root/fs/cifs/cifs_spnego.c

DEFINITIONS

1. cifs_spnego_key_instantiate
2. cifs_spnego_key_destroy
3. cifs_get_spnego_key

/*
 *   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);
        rcu_assign_pointer(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:BA98:7654:3210/60 */
#define MAX_IPV6_ADDR_LEN       42

/* 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=" NIPQUAD_FMT,
                        NIPQUAD(server->addr.sockAddr.sin_addr));
        else if (server->addr.sockAddr.sin_family == AF_INET6)
                sprintf(dp, "ip6=" NIP6_SEQFMT,
                        NIP6(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;
}