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