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