->funcs.F = kadm5_s_ ## F
SET(c, chpass_principal);
SET(c, chpass_principal_with_key);
SET(c, create_principal);
SET(c, delete_principal);
SET(c, destroy);
SET(c, flush);
SET(c, get_principal);
SET(c, get_principals);
SET(c, get_privs);
SET(c, modify_principal);
SET(c, randkey_principal);
SET(c, rename_principal);
SET(c, lock);
SET(c, unlock);
SET(c, setkey_principal_3);
}
#ifndef NO_UNIX_SOCKETS
static void
set_socket_name(krb5_context context, struct sockaddr_un *un)
{
const char *fn = kadm5_log_signal_socket(context);
memset(un, 0, sizeof(*un));
un->sun_family = AF_UNIX;
strlcpy (un->sun_path, fn, sizeof(un->sun_path));
}
#else
static void
set_socket_info(krb5_context context, struct addrinfo **info)
{
kadm5_log_signal_socket_info(context, 0, info);
}
#endif
static kadm5_ret_t
find_db_spec(kadm5_server_context *ctx)
{
krb5_context context = ctx->context;
struct hdb_dbinfo *info, *d;
krb5_error_code ret;
int aret;
if (ctx->config.realm) {
/* fetch the databases */
ret = hdb_get_dbinfo(context, &info);
if (ret)
return ret;
d = NULL;
while ((d = hdb_dbinfo_get_next(info, d)) != NULL) {
const char *p = hdb_dbinfo_get_realm(context, d);
/* match default (realm-less) */
if(p != NULL && strcmp(ctx->config.realm, p) != 0)
continue;
p = hdb_dbinfo_get_dbname(context, d);
if (p) {
ctx->config.dbname = strdup(p);
if (ctx->config.dbname == NULL)
return krb5_enomem(context);
}
p = hdb_dbinfo_get_acl_file(context, d);
if (p) {
ctx->config.acl_file = strdup(p);
if (ctx->config.acl_file == NULL)
return krb5_enomem(context);
}
p = hdb_dbinfo_get_mkey_file(context, d);
if (p) {
ctx->config.stash_file = strdup(p);
if (ctx->config.stash_file == NULL)
return krb5_enomem(context);
}
p = hdb_dbinfo_get_log_file(context, d);
if (p) {
ctx->log_context.log_file = strdup(p);
if (ctx->log_context.log_file == NULL)
return krb5_enomem(context);
}
break;
}
hdb_free_dbinfo(context, &info);
}
/* If any of the values was unset, pick up the default value */
if (ctx->config.dbname == NULL) {
ctx->config.dbname = strdup(hdb_default_db(context));
if (ctx->config.dbname == NULL)
return krb5_enomem(context);
}
if (ctx->config.acl_file == NULL) {
aret = asprintf(&ctx->config.acl_file, "%s/kadmind.acl",
hdb_db_dir(context));
if (aret == -1)
return krb5_enomem(context);
}
if (ctx->config.stash_file == NULL) {
aret = asprintf(&ctx->config.stash_file, "%s/m-key",
hdb_db_dir(context));
if (aret == -1)
return krb5_enomem(context);
}
if (ctx->log_context.log_file == NULL) {
aret = asprintf(&ctx->log_context.log_file, "%s/log",
hdb_db_dir(context));
if (aret == -1)
return krb5_enomem(context);
}
#ifndef NO_UNIX_SOCKETS
set_socket_name(context, &ctx->log_context.socket_name);
#else
set_socket_info(context, &ctx->log_context.socket_info);
#endif
return 0;
}
kadm5_ret_t
_kadm5_s_init_context(kadm5_server_context **ctx,
kadm5_config_params *params,
krb5_context context)
{
kadm5_ret_t ret = 0;
*ctx = calloc(1, sizeof(**ctx));
if (*ctx == NULL)
return krb5_enomem(context);
(*ctx)->log_context.socket_fd = rk_INVALID_SOCKET;
set_funcs(*ctx);
(*ctx)->context = context;
krb5_add_et_list (context, initialize_kadm5_error_table_r);
#define is_set(M) (params && params->mask & KADM5_CONFIG_ ## M)
if (is_set(REALM)) {
(*ctx)->config.realm = strdup(params->realm);
if ((*ctx)->config.realm == NULL)
return krb5_enomem(context);
} else {
ret = krb5_get_default_realm(context, &(*ctx)->config.realm);
if (ret)
return ret;
}
if (is_set(DBNAME)) {
(*ctx)->config.dbname = strdup(params->dbname);
if ((*ctx)->config.dbname == NULL)
return krb5_enomem(context);
}
if (is_set(ACL_FILE)) {
(*ctx)->config.acl_file = strdup(params->acl_file);
if ((*ctx)->config.acl_file == NULL)
return krb5_enomem(context);
}
if (is_set(STASH_FILE)) {
(*ctx)->config.stash_file = strdup(params->stash_file);
if ((*ctx)->config.stash_file == NULL)
return krb5_enomem(context);
}
find_db_spec(*ctx);
ret = _kadm5_s_init_hooks(*ctx);
if (ret != 0) {
kadm5_s_destroy(*ctx);
*ctx = NULL;
return ret;
}
/* PROFILE can't be specified for now */
/* KADMIND_PORT is supposed to be used on the server also,
but this doesn't make sense */
/* ADMIN_SERVER is client only */
/* ADNAME is not used at all (as far as I can tell) */
/* ADB_LOCKFILE ditto */
/* DICT_FILE */
/* ADMIN_KEYTAB */
/* MKEY_FROM_KEYBOARD is not supported */
/* MKEY_NAME neither */
/* ENCTYPE */
/* MAX_LIFE */
/* MAX_RLIFE */
/* EXPIRATION */
/* FLAGS */
/* ENCTYPES */
return 0;
}
HDB *
_kadm5_s_get_db(void *server_handle)
{
kadm5_server_context *context = server_handle;
return context->db;
}