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