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, <[email protected]>
   6  */
   7 /*
   8  * Updated: Hewlett-Packard <[email protected]>
   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 <[email protected]>
  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 #ifdef CONFIG_NETLABEL
  81 /**
  82  * ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
  83  * @ebmap: the ebitmap to export
  84  * @catmap: the NetLabel category bitmap
  85  *
  86  * Description:
  87  * Export a SELinux extensibile bitmap into a NetLabel category bitmap.
  88  * Returns zero on success, negative values on error.
  89  *
  90  */
  91 int ebitmap_netlbl_export(struct ebitmap *ebmap,
  92                           struct netlbl_lsm_catmap **catmap)
  93 {
  94         struct ebitmap_node *e_iter = ebmap->node;
  95         unsigned long e_map;
  96         u32 offset;
  97         unsigned int iter;
  98         int rc;
  99
 100         if (e_iter == NULL) {
 101                 *catmap = NULL;
 102                 return 0;
 103         }
 104
 105         if (*catmap != NULL)
 106                 netlbl_catmap_free(*catmap);
 107         *catmap = NULL;
 108
 109         while (e_iter) {
 110                 offset = e_iter->startbit;
 111                 for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
 112                         e_map = e_iter->maps[iter];
 113                         if (e_map != 0) {
 114                                 rc = netlbl_catmap_setlong(catmap,
 115                                                            offset,
 116                                                            e_map,
 117                                                            GFP_ATOMIC);
 118                                 if (rc != 0)
 119                                         goto netlbl_export_failure;
 120                         }
 121                         offset += EBITMAP_UNIT_SIZE;
 122                 }
 123                 e_iter = e_iter->next;
 124         }
 125
 126         return 0;
 127
 128 netlbl_export_failure:
 129         netlbl_catmap_free(*catmap);
 130         return -ENOMEM;
 131 }
 132
 133 /**
 134  * ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
 135  * @ebmap: the ebitmap to import
 136  * @catmap: the NetLabel category bitmap
 137  *
 138  * Description:
 139  * Import a NetLabel category bitmap into a SELinux extensibile bitmap.
 140  * Returns zero on success, negative values on error.
 141  *
 142  */
 143 int ebitmap_netlbl_import(struct ebitmap *ebmap,
 144                           struct netlbl_lsm_catmap *catmap)
 145 {
 146         int rc;
 147         struct ebitmap_node *e_iter = NULL;
 148         struct ebitmap_node *e_prev = NULL;
 149         u32 offset = 0, idx;
 150         unsigned long bitmap;
 151
 152         for (;;) {
 153                 rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
 154                 if (rc < 0)
 155                         goto netlbl_import_failure;
 156                 if (offset == (u32)-1)
 157                         return 0;
 158
 159                 /* don't waste ebitmap space if the netlabel bitmap is empty */
 160                 if (bitmap == 0) {
 161                         offset += EBITMAP_UNIT_SIZE;
 162                         continue;
 163                 }
 164
 165                 if (e_iter == NULL ||
 166                     offset >= e_iter->startbit + EBITMAP_SIZE) {
 167                         e_prev = e_iter;
 168                         e_iter = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
 169                         if (e_iter == NULL)
 170                                 goto netlbl_import_failure;
 171                         e_iter->startbit = offset - (offset % EBITMAP_SIZE);
 172                         if (e_prev == NULL)
 173                                 ebmap->node = e_iter;
 174                         else
 175                                 e_prev->next = e_iter;
 176                         ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
 177                 }
 178
 179                 /* offset will always be aligned to an unsigned long */
 180                 idx = EBITMAP_NODE_INDEX(e_iter, offset);
 181                 e_iter->maps[idx] = bitmap;
 182
 183                 /* next */
 184                 offset += EBITMAP_UNIT_SIZE;
 185         }
 186
 187         /* NOTE: we should never reach this return */
 188         return 0;
 189
 190 netlbl_import_failure:
 191         ebitmap_destroy(ebmap);
 192         return -ENOMEM;
 193 }
 194 #endif /* CONFIG_NETLABEL */
 195
 196 /*
 197  * Check to see if all the bits set in e2 are also set in e1. Optionally,
 198  * if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
 199  * last_e2bit.
 200  */
 201 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit)
 202 {
 203         struct ebitmap_node *n1, *n2;
 204         int i;
 205
 206         if (e1->highbit < e2->highbit)
 207                 return 0;
 208
 209         n1 = e1->node;
 210         n2 = e2->node;
 211
 212         while (n1 && n2 && (n1->startbit <= n2->startbit)) {
 213                 if (n1->startbit < n2->startbit) {
 214                         n1 = n1->next;
 215                         continue;
 216                 }
 217                 for (i = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i]; )
 218                         i--;    /* Skip trailing NULL map entries */
 219                 if (last_e2bit && (i >= 0)) {
 220                         u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
 221                                          __fls(n2->maps[i]);
 222                         if (lastsetbit > last_e2bit)
 223                                 return 0;
 224                 }
 225
 226                 while (i >= 0) {
 227                         if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
 228                                 return 0;
 229                         i--;
 230                 }
 231
 232                 n1 = n1->next;
 233                 n2 = n2->next;
 234         }
 235
 236         if (n2)
 237                 return 0;
 238
 239         return 1;
 240 }
 241
 242 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit)
 243 {
 244         struct ebitmap_node *n;
 245
 246         if (e->highbit < bit)
 247                 return 0;
 248
 249         n = e->node;
 250         while (n && (n->startbit <= bit)) {
 251                 if ((n->startbit + EBITMAP_SIZE) > bit)
 252                         return ebitmap_node_get_bit(n, bit);
 253                 n = n->next;
 254         }
 255
 256         return 0;
 257 }
 258
 259 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
 260 {
 261         struct ebitmap_node *n, *prev, *new;
 262
 263         prev = NULL;
 264         n = e->node;
 265         while (n && n->startbit <= bit) {
 266                 if ((n->startbit + EBITMAP_SIZE) > bit) {
 267                         if (value) {
 268                                 ebitmap_node_set_bit(n, bit);
 269                         } else {
 270                                 unsigned int s;
 271
 272                                 ebitmap_node_clr_bit(n, bit);
 273
 274                                 s = find_first_bit(n->maps, EBITMAP_SIZE);
 275                                 if (s < EBITMAP_SIZE)
 276                                         return 0;
 277
 278                                 /* drop this node from the bitmap */
 279                                 if (!n->next) {
 280                                         /*
 281                                          * this was the highest map
 282                                          * within the bitmap
 283                                          */
 284                                         if (prev)
 285                                                 e->highbit = prev->startbit
 286                                                              + EBITMAP_SIZE;
 287                                         else
 288                                                 e->highbit = 0;
 289                                 }
 290                                 if (prev)
 291                                         prev->next = n->next;
 292                                 else
 293                                         e->node = n->next;
 294                                 kmem_cache_free(ebitmap_node_cachep, n);
 295                         }
 296                         return 0;
 297                 }
 298                 prev = n;
 299                 n = n->next;
 300         }
 301
 302         if (!value)
 303                 return 0;
 304
 305         new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
 306         if (!new)
 307                 return -ENOMEM;
 308
 309         new->startbit = bit - (bit % EBITMAP_SIZE);
 310         ebitmap_node_set_bit(new, bit);
 311
 312         if (!n)
 313                 /* this node will be the highest map within the bitmap */
 314                 e->highbit = new->startbit + EBITMAP_SIZE;
 315
 316         if (prev) {
 317                 new->next = prev->next;
 318                 prev->next = new;
 319         } else {
 320                 new->next = e->node;
 321                 e->node = new;
 322         }
 323
 324         return 0;
 325 }
 326
 327 void ebitmap_destroy(struct ebitmap *e)
 328 {
 329         struct ebitmap_node *n, *temp;
 330
 331         if (!e)
 332                 return;
 333
 334         n = e->node;
 335         while (n) {
 336                 temp = n;
 337                 n = n->next;
 338                 kmem_cache_free(ebitmap_node_cachep, temp);
 339         }
 340
 341         e->highbit = 0;
 342         e->node = NULL;
 343         return;
 344 }
 345
 346 int ebitmap_read(struct ebitmap *e, void *fp)
 347 {
 348         struct ebitmap_node *n = NULL;
 349         u32 mapunit, count, startbit, index;
 350         u64 map;
 351         __le32 buf[3];
 352         int rc, i;
 353
 354         ebitmap_init(e);
 355
 356         rc = next_entry(buf, fp, sizeof buf);
 357         if (rc < 0)
 358                 goto out;
 359
 360         mapunit = le32_to_cpu(buf[0]);
 361         e->highbit = le32_to_cpu(buf[1]);
 362         count = le32_to_cpu(buf[2]);
 363
 364         if (mapunit != BITS_PER_U64) {
 365                 printk(KERN_ERR "SELinux: ebitmap: map size %u does not "
 366                        "match my size %zd (high bit was %d)\n",
 367                        mapunit, BITS_PER_U64, e->highbit);
 368                 goto bad;
 369         }
 370
 371         /* round up e->highbit */
 372         e->highbit += EBITMAP_SIZE - 1;
 373         e->highbit -= (e->highbit % EBITMAP_SIZE);
 374
 375         if (!e->highbit) {
 376                 e->node = NULL;
 377                 goto ok;
 378         }
 379
 380         if (e->highbit && !count)
 381                 goto bad;
 382
 383         for (i = 0; i < count; i++) {
 384                 rc = next_entry(&startbit, fp, sizeof(u32));
 385                 if (rc < 0) {
 386                         printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
 387                         goto bad;
 388                 }
 389                 startbit = le32_to_cpu(startbit);
 390
 391                 if (startbit & (mapunit - 1)) {
 392                         printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
 393                                "not a multiple of the map unit size (%u)\n",
 394                                startbit, mapunit);
 395                         goto bad;
 396                 }
 397                 if (startbit > e->highbit - mapunit) {
 398                         printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
 399                                "beyond the end of the bitmap (%u)\n",
 400                                startbit, (e->highbit - mapunit));
 401                         goto bad;
 402                 }
 403
 404                 if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
 405                         struct ebitmap_node *tmp;
 406                         tmp = kmem_cache_zalloc(ebitmap_node_cachep, GFP_KERNEL);
 407                         if (!tmp) {
 408                                 printk(KERN_ERR
 409                                        "SELinux: ebitmap: out of memory\n");
 410                                 rc = -ENOMEM;
 411                                 goto bad;
 412                         }
 413                         /* round down */
 414                         tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
 415                         if (n)
 416                                 n->next = tmp;
 417                         else
 418                                 e->node = tmp;
 419                         n = tmp;
 420                 } else if (startbit <= n->startbit) {
 421                         printk(KERN_ERR "SELinux: ebitmap: start bit %d"
 422                                " comes after start bit %d\n",
 423                                startbit, n->startbit);
 424                         goto bad;
 425                 }
 426
 427                 rc = next_entry(&map, fp, sizeof(u64));
 428                 if (rc < 0) {
 429                         printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
 430                         goto bad;
 431                 }
 432                 map = le64_to_cpu(map);
 433
 434                 index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
 435                 while (map) {
 436                         n->maps[index++] = map & (-1UL);
 437                         map = EBITMAP_SHIFT_UNIT_SIZE(map);
 438                 }
 439         }
 440 ok:
 441         rc = 0;
 442 out:
 443         return rc;
 444 bad:
 445         if (!rc)
 446                 rc = -EINVAL;
 447         ebitmap_destroy(e);
 448         goto out;
 449 }
 450
 451 int ebitmap_write(struct ebitmap *e, void *fp)
 452 {
 453         struct ebitmap_node *n;
 454         u32 count;
 455         __le32 buf[3];
 456         u64 map;
 457         int bit, last_bit, last_startbit, rc;
 458
 459         buf[0] = cpu_to_le32(BITS_PER_U64);
 460
 461         count = 0;
 462         last_bit = 0;
 463         last_startbit = -1;
 464         ebitmap_for_each_positive_bit(e, n, bit) {
 465                 if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
 466                         count++;
 467                         last_startbit = rounddown(bit, BITS_PER_U64);
 468                 }
 469                 last_bit = roundup(bit + 1, BITS_PER_U64);
 470         }
 471         buf[1] = cpu_to_le32(last_bit);
 472         buf[2] = cpu_to_le32(count);
 473
 474         rc = put_entry(buf, sizeof(u32), 3, fp);
 475         if (rc)
 476                 return rc;
 477
 478         map = 0;
 479         last_startbit = INT_MIN;
 480         ebitmap_for_each_positive_bit(e, n, bit) {
 481                 if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
 482                         __le64 buf64[1];
 483
 484                         /* this is the very first bit */
 485                         if (!map) {
 486                                 last_startbit = rounddown(bit, BITS_PER_U64);
 487                                 map = (u64)1 << (bit - last_startbit);
 488                                 continue;
 489                         }
 490
 491                         /* write the last node */
 492                         buf[0] = cpu_to_le32(last_startbit);
 493                         rc = put_entry(buf, sizeof(u32), 1, fp);
 494                         if (rc)
 495                                 return rc;
 496
 497                         buf64[0] = cpu_to_le64(map);
 498                         rc = put_entry(buf64, sizeof(u64), 1, fp);
 499                         if (rc)
 500                                 return rc;
 501
 502                         /* set up for the next node */
 503                         map = 0;
 504                         last_startbit = rounddown(bit, BITS_PER_U64);
 505                 }
 506                 map |= (u64)1 << (bit - last_startbit);
 507         }
 508         /* write the last node */
 509         if (map) {
 510                 __le64 buf64[1];
 511
 512                 /* write the last node */
 513                 buf[0] = cpu_to_le32(last_startbit);
 514                 rc = put_entry(buf, sizeof(u32), 1, fp);
 515                 if (rc)
 516                         return rc;
 517
 518                 buf64[0] = cpu_to_le64(map);
 519                 rc = put_entry(buf64, sizeof(u64), 1, fp);
 520                 if (rc)
 521                         return rc;
 522         }
 523         return 0;
 524 }
 525
 526 void ebitmap_cache_init(void)
 527 {
 528         ebitmap_node_cachep = kmem_cache_create("ebitmap_node",
 529                                                         sizeof(struct ebitmap_node),
 530                                                         0, SLAB_PANIC, NULL);
 531 }
 532
 533 void ebitmap_cache_destroy(void)
 534 {
 535         kmem_cache_destroy(ebitmap_node_cachep);
 536 }