net/netlabel/netlabel_kapi.c

   1 /*
   2  * NetLabel Kernel API
   3  *
   4  * This file defines the kernel API for the NetLabel system.  The NetLabel
   5  * system manages static and dynamic label mappings for network protocols such
   6  * 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/init.h>
  32 #include <linux/types.h>
  33 #include <net/ip.h>
  34 #include <net/netlabel.h>
  35 #include <net/cipso_ipv4.h>
  36 #include <asm/bug.h>
  37
  38 #include "netlabel_domainhash.h"
  39 #include "netlabel_unlabeled.h"
  40 #include "netlabel_user.h"
  41
  42 /*
  43  * Security Attribute Functions
  44  */
  45
  46 /**
  47  * netlbl_secattr_catmap_walk - Walk a LSM secattr catmap looking for a bit
  48  * @catmap: the category bitmap
  49  * @offset: the offset to start searching at, in bits
  50  *
  51  * Description:
  52  * This function walks a LSM secattr category bitmap starting at @offset and
  53  * returns the spot of the first set bit or -ENOENT if no bits are set.
  54  *
  55  */
  56 int netlbl_secattr_catmap_walk(struct netlbl_lsm_secattr_catmap *catmap,
  57                                u32 offset)
  58 {
  59         struct netlbl_lsm_secattr_catmap *iter = catmap;
  60         u32 node_idx;
  61         u32 node_bit;
  62         NETLBL_CATMAP_MAPTYPE bitmap;
  63
  64         if (offset > iter->startbit) {
  65                 while (offset >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
  66                         iter = iter->next;
  67                         if (iter == NULL)
  68                                 return -ENOENT;
  69                 }
  70                 node_idx = (offset - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
  71                 node_bit = offset - iter->startbit -
  72                            (NETLBL_CATMAP_MAPSIZE * node_idx);
  73         } else {
  74                 node_idx = 0;
  75                 node_bit = 0;
  76         }
  77         bitmap = iter->bitmap[node_idx] >> node_bit;
  78
  79         for (;;) {
  80                 if (bitmap != 0) {
  81                         while ((bitmap & NETLBL_CATMAP_BIT) == 0) {
  82                                 bitmap >>= 1;
  83                                 node_bit++;
  84                         }
  85                         return iter->startbit +
  86                                 (NETLBL_CATMAP_MAPSIZE * node_idx) + node_bit;
  87                 }
  88                 if (++node_idx >= NETLBL_CATMAP_MAPCNT) {
  89                         if (iter->next != NULL) {
  90                                 iter = iter->next;
  91                                 node_idx = 0;
  92                         } else
  93                                 return -ENOENT;
  94                 }
  95                 bitmap = iter->bitmap[node_idx];
  96                 node_bit = 0;
  97         }
  98
  99         return -ENOENT;
 100 }
 101
 102 /**
 103  * netlbl_secattr_catmap_walk_rng - Find the end of a string of set bits
 104  * @catmap: the category bitmap
 105  * @offset: the offset to start searching at, in bits
 106  *
 107  * Description:
 108  * This function walks a LSM secattr category bitmap starting at @offset and
 109  * returns the spot of the first cleared bit or -ENOENT if the offset is past
 110  * the end of the bitmap.
 111  *
 112  */
 113 int netlbl_secattr_catmap_walk_rng(struct netlbl_lsm_secattr_catmap *catmap,
 114                                    u32 offset)
 115 {
 116         struct netlbl_lsm_secattr_catmap *iter = catmap;
 117         u32 node_idx;
 118         u32 node_bit;
 119         NETLBL_CATMAP_MAPTYPE bitmask;
 120         NETLBL_CATMAP_MAPTYPE bitmap;
 121
 122         if (offset > iter->startbit) {
 123                 while (offset >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
 124                         iter = iter->next;
 125                         if (iter == NULL)
 126                                 return -ENOENT;
 127                 }
 128                 node_idx = (offset - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
 129                 node_bit = offset - iter->startbit -
 130                            (NETLBL_CATMAP_MAPSIZE * node_idx);
 131         } else {
 132                 node_idx = 0;
 133                 node_bit = 0;
 134         }
 135         bitmask = NETLBL_CATMAP_BIT << node_bit;
 136
 137         for (;;) {
 138                 bitmap = iter->bitmap[node_idx];
 139                 while (bitmask != 0 && (bitmap & bitmask) != 0) {
 140                         bitmask <<= 1;
 141                         node_bit++;
 142                 }
 143
 144                 if (bitmask != 0)
 145                         return iter->startbit +
 146                                 (NETLBL_CATMAP_MAPSIZE * node_idx) +
 147                                 node_bit - 1;
 148                 else if (++node_idx >= NETLBL_CATMAP_MAPCNT) {
 149                         if (iter->next == NULL)
 150                                 return iter->startbit + NETLBL_CATMAP_SIZE - 1;
 151                         iter = iter->next;
 152                         node_idx = 0;
 153                 }
 154                 bitmask = NETLBL_CATMAP_BIT;
 155                 node_bit = 0;
 156         }
 157
 158         return -ENOENT;
 159 }
 160
 161 /**
 162  * netlbl_secattr_catmap_setbit - Set a bit in a LSM secattr catmap
 163  * @catmap: the category bitmap
 164  * @bit: the bit to set
 165  * @flags: memory allocation flags
 166  *
 167  * Description:
 168  * Set the bit specified by @bit in @catmap.  Returns zero on success,
 169  * negative values on failure.
 170  *
 171  */
 172 int netlbl_secattr_catmap_setbit(struct netlbl_lsm_secattr_catmap *catmap,
 173                                  u32 bit,
 174                                  gfp_t flags)
 175 {
 176         struct netlbl_lsm_secattr_catmap *iter = catmap;
 177         u32 node_bit;
 178         u32 node_idx;
 179
 180         while (iter->next != NULL &&
 181                bit >= (iter->startbit + NETLBL_CATMAP_SIZE))
 182                 iter = iter->next;
 183         if (bit >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
 184                 iter->next = netlbl_secattr_catmap_alloc(flags);
 185                 if (iter->next == NULL)
 186                         return -ENOMEM;
 187                 iter = iter->next;
 188                 iter->startbit = bit & ~(NETLBL_CATMAP_SIZE - 1);
 189         }
 190
 191         /* gcc always rounds to zero when doing integer division */
 192         node_idx = (bit - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
 193         node_bit = bit - iter->startbit - (NETLBL_CATMAP_MAPSIZE * node_idx);
 194         iter->bitmap[node_idx] |= NETLBL_CATMAP_BIT << node_bit;
 195
 196         return 0;
 197 }
 198
 199 /**
 200  * netlbl_secattr_catmap_setrng - Set a range of bits in a LSM secattr catmap
 201  * @catmap: the category bitmap
 202  * @start: the starting bit
 203  * @end: the last bit in the string
 204  * @flags: memory allocation flags
 205  *
 206  * Description:
 207  * Set a range of bits, starting at @start and ending with @end.  Returns zero
 208  * on success, negative values on failure.
 209  *
 210  */
 211 int netlbl_secattr_catmap_setrng(struct netlbl_lsm_secattr_catmap *catmap,
 212                                  u32 start,
 213                                  u32 end,
 214                                  gfp_t flags)
 215 {
 216         int ret_val = 0;
 217         struct netlbl_lsm_secattr_catmap *iter = catmap;
 218         u32 iter_max_spot;
 219         u32 spot;
 220
 221         /* XXX - This could probably be made a bit faster by combining writes
 222          * to the catmap instead of setting a single bit each time, but for
 223          * right now skipping to the start of the range in the catmap should
 224          * be a nice improvement over calling the individual setbit function
 225          * repeatedly from a loop. */
 226
 227         while (iter->next != NULL &&
 228                start >= (iter->startbit + NETLBL_CATMAP_SIZE))
 229                 iter = iter->next;
 230         iter_max_spot = iter->startbit + NETLBL_CATMAP_SIZE;
 231
 232         for (spot = start; spot <= end && ret_val == 0; spot++) {
 233                 if (spot >= iter_max_spot && iter->next != NULL) {
 234                         iter = iter->next;
 235                         iter_max_spot = iter->startbit + NETLBL_CATMAP_SIZE;
 236                 }
 237                 ret_val = netlbl_secattr_catmap_setbit(iter, spot, GFP_ATOMIC);
 238         }
 239
 240         return ret_val;
 241 }
 242
 243 /*
 244  * LSM Functions
 245  */
 246
 247 /**
 248  * netlbl_socket_setattr - Label a socket using the correct protocol
 249  * @sk: the socket to label
 250  * @secattr: the security attributes
 251  *
 252  * Description:
 253  * Attach the correct label to the given socket using the security attributes
 254  * specified in @secattr.  This function requires exclusive access to @sk,
 255  * which means it either needs to be in the process of being created or locked.
 256  * Returns zero on success, negative values on failure.
 257  *
 258  */
 259 int netlbl_sock_setattr(struct sock *sk,
 260                         const struct netlbl_lsm_secattr *secattr)
 261 {
 262         int ret_val = -ENOENT;
 263         struct netlbl_dom_map *dom_entry;
 264
 265         rcu_read_lock();
 266         dom_entry = netlbl_domhsh_getentry(secattr->domain);
 267         if (dom_entry == NULL)
 268                 goto socket_setattr_return;
 269         switch (dom_entry->type) {
 270         case NETLBL_NLTYPE_CIPSOV4:
 271                 ret_val = cipso_v4_sock_setattr(sk,
 272                                                 dom_entry->type_def.cipsov4,
 273                                                 secattr);
 274                 break;
 275         case NETLBL_NLTYPE_UNLABELED:
 276                 ret_val = 0;
 277                 break;
 278         default:
 279                 ret_val = -ENOENT;
 280         }
 281
 282 socket_setattr_return:
 283         rcu_read_unlock();
 284         return ret_val;
 285 }
 286
 287 /**
 288  * netlbl_sock_getattr - Determine the security attributes of a sock
 289  * @sk: the sock
 290  * @secattr: the security attributes
 291  *
 292  * Description:
 293  * Examines the given sock to see any NetLabel style labeling has been
 294  * applied to the sock, if so it parses the socket label and returns the
 295  * security attributes in @secattr.  Returns zero on success, negative values
 296  * on failure.
 297  *
 298  */
 299 int netlbl_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
 300 {
 301         int ret_val;
 302
 303         ret_val = cipso_v4_sock_getattr(sk, secattr);
 304         if (ret_val == 0)
 305                 return 0;
 306
 307         return netlbl_unlabel_getattr(secattr);
 308 }
 309
 310 /**
 311  * netlbl_skbuff_getattr - Determine the security attributes of a packet
 312  * @skb: the packet
 313  * @secattr: the security attributes
 314  *
 315  * Description:
 316  * Examines the given packet to see if a recognized form of packet labeling
 317  * is present, if so it parses the packet label and returns the security
 318  * attributes in @secattr.  Returns zero on success, negative values on
 319  * failure.
 320  *
 321  */
 322 int netlbl_skbuff_getattr(const struct sk_buff *skb,
 323                           struct netlbl_lsm_secattr *secattr)
 324 {
 325         if (CIPSO_V4_OPTEXIST(skb) &&
 326             cipso_v4_skbuff_getattr(skb, secattr) == 0)
 327                 return 0;
 328
 329         return netlbl_unlabel_getattr(secattr);
 330 }
 331
 332 /**
 333  * netlbl_skbuff_err - Handle a LSM error on a sk_buff
 334  * @skb: the packet
 335  * @error: the error code
 336  *
 337  * Description:
 338  * Deal with a LSM problem when handling the packet in @skb, typically this is
 339  * a permission denied problem (-EACCES).  The correct action is determined
 340  * according to the packet's labeling protocol.
 341  *
 342  */
 343 void netlbl_skbuff_err(struct sk_buff *skb, int error)
 344 {
 345         if (CIPSO_V4_OPTEXIST(skb))
 346                 cipso_v4_error(skb, error, 0);
 347 }
 348
 349 /**
 350  * netlbl_cache_invalidate - Invalidate all of the NetLabel protocol caches
 351  *
 352  * Description:
 353  * For all of the NetLabel protocols that support some form of label mapping
 354  * cache, invalidate the cache.  Returns zero on success, negative values on
 355  * error.
 356  *
 357  */
 358 void netlbl_cache_invalidate(void)
 359 {
 360         cipso_v4_cache_invalidate();
 361 }
 362
 363 /**
 364  * netlbl_cache_add - Add an entry to a NetLabel protocol cache
 365  * @skb: the packet
 366  * @secattr: the packet's security attributes
 367  *
 368  * Description:
 369  * Add the LSM security attributes for the given packet to the underlying
 370  * NetLabel protocol's label mapping cache.  Returns zero on success, negative
 371  * values on error.
 372  *
 373  */
 374 int netlbl_cache_add(const struct sk_buff *skb,
 375                      const struct netlbl_lsm_secattr *secattr)
 376 {
 377         if ((secattr->flags & NETLBL_SECATTR_CACHE) == 0)
 378                 return -ENOMSG;
 379
 380         if (CIPSO_V4_OPTEXIST(skb))
 381                 return cipso_v4_cache_add(skb, secattr);
 382
 383         return -ENOMSG;
 384 }
 385
 386 /*
 387  * Setup Functions
 388  */
 389
 390 /**
 391  * netlbl_init - Initialize NetLabel
 392  *
 393  * Description:
 394  * Perform the required NetLabel initialization before first use.
 395  *
 396  */
 397 static int __init netlbl_init(void)
 398 {
 399         int ret_val;
 400
 401         printk(KERN_INFO "NetLabel: Initializing\n");
 402         printk(KERN_INFO "NetLabel:  domain hash size = %u\n",
 403                (1 << NETLBL_DOMHSH_BITSIZE));
 404         printk(KERN_INFO "NetLabel:  protocols ="
 405                " UNLABELED"
 406                " CIPSOv4"
 407                "\n");
 408
 409         ret_val = netlbl_domhsh_init(NETLBL_DOMHSH_BITSIZE);
 410         if (ret_val != 0)
 411                 goto init_failure;
 412
 413         ret_val = netlbl_netlink_init();
 414         if (ret_val != 0)
 415                 goto init_failure;
 416
 417         ret_val = netlbl_unlabel_defconf();
 418         if (ret_val != 0)
 419                 goto init_failure;
 420         printk(KERN_INFO "NetLabel:  unlabeled traffic allowed by default\n");
 421
 422         return 0;
 423
 424 init_failure:
 425         panic("NetLabel: failed to initialize properly (%d)\n", ret_val);
 426 }
 427
 428 subsys_initcall(netlbl_init);