security/selinux/ss/avtab.c

   1 /*
   2  * Implementation of the access vector table type.
   3  *
   4  * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
   5  */
   6
   7 /* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
   8  *
   9  *      Added conditional policy language extensions
  10  *
  11  * Copyright (C) 2003 Tresys Technology, LLC
  12  *      This program is free software; you can redistribute it and/or modify
  13  *      it under the terms of the GNU General Public License as published by
  14  *      the Free Software Foundation, version 2.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/slab.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/errno.h>
  21
  22 #include "avtab.h"
  23 #include "policydb.h"
  24
  25 #define AVTAB_HASH(keyp) \
  26 ((keyp->target_class + \
  27  (keyp->target_type << 2) + \
  28  (keyp->source_type << 9)) & \
  29  AVTAB_HASH_MASK)
  30
  31 static kmem_cache_t *avtab_node_cachep;
  32
  33 static struct avtab_node*
  34 avtab_insert_node(struct avtab *h, int hvalue,
  35                   struct avtab_node * prev, struct avtab_node * cur,
  36                   struct avtab_key *key, struct avtab_datum *datum)
  37 {
  38         struct avtab_node * newnode;
  39         newnode = kmem_cache_alloc(avtab_node_cachep, SLAB_KERNEL);
  40         if (newnode == NULL)
  41                 return NULL;
  42         memset(newnode, 0, sizeof(struct avtab_node));
  43         newnode->key = *key;
  44         newnode->datum = *datum;
  45         if (prev) {
  46                 newnode->next = prev->next;
  47                 prev->next = newnode;
  48         } else {
  49                 newnode->next = h->htable[hvalue];
  50                 h->htable[hvalue] = newnode;
  51         }
  52
  53         h->nel++;
  54         return newnode;
  55 }
  56
  57 static int avtab_insert(struct avtab *h, struct avtab_key *key, struct avtab_datum *datum)
  58 {
  59         int hvalue;
  60         struct avtab_node *prev, *cur, *newnode;
  61         u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
  62
  63         if (!h)
  64                 return -EINVAL;
  65
  66         hvalue = AVTAB_HASH(key);
  67         for (prev = NULL, cur = h->htable[hvalue];
  68              cur;
  69              prev = cur, cur = cur->next) {
  70                 if (key->source_type == cur->key.source_type &&
  71                     key->target_type == cur->key.target_type &&
  72                     key->target_class == cur->key.target_class &&
  73                     (specified & cur->key.specified))
  74                         return -EEXIST;
  75                 if (key->source_type < cur->key.source_type)
  76                         break;
  77                 if (key->source_type == cur->key.source_type &&
  78                     key->target_type < cur->key.target_type)
  79                         break;
  80                 if (key->source_type == cur->key.source_type &&
  81                     key->target_type == cur->key.target_type &&
  82                     key->target_class < cur->key.target_class)
  83                         break;
  84         }
  85
  86         newnode = avtab_insert_node(h, hvalue, prev, cur, key, datum);
  87         if(!newnode)
  88                 return -ENOMEM;
  89
  90         return 0;
  91 }
  92
  93 /* Unlike avtab_insert(), this function allow multiple insertions of the same
  94  * key/specified mask into the table, as needed by the conditional avtab.
  95  * It also returns a pointer to the node inserted.
  96  */
  97 struct avtab_node *
  98 avtab_insert_nonunique(struct avtab * h, struct avtab_key * key, struct avtab_datum * datum)
  99 {
 100         int hvalue;
 101         struct avtab_node *prev, *cur, *newnode;
 102         u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
 103
 104         if (!h)
 105                 return NULL;
 106         hvalue = AVTAB_HASH(key);
 107         for (prev = NULL, cur = h->htable[hvalue];
 108              cur;
 109              prev = cur, cur = cur->next) {
 110                 if (key->source_type == cur->key.source_type &&
 111                     key->target_type == cur->key.target_type &&
 112                     key->target_class == cur->key.target_class &&
 113                     (specified & cur->key.specified))
 114                         break;
 115                 if (key->source_type < cur->key.source_type)
 116                         break;
 117                 if (key->source_type == cur->key.source_type &&
 118                     key->target_type < cur->key.target_type)
 119                         break;
 120                 if (key->source_type == cur->key.source_type &&
 121                     key->target_type == cur->key.target_type &&
 122                     key->target_class < cur->key.target_class)
 123                         break;
 124         }
 125         newnode = avtab_insert_node(h, hvalue, prev, cur, key, datum);
 126
 127         return newnode;
 128 }
 129
 130 struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key)
 131 {
 132         int hvalue;
 133         struct avtab_node *cur;
 134         u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
 135
 136         if (!h)
 137                 return NULL;
 138
 139         hvalue = AVTAB_HASH(key);
 140         for (cur = h->htable[hvalue]; cur; cur = cur->next) {
 141                 if (key->source_type == cur->key.source_type &&
 142                     key->target_type == cur->key.target_type &&
 143                     key->target_class == cur->key.target_class &&
 144                     (specified & cur->key.specified))
 145                         return &cur->datum;
 146
 147                 if (key->source_type < cur->key.source_type)
 148                         break;
 149                 if (key->source_type == cur->key.source_type &&
 150                     key->target_type < cur->key.target_type)
 151                         break;
 152                 if (key->source_type == cur->key.source_type &&
 153                     key->target_type == cur->key.target_type &&
 154                     key->target_class < cur->key.target_class)
 155                         break;
 156         }
 157
 158         return NULL;
 159 }
 160
 161 /* This search function returns a node pointer, and can be used in
 162  * conjunction with avtab_search_next_node()
 163  */
 164 struct avtab_node*
 165 avtab_search_node(struct avtab *h, struct avtab_key *key)
 166 {
 167         int hvalue;
 168         struct avtab_node *cur;
 169         u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
 170
 171         if (!h)
 172                 return NULL;
 173
 174         hvalue = AVTAB_HASH(key);
 175         for (cur = h->htable[hvalue]; cur; cur = cur->next) {
 176                 if (key->source_type == cur->key.source_type &&
 177                     key->target_type == cur->key.target_type &&
 178                     key->target_class == cur->key.target_class &&
 179                     (specified & cur->key.specified))
 180                         return cur;
 181
 182                 if (key->source_type < cur->key.source_type)
 183                         break;
 184                 if (key->source_type == cur->key.source_type &&
 185                     key->target_type < cur->key.target_type)
 186                         break;
 187                 if (key->source_type == cur->key.source_type &&
 188                     key->target_type == cur->key.target_type &&
 189                     key->target_class < cur->key.target_class)
 190                         break;
 191         }
 192         return NULL;
 193 }
 194
 195 struct avtab_node*
 196 avtab_search_node_next(struct avtab_node *node, int specified)
 197 {
 198         struct avtab_node *cur;
 199
 200         if (!node)
 201                 return NULL;
 202
 203         specified &= ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
 204         for (cur = node->next; cur; cur = cur->next) {
 205                 if (node->key.source_type == cur->key.source_type &&
 206                     node->key.target_type == cur->key.target_type &&
 207                     node->key.target_class == cur->key.target_class &&
 208                     (specified & cur->key.specified))
 209                         return cur;
 210
 211                 if (node->key.source_type < cur->key.source_type)
 212                         break;
 213                 if (node->key.source_type == cur->key.source_type &&
 214                     node->key.target_type < cur->key.target_type)
 215                         break;
 216                 if (node->key.source_type == cur->key.source_type &&
 217                     node->key.target_type == cur->key.target_type &&
 218                     node->key.target_class < cur->key.target_class)
 219                         break;
 220         }
 221         return NULL;
 222 }
 223
 224 void avtab_destroy(struct avtab *h)
 225 {
 226         int i;
 227         struct avtab_node *cur, *temp;
 228
 229         if (!h || !h->htable)
 230                 return;
 231
 232         for (i = 0; i < AVTAB_SIZE; i++) {
 233                 cur = h->htable[i];
 234                 while (cur != NULL) {
 235                         temp = cur;
 236                         cur = cur->next;
 237                         kmem_cache_free(avtab_node_cachep, temp);
 238                 }
 239                 h->htable[i] = NULL;
 240         }
 241         vfree(h->htable);
 242         h->htable = NULL;
 243 }
 244
 245
 246 int avtab_init(struct avtab *h)
 247 {
 248         int i;
 249
 250         h->htable = vmalloc(sizeof(*(h->htable)) * AVTAB_SIZE);
 251         if (!h->htable)
 252                 return -ENOMEM;
 253         for (i = 0; i < AVTAB_SIZE; i++)
 254                 h->htable[i] = NULL;
 255         h->nel = 0;
 256         return 0;
 257 }
 258
 259 void avtab_hash_eval(struct avtab *h, char *tag)
 260 {
 261         int i, chain_len, slots_used, max_chain_len;
 262         struct avtab_node *cur;
 263
 264         slots_used = 0;
 265         max_chain_len = 0;
 266         for (i = 0; i < AVTAB_SIZE; i++) {
 267                 cur = h->htable[i];
 268                 if (cur) {
 269                         slots_used++;
 270                         chain_len = 0;
 271                         while (cur) {
 272                                 chain_len++;
 273                                 cur = cur->next;
 274                         }
 275
 276                         if (chain_len > max_chain_len)
 277                                 max_chain_len = chain_len;
 278                 }
 279         }
 280
 281         printk(KERN_INFO "%s:  %d entries and %d/%d buckets used, longest "
 282                "chain length %d\n", tag, h->nel, slots_used, AVTAB_SIZE,
 283                max_chain_len);
 284 }
 285
 286 static uint16_t spec_order[] = {
 287         AVTAB_ALLOWED,
 288         AVTAB_AUDITDENY,
 289         AVTAB_AUDITALLOW,
 290         AVTAB_TRANSITION,
 291         AVTAB_CHANGE,
 292         AVTAB_MEMBER
 293 };
 294
 295 int avtab_read_item(void *fp, u32 vers, struct avtab *a,
 296                     int (*insertf)(struct avtab *a, struct avtab_key *k,
 297                                    struct avtab_datum *d, void *p),
 298                     void *p)
 299 {
 300         __le16 buf16[4];
 301         u16 enabled;
 302         __le32 buf32[7];
 303         u32 items, items2, val;
 304         struct avtab_key key;
 305         struct avtab_datum datum;
 306         int i, rc;
 307
 308         memset(&key, 0, sizeof(struct avtab_key));
 309         memset(&datum, 0, sizeof(struct avtab_datum));
 310
 311         if (vers < POLICYDB_VERSION_AVTAB) {
 312                 rc = next_entry(buf32, fp, sizeof(u32));
 313                 if (rc < 0) {
 314                         printk(KERN_ERR "security: avtab: truncated entry\n");
 315                         return -1;
 316                 }
 317                 items2 = le32_to_cpu(buf32[0]);
 318                 if (items2 > ARRAY_SIZE(buf32)) {
 319                         printk(KERN_ERR "security: avtab: entry overflow\n");
 320                         return -1;
 321
 322                 }
 323                 rc = next_entry(buf32, fp, sizeof(u32)*items2);
 324                 if (rc < 0) {
 325                         printk(KERN_ERR "security: avtab: truncated entry\n");
 326                         return -1;
 327                 }
 328                 items = 0;
 329
 330                 val = le32_to_cpu(buf32[items++]);
 331                 key.source_type = (u16)val;
 332                 if (key.source_type != val) {
 333                         printk("security: avtab: truncated source type\n");
 334                         return -1;
 335                 }
 336                 val = le32_to_cpu(buf32[items++]);
 337                 key.target_type = (u16)val;
 338                 if (key.target_type != val) {
 339                         printk("security: avtab: truncated target type\n");
 340                         return -1;
 341                 }
 342                 val = le32_to_cpu(buf32[items++]);
 343                 key.target_class = (u16)val;
 344                 if (key.target_class != val) {
 345                         printk("security: avtab: truncated target class\n");
 346                         return -1;
 347                 }
 348
 349                 val = le32_to_cpu(buf32[items++]);
 350                 enabled = (val & AVTAB_ENABLED_OLD) ? AVTAB_ENABLED : 0;
 351
 352                 if (!(val & (AVTAB_AV | AVTAB_TYPE))) {
 353                         printk("security: avtab: null entry\n");
 354                         return -1;
 355                 }
 356                 if ((val & AVTAB_AV) &&
 357                     (val & AVTAB_TYPE)) {
 358                         printk("security: avtab: entry has both access vectors and types\n");
 359                         return -1;
 360                 }
 361
 362                 for (i = 0; i < sizeof(spec_order)/sizeof(u16); i++) {
 363                         if (val & spec_order[i]) {
 364                                 key.specified = spec_order[i] | enabled;
 365                                 datum.data = le32_to_cpu(buf32[items++]);
 366                                 rc = insertf(a, &key, &datum, p);
 367                                 if (rc) return rc;
 368                         }
 369                 }
 370
 371                 if (items != items2) {
 372                         printk("security: avtab: entry only had %d items, expected %d\n", items2, items);
 373                         return -1;
 374                 }
 375                 return 0;
 376         }
 377
 378         rc = next_entry(buf16, fp, sizeof(u16)*4);
 379         if (rc < 0) {
 380                 printk("security: avtab: truncated entry\n");
 381                 return -1;
 382         }
 383
 384         items = 0;
 385         key.source_type = le16_to_cpu(buf16[items++]);
 386         key.target_type = le16_to_cpu(buf16[items++]);
 387         key.target_class = le16_to_cpu(buf16[items++]);
 388         key.specified = le16_to_cpu(buf16[items++]);
 389
 390         rc = next_entry(buf32, fp, sizeof(u32));
 391         if (rc < 0) {
 392                 printk("security: avtab: truncated entry\n");
 393                 return -1;
 394         }
 395         datum.data = le32_to_cpu(*buf32);
 396         return insertf(a, &key, &datum, p);
 397 }
 398
 399 static int avtab_insertf(struct avtab *a, struct avtab_key *k,
 400                          struct avtab_datum *d, void *p)
 401 {
 402         return avtab_insert(a, k, d);
 403 }
 404
 405 int avtab_read(struct avtab *a, void *fp, u32 vers)
 406 {
 407         int rc;
 408         __le32 buf[1];
 409         u32 nel, i;
 410
 411
 412         rc = next_entry(buf, fp, sizeof(u32));
 413         if (rc < 0) {
 414                 printk(KERN_ERR "security: avtab: truncated table\n");
 415                 goto bad;
 416         }
 417         nel = le32_to_cpu(buf[0]);
 418         if (!nel) {
 419                 printk(KERN_ERR "security: avtab: table is empty\n");
 420                 rc = -EINVAL;
 421                 goto bad;
 422         }
 423         for (i = 0; i < nel; i++) {
 424                 rc = avtab_read_item(fp,vers, a, avtab_insertf, NULL);
 425                 if (rc) {
 426                         if (rc == -ENOMEM)
 427                                 printk(KERN_ERR "security: avtab: out of memory\n");
 428                         else if (rc == -EEXIST)
 429                                 printk(KERN_ERR "security: avtab: duplicate entry\n");
 430                         else
 431                                 rc = -EINVAL;
 432                         goto bad;
 433                 }
 434         }
 435
 436         rc = 0;
 437 out:
 438         return rc;
 439
 440 bad:
 441         avtab_destroy(a);
 442         goto out;
 443 }
 444
 445 void avtab_cache_init(void)
 446 {
 447         avtab_node_cachep = kmem_cache_create("avtab_node",
 448                                               sizeof(struct avtab_node),
 449                                               0, SLAB_PANIC, NULL, NULL);
 450 }
 451
 452 void avtab_cache_destroy(void)
 453 {
 454         kmem_cache_destroy (avtab_node_cachep);
 455 }