![Michael LeMay](/assets/img/avatar_default.png)
Introduce SELinux hooks to support the access key retention subsystem within the kernel. Incorporate new flask headers from a modified version of the SELinux reference policy, with support for the new security class representing retained keys. Extend the "key_alloc" security hook with a task parameter representing the intended ownership context for the key being allocated. Attach security information to root's default keyrings within the SELinux initialization routine. Has passed David's testsuite. Signed-off-by: Michael LeMay <mdlemay@epoch.ncsc.mil> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
226 lines
6.1 KiB
C
226 lines
6.1 KiB
C
/* request_key_auth.c: request key authorisation controlling key def
|
|
*
|
|
* Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*
|
|
* See Documentation/keys-request-key.txt
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/err.h>
|
|
#include <linux/seq_file.h>
|
|
#include <asm/uaccess.h>
|
|
#include "internal.h"
|
|
|
|
static int request_key_auth_instantiate(struct key *, const void *, size_t);
|
|
static void request_key_auth_describe(const struct key *, struct seq_file *);
|
|
static void request_key_auth_destroy(struct key *);
|
|
static long request_key_auth_read(const struct key *, char __user *, size_t);
|
|
|
|
/*
|
|
* the request-key authorisation key type definition
|
|
*/
|
|
struct key_type key_type_request_key_auth = {
|
|
.name = ".request_key_auth",
|
|
.def_datalen = sizeof(struct request_key_auth),
|
|
.instantiate = request_key_auth_instantiate,
|
|
.describe = request_key_auth_describe,
|
|
.destroy = request_key_auth_destroy,
|
|
.read = request_key_auth_read,
|
|
};
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* instantiate a request-key authorisation key
|
|
*/
|
|
static int request_key_auth_instantiate(struct key *key,
|
|
const void *data,
|
|
size_t datalen)
|
|
{
|
|
key->payload.data = (struct request_key_auth *) data;
|
|
return 0;
|
|
|
|
} /* end request_key_auth_instantiate() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* reading a request-key authorisation key retrieves the callout information
|
|
*/
|
|
static void request_key_auth_describe(const struct key *key,
|
|
struct seq_file *m)
|
|
{
|
|
struct request_key_auth *rka = key->payload.data;
|
|
|
|
seq_puts(m, "key:");
|
|
seq_puts(m, key->description);
|
|
seq_printf(m, " pid:%d ci:%zu", rka->pid, strlen(rka->callout_info));
|
|
|
|
} /* end request_key_auth_describe() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* read the callout_info data
|
|
* - the key's semaphore is read-locked
|
|
*/
|
|
static long request_key_auth_read(const struct key *key,
|
|
char __user *buffer, size_t buflen)
|
|
{
|
|
struct request_key_auth *rka = key->payload.data;
|
|
size_t datalen;
|
|
long ret;
|
|
|
|
datalen = strlen(rka->callout_info);
|
|
ret = datalen;
|
|
|
|
/* we can return the data as is */
|
|
if (buffer && buflen > 0) {
|
|
if (buflen > datalen)
|
|
buflen = datalen;
|
|
|
|
if (copy_to_user(buffer, rka->callout_info, buflen) != 0)
|
|
ret = -EFAULT;
|
|
}
|
|
|
|
return ret;
|
|
|
|
} /* end request_key_auth_read() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* destroy an instantiation authorisation token key
|
|
*/
|
|
static void request_key_auth_destroy(struct key *key)
|
|
{
|
|
struct request_key_auth *rka = key->payload.data;
|
|
|
|
kenter("{%d}", key->serial);
|
|
|
|
key_put(rka->target_key);
|
|
kfree(rka);
|
|
|
|
} /* end request_key_auth_destroy() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* create an authorisation token for /sbin/request-key or whoever to gain
|
|
* access to the caller's security data
|
|
*/
|
|
struct key *request_key_auth_new(struct key *target, const char *callout_info)
|
|
{
|
|
struct request_key_auth *rka, *irka;
|
|
struct key *authkey = NULL;
|
|
char desc[20];
|
|
int ret;
|
|
|
|
kenter("%d,", target->serial);
|
|
|
|
/* allocate a auth record */
|
|
rka = kmalloc(sizeof(*rka), GFP_KERNEL);
|
|
if (!rka) {
|
|
kleave(" = -ENOMEM");
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/* see if the calling process is already servicing the key request of
|
|
* another process */
|
|
if (current->request_key_auth) {
|
|
/* it is - use that instantiation context here too */
|
|
irka = current->request_key_auth->payload.data;
|
|
rka->context = irka->context;
|
|
rka->pid = irka->pid;
|
|
}
|
|
else {
|
|
/* it isn't - use this process as the context */
|
|
rka->context = current;
|
|
rka->pid = current->pid;
|
|
}
|
|
|
|
rka->target_key = key_get(target);
|
|
rka->callout_info = callout_info;
|
|
|
|
/* allocate the auth key */
|
|
sprintf(desc, "%x", target->serial);
|
|
|
|
authkey = key_alloc(&key_type_request_key_auth, desc,
|
|
current->fsuid, current->fsgid, current,
|
|
KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
|
|
KEY_USR_VIEW, 1);
|
|
if (IS_ERR(authkey)) {
|
|
ret = PTR_ERR(authkey);
|
|
goto error_alloc;
|
|
}
|
|
|
|
/* construct and attach to the keyring */
|
|
ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
|
|
if (ret < 0)
|
|
goto error_inst;
|
|
|
|
kleave(" = {%d})", authkey->serial);
|
|
return authkey;
|
|
|
|
error_inst:
|
|
key_revoke(authkey);
|
|
key_put(authkey);
|
|
error_alloc:
|
|
key_put(rka->target_key);
|
|
kfree(rka);
|
|
kleave("= %d", ret);
|
|
return ERR_PTR(ret);
|
|
|
|
} /* end request_key_auth_new() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* see if an authorisation key is associated with a particular key
|
|
*/
|
|
static int key_get_instantiation_authkey_match(const struct key *key,
|
|
const void *_id)
|
|
{
|
|
struct request_key_auth *rka = key->payload.data;
|
|
key_serial_t id = (key_serial_t)(unsigned long) _id;
|
|
|
|
return rka->target_key->serial == id;
|
|
|
|
} /* end key_get_instantiation_authkey_match() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* get the authorisation key for instantiation of a specific key if attached to
|
|
* the current process's keyrings
|
|
* - this key is inserted into a keyring and that is set as /sbin/request-key's
|
|
* session keyring
|
|
* - a target_id of zero specifies any valid token
|
|
*/
|
|
struct key *key_get_instantiation_authkey(key_serial_t target_id)
|
|
{
|
|
struct key *authkey;
|
|
key_ref_t authkey_ref;
|
|
|
|
authkey_ref = search_process_keyrings(
|
|
&key_type_request_key_auth,
|
|
(void *) (unsigned long) target_id,
|
|
key_get_instantiation_authkey_match,
|
|
current);
|
|
|
|
if (IS_ERR(authkey_ref)) {
|
|
authkey = ERR_PTR(PTR_ERR(authkey_ref));
|
|
goto error;
|
|
}
|
|
|
|
authkey = key_ref_to_ptr(authkey_ref);
|
|
if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
|
|
key_put(authkey);
|
|
authkey = ERR_PTR(-EKEYREVOKED);
|
|
}
|
|
|
|
error:
|
|
return authkey;
|
|
|
|
} /* end key_get_instantiation_authkey() */
|