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         rcu_read_lock();
  88         old_val = netlabel_unlabel_acceptflg;
  89         spin_lock(&netlabel_unlabel_acceptflg_lock);
  90         netlabel_unlabel_acceptflg = value;
  91         spin_unlock(&netlabel_unlabel_acceptflg_lock);
  92         rcu_read_unlock();
  93
  94         audit_buf = netlbl_audit_start_common(AUDIT_MAC_UNLBL_ALLOW,
  95                                               audit_info);
  96         if (audit_buf != NULL) {
  97                 audit_log_format(audit_buf,
  98                                  " unlbl_accept=%u old=%u", value, old_val);
  99                 audit_log_end(audit_buf);
 100         }
 101 }
 102
 103 /*
 104  * NetLabel Command Handlers
 105  */
 106
 107 /**
 108  * netlbl_unlabel_accept - Handle an ACCEPT message
 109  * @skb: the NETLINK buffer
 110  * @info: the Generic NETLINK info block
 111  *
 112  * Description:
 113  * Process a user generated ACCEPT message and set the accept flag accordingly.
 114  * Returns zero on success, negative values on failure.
 115  *
 116  */
 117 static int netlbl_unlabel_accept(struct sk_buff *skb, struct genl_info *info)
 118 {
 119         u8 value;
 120         struct netlbl_audit audit_info;
 121
 122         if (info->attrs[NLBL_UNLABEL_A_ACPTFLG]) {
 123                 value = nla_get_u8(info->attrs[NLBL_UNLABEL_A_ACPTFLG]);
 124                 if (value == 1 || value == 0) {
 125                         netlbl_netlink_auditinfo(skb, &audit_info);
 126                         netlbl_unlabel_acceptflg_set(value, &audit_info);
 127                         return 0;
 128                 }
 129         }
 130
 131         return -EINVAL;
 132 }
 133
 134 /**
 135  * netlbl_unlabel_list - Handle a LIST message
 136  * @skb: the NETLINK buffer
 137  * @info: the Generic NETLINK info block
 138  *
 139  * Description:
 140  * Process a user generated LIST message and respond with the current status.
 141  * Returns zero on success, negative values on failure.
 142  *
 143  */
 144 static int netlbl_unlabel_list(struct sk_buff *skb, struct genl_info *info)
 145 {
 146         int ret_val = -EINVAL;
 147         struct sk_buff *ans_skb;
 148         void *data;
 149
 150         ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 151         if (ans_skb == NULL)
 152                 goto list_failure;
 153         data = genlmsg_put_reply(ans_skb, info, &netlbl_unlabel_gnl_family,
 154                                  0, NLBL_UNLABEL_C_LIST);
 155         if (data == NULL) {
 156                 ret_val = -ENOMEM;
 157                 goto list_failure;
 158         }
 159
 160         rcu_read_lock();
 161         ret_val = nla_put_u8(ans_skb,
 162                              NLBL_UNLABEL_A_ACPTFLG,
 163                              netlabel_unlabel_acceptflg);
 164         rcu_read_unlock();
 165         if (ret_val != 0)
 166                 goto list_failure;
 167
 168         genlmsg_end(ans_skb, data);
 169
 170         ret_val = genlmsg_reply(ans_skb, info);
 171         if (ret_val != 0)
 172                 goto list_failure;
 173         return 0;
 174
 175 list_failure:
 176         kfree_skb(ans_skb);
 177         return ret_val;
 178 }
 179
 180
 181 /*
 182  * NetLabel Generic NETLINK Command Definitions
 183  */
 184
 185 static struct genl_ops netlbl_unlabel_genl_c_accept = {
 186         .cmd = NLBL_UNLABEL_C_ACCEPT,
 187         .flags = GENL_ADMIN_PERM,
 188         .policy = netlbl_unlabel_genl_policy,
 189         .doit = netlbl_unlabel_accept,
 190         .dumpit = NULL,
 191 };
 192
 193 static struct genl_ops netlbl_unlabel_genl_c_list = {
 194         .cmd = NLBL_UNLABEL_C_LIST,
 195         .flags = 0,
 196         .policy = netlbl_unlabel_genl_policy,
 197         .doit = netlbl_unlabel_list,
 198         .dumpit = NULL,
 199 };
 200
 201
 202 /*
 203  * NetLabel Generic NETLINK Protocol Functions
 204  */
 205
 206 /**
 207  * netlbl_unlabel_genl_init - Register the Unlabeled NetLabel component
 208  *
 209  * Description:
 210  * Register the unlabeled packet NetLabel component with the Generic NETLINK
 211  * mechanism.  Returns zero on success, negative values on failure.
 212  *
 213  */
 214 int netlbl_unlabel_genl_init(void)
 215 {
 216         int ret_val;
 217
 218         ret_val = genl_register_family(&netlbl_unlabel_gnl_family);
 219         if (ret_val != 0)
 220                 return ret_val;
 221
 222         ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
 223                                     &netlbl_unlabel_genl_c_accept);
 224         if (ret_val != 0)
 225                 return ret_val;
 226
 227         ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
 228                                     &netlbl_unlabel_genl_c_list);
 229         if (ret_val != 0)
 230                 return ret_val;
 231
 232         return 0;
 233 }
 234
 235 /*
 236  * NetLabel KAPI Hooks
 237  */
 238
 239 /**
 240  * netlbl_unlabel_getattr - Get the security attributes for an unlabled packet
 241  * @secattr: the security attributes
 242  *
 243  * Description:
 244  * Determine the security attributes, if any, for an unlabled packet and return
 245  * them in @secattr.  Returns zero on success and negative values on failure.
 246  *
 247  */
 248 int netlbl_unlabel_getattr(struct netlbl_lsm_secattr *secattr)
 249 {
 250         int ret_val;
 251
 252         rcu_read_lock();
 253         if (netlabel_unlabel_acceptflg == 1) {
 254                 netlbl_secattr_init(secattr);
 255                 ret_val = 0;
 256         } else
 257                 ret_val = -ENOMSG;
 258         rcu_read_unlock();
 259
 260         return ret_val;
 261 }
 262
 263 /**
 264  * netlbl_unlabel_defconf - Set the default config to allow unlabeled packets
 265  *
 266  * Description:
 267  * Set the default NetLabel configuration to allow incoming unlabeled packets
 268  * and to send unlabeled network traffic by default.
 269  *
 270  */
 271 int netlbl_unlabel_defconf(void)
 272 {
 273         int ret_val;
 274         struct netlbl_dom_map *entry;
 275         struct netlbl_audit audit_info;
 276
 277         /* Only the kernel is allowed to call this function and the only time
 278          * it is called is at bootup before the audit subsystem is reporting
 279          * messages so don't worry to much about these values. */
 280         security_task_getsecid(current, &audit_info.secid);
 281         audit_info.loginuid = 0;
 282
 283         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 284         if (entry == NULL)
 285                 return -ENOMEM;
 286         entry->type = NETLBL_NLTYPE_UNLABELED;
 287         ret_val = netlbl_domhsh_add_default(entry, &audit_info);
 288         if (ret_val != 0)
 289                 return ret_val;
 290
 291         netlbl_unlabel_acceptflg_set(1, &audit_info);
 292
 293         return 0;
 294 }