fs/cifs/cifs_spnego.c

   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/string.h>
  24 #include <keys/user-type.h>
  25 #include <linux/key-type.h>
  26 #include "cifsglob.h"
  27 #include "cifs_spnego.h"
  28 #include "cifs_debug.h"
  29
  30 /* create a new cifs key */
  31 static int
  32 cifs_spnego_key_instantiate(struct key *key, const void *data, size_t datalen)
  33 {
  34         char *payload;
  35         int ret;
  36
  37         ret = -ENOMEM;
  38         payload = kmalloc(datalen, GFP_KERNEL);
  39         if (!payload)
  40                 goto error;
  41
  42         /* attach the data */
  43         memcpy(payload, data, datalen);
  44         rcu_assign_pointer(key->payload.data, payload);
  45         ret = 0;
  46
  47 error:
  48         return ret;
  49 }
  50
  51 static void
  52 cifs_spnego_key_destroy(struct key *key)
  53 {
  54         kfree(key->payload.data);
  55 }
  56
  57
  58 /*
  59  * keytype for CIFS spnego keys
  60  */
  61 struct key_type cifs_spnego_key_type = {
  62         .name           = "cifs.spnego",
  63         .instantiate    = cifs_spnego_key_instantiate,
  64         .match          = user_match,
  65         .destroy        = cifs_spnego_key_destroy,
  66         .describe       = user_describe,
  67 };
  68
  69 /* get a key struct with a SPNEGO security blob, suitable for session setup */
  70 struct key *
  71 cifs_get_spnego_key(struct cifsSesInfo *sesInfo, const char *hostname)
  72 {
  73         struct TCP_Server_Info *server = sesInfo->server;
  74         char *description, *dp;
  75         size_t desc_len;
  76         struct key *spnego_key;
  77
  78
  79         /* version + ;ip{4|6}= + address + ;host=hostname +
  80                 ;sec= + ;uid= + NULL */
  81         desc_len = 4 + 5 + 32 + 1 + 5 + strlen(hostname) +
  82                    strlen(";sec=krb5") + 7 + sizeof(uid_t)*2 + 1;
  83         spnego_key = ERR_PTR(-ENOMEM);
  84         description = kzalloc(desc_len, GFP_KERNEL);
  85         if (description == NULL)
  86                 goto out;
  87
  88         dp = description;
  89         /* start with version and hostname portion of UNC string */
  90         spnego_key = ERR_PTR(-EINVAL);
  91         sprintf(dp, "0x%2.2x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
  92                 hostname);
  93         dp = description + strlen(description);
  94
  95         /* add the server address */
  96         if (server->addr.sockAddr.sin_family == AF_INET)
  97                 sprintf(dp, "ip4=" NIPQUAD_FMT,
  98                         NIPQUAD(server->addr.sockAddr.sin_addr));
  99         else if (server->addr.sockAddr.sin_family == AF_INET6)
 100                 sprintf(dp, "ip6=" NIP6_SEQFMT,
 101                         NIP6(server->addr.sockAddr6.sin6_addr));
 102         else
 103                 goto out;
 104
 105         dp = description + strlen(description);
 106
 107         /* for now, only sec=krb5 is valid */
 108         if (server->secType == Kerberos)
 109                 sprintf(dp, ";sec=krb5");
 110         else
 111                 goto out;
 112
 113         dp = description + strlen(description);
 114         sprintf(dp, ";uid=0x%x", sesInfo->linux_uid);
 115
 116         cFYI(1, ("key description = %s", description));
 117         spnego_key = request_key(&cifs_spnego_key_type, description, "");
 118
 119         if (cifsFYI && !IS_ERR(spnego_key)) {
 120                 struct cifs_spnego_msg *msg = spnego_key->payload.data;
 121                 cifs_dump_mem("SPNEGO reply blob:", msg->data,
 122                                 msg->secblob_len + msg->sesskey_len);
 123         }
 124
 125 out:
 126         kfree(description);
 127         return spnego_key;
 128 }