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[0] = 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[0]);
  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         .destroy        = cifs_spnego_key_destroy,
  66         .describe       = user_describe,
  67 };
  68
  69 /* length of longest version string e.g.  strlen("ver=0xFF") */
  70 #define MAX_VER_STR_LEN         8
  71
  72 /* length of longest security mechanism name, eg in future could have
  73  * strlen(";sec=ntlmsspi") */
  74 #define MAX_MECH_STR_LEN        13
  75
  76 /* strlen of "host=" */
  77 #define HOST_KEY_LEN            5
  78
  79 /* strlen of ";ip4=" or ";ip6=" */
  80 #define IP_KEY_LEN              5
  81
  82 /* strlen of ";uid=0x" */
  83 #define UID_KEY_LEN             7
  84
  85 /* strlen of ";creduid=0x" */
  86 #define CREDUID_KEY_LEN         11
  87
  88 /* strlen of ";user=" */
  89 #define USER_KEY_LEN            6
  90
  91 /* strlen of ";pid=0x" */
  92 #define PID_KEY_LEN             7
  93
  94 /* get a key struct with a SPNEGO security blob, suitable for session setup */
  95 struct key *
  96 cifs_get_spnego_key(struct cifs_ses *sesInfo)
  97 {
  98         struct TCP_Server_Info *server = sesInfo->server;
  99         struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
 100         struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
 101         char *description, *dp;
 102         size_t desc_len;
 103         struct key *spnego_key;
 104         const char *hostname = server->hostname;
 105
 106         /* length of fields (with semicolons): ver=0xyz ip4=ipaddress
 107            host=hostname sec=mechanism uid=0xFF user=username */
 108         desc_len = MAX_VER_STR_LEN +
 109                    HOST_KEY_LEN + strlen(hostname) +
 110                    IP_KEY_LEN + INET6_ADDRSTRLEN +
 111                    MAX_MECH_STR_LEN +
 112                    UID_KEY_LEN + (sizeof(uid_t) * 2) +
 113                    CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
 114                    PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
 115
 116         if (sesInfo->user_name)
 117                 desc_len += USER_KEY_LEN + strlen(sesInfo->user_name);
 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                 cifs_dbg(VFS, "unknown or missing server auth type, use krb5\n");
 148                 sprintf(dp, ";sec=krb5");
 149         }
 150
 151         dp = description + strlen(description);
 152         sprintf(dp, ";uid=0x%x",
 153                 from_kuid_munged(&init_user_ns, sesInfo->linux_uid));
 154
 155         dp = description + strlen(description);
 156         sprintf(dp, ";creduid=0x%x",
 157                 from_kuid_munged(&init_user_ns, sesInfo->cred_uid));
 158
 159         if (sesInfo->user_name) {
 160                 dp = description + strlen(description);
 161                 sprintf(dp, ";user=%s", sesInfo->user_name);
 162         }
 163
 164         dp = description + strlen(description);
 165         sprintf(dp, ";pid=0x%x", current->pid);
 166
 167         cifs_dbg(FYI, "key description = %s\n", description);
 168         spnego_key = request_key(&cifs_spnego_key_type, description, "");
 169
 170 #ifdef CONFIG_CIFS_DEBUG2
 171         if (cifsFYI && !IS_ERR(spnego_key)) {
 172                 struct cifs_spnego_msg *msg = spnego_key->payload.data[0];
 173                 cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
 174                                 msg->secblob_len + msg->sesskey_len));
 175         }
 176 #endif /* CONFIG_CIFS_DEBUG2 */
 177
 178 out:
 179         kfree(description);
 180         return spnego_key;
 181 }