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
  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                     (datum->specified & cur->datum.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
 102         if (!h)
 103                 return NULL;
 104         hvalue = AVTAB_HASH(key);
 105         for (prev = NULL, cur = h->htable[hvalue];
 106              cur;
 107              prev = cur, cur = cur->next) {
 108                 if (key->source_type == cur->key.source_type &&
 109                     key->target_type == cur->key.target_type &&
 110                     key->target_class == cur->key.target_class &&
 111                     (datum->specified & cur->datum.specified))
 112                         break;
 113                 if (key->source_type < cur->key.source_type)
 114                         break;
 115                 if (key->source_type == cur->key.source_type &&
 116                     key->target_type < cur->key.target_type)
 117                         break;
 118                 if (key->source_type == cur->key.source_type &&
 119                     key->target_type == cur->key.target_type &&
 120                     key->target_class < cur->key.target_class)
 121                         break;
 122         }
 123         newnode = avtab_insert_node(h, hvalue, prev, cur, key, datum);
 124
 125         return newnode;
 126 }
 127
 128 struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key, int specified)
 129 {
 130         int hvalue;
 131         struct avtab_node *cur;
 132
 133         if (!h)
 134                 return NULL;
 135
 136         hvalue = AVTAB_HASH(key);
 137         for (cur = h->htable[hvalue]; cur; cur = cur->next) {
 138                 if (key->source_type == cur->key.source_type &&
 139                     key->target_type == cur->key.target_type &&
 140                     key->target_class == cur->key.target_class &&
 141                     (specified & cur->datum.specified))
 142                         return &cur->datum;
 143
 144                 if (key->source_type < cur->key.source_type)
 145                         break;
 146                 if (key->source_type == cur->key.source_type &&
 147                     key->target_type < cur->key.target_type)
 148                         break;
 149                 if (key->source_type == cur->key.source_type &&
 150                     key->target_type == cur->key.target_type &&
 151                     key->target_class < cur->key.target_class)
 152                         break;
 153         }
 154
 155         return NULL;
 156 }
 157
 158 /* This search function returns a node pointer, and can be used in
 159  * conjunction with avtab_search_next_node()
 160  */
 161 struct avtab_node*
 162 avtab_search_node(struct avtab *h, struct avtab_key *key, int specified)
 163 {
 164         int hvalue;
 165         struct avtab_node *cur;
 166
 167         if (!h)
 168                 return NULL;
 169
 170         hvalue = AVTAB_HASH(key);
 171         for (cur = h->htable[hvalue]; cur; cur = cur->next) {
 172                 if (key->source_type == cur->key.source_type &&
 173                     key->target_type == cur->key.target_type &&
 174                     key->target_class == cur->key.target_class &&
 175                     (specified & cur->datum.specified))
 176                         return cur;
 177
 178                 if (key->source_type < cur->key.source_type)
 179                         break;
 180                 if (key->source_type == cur->key.source_type &&
 181                     key->target_type < cur->key.target_type)
 182                         break;
 183                 if (key->source_type == cur->key.source_type &&
 184                     key->target_type == cur->key.target_type &&
 185                     key->target_class < cur->key.target_class)
 186                         break;
 187         }
 188         return NULL;
 189 }
 190
 191 struct avtab_node*
 192 avtab_search_node_next(struct avtab_node *node, int specified)
 193 {
 194         struct avtab_node *cur;
 195
 196         if (!node)
 197                 return NULL;
 198
 199         for (cur = node->next; cur; cur = cur->next) {
 200                 if (node->key.source_type == cur->key.source_type &&
 201                     node->key.target_type == cur->key.target_type &&
 202                     node->key.target_class == cur->key.target_class &&
 203                     (specified & cur->datum.specified))
 204                         return cur;
 205
 206                 if (node->key.source_type < cur->key.source_type)
 207                         break;
 208                 if (node->key.source_type == cur->key.source_type &&
 209                     node->key.target_type < cur->key.target_type)
 210                         break;
 211                 if (node->key.source_type == cur->key.source_type &&
 212                     node->key.target_type == cur->key.target_type &&
 213                     node->key.target_class < cur->key.target_class)
 214                         break;
 215         }
 216         return NULL;
 217 }
 218
 219 void avtab_destroy(struct avtab *h)
 220 {
 221         int i;
 222         struct avtab_node *cur, *temp;
 223
 224         if (!h || !h->htable)
 225                 return;
 226
 227         for (i = 0; i < AVTAB_SIZE; i++) {
 228                 cur = h->htable[i];
 229                 while (cur != NULL) {
 230                         temp = cur;
 231                         cur = cur->next;
 232                         kmem_cache_free(avtab_node_cachep, temp);
 233                 }
 234                 h->htable[i] = NULL;
 235         }
 236         vfree(h->htable);
 237         h->htable = NULL;
 238 }
 239
 240
 241 int avtab_init(struct avtab *h)
 242 {
 243         int i;
 244
 245         h->htable = vmalloc(sizeof(*(h->htable)) * AVTAB_SIZE);
 246         if (!h->htable)
 247                 return -ENOMEM;
 248         for (i = 0; i < AVTAB_SIZE; i++)
 249                 h->htable[i] = NULL;
 250         h->nel = 0;
 251         return 0;
 252 }
 253
 254 void avtab_hash_eval(struct avtab *h, char *tag)
 255 {
 256         int i, chain_len, slots_used, max_chain_len;
 257         struct avtab_node *cur;
 258
 259         slots_used = 0;
 260         max_chain_len = 0;
 261         for (i = 0; i < AVTAB_SIZE; i++) {
 262                 cur = h->htable[i];
 263                 if (cur) {
 264                         slots_used++;
 265                         chain_len = 0;
 266                         while (cur) {
 267                                 chain_len++;
 268                                 cur = cur->next;
 269                         }
 270
 271                         if (chain_len > max_chain_len)
 272                                 max_chain_len = chain_len;
 273                 }
 274         }
 275
 276         printk(KERN_INFO "%s:  %d entries and %d/%d buckets used, longest "
 277                "chain length %d\n", tag, h->nel, slots_used, AVTAB_SIZE,
 278                max_chain_len);
 279 }
 280
 281 int avtab_read_item(void *fp, struct avtab_datum *avdatum, struct avtab_key *avkey)
 282 {
 283         u32 buf[7];
 284         u32 items, items2;
 285         int rc;
 286
 287         memset(avkey, 0, sizeof(struct avtab_key));
 288         memset(avdatum, 0, sizeof(struct avtab_datum));
 289
 290         rc = next_entry(buf, fp, sizeof(u32));
 291         if (rc < 0) {
 292                 printk(KERN_ERR "security: avtab: truncated entry\n");
 293                 goto bad;
 294         }
 295         items2 = le32_to_cpu(buf[0]);
 296         if (items2 > ARRAY_SIZE(buf)) {
 297                 printk(KERN_ERR "security: avtab: entry overflow\n");
 298                 goto bad;
 299         }
 300         rc = next_entry(buf, fp, sizeof(u32)*items2);
 301         if (rc < 0) {
 302                 printk(KERN_ERR "security: avtab: truncated entry\n");
 303                 goto bad;
 304         }
 305         items = 0;
 306         avkey->source_type = le32_to_cpu(buf[items++]);
 307         avkey->target_type = le32_to_cpu(buf[items++]);
 308         avkey->target_class = le32_to_cpu(buf[items++]);
 309         avdatum->specified = le32_to_cpu(buf[items++]);
 310         if (!(avdatum->specified & (AVTAB_AV | AVTAB_TYPE))) {
 311                 printk(KERN_ERR "security: avtab: null entry\n");
 312                 goto bad;
 313         }
 314         if ((avdatum->specified & AVTAB_AV) &&
 315             (avdatum->specified & AVTAB_TYPE)) {
 316                 printk(KERN_ERR "security: avtab: entry has both access vectors and types\n");
 317                 goto bad;
 318         }
 319         if (avdatum->specified & AVTAB_AV) {
 320                 if (avdatum->specified & AVTAB_ALLOWED)
 321                         avtab_allowed(avdatum) = le32_to_cpu(buf[items++]);
 322                 if (avdatum->specified & AVTAB_AUDITDENY)
 323                         avtab_auditdeny(avdatum) = le32_to_cpu(buf[items++]);
 324                 if (avdatum->specified & AVTAB_AUDITALLOW)
 325                         avtab_auditallow(avdatum) = le32_to_cpu(buf[items++]);
 326         } else {
 327                 if (avdatum->specified & AVTAB_TRANSITION)
 328                         avtab_transition(avdatum) = le32_to_cpu(buf[items++]);
 329                 if (avdatum->specified & AVTAB_CHANGE)
 330                         avtab_change(avdatum) = le32_to_cpu(buf[items++]);
 331                 if (avdatum->specified & AVTAB_MEMBER)
 332                         avtab_member(avdatum) = le32_to_cpu(buf[items++]);
 333         }
 334         if (items != items2) {
 335                 printk(KERN_ERR "security: avtab: entry only had %d items, expected %d\n",
 336                        items2, items);
 337                 goto bad;
 338         }
 339
 340         return 0;
 341 bad:
 342         return -1;
 343 }
 344
 345 int avtab_read(struct avtab *a, void *fp, u32 config)
 346 {
 347         int rc;
 348         struct avtab_key avkey;
 349         struct avtab_datum avdatum;
 350         u32 buf[1];
 351         u32 nel, i;
 352
 353
 354         rc = next_entry(buf, fp, sizeof(u32));
 355         if (rc < 0) {
 356                 printk(KERN_ERR "security: avtab: truncated table\n");
 357                 goto bad;
 358         }
 359         nel = le32_to_cpu(buf[0]);
 360         if (!nel) {
 361                 printk(KERN_ERR "security: avtab: table is empty\n");
 362                 rc = -EINVAL;
 363                 goto bad;
 364         }
 365         for (i = 0; i < nel; i++) {
 366                 if (avtab_read_item(fp, &avdatum, &avkey)) {
 367                         rc = -EINVAL;
 368                         goto bad;
 369                 }
 370                 rc = avtab_insert(a, &avkey, &avdatum);
 371                 if (rc) {
 372                         if (rc == -ENOMEM)
 373                                 printk(KERN_ERR "security: avtab: out of memory\n");
 374                         if (rc == -EEXIST)
 375                                 printk(KERN_ERR "security: avtab: duplicate entry\n");
 376                         goto bad;
 377                 }
 378         }
 379
 380         rc = 0;
 381 out:
 382         return rc;
 383
 384 bad:
 385         avtab_destroy(a);
 386         goto out;
 387 }
 388
 389 void avtab_cache_init(void)
 390 {
 391         avtab_node_cachep = kmem_cache_create("avtab_node",
 392                                               sizeof(struct avtab_node),
 393                                               0, SLAB_PANIC, NULL, NULL);
 394 }
 395
 396 void avtab_cache_destroy(void)
 397 {
 398         kmem_cache_destroy (avtab_node_cachep);
 399 }