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