linux/fs/cifs/cifs_spnego.c
Jeff Layton d9fb5c091b cifs: no need to use rcu_assign_pointer on immutable keys
cifs: no need to use rcu_assign_pointer on immutable keys

Neither keytype in use by CIFS has an "update" method. This means that
the keys are immutable once instantiated. We don't need to use RCU
to set the payload data pointers.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2009-04-17 01:26:49 +00:00

161 lines
4.3 KiB
C

/*
* fs/cifs/cifs_spnego.c -- SPNEGO upcall management for CIFS
*
* Copyright (c) 2007 Red Hat, Inc.
* Author(s): Jeff Layton (jlayton@redhat.com)
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/list.h>
#include <linux/string.h>
#include <keys/user-type.h>
#include <linux/key-type.h>
#include "cifsglob.h"
#include "cifs_spnego.h"
#include "cifs_debug.h"
/* create a new cifs key */
static int
cifs_spnego_key_instantiate(struct key *key, const void *data, size_t datalen)
{
char *payload;
int ret;
ret = -ENOMEM;
payload = kmalloc(datalen, GFP_KERNEL);
if (!payload)
goto error;
/* attach the data */
memcpy(payload, data, datalen);
key->payload.data = payload;
ret = 0;
error:
return ret;
}
static void
cifs_spnego_key_destroy(struct key *key)
{
kfree(key->payload.data);
}
/*
* keytype for CIFS spnego keys
*/
struct key_type cifs_spnego_key_type = {
.name = "cifs.spnego",
.instantiate = cifs_spnego_key_instantiate,
.match = user_match,
.destroy = cifs_spnego_key_destroy,
.describe = user_describe,
};
/* length of longest version string e.g. strlen("ver=0xFF") */
#define MAX_VER_STR_LEN 8
/* length of longest security mechanism name, eg in future could have
* strlen(";sec=ntlmsspi") */
#define MAX_MECH_STR_LEN 13
/* max possible addr len eg FEDC:BA98:7654:3210:FEDC:BA98:7654:3210/128 */
#define MAX_IPV6_ADDR_LEN 43
/* strlen of "host=" */
#define HOST_KEY_LEN 5
/* strlen of ";ip4=" or ";ip6=" */
#define IP_KEY_LEN 5
/* strlen of ";uid=0x" */
#define UID_KEY_LEN 7
/* strlen of ";user=" */
#define USER_KEY_LEN 6
/* get a key struct with a SPNEGO security blob, suitable for session setup */
struct key *
cifs_get_spnego_key(struct cifsSesInfo *sesInfo)
{
struct TCP_Server_Info *server = sesInfo->server;
char *description, *dp;
size_t desc_len;
struct key *spnego_key;
const char *hostname = server->hostname;
/* length of fields (with semicolons): ver=0xyz ip4=ipaddress
host=hostname sec=mechanism uid=0xFF user=username */
desc_len = MAX_VER_STR_LEN +
HOST_KEY_LEN + strlen(hostname) +
IP_KEY_LEN + MAX_IPV6_ADDR_LEN +
MAX_MECH_STR_LEN +
UID_KEY_LEN + (sizeof(uid_t) * 2) +
USER_KEY_LEN + strlen(sesInfo->userName) + 1;
spnego_key = ERR_PTR(-ENOMEM);
description = kzalloc(desc_len, GFP_KERNEL);
if (description == NULL)
goto out;
dp = description;
/* start with version and hostname portion of UNC string */
spnego_key = ERR_PTR(-EINVAL);
sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
hostname);
dp = description + strlen(description);
/* add the server address */
if (server->addr.sockAddr.sin_family == AF_INET)
sprintf(dp, "ip4=%pI4", &server->addr.sockAddr.sin_addr);
else if (server->addr.sockAddr.sin_family == AF_INET6)
sprintf(dp, "ip6=%pi6", &server->addr.sockAddr6.sin6_addr);
else
goto out;
dp = description + strlen(description);
/* for now, only sec=krb5 and sec=mskrb5 are valid */
if (server->secType == Kerberos)
sprintf(dp, ";sec=krb5");
else if (server->secType == MSKerberos)
sprintf(dp, ";sec=mskrb5");
else
goto out;
dp = description + strlen(description);
sprintf(dp, ";uid=0x%x", sesInfo->linux_uid);
dp = description + strlen(description);
sprintf(dp, ";user=%s", sesInfo->userName);
cFYI(1, ("key description = %s", description));
spnego_key = request_key(&cifs_spnego_key_type, description, "");
#ifdef CONFIG_CIFS_DEBUG2
if (cifsFYI && !IS_ERR(spnego_key)) {
struct cifs_spnego_msg *msg = spnego_key->payload.data;
cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
msg->secblob_len + msg->sesskey_len));
}
#endif /* CONFIG_CIFS_DEBUG2 */
out:
kfree(description);
return spnego_key;
}