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, <sds@tycho.nsa.gov>
   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 <net/netlabel.h>
  23 #include "ebitmap.h"
  24 #include "policydb.h"
  25
  26 #define BITS_PER_U64    (sizeof(u64) * 8)
  27
  28 static struct kmem_cache *ebitmap_node_cachep;
  29
  30 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2)
  31 {
  32         struct ebitmap_node *n1, *n2;
  33
  34         if (e1->highbit != e2->highbit)
  35                 return 0;
  36
  37         n1 = e1->node;
  38         n2 = e2->node;
  39         while (n1 && n2 &&
  40                (n1->startbit == n2->startbit) &&
  41                !memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
  42                 n1 = n1->next;
  43                 n2 = n2->next;
  44         }
  45
  46         if (n1 || n2)
  47                 return 0;
  48
  49         return 1;
  50 }
  51
  52 int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src)
  53 {
  54         struct ebitmap_node *n, *new, *prev;
  55
  56         ebitmap_init(dst);
  57         n = src->node;
  58         prev = NULL;
  59         while (n) {
  60                 new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
  61                 if (!new) {
  62                         ebitmap_destroy(dst);
  63                         return -ENOMEM;
  64                 }
  65                 new->startbit = n->startbit;
  66                 memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
  67                 new->next = NULL;
  68                 if (prev)
  69                         prev->next = new;
  70                 else
  71                         dst->node = new;
  72                 prev = new;
  73                 n = n->next;
  74         }
  75
  76         dst->highbit = src->highbit;
  77         return 0;
  78 }
  79
  80 int ebitmap_and(struct ebitmap *dst, struct ebitmap *e1, struct ebitmap *e2)
  81 {
  82         struct ebitmap_node *n;
  83         int bit, rc;
  84
  85         ebitmap_init(dst);
  86
  87         ebitmap_for_each_positive_bit(e1, n, bit) {
  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
  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,
 133                                                            offset,
 134                                                            e_map,
 135                                                            GFP_ATOMIC);
 136                                 if (rc != 0)
 137                                         goto netlbl_export_failure;
 138                         }
 139                         offset += EBITMAP_UNIT_SIZE;
 140                 }
 141                 e_iter = e_iter->next;
 142         }
 143
 144         return 0;
 145
 146 netlbl_export_failure:
 147         netlbl_catmap_free(*catmap);
 148         return -ENOMEM;
 149 }
 150
 151 /**
 152  * ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
 153  * @ebmap: the ebitmap to import
 154  * @catmap: the NetLabel category bitmap
 155  *
 156  * Description:
 157  * Import a NetLabel category bitmap into a SELinux extensibile bitmap.
 158  * Returns zero on success, negative values on error.
 159  *
 160  */
 161 int ebitmap_netlbl_import(struct ebitmap *ebmap,
 162                           struct netlbl_lsm_catmap *catmap)
 163 {
 164         int rc;
 165         struct ebitmap_node *e_iter = NULL;
 166         struct ebitmap_node *e_prev = NULL;
 167         u32 offset = 0, idx;
 168         unsigned long bitmap;
 169
 170         for (;;) {
 171                 rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
 172                 if (rc < 0)
 173                         goto netlbl_import_failure;
 174                 if (offset == (u32)-1)
 175                         return 0;
 176
 177                 /* don't waste ebitmap space if the netlabel bitmap is empty */
 178                 if (bitmap == 0) {
 179                         offset += EBITMAP_UNIT_SIZE;
 180                         continue;
 181                 }
 182
 183                 if (e_iter == NULL ||
 184                     offset >= e_iter->startbit + EBITMAP_SIZE) {
 185                         e_prev = e_iter;
 186                         e_iter = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
 187                         if (e_iter == NULL)
 188                                 goto netlbl_import_failure;
 189                         e_iter->startbit = offset - (offset % EBITMAP_SIZE);
 190                         if (e_prev == NULL)
 191                                 ebmap->node = e_iter;
 192                         else
 193                                 e_prev->next = e_iter;
 194                         ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
 195                 }
 196
 197                 /* offset will always be aligned to an unsigned long */
 198                 idx = EBITMAP_NODE_INDEX(e_iter, offset);
 199                 e_iter->maps[idx] = bitmap;
 200
 201                 /* next */
 202                 offset += EBITMAP_UNIT_SIZE;
 203         }
 204
 205         /* NOTE: we should never reach this return */
 206         return 0;
 207
 208 netlbl_import_failure:
 209         ebitmap_destroy(ebmap);
 210         return -ENOMEM;
 211 }
 212 #endif /* CONFIG_NETLABEL */
 213
 214 /*
 215  * Check to see if all the bits set in e2 are also set in e1. Optionally,
 216  * if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
 217  * last_e2bit.
 218  */
 219 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit)
 220 {
 221         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(struct ebitmap *e, unsigned long bit)
 261 {
 262         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, unsigned long 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                                 unsigned int 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         return;
 362 }
 363
 364 int ebitmap_read(struct ebitmap *e, void *fp)
 365 {
 366         struct ebitmap_node *n = NULL;
 367         u32 mapunit, count, startbit, index;
 368         __le32 ebitmap_start;
 369         u64 map;
 370         __le64 mapbits;
 371         __le32 buf[3];
 372         int rc, i;
 373
 374         ebitmap_init(e);
 375
 376         rc = next_entry(buf, fp, sizeof buf);
 377         if (rc < 0)
 378                 goto out;
 379
 380         mapunit = le32_to_cpu(buf[0]);
 381         e->highbit = le32_to_cpu(buf[1]);
 382         count = le32_to_cpu(buf[2]);
 383
 384         if (mapunit != BITS_PER_U64) {
 385                 pr_err("SELinux: ebitmap: map size %u does not "
 386                        "match my size %zd (high bit was %d)\n",
 387                        mapunit, BITS_PER_U64, e->highbit);
 388                 goto bad;
 389         }
 390
 391         /* round up e->highbit */
 392         e->highbit += EBITMAP_SIZE - 1;
 393         e->highbit -= (e->highbit % EBITMAP_SIZE);
 394
 395         if (!e->highbit) {
 396                 e->node = NULL;
 397                 goto ok;
 398         }
 399
 400         if (e->highbit && !count)
 401                 goto bad;
 402
 403         for (i = 0; i < count; i++) {
 404                 rc = next_entry(&ebitmap_start, fp, sizeof(u32));
 405                 if (rc < 0) {
 406                         pr_err("SELinux: ebitmap: truncated map\n");
 407                         goto bad;
 408                 }
 409                 startbit = le32_to_cpu(ebitmap_start);
 410
 411                 if (startbit & (mapunit - 1)) {
 412                         pr_err("SELinux: ebitmap start bit (%d) is "
 413                                "not a multiple of the map unit size (%u)\n",
 414                                startbit, mapunit);
 415                         goto bad;
 416                 }
 417                 if (startbit > e->highbit - mapunit) {
 418                         pr_err("SELinux: ebitmap start bit (%d) is "
 419                                "beyond the end of the bitmap (%u)\n",
 420                                startbit, (e->highbit - mapunit));
 421                         goto bad;
 422                 }
 423
 424                 if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
 425                         struct ebitmap_node *tmp;
 426                         tmp = kmem_cache_zalloc(ebitmap_node_cachep, 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 %d"
 441                                " comes after start bit %d\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
 453                 index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
 454                 while (map) {
 455                         n->maps[index++] = map & (-1UL);
 456                         map = EBITMAP_SHIFT_UNIT_SIZE(map);
 457                 }
 458         }
 459 ok:
 460         rc = 0;
 461 out:
 462         return rc;
 463 bad:
 464         if (!rc)
 465                 rc = -EINVAL;
 466         ebitmap_destroy(e);
 467         goto out;
 468 }
 469
 470 int ebitmap_write(struct ebitmap *e, void *fp)
 471 {
 472         struct ebitmap_node *n;
 473         u32 count;
 474         __le32 buf[3];
 475         u64 map;
 476         int bit, last_bit, last_startbit, rc;
 477
 478         buf[0] = cpu_to_le32(BITS_PER_U64);
 479
 480         count = 0;
 481         last_bit = 0;
 482         last_startbit = -1;
 483         ebitmap_for_each_positive_bit(e, n, bit) {
 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                 if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
 501                         __le64 buf64[1];
 502
 503                         /* this is the very first bit */
 504                         if (!map) {
 505                                 last_startbit = rounddown(bit, BITS_PER_U64);
 506                                 map = (u64)1 << (bit - last_startbit);
 507                                 continue;
 508                         }
 509
 510                         /* write the last node */
 511                         buf[0] = cpu_to_le32(last_startbit);
 512                         rc = put_entry(buf, sizeof(u32), 1, fp);
 513                         if (rc)
 514                                 return rc;
 515
 516                         buf64[0] = cpu_to_le64(map);
 517                         rc = put_entry(buf64, sizeof(u64), 1, fp);
 518                         if (rc)
 519                                 return rc;
 520
 521                         /* set up for the next node */
 522                         map = 0;
 523                         last_startbit = rounddown(bit, BITS_PER_U64);
 524                 }
 525                 map |= (u64)1 << (bit - last_startbit);
 526         }
 527         /* write the last node */
 528         if (map) {
 529                 __le64 buf64[1];
 530
 531                 /* write the last node */
 532                 buf[0] = cpu_to_le32(last_startbit);
 533                 rc = put_entry(buf, sizeof(u32), 1, fp);
 534                 if (rc)
 535                         return rc;
 536
 537                 buf64[0] = cpu_to_le64(map);
 538                 rc = put_entry(buf64, sizeof(u64), 1, fp);
 539                 if (rc)
 540                         return rc;
 541         }
 542         return 0;
 543 }
 544
 545 void __init ebitmap_cache_init(void)
 546 {
 547         ebitmap_node_cachep = kmem_cache_create("ebitmap_node",
 548                                                         sizeof(struct ebitmap_node),
 549                                                         0, SLAB_PANIC, NULL);
 550 }