2 * Implementation of the access vector table type.
4 * Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
7 /* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
9 * Added conditional policy language extensions
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.
16 * Updated: Yuichi Nakamura <ynakam@hitachisoft.jp>
17 * Tuned number of hash slots for avtab to reduce memory usage
20 #include <linux/bitops.h>
21 #include <linux/kernel.h>
22 #include <linux/slab.h>
23 #include <linux/errno.h>
27 static struct kmem_cache *avtab_node_cachep __ro_after_init;
28 static struct kmem_cache *avtab_xperms_cachep __ro_after_init;
30 /* Based on MurmurHash3, written by Austin Appleby and placed in the
33 static inline u32 avtab_hash(const struct avtab_key *keyp, u32 mask)
35 static const u32 c1 = 0xcc9e2d51;
36 static const u32 c2 = 0x1b873593;
37 static const u32 r1 = 15;
38 static const u32 r2 = 13;
39 static const u32 m = 5;
40 static const u32 n = 0xe6546b64;
44 #define mix(input) do { \
47 v = (v << r1) | (v >> (32 - r1)); \
50 hash = (hash << r2) | (hash >> (32 - r2)); \
51 hash = hash * m + n; \
54 mix(keyp->target_class);
55 mix(keyp->target_type);
56 mix(keyp->source_type);
69 static struct avtab_node*
70 avtab_insert_node(struct avtab *h, struct avtab_node **dst,
71 const struct avtab_key *key, const struct avtab_datum *datum)
73 struct avtab_node *newnode;
74 struct avtab_extended_perms *xperms;
75 newnode = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL);
80 if (key->specified & AVTAB_XPERMS) {
81 xperms = kmem_cache_zalloc(avtab_xperms_cachep, GFP_KERNEL);
83 kmem_cache_free(avtab_node_cachep, newnode);
86 *xperms = *(datum->u.xperms);
87 newnode->datum.u.xperms = xperms;
89 newnode->datum.u.data = datum->u.data;
99 static int avtab_node_cmp(const struct avtab_key *key1,
100 const struct avtab_key *key2)
102 u16 specified = key1->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
104 if (key1->source_type == key2->source_type &&
105 key1->target_type == key2->target_type &&
106 key1->target_class == key2->target_class &&
107 (specified & key2->specified))
109 if (key1->source_type < key2->source_type)
111 if (key1->source_type == key2->source_type &&
112 key1->target_type < key2->target_type)
114 if (key1->source_type == key2->source_type &&
115 key1->target_type == key2->target_type &&
116 key1->target_class < key2->target_class)
121 static int avtab_insert(struct avtab *h, const struct avtab_key *key,
122 const struct avtab_datum *datum)
125 struct avtab_node *prev, *cur, *newnode;
128 if (!h || !h->nslot || h->nel == U32_MAX)
131 hvalue = avtab_hash(key, h->mask);
132 for (prev = NULL, cur = h->htable[hvalue];
134 prev = cur, cur = cur->next) {
135 cmp = avtab_node_cmp(key, &cur->key);
136 /* extended perms may not be unique */
137 if (cmp == 0 && !(key->specified & AVTAB_XPERMS))
143 newnode = avtab_insert_node(h, prev ? &prev->next : &h->htable[hvalue],
151 /* Unlike avtab_insert(), this function allow multiple insertions of the same
152 * key/specified mask into the table, as needed by the conditional avtab.
153 * It also returns a pointer to the node inserted.
155 struct avtab_node *avtab_insert_nonunique(struct avtab *h,
156 const struct avtab_key *key,
157 const struct avtab_datum *datum)
160 struct avtab_node *prev, *cur;
163 if (!h || !h->nslot || h->nel == U32_MAX)
165 hvalue = avtab_hash(key, h->mask);
166 for (prev = NULL, cur = h->htable[hvalue];
168 prev = cur, cur = cur->next) {
169 cmp = avtab_node_cmp(key, &cur->key);
173 return avtab_insert_node(h, prev ? &prev->next : &h->htable[hvalue],
177 /* This search function returns a node pointer, and can be used in
178 * conjunction with avtab_search_next_node()
180 struct avtab_node *avtab_search_node(struct avtab *h,
181 const struct avtab_key *key)
184 struct avtab_node *cur;
190 hvalue = avtab_hash(key, h->mask);
191 for (cur = h->htable[hvalue]; cur;
193 cmp = avtab_node_cmp(key, &cur->key);
203 avtab_search_node_next(struct avtab_node *node, u16 specified)
205 struct avtab_key tmp_key;
206 struct avtab_node *cur;
212 tmp_key.specified = specified;
213 for (cur = node->next; cur; cur = cur->next) {
214 cmp = avtab_node_cmp(&tmp_key, &cur->key);
223 void avtab_destroy(struct avtab *h)
226 struct avtab_node *cur, *temp;
231 for (i = 0; i < h->nslot; i++) {
236 if (temp->key.specified & AVTAB_XPERMS)
237 kmem_cache_free(avtab_xperms_cachep,
238 temp->datum.u.xperms);
239 kmem_cache_free(avtab_node_cachep, temp);
249 void avtab_init(struct avtab *h)
257 static int avtab_alloc_common(struct avtab *h, u32 nslot)
262 h->htable = kvcalloc(nslot, sizeof(void *), GFP_KERNEL);
271 int avtab_alloc(struct avtab *h, u32 nrules)
277 nslot = nrules > 3 ? rounddown_pow_of_two(nrules / 2) : 2;
278 if (nslot > MAX_AVTAB_HASH_BUCKETS)
279 nslot = MAX_AVTAB_HASH_BUCKETS;
281 rc = avtab_alloc_common(h, nslot);
286 pr_debug("SELinux: %d avtab hash slots, %d rules.\n", nslot, nrules);
290 int avtab_alloc_dup(struct avtab *new, const struct avtab *orig)
292 return avtab_alloc_common(new, orig->nslot);
295 #ifdef CONFIG_SECURITY_SELINUX_DEBUG
296 void avtab_hash_eval(struct avtab *h, const char *tag)
298 u32 i, chain_len, slots_used, max_chain_len;
299 unsigned long long chain2_len_sum;
300 struct avtab_node *cur;
305 for (i = 0; i < h->nslot; i++) {
315 if (chain_len > max_chain_len)
316 max_chain_len = chain_len;
317 chain2_len_sum += (unsigned long long)chain_len * chain_len;
321 pr_debug("SELinux: %s: %d entries and %d/%d buckets used, "
322 "longest chain length %d, sum of chain length^2 %llu\n",
323 tag, h->nel, slots_used, h->nslot, max_chain_len,
326 #endif /* CONFIG_SECURITY_SELINUX_DEBUG */
328 static const uint16_t spec_order[] = {
335 AVTAB_XPERMS_ALLOWED,
336 AVTAB_XPERMS_AUDITALLOW,
337 AVTAB_XPERMS_DONTAUDIT
340 int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
341 int (*insertf)(struct avtab *a, const struct avtab_key *k,
342 const struct avtab_datum *d, void *p),
347 u32 items, items2, val, i;
348 struct avtab_key key;
349 struct avtab_datum datum;
350 struct avtab_extended_perms xperms;
351 __le32 buf32[ARRAY_SIZE(xperms.perms.p)];
353 unsigned int set, vers = pol->policyvers;
355 memset(&key, 0, sizeof(struct avtab_key));
356 memset(&datum, 0, sizeof(struct avtab_datum));
358 if (vers < POLICYDB_VERSION_AVTAB) {
359 rc = next_entry(buf32, fp, sizeof(u32));
361 pr_err("SELinux: avtab: truncated entry\n");
364 items2 = le32_to_cpu(buf32[0]);
365 if (items2 > ARRAY_SIZE(buf32)) {
366 pr_err("SELinux: avtab: entry overflow\n");
370 rc = next_entry(buf32, fp, sizeof(u32)*items2);
372 pr_err("SELinux: avtab: truncated entry\n");
377 val = le32_to_cpu(buf32[items++]);
378 key.source_type = (u16)val;
379 if (key.source_type != val) {
380 pr_err("SELinux: avtab: truncated source type\n");
383 val = le32_to_cpu(buf32[items++]);
384 key.target_type = (u16)val;
385 if (key.target_type != val) {
386 pr_err("SELinux: avtab: truncated target type\n");
389 val = le32_to_cpu(buf32[items++]);
390 key.target_class = (u16)val;
391 if (key.target_class != val) {
392 pr_err("SELinux: avtab: truncated target class\n");
396 val = le32_to_cpu(buf32[items++]);
397 enabled = (val & AVTAB_ENABLED_OLD) ? AVTAB_ENABLED : 0;
399 if (!(val & (AVTAB_AV | AVTAB_TYPE))) {
400 pr_err("SELinux: avtab: null entry\n");
403 if ((val & AVTAB_AV) &&
404 (val & AVTAB_TYPE)) {
405 pr_err("SELinux: avtab: entry has both access vectors and types\n");
408 if (val & AVTAB_XPERMS) {
409 pr_err("SELinux: avtab: entry has extended permissions\n");
413 for (i = 0; i < ARRAY_SIZE(spec_order); i++) {
414 if (val & spec_order[i]) {
415 key.specified = spec_order[i] | enabled;
416 datum.u.data = le32_to_cpu(buf32[items++]);
417 rc = insertf(a, &key, &datum, p);
423 if (items != items2) {
424 pr_err("SELinux: avtab: entry only had %d items, expected %d\n",
431 rc = next_entry(buf16, fp, sizeof(u16)*4);
433 pr_err("SELinux: avtab: truncated entry\n");
438 key.source_type = le16_to_cpu(buf16[items++]);
439 key.target_type = le16_to_cpu(buf16[items++]);
440 key.target_class = le16_to_cpu(buf16[items++]);
441 key.specified = le16_to_cpu(buf16[items++]);
443 if (!policydb_type_isvalid(pol, key.source_type) ||
444 !policydb_type_isvalid(pol, key.target_type) ||
445 !policydb_class_isvalid(pol, key.target_class)) {
446 pr_err("SELinux: avtab: invalid type or class\n");
450 set = hweight16(key.specified & (AVTAB_XPERMS | AVTAB_TYPE | AVTAB_AV));
451 if (!set || set > 1) {
452 pr_err("SELinux: avtab: more than one specifier\n");
456 if ((vers < POLICYDB_VERSION_XPERMS_IOCTL) &&
457 (key.specified & AVTAB_XPERMS)) {
458 pr_err("SELinux: avtab: policy version %u does not "
459 "support extended permissions rules and one "
460 "was specified\n", vers);
462 } else if (key.specified & AVTAB_XPERMS) {
463 memset(&xperms, 0, sizeof(struct avtab_extended_perms));
464 rc = next_entry(&xperms.specified, fp, sizeof(u8));
466 pr_err("SELinux: avtab: truncated entry\n");
469 rc = next_entry(&xperms.driver, fp, sizeof(u8));
471 pr_err("SELinux: avtab: truncated entry\n");
474 rc = next_entry(buf32, fp, sizeof(u32)*ARRAY_SIZE(xperms.perms.p));
476 pr_err("SELinux: avtab: truncated entry\n");
479 for (i = 0; i < ARRAY_SIZE(xperms.perms.p); i++)
480 xperms.perms.p[i] = le32_to_cpu(buf32[i]);
481 datum.u.xperms = &xperms;
483 rc = next_entry(buf32, fp, sizeof(u32));
485 pr_err("SELinux: avtab: truncated entry\n");
488 datum.u.data = le32_to_cpu(*buf32);
490 if ((key.specified & AVTAB_TYPE) &&
491 !policydb_type_isvalid(pol, datum.u.data)) {
492 pr_err("SELinux: avtab: invalid type\n");
495 return insertf(a, &key, &datum, p);
498 static int avtab_insertf(struct avtab *a, const struct avtab_key *k,
499 const struct avtab_datum *d, void *p)
501 return avtab_insert(a, k, d);
504 int avtab_read(struct avtab *a, void *fp, struct policydb *pol)
511 rc = next_entry(buf, fp, sizeof(u32));
513 pr_err("SELinux: avtab: truncated table\n");
516 nel = le32_to_cpu(buf[0]);
518 pr_err("SELinux: avtab: table is empty\n");
523 rc = avtab_alloc(a, nel);
527 for (i = 0; i < nel; i++) {
528 rc = avtab_read_item(a, fp, pol, avtab_insertf, NULL);
531 pr_err("SELinux: avtab: out of memory\n");
532 else if (rc == -EEXIST)
533 pr_err("SELinux: avtab: duplicate entry\n");
548 int avtab_write_item(struct policydb *p, const struct avtab_node *cur, void *fp)
551 __le32 buf32[ARRAY_SIZE(cur->datum.u.xperms->perms.p)];
555 buf16[0] = cpu_to_le16(cur->key.source_type);
556 buf16[1] = cpu_to_le16(cur->key.target_type);
557 buf16[2] = cpu_to_le16(cur->key.target_class);
558 buf16[3] = cpu_to_le16(cur->key.specified);
559 rc = put_entry(buf16, sizeof(u16), 4, fp);
563 if (cur->key.specified & AVTAB_XPERMS) {
564 rc = put_entry(&cur->datum.u.xperms->specified, sizeof(u8), 1, fp);
567 rc = put_entry(&cur->datum.u.xperms->driver, sizeof(u8), 1, fp);
570 for (i = 0; i < ARRAY_SIZE(cur->datum.u.xperms->perms.p); i++)
571 buf32[i] = cpu_to_le32(cur->datum.u.xperms->perms.p[i]);
572 rc = put_entry(buf32, sizeof(u32),
573 ARRAY_SIZE(cur->datum.u.xperms->perms.p), fp);
575 buf32[0] = cpu_to_le32(cur->datum.u.data);
576 rc = put_entry(buf32, sizeof(u32), 1, fp);
583 int avtab_write(struct policydb *p, struct avtab *a, void *fp)
587 struct avtab_node *cur;
590 buf[0] = cpu_to_le32(a->nel);
591 rc = put_entry(buf, sizeof(u32), 1, fp);
595 for (i = 0; i < a->nslot; i++) {
596 for (cur = a->htable[i]; cur;
598 rc = avtab_write_item(p, cur, fp);
607 void __init avtab_cache_init(void)
609 avtab_node_cachep = kmem_cache_create("avtab_node",
610 sizeof(struct avtab_node),
611 0, SLAB_PANIC, NULL);
612 avtab_xperms_cachep = kmem_cache_create("avtab_extended_perms",
613 sizeof(struct avtab_extended_perms),
614 0, SLAB_PANIC, NULL);