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, 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
  48 error:
  49         return ret;
  50 }
  51
  52 static void
  53 cifs_spnego_key_destroy(struct key *key)
  54 {
  55         kfree(key->payload.data);
  56 }
  57
  58
  59 /*
  60  * keytype for CIFS spnego keys
  61  */
  62 struct 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 */
  96 struct key *
  97 cifs_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
 177 out:
 178         kfree(description);
 179         return spnego_key;
 180 }