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 <linux/audit.h>
  39 #include <net/sock.h>
  40 #include <net/netlink.h>
  41 #include <net/genetlink.h>
  42
  43 #include <net/netlabel.h>
  44 #include <asm/bug.h>
  45
  46 #include "netlabel_user.h"
  47 #include "netlabel_domainhash.h"
  48 #include "netlabel_unlabeled.h"
  49
  50 /* Accept unlabeled packets flag */
  51 static DEFINE_SPINLOCK(netlabel_unlabel_acceptflg_lock);
  52 static u8 netlabel_unlabel_acceptflg = 0;
  53
  54 /* NetLabel Generic NETLINK CIPSOv4 family */
  55 static struct genl_family netlbl_unlabel_gnl_family = {
  56         .id = GENL_ID_GENERATE,
  57         .hdrsize = 0,
  58         .name = NETLBL_NLTYPE_UNLABELED_NAME,
  59         .version = NETLBL_PROTO_VERSION,
  60         .maxattr = NLBL_UNLABEL_A_MAX,
  61 };
  62
  63 /* NetLabel Netlink attribute policy */
  64 static const struct nla_policy netlbl_unlabel_genl_policy[NLBL_UNLABEL_A_MAX + 1] = {
  65         [NLBL_UNLABEL_A_ACPTFLG] = { .type = NLA_U8 },
  66 };
  67
  68 /*
  69  * Helper Functions
  70  */
  71
  72 /**
  73  * netlbl_unlabel_acceptflg_set - Set the unlabeled accept flag
  74  * @value: desired value
  75  * @audit_info: NetLabel audit information
  76  *
  77  * Description:
  78  * Set the value of the unlabeled accept flag to @value.
  79  *
  80  */
  81 static void netlbl_unlabel_acceptflg_set(u8 value,
  82                                          struct netlbl_audit *audit_info)
  83 {
  84         struct audit_buffer *audit_buf;
  85         u8 old_val;
  86
  87         spin_lock(&netlabel_unlabel_acceptflg_lock);
  88         old_val = netlabel_unlabel_acceptflg;
  89         netlabel_unlabel_acceptflg = value;
  90         spin_unlock(&netlabel_unlabel_acceptflg_lock);
  91
  92         audit_buf = netlbl_audit_start_common(AUDIT_MAC_UNLBL_ALLOW,
  93                                               audit_info);
  94         if (audit_buf != NULL) {
  95                 audit_log_format(audit_buf,
  96                                  " unlbl_accept=%u old=%u", value, old_val);
  97                 audit_log_end(audit_buf);
  98         }
  99 }
 100
 101 /*
 102  * NetLabel Command Handlers
 103  */
 104
 105 /**
 106  * netlbl_unlabel_accept - Handle an ACCEPT message
 107  * @skb: the NETLINK buffer
 108  * @info: the Generic NETLINK info block
 109  *
 110  * Description:
 111  * Process a user generated ACCEPT message and set the accept flag accordingly.
 112  * Returns zero on success, negative values on failure.
 113  *
 114  */
 115 static int netlbl_unlabel_accept(struct sk_buff *skb, struct genl_info *info)
 116 {
 117         u8 value;
 118         struct netlbl_audit audit_info;
 119
 120         if (info->attrs[NLBL_UNLABEL_A_ACPTFLG]) {
 121                 value = nla_get_u8(info->attrs[NLBL_UNLABEL_A_ACPTFLG]);
 122                 if (value == 1 || value == 0) {
 123                         netlbl_netlink_auditinfo(skb, &audit_info);
 124                         netlbl_unlabel_acceptflg_set(value, &audit_info);
 125                         return 0;
 126                 }
 127         }
 128
 129         return -EINVAL;
 130 }
 131
 132 /**
 133  * netlbl_unlabel_list - Handle a LIST message
 134  * @skb: the NETLINK buffer
 135  * @info: the Generic NETLINK info block
 136  *
 137  * Description:
 138  * Process a user generated LIST message and respond with the current status.
 139  * Returns zero on success, negative values on failure.
 140  *
 141  */
 142 static int netlbl_unlabel_list(struct sk_buff *skb, struct genl_info *info)
 143 {
 144         int ret_val = -EINVAL;
 145         struct sk_buff *ans_skb;
 146         void *data;
 147
 148         ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 149         if (ans_skb == NULL)
 150                 goto list_failure;
 151         data = genlmsg_put_reply(ans_skb, info, &netlbl_unlabel_gnl_family,
 152                                  0, NLBL_UNLABEL_C_LIST);
 153         if (data == NULL) {
 154                 ret_val = -ENOMEM;
 155                 goto list_failure;
 156         }
 157
 158         rcu_read_lock();
 159         ret_val = nla_put_u8(ans_skb,
 160                              NLBL_UNLABEL_A_ACPTFLG,
 161                              netlabel_unlabel_acceptflg);
 162         rcu_read_unlock();
 163         if (ret_val != 0)
 164                 goto list_failure;
 165
 166         genlmsg_end(ans_skb, data);
 167
 168         ret_val = genlmsg_reply(ans_skb, info);
 169         if (ret_val != 0)
 170                 goto list_failure;
 171         return 0;
 172
 173 list_failure:
 174         kfree_skb(ans_skb);
 175         return ret_val;
 176 }
 177
 178
 179 /*
 180  * NetLabel Generic NETLINK Command Definitions
 181  */
 182
 183 static struct genl_ops netlbl_unlabel_genl_c_accept = {
 184         .cmd = NLBL_UNLABEL_C_ACCEPT,
 185         .flags = GENL_ADMIN_PERM,
 186         .policy = netlbl_unlabel_genl_policy,
 187         .doit = netlbl_unlabel_accept,
 188         .dumpit = NULL,
 189 };
 190
 191 static struct genl_ops netlbl_unlabel_genl_c_list = {
 192         .cmd = NLBL_UNLABEL_C_LIST,
 193         .flags = 0,
 194         .policy = netlbl_unlabel_genl_policy,
 195         .doit = netlbl_unlabel_list,
 196         .dumpit = NULL,
 197 };
 198
 199
 200 /*
 201  * NetLabel Generic NETLINK Protocol Functions
 202  */
 203
 204 /**
 205  * netlbl_unlabel_genl_init - Register the Unlabeled NetLabel component
 206  *
 207  * Description:
 208  * Register the unlabeled packet NetLabel component with the Generic NETLINK
 209  * mechanism.  Returns zero on success, negative values on failure.
 210  *
 211  */
 212 int netlbl_unlabel_genl_init(void)
 213 {
 214         int ret_val;
 215
 216         ret_val = genl_register_family(&netlbl_unlabel_gnl_family);
 217         if (ret_val != 0)
 218                 return ret_val;
 219
 220         ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
 221                                     &netlbl_unlabel_genl_c_accept);
 222         if (ret_val != 0)
 223                 return ret_val;
 224
 225         ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
 226                                     &netlbl_unlabel_genl_c_list);
 227         if (ret_val != 0)
 228                 return ret_val;
 229
 230         return 0;
 231 }
 232
 233 /*
 234  * NetLabel KAPI Hooks
 235  */
 236
 237 /**
 238  * netlbl_unlabel_getattr - Get the security attributes for an unlabled packet
 239  * @secattr: the security attributes
 240  *
 241  * Description:
 242  * Determine the security attributes, if any, for an unlabled packet and return
 243  * them in @secattr.  Returns zero on success and negative values on failure.
 244  *
 245  */
 246 int netlbl_unlabel_getattr(struct netlbl_lsm_secattr *secattr)
 247 {
 248         int ret_val;
 249
 250         rcu_read_lock();
 251         if (netlabel_unlabel_acceptflg == 1) {
 252                 netlbl_secattr_init(secattr);
 253                 ret_val = 0;
 254         } else
 255                 ret_val = -ENOMSG;
 256         rcu_read_unlock();
 257
 258         return ret_val;
 259 }
 260
 261 /**
 262  * netlbl_unlabel_defconf - Set the default config to allow unlabeled packets
 263  *
 264  * Description:
 265  * Set the default NetLabel configuration to allow incoming unlabeled packets
 266  * and to send unlabeled network traffic by default.
 267  *
 268  */
 269 int netlbl_unlabel_defconf(void)
 270 {
 271         int ret_val;
 272         struct netlbl_dom_map *entry;
 273         struct netlbl_audit audit_info;
 274
 275         /* Only the kernel is allowed to call this function and the only time
 276          * it is called is at bootup before the audit subsystem is reporting
 277          * messages so don't worry to much about these values. */
 278         security_task_getsecid(current, &audit_info.secid);
 279         audit_info.loginuid = 0;
 280
 281         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 282         if (entry == NULL)
 283                 return -ENOMEM;
 284         entry->type = NETLBL_NLTYPE_UNLABELED;
 285         ret_val = netlbl_domhsh_add_default(entry, &audit_info);
 286         if (ret_val != 0)
 287                 return ret_val;
 288
 289         netlbl_unlabel_acceptflg_set(1, &audit_info);
 290
 291         return 0;
 292 }