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 = 0,
  59 };
  60
  61
  62 /*
  63  * NetLabel Command Handlers
  64  */
  65
  66 /**
  67  * netlbl_unlabel_accept - Handle an ACCEPT message
  68  * @skb: the NETLINK buffer
  69  * @info: the Generic NETLINK info block
  70  *
  71  * Description:
  72  * Process a user generated ACCEPT message and set the accept flag accordingly.
  73  * Returns zero on success, negative values on failure.
  74  *
  75  */
  76 static int netlbl_unlabel_accept(struct sk_buff *skb, struct genl_info *info)
  77 {
  78         int ret_val;
  79         struct nlattr *data = netlbl_netlink_payload_data(skb);
  80         u32 value;
  81
  82         ret_val = netlbl_netlink_cap_check(skb, CAP_NET_ADMIN);
  83         if (ret_val != 0)
  84                 return ret_val;
  85
  86         if (netlbl_netlink_payload_len(skb) == NETLBL_LEN_U32) {
  87                 value = nla_get_u32(data);
  88                 if (value == 1 || value == 0) {
  89                         atomic_set(&netlabel_unlabel_accept_flg, value);
  90                         netlbl_netlink_send_ack(info,
  91                                                 netlbl_unlabel_gnl_family.id,
  92                                                 NLBL_UNLABEL_C_ACK,
  93                                                 NETLBL_E_OK);
  94                         return 0;
  95                 }
  96         }
  97
  98         netlbl_netlink_send_ack(info,
  99                                 netlbl_unlabel_gnl_family.id,
 100                                 NLBL_UNLABEL_C_ACK,
 101                                 EINVAL);
 102         return -EINVAL;
 103 }
 104
 105 /**
 106  * netlbl_unlabel_list - Handle a LIST message
 107  * @skb: the NETLINK buffer
 108  * @info: the Generic NETLINK info block
 109  *
 110  * Description:
 111  * Process a user generated LIST message and respond with the current status.
 112  * Returns zero on success, negative values on failure.
 113  *
 114  */
 115 static int netlbl_unlabel_list(struct sk_buff *skb, struct genl_info *info)
 116 {
 117         int ret_val = -ENOMEM;
 118         struct sk_buff *ans_skb;
 119
 120         ans_skb = netlbl_netlink_alloc_skb(0,
 121                                            GENL_HDRLEN + NETLBL_LEN_U32,
 122                                            GFP_KERNEL);
 123         if (ans_skb == NULL)
 124                 goto list_failure;
 125
 126         if (netlbl_netlink_hdr_put(ans_skb,
 127                                    info->snd_pid,
 128                                    0,
 129                                    netlbl_unlabel_gnl_family.id,
 130                                    NLBL_UNLABEL_C_LIST) == NULL)
 131                 goto list_failure;
 132
 133         ret_val = nla_put_u32(ans_skb,
 134                               NLA_U32,
 135                               atomic_read(&netlabel_unlabel_accept_flg));
 136         if (ret_val != 0)
 137                 goto list_failure;
 138
 139         ret_val = netlbl_netlink_snd(ans_skb, info->snd_pid);
 140         if (ret_val != 0)
 141                 goto list_failure;
 142
 143         return 0;
 144
 145 list_failure:
 146         netlbl_netlink_send_ack(info,
 147                                 netlbl_unlabel_gnl_family.id,
 148                                 NLBL_UNLABEL_C_ACK,
 149                                 -ret_val);
 150         return ret_val;
 151 }
 152
 153
 154 /*
 155  * NetLabel Generic NETLINK Command Definitions
 156  */
 157
 158 static struct genl_ops netlbl_unlabel_genl_c_accept = {
 159         .cmd = NLBL_UNLABEL_C_ACCEPT,
 160         .flags = 0,
 161         .doit = netlbl_unlabel_accept,
 162         .dumpit = NULL,
 163 };
 164
 165 static struct genl_ops netlbl_unlabel_genl_c_list = {
 166         .cmd = NLBL_UNLABEL_C_LIST,
 167         .flags = 0,
 168         .doit = netlbl_unlabel_list,
 169         .dumpit = NULL,
 170 };
 171
 172
 173 /*
 174  * NetLabel Generic NETLINK Protocol Functions
 175  */
 176
 177 /**
 178  * netlbl_unlabel_genl_init - Register the Unlabeled NetLabel component
 179  *
 180  * Description:
 181  * Register the unlabeled packet NetLabel component with the Generic NETLINK
 182  * mechanism.  Returns zero on success, negative values on failure.
 183  *
 184  */
 185 int netlbl_unlabel_genl_init(void)
 186 {
 187         int ret_val;
 188
 189         ret_val = genl_register_family(&netlbl_unlabel_gnl_family);
 190         if (ret_val != 0)
 191                 return ret_val;
 192
 193         ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
 194                                     &netlbl_unlabel_genl_c_accept);
 195         if (ret_val != 0)
 196                 return ret_val;
 197
 198         ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
 199                                     &netlbl_unlabel_genl_c_list);
 200         if (ret_val != 0)
 201                 return ret_val;
 202
 203         return 0;
 204 }
 205
 206 /*
 207  * NetLabel KAPI Hooks
 208  */
 209
 210 /**
 211  * netlbl_unlabel_getattr - Get the security attributes for an unlabled packet
 212  * @secattr: the security attributes
 213  *
 214  * Description:
 215  * Determine the security attributes, if any, for an unlabled packet and return
 216  * them in @secattr.  Returns zero on success and negative values on failure.
 217  *
 218  */
 219 int netlbl_unlabel_getattr(struct netlbl_lsm_secattr *secattr)
 220 {
 221         if (atomic_read(&netlabel_unlabel_accept_flg) == 1) {
 222                 memset(secattr, 0, sizeof(*secattr));
 223                 return 0;
 224         }
 225
 226         return -ENOMSG;
 227 }
 228
 229 /**
 230  * netlbl_unlabel_defconf - Set the default config to allow unlabeled packets
 231  *
 232  * Description:
 233  * Set the default NetLabel configuration to allow incoming unlabeled packets
 234  * and to send unlabeled network traffic by default.
 235  *
 236  */
 237 int netlbl_unlabel_defconf(void)
 238 {
 239         int ret_val;
 240         struct netlbl_dom_map *entry;
 241
 242         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 243         if (entry == NULL)
 244                 return -ENOMEM;
 245         entry->type = NETLBL_NLTYPE_UNLABELED;
 246         ret_val = netlbl_domhsh_add_default(entry);
 247         if (ret_val != 0)
 248                 return ret_val;
 249
 250         atomic_set(&netlabel_unlabel_accept_flg, 1);
 251
 252         return 0;
 253 }