linux/fs/cifs/cifs_spnego.c
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   1/*
   2 *   fs/cifs/cifs_spnego.c -- SPNEGO upcall management for CIFS
   3 *
   4 *   Copyright (c) 2007 Red Hat, Inc.
   5 *   Author(s): Jeff Layton (jlayton@redhat.com)
   6 *
   7 *   This library is free software; you can redistribute it and/or modify
   8 *   it under the terms of the GNU Lesser General Public License as published
   9 *   by the Free Software Foundation; either version 2.1 of the License, or
  10 *   (at your option) any later version.
  11 *
  12 *   This library is distributed in the hope that it will be useful,
  13 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15 *   the GNU Lesser General Public License for more details.
  16 *
  17 *   You should have received a copy of the GNU Lesser General Public License
  18 *   along with this library; if not, write to the Free Software
  19 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20 */
  21
  22#include <linux/list.h>
  23#include <linux/slab.h>
  24#include <linux/string.h>
  25#include <keys/user-type.h>
  26#include <linux/key-type.h>
  27#include <linux/inet.h>
  28#include "cifsglob.h"
  29#include "cifs_spnego.h"
  30#include "cifs_debug.h"
  31
  32/* create a new cifs key */
  33static int
  34cifs_spnego_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
  35{
  36        char *payload;
  37        int ret;
  38
  39        ret = -ENOMEM;
  40        payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
  41        if (!payload)
  42                goto error;
  43
  44        /* attach the data */
  45        key->payload.data = payload;
  46        ret = 0;
  47
  48error:
  49        return ret;
  50}
  51
  52static void
  53cifs_spnego_key_destroy(struct key *key)
  54{
  55        kfree(key->payload.data);
  56}
  57
  58
  59/*
  60 * keytype for CIFS spnego keys
  61 */
  62struct key_type cifs_spnego_key_type = {
  63        .name           = "cifs.spnego",
  64        .instantiate    = cifs_spnego_key_instantiate,
  65        .match          = user_match,
  66        .destroy        = cifs_spnego_key_destroy,
  67        .describe       = user_describe,
  68};
  69
  70/* length of longest version string e.g.  strlen("ver=0xFF") */
  71#define MAX_VER_STR_LEN         8
  72
  73/* length of longest security mechanism name, eg in future could have
  74 * strlen(";sec=ntlmsspi") */
  75#define MAX_MECH_STR_LEN        13
  76
  77/* strlen of "host=" */
  78#define HOST_KEY_LEN            5
  79
  80/* strlen of ";ip4=" or ";ip6=" */
  81#define IP_KEY_LEN              5
  82
  83/* strlen of ";uid=0x" */
  84#define UID_KEY_LEN             7
  85
  86/* strlen of ";creduid=0x" */
  87#define CREDUID_KEY_LEN         11
  88
  89/* strlen of ";user=" */
  90#define USER_KEY_LEN            6
  91
  92/* strlen of ";pid=0x" */
  93#define PID_KEY_LEN             7
  94
  95/* get a key struct with a SPNEGO security blob, suitable for session setup */
  96struct key *
  97cifs_get_spnego_key(struct cifs_ses *sesInfo)
  98{
  99        struct TCP_Server_Info *server = sesInfo->server;
 100        struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
 101        struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
 102        char *description, *dp;
 103        size_t desc_len;
 104        struct key *spnego_key;
 105        const char *hostname = server->hostname;
 106
 107        /* length of fields (with semicolons): ver=0xyz ip4=ipaddress
 108           host=hostname sec=mechanism uid=0xFF user=username */
 109        desc_len = MAX_VER_STR_LEN +
 110                   HOST_KEY_LEN + strlen(hostname) +
 111                   IP_KEY_LEN + INET6_ADDRSTRLEN +
 112                   MAX_MECH_STR_LEN +
 113                   UID_KEY_LEN + (sizeof(uid_t) * 2) +
 114                   CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
 115                   PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
 116
 117        if (sesInfo->user_name)
 118                desc_len += USER_KEY_LEN + strlen(sesInfo->user_name);
 119
 120        spnego_key = ERR_PTR(-ENOMEM);
 121        description = kzalloc(desc_len, GFP_KERNEL);
 122        if (description == NULL)
 123                goto out;
 124
 125        dp = description;
 126        /* start with version and hostname portion of UNC string */
 127        spnego_key = ERR_PTR(-EINVAL);
 128        sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
 129                hostname);
 130        dp = description + strlen(description);
 131
 132        /* add the server address */
 133        if (server->dstaddr.ss_family == AF_INET)
 134                sprintf(dp, "ip4=%pI4", &sa->sin_addr);
 135        else if (server->dstaddr.ss_family == AF_INET6)
 136                sprintf(dp, "ip6=%pI6", &sa6->sin6_addr);
 137        else
 138                goto out;
 139
 140        dp = description + strlen(description);
 141
 142        /* for now, only sec=krb5 and sec=mskrb5 are valid */
 143        if (server->sec_kerberos)
 144                sprintf(dp, ";sec=krb5");
 145        else if (server->sec_mskerberos)
 146                sprintf(dp, ";sec=mskrb5");
 147        else
 148                goto out;
 149
 150        dp = description + strlen(description);
 151        sprintf(dp, ";uid=0x%x",
 152                from_kuid_munged(&init_user_ns, sesInfo->linux_uid));
 153
 154        dp = description + strlen(description);
 155        sprintf(dp, ";creduid=0x%x",
 156                from_kuid_munged(&init_user_ns, sesInfo->cred_uid));
 157
 158        if (sesInfo->user_name) {
 159                dp = description + strlen(description);
 160                sprintf(dp, ";user=%s", sesInfo->user_name);
 161        }
 162
 163        dp = description + strlen(description);
 164        sprintf(dp, ";pid=0x%x", current->pid);
 165
 166        cifs_dbg(FYI, "key description = %s\n", description);
 167        spnego_key = request_key(&cifs_spnego_key_type, description, "");
 168
 169#ifdef CONFIG_CIFS_DEBUG2
 170        if (cifsFYI && !IS_ERR(spnego_key)) {
 171                struct cifs_spnego_msg *msg = spnego_key->payload.data;
 172                cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
 173                                msg->secblob_len + msg->sesskey_len));
 174        }
 175#endif /* CONFIG_CIFS_DEBUG2 */
 176
 177out:
 178        kfree(description);
 179        return spnego_key;
 180}
 181
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