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, const void *data, size_t datalen)
  35{
  36        char *payload;
  37        int ret;
  38
  39        ret = -ENOMEM;
  40        payload = kmalloc(datalen, GFP_KERNEL);
  41        if (!payload)
  42                goto error;
  43
  44        /* attach the data */
  45        memcpy(payload, data, datalen);
  46        key->payload.data = payload;
  47        ret = 0;
  48
  49error:
  50        return ret;
  51}
  52
  53static void
  54cifs_spnego_key_destroy(struct key *key)
  55{
  56        kfree(key->payload.data);
  57}
  58
  59
  60/*
  61 * keytype for CIFS spnego keys
  62 */
  63struct key_type cifs_spnego_key_type = {
  64        .name           = "cifs.spnego",
  65        .instantiate    = cifs_spnego_key_instantiate,
  66        .match          = user_match,
  67        .destroy        = cifs_spnego_key_destroy,
  68        .describe       = user_describe,
  69};
  70
  71/* length of longest version string e.g.  strlen("ver=0xFF") */
  72#define MAX_VER_STR_LEN         8
  73
  74/* length of longest security mechanism name, eg in future could have
  75 * strlen(";sec=ntlmsspi") */
  76#define MAX_MECH_STR_LEN        13
  77
  78/* strlen of "host=" */
  79#define HOST_KEY_LEN            5
  80
  81/* strlen of ";ip4=" or ";ip6=" */
  82#define IP_KEY_LEN              5
  83
  84/* strlen of ";uid=0x" */
  85#define UID_KEY_LEN             7
  86
  87/* strlen of ";creduid=0x" */
  88#define CREDUID_KEY_LEN         11
  89
  90/* strlen of ";user=" */
  91#define USER_KEY_LEN            6
  92
  93/* strlen of ";pid=0x" */
  94#define PID_KEY_LEN             7
  95
  96/* get a key struct with a SPNEGO security blob, suitable for session setup */
  97struct key *
  98cifs_get_spnego_key(struct cifsSesInfo *sesInfo)
  99{
 100        struct TCP_Server_Info *server = sesInfo->server;
 101        struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
 102        struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
 103        char *description, *dp;
 104        size_t desc_len;
 105        struct key *spnego_key;
 106        const char *hostname = server->hostname;
 107
 108        /* length of fields (with semicolons): ver=0xyz ip4=ipaddress
 109           host=hostname sec=mechanism uid=0xFF user=username */
 110        desc_len = MAX_VER_STR_LEN +
 111                   HOST_KEY_LEN + strlen(hostname) +
 112                   IP_KEY_LEN + INET6_ADDRSTRLEN +
 113                   MAX_MECH_STR_LEN +
 114                   UID_KEY_LEN + (sizeof(uid_t) * 2) +
 115                   CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
 116                   USER_KEY_LEN + strlen(sesInfo->user_name) +
 117                   PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
 118
 119        spnego_key = ERR_PTR(-ENOMEM);
 120        description = kzalloc(desc_len, GFP_KERNEL);
 121        if (description == NULL)
 122                goto out;
 123
 124        dp = description;
 125        /* start with version and hostname portion of UNC string */
 126        spnego_key = ERR_PTR(-EINVAL);
 127        sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
 128                hostname);
 129        dp = description + strlen(description);
 130
 131        /* add the server address */
 132        if (server->dstaddr.ss_family == AF_INET)
 133                sprintf(dp, "ip4=%pI4", &sa->sin_addr);
 134        else if (server->dstaddr.ss_family == AF_INET6)
 135                sprintf(dp, "ip6=%pI6", &sa6->sin6_addr);
 136        else
 137                goto out;
 138
 139        dp = description + strlen(description);
 140
 141        /* for now, only sec=krb5 and sec=mskrb5 are valid */
 142        if (server->sec_kerberos)
 143                sprintf(dp, ";sec=krb5");
 144        else if (server->sec_mskerberos)
 145                sprintf(dp, ";sec=mskrb5");
 146        else
 147                goto out;
 148
 149        dp = description + strlen(description);
 150        sprintf(dp, ";uid=0x%x", sesInfo->linux_uid);
 151
 152        dp = description + strlen(description);
 153        sprintf(dp, ";creduid=0x%x", sesInfo->cred_uid);
 154
 155        dp = description + strlen(description);
 156        sprintf(dp, ";user=%s", sesInfo->user_name);
 157
 158        dp = description + strlen(description);
 159        sprintf(dp, ";pid=0x%x", current->pid);
 160
 161        cFYI(1, "key description = %s", description);
 162        spnego_key = request_key(&cifs_spnego_key_type, description, "");
 163
 164#ifdef CONFIG_CIFS_DEBUG2
 165        if (cifsFYI && !IS_ERR(spnego_key)) {
 166                struct cifs_spnego_msg *msg = spnego_key->payload.data;
 167                cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
 168                                msg->secblob_len + msg->sesskey_len));
 169        }
 170#endif /* CONFIG_CIFS_DEBUG2 */
 171
 172out:
 173        kfree(description);
 174        return spnego_key;
 175}
 176