net/netlabel/netlabel_unlabeled.c

   1 /*
   2  * NetLabel Unlabeled Support
   3  *
   4  * This file defines functions for dealing with unlabeled packets for the
   5  * NetLabel system.  The NetLabel system manages static and dynamic label
   6  * mappings for network protocols such as CIPSO and RIPSO.
   7  *
   8  * Author: Paul Moore <paul.moore@hp.com>
   9  *
  10  */
  11
  12 /*
  13  * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
  14  *
  15  * This program is free software;  you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License as published by
  17  * the Free Software Foundation; either version 2 of the License, or
  18  * (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY;  without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  23  * the GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program;  if not, write to the Free Software
  27  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  28  *
  29  */
  30
  31 #include <linux/types.h>
  32 #include <linux/rcupdate.h>
  33 #include <linux/list.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/socket.h>
  36 #include <linux/string.h>
  37 #include <linux/skbuff.h>
  38 #include <net/sock.h>
  39 #include <net/netlink.h>
  40 #include <net/genetlink.h>
  41
  42 #include <net/netlabel.h>
  43 #include <asm/bug.h>
  44
  45 #include "netlabel_user.h"
  46 #include "netlabel_domainhash.h"
  47 #include "netlabel_unlabeled.h"
  48
  49 /* Accept unlabeled packets flag */
  50 static atomic_t netlabel_unlabel_accept_flg = ATOMIC_INIT(0);
  51
  52 /* NetLabel Generic NETLINK CIPSOv4 family */
  53 static struct genl_family netlbl_unlabel_gnl_family = {
  54         .id = GENL_ID_GENERATE,
  55         .hdrsize = 0,
  56         .name = NETLBL_NLTYPE_UNLABELED_NAME,
  57         .version = NETLBL_PROTO_VERSION,
  58         .maxattr = NLBL_UNLABEL_A_MAX,
  59 };
  60
  61 /* NetLabel Netlink attribute policy */
  62 static struct nla_policy netlbl_unlabel_genl_policy[NLBL_UNLABEL_A_MAX + 1] = {
  63         [NLBL_UNLABEL_A_ACPTFLG] = { .type = NLA_U8 },
  64 };
  65
  66 /*
  67  * NetLabel Command Handlers
  68  */
  69
  70 /**
  71  * netlbl_unlabel_accept - Handle an ACCEPT message
  72  * @skb: the NETLINK buffer
  73  * @info: the Generic NETLINK info block
  74  *
  75  * Description:
  76  * Process a user generated ACCEPT message and set the accept flag accordingly.
  77  * Returns zero on success, negative values on failure.
  78  *
  79  */
  80 static int netlbl_unlabel_accept(struct sk_buff *skb, struct genl_info *info)
  81 {
  82         int ret_val = -EINVAL;
  83         u8 value;
  84
  85         if (info->attrs[NLBL_UNLABEL_A_ACPTFLG]) {
  86                 value = nla_get_u8(info->attrs[NLBL_UNLABEL_A_ACPTFLG]);
  87                 if (value == 1 || value == 0) {
  88                         atomic_set(&netlabel_unlabel_accept_flg, value);
  89                         ret_val = 0;
  90                 }
  91         }
  92
  93         return ret_val;
  94 }
  95
  96 /**
  97  * netlbl_unlabel_list - Handle a LIST message
  98  * @skb: the NETLINK buffer
  99  * @info: the Generic NETLINK info block
 100  *
 101  * Description:
 102  * Process a user generated LIST message and respond with the current status.
 103  * Returns zero on success, negative values on failure.
 104  *
 105  */
 106 static int netlbl_unlabel_list(struct sk_buff *skb, struct genl_info *info)
 107 {
 108         int ret_val = -EINVAL;
 109         struct sk_buff *ans_skb;
 110         void *data;
 111
 112         ans_skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 113         if (ans_skb == NULL)
 114                 goto list_failure;
 115         data = netlbl_netlink_hdr_put(ans_skb,
 116                                       info->snd_pid,
 117                                       info->snd_seq,
 118                                       netlbl_unlabel_gnl_family.id,
 119                                       0,
 120                                       NLBL_UNLABEL_C_LIST);
 121         if (data == NULL) {
 122                 ret_val = -ENOMEM;
 123                 goto list_failure;
 124         }
 125
 126         ret_val = nla_put_u8(ans_skb,
 127                              NLBL_UNLABEL_A_ACPTFLG,
 128                              atomic_read(&netlabel_unlabel_accept_flg));
 129         if (ret_val != 0)
 130                 goto list_failure;
 131
 132         genlmsg_end(ans_skb, data);
 133
 134         ret_val = genlmsg_unicast(ans_skb, info->snd_pid);
 135         if (ret_val != 0)
 136                 goto list_failure;
 137         return 0;
 138
 139 list_failure:
 140         kfree(ans_skb);
 141         return ret_val;
 142 }
 143
 144
 145 /*
 146  * NetLabel Generic NETLINK Command Definitions
 147  */
 148
 149 static struct genl_ops netlbl_unlabel_genl_c_accept = {
 150         .cmd = NLBL_UNLABEL_C_ACCEPT,
 151         .flags = GENL_ADMIN_PERM,
 152         .policy = netlbl_unlabel_genl_policy,
 153         .doit = netlbl_unlabel_accept,
 154         .dumpit = NULL,
 155 };
 156
 157 static struct genl_ops netlbl_unlabel_genl_c_list = {
 158         .cmd = NLBL_UNLABEL_C_LIST,
 159         .flags = 0,
 160         .policy = netlbl_unlabel_genl_policy,
 161         .doit = netlbl_unlabel_list,
 162         .dumpit = NULL,
 163 };
 164
 165
 166 /*
 167  * NetLabel Generic NETLINK Protocol Functions
 168  */
 169
 170 /**
 171  * netlbl_unlabel_genl_init - Register the Unlabeled NetLabel component
 172  *
 173  * Description:
 174  * Register the unlabeled packet NetLabel component with the Generic NETLINK
 175  * mechanism.  Returns zero on success, negative values on failure.
 176  *
 177  */
 178 int netlbl_unlabel_genl_init(void)
 179 {
 180         int ret_val;
 181
 182         ret_val = genl_register_family(&netlbl_unlabel_gnl_family);
 183         if (ret_val != 0)
 184                 return ret_val;
 185
 186         ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
 187                                     &netlbl_unlabel_genl_c_accept);
 188         if (ret_val != 0)
 189                 return ret_val;
 190
 191         ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
 192                                     &netlbl_unlabel_genl_c_list);
 193         if (ret_val != 0)
 194                 return ret_val;
 195
 196         return 0;
 197 }
 198
 199 /*
 200  * NetLabel KAPI Hooks
 201  */
 202
 203 /**
 204  * netlbl_unlabel_getattr - Get the security attributes for an unlabled packet
 205  * @secattr: the security attributes
 206  *
 207  * Description:
 208  * Determine the security attributes, if any, for an unlabled packet and return
 209  * them in @secattr.  Returns zero on success and negative values on failure.
 210  *
 211  */
 212 int netlbl_unlabel_getattr(struct netlbl_lsm_secattr *secattr)
 213 {
 214         if (atomic_read(&netlabel_unlabel_accept_flg) == 1)
 215                 return netlbl_secattr_init(secattr);
 216
 217         return -ENOMSG;
 218 }
 219
 220 /**
 221  * netlbl_unlabel_defconf - Set the default config to allow unlabeled packets
 222  *
 223  * Description:
 224  * Set the default NetLabel configuration to allow incoming unlabeled packets
 225  * and to send unlabeled network traffic by default.
 226  *
 227  */
 228 int netlbl_unlabel_defconf(void)
 229 {
 230         int ret_val;
 231         struct netlbl_dom_map *entry;
 232
 233         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 234         if (entry == NULL)
 235                 return -ENOMEM;
 236         entry->type = NETLBL_NLTYPE_UNLABELED;
 237         ret_val = netlbl_domhsh_add_default(entry);
 238         if (ret_val != 0)
 239                 return ret_val;
 240
 241         atomic_set(&netlabel_unlabel_accept_flg, 1);
 242
 243         return 0;
 244 }