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