security/selinux/ss/ebitmap.c

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Implementation of the extensible bitmap type.
   4  *
   5  * Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
   6  */
   7 /*
   8  * Updated: Hewlett-Packard <paul@paul-moore.com>
   9  *          Added support to import/export the NetLabel category bitmap
  10  *          (c) Copyright Hewlett-Packard Development Company, L.P., 2006
  11  *
  12  * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
  13  *          Applied standard bit operations to improve bitmap scanning.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/slab.h>
  18 #include <linux/errno.h>
  19 #include <linux/jhash.h>
  20 #include <net/netlabel.h>
  21 #include "ebitmap.h"
  22 #include "policydb.h"
  23
  24 #define BITS_PER_U64 ((u32)(sizeof(u64) * 8))
  25
  26 static struct kmem_cache *ebitmap_node_cachep __ro_after_init;
  27
  28 int ebitmap_cmp(const struct ebitmap *e1, const struct ebitmap *e2)
  29 {
  30         const struct ebitmap_node *n1, *n2;
  31
  32         if (e1->highbit != e2->highbit)
  33                 return 0;
  34
  35         n1 = e1->node;
  36         n2 = e2->node;
  37         while (n1 && n2 && (n1->startbit == n2->startbit) &&
  38                !memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
  39                 n1 = n1->next;
  40                 n2 = n2->next;
  41         }
  42
  43         if (n1 || n2)
  44                 return 0;
  45
  46         return 1;
  47 }
  48
  49 int ebitmap_cpy(struct ebitmap *dst, const struct ebitmap *src)
  50 {
  51         struct ebitmap_node *new, *prev;
  52         const struct ebitmap_node *n;
  53
  54         ebitmap_init(dst);
  55         n = src->node;
  56         prev = NULL;
  57         while (n) {
  58                 new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
  59                 if (!new) {
  60                         ebitmap_destroy(dst);
  61                         return -ENOMEM;
  62                 }
  63                 new->startbit = n->startbit;
  64                 memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
  65                 new->next = NULL;
  66                 if (prev)
  67                         prev->next = new;
  68                 else
  69                         dst->node = new;
  70                 prev = new;
  71                 n = n->next;
  72         }
  73
  74         dst->highbit = src->highbit;
  75         return 0;
  76 }
  77
  78 int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1,
  79                 const struct ebitmap *e2)
  80 {
  81         struct ebitmap_node *n;
  82         u32 bit;
  83         int rc;
  84
  85         ebitmap_init(dst);
  86
  87         ebitmap_for_each_positive_bit(e1, n, bit)
  88         {
  89                 if (ebitmap_get_bit(e2, bit)) {
  90                         rc = ebitmap_set_bit(dst, bit, 1);
  91                         if (rc < 0)
  92                                 return rc;
  93                 }
  94         }
  95         return 0;
  96 }
  97
  98 #ifdef CONFIG_NETLABEL
  99 /**
 100  * ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
 101  * @ebmap: the ebitmap to export
 102  * @catmap: the NetLabel category bitmap
 103  *
 104  * Description:
 105  * Export a SELinux extensibile bitmap into a NetLabel category bitmap.
 106  * Returns zero on success, negative values on error.
 107  *
 108  */
 109 int ebitmap_netlbl_export(struct ebitmap *ebmap,
 110                           struct netlbl_lsm_catmap **catmap)
 111 {
 112         struct ebitmap_node *e_iter = ebmap->node;
 113         unsigned long e_map;
 114         u32 offset;
 115         unsigned int iter;
 116         int rc;
 117
 118         if (e_iter == NULL) {
 119                 *catmap = NULL;
 120                 return 0;
 121         }
 122
 123         if (*catmap != NULL)
 124                 netlbl_catmap_free(*catmap);
 125         *catmap = NULL;
 126
 127         while (e_iter) {
 128                 offset = e_iter->startbit;
 129                 for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
 130                         e_map = e_iter->maps[iter];
 131                         if (e_map != 0) {
 132                                 rc = netlbl_catmap_setlong(catmap, offset,
 133                                                            e_map, GFP_ATOMIC);
 134                                 if (rc != 0)
 135                                         goto netlbl_export_failure;
 136                         }
 137                         offset += EBITMAP_UNIT_SIZE;
 138                 }
 139                 e_iter = e_iter->next;
 140         }
 141
 142         return 0;
 143
 144 netlbl_export_failure:
 145         netlbl_catmap_free(*catmap);
 146         return -ENOMEM;
 147 }
 148
 149 /**
 150  * ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
 151  * @ebmap: the ebitmap to import
 152  * @catmap: the NetLabel category bitmap
 153  *
 154  * Description:
 155  * Import a NetLabel category bitmap into a SELinux extensibile bitmap.
 156  * Returns zero on success, negative values on error.
 157  *
 158  */
 159 int ebitmap_netlbl_import(struct ebitmap *ebmap,
 160                           struct netlbl_lsm_catmap *catmap)
 161 {
 162         int rc;
 163         struct ebitmap_node *e_iter = NULL;
 164         struct ebitmap_node *e_prev = NULL;
 165         u32 offset = 0, idx;
 166         unsigned long bitmap;
 167
 168         for (;;) {
 169                 rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
 170                 if (rc < 0)
 171                         goto netlbl_import_failure;
 172                 if (offset == (u32)-1)
 173                         return 0;
 174
 175                 /* don't waste ebitmap space if the netlabel bitmap is empty */
 176                 if (bitmap == 0) {
 177                         offset += EBITMAP_UNIT_SIZE;
 178                         continue;
 179                 }
 180
 181                 if (e_iter == NULL ||
 182                     offset >= e_iter->startbit + EBITMAP_SIZE) {
 183                         e_prev = e_iter;
 184                         e_iter = kmem_cache_zalloc(ebitmap_node_cachep,
 185                                                    GFP_ATOMIC);
 186                         if (e_iter == NULL)
 187                                 goto netlbl_import_failure;
 188                         e_iter->startbit = offset - (offset % EBITMAP_SIZE);
 189                         if (e_prev == NULL)
 190                                 ebmap->node = e_iter;
 191                         else
 192                                 e_prev->next = e_iter;
 193                         ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
 194                 }
 195
 196                 /* offset will always be aligned to an unsigned long */
 197                 idx = EBITMAP_NODE_INDEX(e_iter, offset);
 198                 e_iter->maps[idx] = bitmap;
 199
 200                 /* next */
 201                 offset += EBITMAP_UNIT_SIZE;
 202         }
 203
 204         /* NOTE: we should never reach this return */
 205         return 0;
 206
 207 netlbl_import_failure:
 208         ebitmap_destroy(ebmap);
 209         return -ENOMEM;
 210 }
 211 #endif /* CONFIG_NETLABEL */
 212
 213 /*
 214  * Check to see if all the bits set in e2 are also set in e1. Optionally,
 215  * if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
 216  * last_e2bit.
 217  */
 218 int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2,
 219                      u32 last_e2bit)
 220 {
 221         const struct ebitmap_node *n1, *n2;
 222         int i;
 223
 224         if (e1->highbit < e2->highbit)
 225                 return 0;
 226
 227         n1 = e1->node;
 228         n2 = e2->node;
 229
 230         while (n1 && n2 && (n1->startbit <= n2->startbit)) {
 231                 if (n1->startbit < n2->startbit) {
 232                         n1 = n1->next;
 233                         continue;
 234                 }
 235                 for (i = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i];)
 236                         i--; /* Skip trailing NULL map entries */
 237                 if (last_e2bit && (i >= 0)) {
 238                         u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
 239                                          __fls(n2->maps[i]);
 240                         if (lastsetbit > last_e2bit)
 241                                 return 0;
 242                 }
 243
 244                 while (i >= 0) {
 245                         if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
 246                                 return 0;
 247                         i--;
 248                 }
 249
 250                 n1 = n1->next;
 251                 n2 = n2->next;
 252         }
 253
 254         if (n2)
 255                 return 0;
 256
 257         return 1;
 258 }
 259
 260 int ebitmap_get_bit(const struct ebitmap *e, u32 bit)
 261 {
 262         const struct ebitmap_node *n;
 263
 264         if (e->highbit < bit)
 265                 return 0;
 266
 267         n = e->node;
 268         while (n && (n->startbit <= bit)) {
 269                 if ((n->startbit + EBITMAP_SIZE) > bit)
 270                         return ebitmap_node_get_bit(n, bit);
 271                 n = n->next;
 272         }
 273
 274         return 0;
 275 }
 276
 277 int ebitmap_set_bit(struct ebitmap *e, u32 bit, int value)
 278 {
 279         struct ebitmap_node *n, *prev, *new;
 280
 281         prev = NULL;
 282         n = e->node;
 283         while (n && n->startbit <= bit) {
 284                 if ((n->startbit + EBITMAP_SIZE) > bit) {
 285                         if (value) {
 286                                 ebitmap_node_set_bit(n, bit);
 287                         } else {
 288                                 u32 s;
 289
 290                                 ebitmap_node_clr_bit(n, bit);
 291
 292                                 s = find_first_bit(n->maps, EBITMAP_SIZE);
 293                                 if (s < EBITMAP_SIZE)
 294                                         return 0;
 295
 296                                 /* drop this node from the bitmap */
 297                                 if (!n->next) {
 298                                         /*
 299                                          * this was the highest map
 300                                          * within the bitmap
 301                                          */
 302                                         if (prev)
 303                                                 e->highbit = prev->startbit +
 304                                                              EBITMAP_SIZE;
 305                                         else
 306                                                 e->highbit = 0;
 307                                 }
 308                                 if (prev)
 309                                         prev->next = n->next;
 310                                 else
 311                                         e->node = n->next;
 312                                 kmem_cache_free(ebitmap_node_cachep, n);
 313                         }
 314                         return 0;
 315                 }
 316                 prev = n;
 317                 n = n->next;
 318         }
 319
 320         if (!value)
 321                 return 0;
 322
 323         new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
 324         if (!new)
 325                 return -ENOMEM;
 326
 327         new->startbit = bit - (bit % EBITMAP_SIZE);
 328         ebitmap_node_set_bit(new, bit);
 329
 330         if (!n)
 331                 /* this node will be the highest map within the bitmap */
 332                 e->highbit = new->startbit + EBITMAP_SIZE;
 333
 334         if (prev) {
 335                 new->next = prev->next;
 336                 prev->next = new;
 337         } else {
 338                 new->next = e->node;
 339                 e->node = new;
 340         }
 341
 342         return 0;
 343 }
 344
 345 void ebitmap_destroy(struct ebitmap *e)
 346 {
 347         struct ebitmap_node *n, *temp;
 348
 349         if (!e)
 350                 return;
 351
 352         n = e->node;
 353         while (n) {
 354                 temp = n;
 355                 n = n->next;
 356                 kmem_cache_free(ebitmap_node_cachep, temp);
 357         }
 358
 359         e->highbit = 0;
 360         e->node = NULL;
 361 }
 362
 363 int ebitmap_read(struct ebitmap *e, void *fp)
 364 {
 365         struct ebitmap_node *n = NULL;
 366         u32 mapunit, count, startbit, index, i;
 367         __le32 ebitmap_start;
 368         u64 map;
 369         __le64 mapbits;
 370         __le32 buf[3];
 371         int rc;
 372
 373         ebitmap_init(e);
 374
 375         rc = next_entry(buf, fp, sizeof buf);
 376         if (rc < 0)
 377                 goto out;
 378
 379         mapunit = le32_to_cpu(buf[0]);
 380         e->highbit = le32_to_cpu(buf[1]);
 381         count = le32_to_cpu(buf[2]);
 382
 383         if (mapunit != BITS_PER_U64) {
 384                 pr_err("SELinux: ebitmap: map size %u does not "
 385                        "match my size %u (high bit was %u)\n",
 386                        mapunit, BITS_PER_U64, e->highbit);
 387                 goto bad;
 388         }
 389
 390         /* round up e->highbit */
 391         e->highbit += EBITMAP_SIZE - 1;
 392         e->highbit -= (e->highbit % EBITMAP_SIZE);
 393
 394         if (!e->highbit) {
 395                 e->node = NULL;
 396                 goto ok;
 397         }
 398
 399         if (e->highbit && !count)
 400                 goto bad;
 401
 402         for (i = 0; i < count; i++) {
 403                 rc = next_entry(&ebitmap_start, fp, sizeof(u32));
 404                 if (rc < 0) {
 405                         pr_err("SELinux: ebitmap: truncated map\n");
 406                         goto bad;
 407                 }
 408                 startbit = le32_to_cpu(ebitmap_start);
 409
 410                 if (startbit & (mapunit - 1)) {
 411                         pr_err("SELinux: ebitmap start bit (%u) is "
 412                                "not a multiple of the map unit size (%u)\n",
 413                                startbit, mapunit);
 414                         goto bad;
 415                 }
 416                 if (startbit > e->highbit - mapunit) {
 417                         pr_err("SELinux: ebitmap start bit (%u) is "
 418                                "beyond the end of the bitmap (%u)\n",
 419                                startbit, (e->highbit - mapunit));
 420                         goto bad;
 421                 }
 422
 423                 if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
 424                         struct ebitmap_node *tmp;
 425                         tmp = kmem_cache_zalloc(ebitmap_node_cachep,
 426                                                 GFP_KERNEL);
 427                         if (!tmp) {
 428                                 pr_err("SELinux: ebitmap: out of memory\n");
 429                                 rc = -ENOMEM;
 430                                 goto bad;
 431                         }
 432                         /* round down */
 433                         tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
 434                         if (n)
 435                                 n->next = tmp;
 436                         else
 437                                 e->node = tmp;
 438                         n = tmp;
 439                 } else if (startbit <= n->startbit) {
 440                         pr_err("SELinux: ebitmap: start bit %u"
 441                                " comes after start bit %u\n",
 442                                startbit, n->startbit);
 443                         goto bad;
 444                 }
 445
 446                 rc = next_entry(&mapbits, fp, sizeof(u64));
 447                 if (rc < 0) {
 448                         pr_err("SELinux: ebitmap: truncated map\n");
 449                         goto bad;
 450                 }
 451                 map = le64_to_cpu(mapbits);
 452                 if (!map) {
 453                         pr_err("SELinux: ebitmap: empty map\n");
 454                         goto bad;
 455                 }
 456
 457                 index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
 458                 while (map) {
 459                         n->maps[index++] = map & (-1UL);
 460                         map = EBITMAP_SHIFT_UNIT_SIZE(map);
 461                 }
 462         }
 463
 464         if (n && n->startbit + EBITMAP_SIZE != e->highbit) {
 465                 pr_err("SELinux: ebitmap: high bit %u is not equal to the expected value %zu\n",
 466                        e->highbit, n->startbit + EBITMAP_SIZE);
 467                 goto bad;
 468         }
 469
 470 ok:
 471         rc = 0;
 472 out:
 473         return rc;
 474 bad:
 475         if (!rc)
 476                 rc = -EINVAL;
 477         ebitmap_destroy(e);
 478         goto out;
 479 }
 480
 481 int ebitmap_write(const struct ebitmap *e, void *fp)
 482 {
 483         struct ebitmap_node *n;
 484         u32 bit, count, last_bit, last_startbit;
 485         __le32 buf[3];
 486         u64 map;
 487         int rc;
 488
 489         buf[0] = cpu_to_le32(BITS_PER_U64);
 490
 491         count = 0;
 492         last_bit = 0;
 493         last_startbit = U32_MAX;
 494         ebitmap_for_each_positive_bit(e, n, bit)
 495         {
 496                 if (last_startbit == U32_MAX ||
 497                     rounddown(bit, BITS_PER_U64) > last_startbit) {
 498                         count++;
 499                         last_startbit = rounddown(bit, BITS_PER_U64);
 500                 }
 501                 last_bit = roundup(bit + 1, BITS_PER_U64);
 502         }
 503         buf[1] = cpu_to_le32(last_bit);
 504         buf[2] = cpu_to_le32(count);
 505
 506         rc = put_entry(buf, sizeof(u32), 3, fp);
 507         if (rc)
 508                 return rc;
 509
 510         map = 0;
 511         last_startbit = U32_MAX;
 512         ebitmap_for_each_positive_bit(e, n, bit)
 513         {
 514                 if (last_startbit == U32_MAX ||
 515                     rounddown(bit, BITS_PER_U64) > last_startbit) {
 516                         __le64 buf64[1];
 517
 518                         /* this is the very first bit */
 519                         if (!map) {
 520                                 last_startbit = rounddown(bit, BITS_PER_U64);
 521                                 map = (u64)1 << (bit - last_startbit);
 522                                 continue;
 523                         }
 524
 525                         /* write the last node */
 526                         buf[0] = cpu_to_le32(last_startbit);
 527                         rc = put_entry(buf, sizeof(u32), 1, fp);
 528                         if (rc)
 529                                 return rc;
 530
 531                         buf64[0] = cpu_to_le64(map);
 532                         rc = put_entry(buf64, sizeof(u64), 1, fp);
 533                         if (rc)
 534                                 return rc;
 535
 536                         /* set up for the next node */
 537                         map = 0;
 538                         last_startbit = rounddown(bit, BITS_PER_U64);
 539                 }
 540                 map |= (u64)1 << (bit - last_startbit);
 541         }
 542         /* write the last node */
 543         if (map) {
 544                 __le64 buf64[1];
 545
 546                 /* write the last node */
 547                 buf[0] = cpu_to_le32(last_startbit);
 548                 rc = put_entry(buf, sizeof(u32), 1, fp);
 549                 if (rc)
 550                         return rc;
 551
 552                 buf64[0] = cpu_to_le64(map);
 553                 rc = put_entry(buf64, sizeof(u64), 1, fp);
 554                 if (rc)
 555                         return rc;
 556         }
 557         return 0;
 558 }
 559
 560 u32 ebitmap_hash(const struct ebitmap *e, u32 hash)
 561 {
 562         struct ebitmap_node *node;
 563
 564         /* need to change hash even if ebitmap is empty */
 565         hash = jhash_1word(e->highbit, hash);
 566         for (node = e->node; node; node = node->next) {
 567                 hash = jhash_1word(node->startbit, hash);
 568                 hash = jhash(node->maps, sizeof(node->maps), hash);
 569         }
 570         return hash;
 571 }
 572
 573 void __init ebitmap_cache_init(void)
 574 {
 575         ebitmap_node_cachep = KMEM_CACHE(ebitmap_node, SLAB_PANIC);
 576 }