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/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 */
  33 static int
  34 cifs_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
  49 error:
  50         return ret;
  51 }
  52
  53 static void
  54 cifs_spnego_key_destroy(struct key *key)
  55 {
  56         kfree(key->payload.data);
  57 }
  58
  59
  60 /*
  61  * keytype for CIFS spnego keys
  62  */
  63 struct 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 ";user=" */
  88 #define USER_KEY_LEN            6
  89
  90 /* strlen of ";pid=0x" */
  91 #define PID_KEY_LEN             7
  92
  93 /* get a key struct with a SPNEGO security blob, suitable for session setup */
  94 struct key *
  95 cifs_get_spnego_key(struct cifsSesInfo *sesInfo)
  96 {
  97         struct TCP_Server_Info *server = sesInfo->server;
  98         char *description, *dp;
  99         size_t desc_len;
 100         struct key *spnego_key;
 101         const char *hostname = server->hostname;
 102
 103         /* length of fields (with semicolons): ver=0xyz ip4=ipaddress
 104            host=hostname sec=mechanism uid=0xFF user=username */
 105         desc_len = MAX_VER_STR_LEN +
 106                    HOST_KEY_LEN + strlen(hostname) +
 107                    IP_KEY_LEN + INET6_ADDRSTRLEN +
 108                    MAX_MECH_STR_LEN +
 109                    UID_KEY_LEN + (sizeof(uid_t) * 2) +
 110                    USER_KEY_LEN + strlen(sesInfo->userName) +
 111                    PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
 112
 113         spnego_key = ERR_PTR(-ENOMEM);
 114         description = kzalloc(desc_len, GFP_KERNEL);
 115         if (description == NULL)
 116                 goto out;
 117
 118         dp = description;
 119         /* start with version and hostname portion of UNC string */
 120         spnego_key = ERR_PTR(-EINVAL);
 121         sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
 122                 hostname);
 123         dp = description + strlen(description);
 124
 125         /* add the server address */
 126         if (server->addr.sockAddr.sin_family == AF_INET)
 127                 sprintf(dp, "ip4=%pI4", &server->addr.sockAddr.sin_addr);
 128         else if (server->addr.sockAddr.sin_family == AF_INET6)
 129                 sprintf(dp, "ip6=%pI6", &server->addr.sockAddr6.sin6_addr);
 130         else
 131                 goto out;
 132
 133         dp = description + strlen(description);
 134
 135         /* for now, only sec=krb5 and sec=mskrb5 are valid */
 136         if (server->secType == Kerberos)
 137                 sprintf(dp, ";sec=krb5");
 138         else if (server->secType == MSKerberos)
 139                 sprintf(dp, ";sec=mskrb5");
 140         else
 141                 goto out;
 142
 143         dp = description + strlen(description);
 144         sprintf(dp, ";uid=0x%x", sesInfo->linux_uid);
 145
 146         dp = description + strlen(description);
 147         sprintf(dp, ";user=%s", sesInfo->userName);
 148
 149         dp = description + strlen(description);
 150         sprintf(dp, ";pid=0x%x", current->pid);
 151
 152         cFYI(1, ("key description = %s", description));
 153         spnego_key = request_key(&cifs_spnego_key_type, description, "");
 154
 155 #ifdef CONFIG_CIFS_DEBUG2
 156         if (cifsFYI && !IS_ERR(spnego_key)) {
 157                 struct cifs_spnego_msg *msg = spnego_key->payload.data;
 158                 cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
 159                                 msg->secblob_len + msg->sesskey_len));
 160         }
 161 #endif /* CONFIG_CIFS_DEBUG2 */
 162
 163 out:
 164         kfree(description);
 165         return spnego_key;
 166 }