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