include/net/netlabel.h

   1 /*
   2  * NetLabel System
   3  *
   4  * The NetLabel system manages static and dynamic label mappings for network
   5  * protocols such as CIPSO and RIPSO.
   6  *
   7  * Author: Paul Moore <paul.moore@hp.com>
   8  *
   9  */
  10
  11 /*
  12  * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
  13  *
  14  * This program is free software;  you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY;  without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  22  * the GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program;  if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  27  *
  28  */
  29
  30 #ifndef _NETLABEL_H
  31 #define _NETLABEL_H
  32
  33 #include <linux/types.h>
  34 #include <linux/skbuff.h>
  35 #include <net/netlink.h>
  36
  37 /*
  38  * NetLabel - A management interface for maintaining network packet label
  39  *            mapping tables for explicit packet labling protocols.
  40  *
  41  * Network protocols such as CIPSO and RIPSO require a label translation layer
  42  * to convert the label on the packet into something meaningful on the host
  43  * machine.  In the current Linux implementation these mapping tables live
  44  * inside the kernel; NetLabel provides a mechanism for user space applications
  45  * to manage these mapping tables.
  46  *
  47  * NetLabel makes use of the Generic NETLINK mechanism as a transport layer to
  48  * send messages between kernel and user space.  The general format of a
  49  * NetLabel message is shown below:
  50  *
  51  *  +-----------------+-------------------+--------- --- -- -
  52  *  | struct nlmsghdr | struct genlmsghdr | payload
  53  *  +-----------------+-------------------+--------- --- -- -
  54  *
  55  * The 'nlmsghdr' and 'genlmsghdr' structs should be dealt with like normal.
  56  * The payload is dependent on the subsystem specified in the
  57  * 'nlmsghdr->nlmsg_type' and should be defined below, supporting functions
  58  * should be defined in the corresponding net/netlabel/netlabel_<subsys>.h|c
  59  * file.  All of the fields in the NetLabel payload are NETLINK attributes, the
  60  * length of each field is the length of the NETLINK attribute payload, see
  61  * include/net/netlink.h for more information on NETLINK attributes.
  62  *
  63  */
  64
  65 /*
  66  * NetLabel NETLINK protocol
  67  */
  68
  69 #define NETLBL_PROTO_VERSION            1
  70
  71 /* NetLabel NETLINK types/families */
  72 #define NETLBL_NLTYPE_NONE              0
  73 #define NETLBL_NLTYPE_MGMT              1
  74 #define NETLBL_NLTYPE_MGMT_NAME         "NLBL_MGMT"
  75 #define NETLBL_NLTYPE_RIPSO             2
  76 #define NETLBL_NLTYPE_RIPSO_NAME        "NLBL_RIPSO"
  77 #define NETLBL_NLTYPE_CIPSOV4           3
  78 #define NETLBL_NLTYPE_CIPSOV4_NAME      "NLBL_CIPSOv4"
  79 #define NETLBL_NLTYPE_CIPSOV6           4
  80 #define NETLBL_NLTYPE_CIPSOV6_NAME      "NLBL_CIPSOv6"
  81 #define NETLBL_NLTYPE_UNLABELED         5
  82 #define NETLBL_NLTYPE_UNLABELED_NAME    "NLBL_UNLBL"
  83
  84 /* NetLabel return codes */
  85 #define NETLBL_E_OK                     0
  86
  87 /*
  88  * Helper functions
  89  */
  90
  91 #define NETLBL_LEN_U8                   nla_total_size(sizeof(u8))
  92 #define NETLBL_LEN_U16                  nla_total_size(sizeof(u16))
  93 #define NETLBL_LEN_U32                  nla_total_size(sizeof(u32))
  94
  95 /**
  96  * netlbl_netlink_alloc_skb - Allocate a NETLINK message buffer
  97  * @head: the amount of headroom in bytes
  98  * @body: the desired size (minus headroom) in bytes
  99  * @gfp_flags: the alloc flags to pass to alloc_skb()
 100  *
 101  * Description:
 102  * Allocate a NETLINK message buffer based on the sizes given in @head and
 103  * @body.  If @head is greater than zero skb_reserve() is called to reserve
 104  * @head bytes at the start of the buffer.  Returns a valid sk_buff pointer on
 105  * success, NULL on failure.
 106  *
 107  */
 108 static inline struct sk_buff *netlbl_netlink_alloc_skb(size_t head,
 109                                                        size_t body,
 110                                                        int gfp_flags)
 111 {
 112         struct sk_buff *skb;
 113
 114         skb = alloc_skb(NLMSG_ALIGN(head + body), gfp_flags);
 115         if (skb == NULL)
 116                 return NULL;
 117         if (head > 0) {
 118                 skb_reserve(skb, head);
 119                 if (skb_tailroom(skb) < body) {
 120                         kfree_skb(skb);
 121                         return NULL;
 122                 }
 123         }
 124
 125         return skb;
 126 }
 127
 128 /*
 129  * NetLabel - Kernel API for accessing the network packet label mappings.
 130  *
 131  * The following functions are provided for use by other kernel modules,
 132  * specifically kernel LSM modules, to provide a consistent, transparent API
 133  * for dealing with explicit packet labeling protocols such as CIPSO and
 134  * RIPSO.  The functions defined here are implemented in the
 135  * net/netlabel/netlabel_kapi.c file.
 136  *
 137  */
 138
 139 /* Domain mapping definition struct */
 140 struct netlbl_dom_map;
 141
 142 /* Domain mapping operations */
 143 int netlbl_domhsh_remove(const char *domain);
 144
 145 /* LSM security attributes */
 146 struct netlbl_lsm_cache {
 147         void (*free) (const void *data);
 148         void *data;
 149 };
 150 struct netlbl_lsm_secattr {
 151         char *domain;
 152
 153         u32 mls_lvl;
 154         u32 mls_lvl_vld;
 155         unsigned char *mls_cat;
 156         size_t mls_cat_len;
 157
 158         struct netlbl_lsm_cache cache;
 159 };
 160
 161 /*
 162  * LSM security attribute operations
 163  */
 164
 165
 166 /**
 167  * netlbl_secattr_init - Initialize a netlbl_lsm_secattr struct
 168  * @secattr: the struct to initialize
 169  *
 170  * Description:
 171  * Initialize an already allocated netlbl_lsm_secattr struct.  Returns zero on
 172  * success, negative values on error.
 173  *
 174  */
 175 static inline int netlbl_secattr_init(struct netlbl_lsm_secattr *secattr)
 176 {
 177         memset(secattr, 0, sizeof(*secattr));
 178         return 0;
 179 }
 180
 181 /**
 182  * netlbl_secattr_destroy - Clears a netlbl_lsm_secattr struct
 183  * @secattr: the struct to clear
 184  * @clear_cache: cache clear flag
 185  *
 186  * Description:
 187  * Destroys the @secattr struct, including freeing all of the internal buffers.
 188  * If @clear_cache is true then free the cache fields, otherwise leave them
 189  * intact.  The struct must be reset with a call to netlbl_secattr_init()
 190  * before reuse.
 191  *
 192  */
 193 static inline void netlbl_secattr_destroy(struct netlbl_lsm_secattr *secattr,
 194                                           u32 clear_cache)
 195 {
 196         if (clear_cache && secattr->cache.data != NULL && secattr->cache.free)
 197                 secattr->cache.free(secattr->cache.data);
 198         kfree(secattr->domain);
 199         kfree(secattr->mls_cat);
 200 }
 201
 202 /**
 203  * netlbl_secattr_alloc - Allocate and initialize a netlbl_lsm_secattr struct
 204  * @flags: the memory allocation flags
 205  *
 206  * Description:
 207  * Allocate and initialize a netlbl_lsm_secattr struct.  Returns a valid
 208  * pointer on success, or NULL on failure.
 209  *
 210  */
 211 static inline struct netlbl_lsm_secattr *netlbl_secattr_alloc(int flags)
 212 {
 213         return kzalloc(sizeof(struct netlbl_lsm_secattr), flags);
 214 }
 215
 216 /**
 217  * netlbl_secattr_free - Frees a netlbl_lsm_secattr struct
 218  * @secattr: the struct to free
 219  * @clear_cache: cache clear flag
 220  *
 221  * Description:
 222  * Frees @secattr including all of the internal buffers.  If @clear_cache is
 223  * true then free the cache fields, otherwise leave them intact.
 224  *
 225  */
 226 static inline void netlbl_secattr_free(struct netlbl_lsm_secattr *secattr,
 227                                        u32 clear_cache)
 228 {
 229         netlbl_secattr_destroy(secattr, clear_cache);
 230         kfree(secattr);
 231 }
 232
 233 /*
 234  * LSM protocol operations
 235  */
 236
 237 #ifdef CONFIG_NETLABEL
 238 int netlbl_socket_setattr(const struct socket *sock,
 239                           const struct netlbl_lsm_secattr *secattr);
 240 int netlbl_socket_getattr(const struct socket *sock,
 241                           struct netlbl_lsm_secattr *secattr);
 242 int netlbl_skbuff_getattr(const struct sk_buff *skb,
 243                           struct netlbl_lsm_secattr *secattr);
 244 void netlbl_skbuff_err(struct sk_buff *skb, int error);
 245 #else
 246 static inline int netlbl_socket_setattr(const struct socket *sock,
 247                                      const struct netlbl_lsm_secattr *secattr)
 248 {
 249         return -ENOSYS;
 250 }
 251
 252 static inline int netlbl_socket_getattr(const struct socket *sock,
 253                                         struct netlbl_lsm_secattr *secattr)
 254 {
 255         return -ENOSYS;
 256 }
 257
 258 static inline int netlbl_skbuff_getattr(const struct sk_buff *skb,
 259                                         struct netlbl_lsm_secattr *secattr)
 260 {
 261         return -ENOSYS;
 262 }
 263
 264 static inline void netlbl_skbuff_err(struct sk_buff *skb, int error)
 265 {
 266         return;
 267 }
 268 #endif /* CONFIG_NETLABEL */
 269
 270 /*
 271  * LSM label mapping cache operations
 272  */
 273
 274 #ifdef CONFIG_NETLABEL
 275 void netlbl_cache_invalidate(void);
 276 int netlbl_cache_add(const struct sk_buff *skb,
 277                      const struct netlbl_lsm_secattr *secattr);
 278 #else
 279 static inline void netlbl_cache_invalidate(void)
 280 {
 281         return;
 282 }
 283
 284 static inline int netlbl_cache_add(const struct sk_buff *skb,
 285                                    const struct netlbl_lsm_secattr *secattr)
 286 {
 287         return 0;
 288 }
 289 #endif /* CONFIG_NETLABEL */
 290
 291 #endif /* _NETLABEL_H */