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-rw-r--r--security/selinux/ss/avtab.c679
1 files changed, 679 insertions, 0 deletions
diff --git a/security/selinux/ss/avtab.c b/security/selinux/ss/avtab.c
new file mode 100644
index 000000000..8480ec6c6
--- /dev/null
+++ b/security/selinux/ss/avtab.c
@@ -0,0 +1,679 @@
+/*
+ * Implementation of the access vector table type.
+ *
+ * Author : Stephen Smalley, <sds@tycho.nsa.gov>
+ */
+
+/* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
+ *
+ * Added conditional policy language extensions
+ *
+ * Copyright (C) 2003 Tresys Technology, LLC
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2.
+ *
+ * Updated: Yuichi Nakamura <ynakam@hitachisoft.jp>
+ * Tuned number of hash slots for avtab to reduce memory usage
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include "avtab.h"
+#include "policydb.h"
+
+static struct kmem_cache *avtab_node_cachep __ro_after_init;
+static struct kmem_cache *avtab_xperms_cachep __ro_after_init;
+
+/* Based on MurmurHash3, written by Austin Appleby and placed in the
+ * public domain.
+ */
+static inline int avtab_hash(const struct avtab_key *keyp, u32 mask)
+{
+ static const u32 c1 = 0xcc9e2d51;
+ static const u32 c2 = 0x1b873593;
+ static const u32 r1 = 15;
+ static const u32 r2 = 13;
+ static const u32 m = 5;
+ static const u32 n = 0xe6546b64;
+
+ u32 hash = 0;
+
+#define mix(input) do { \
+ u32 v = input; \
+ v *= c1; \
+ v = (v << r1) | (v >> (32 - r1)); \
+ v *= c2; \
+ hash ^= v; \
+ hash = (hash << r2) | (hash >> (32 - r2)); \
+ hash = hash * m + n; \
+ } while (0)
+
+ mix(keyp->target_class);
+ mix(keyp->target_type);
+ mix(keyp->source_type);
+
+#undef mix
+
+ hash ^= hash >> 16;
+ hash *= 0x85ebca6b;
+ hash ^= hash >> 13;
+ hash *= 0xc2b2ae35;
+ hash ^= hash >> 16;
+
+ return hash & mask;
+}
+
+static struct avtab_node*
+avtab_insert_node(struct avtab *h, int hvalue,
+ struct avtab_node *prev,
+ const struct avtab_key *key, const struct avtab_datum *datum)
+{
+ struct avtab_node *newnode;
+ struct avtab_extended_perms *xperms;
+ newnode = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL);
+ if (newnode == NULL)
+ return NULL;
+ newnode->key = *key;
+
+ if (key->specified & AVTAB_XPERMS) {
+ xperms = kmem_cache_zalloc(avtab_xperms_cachep, GFP_KERNEL);
+ if (xperms == NULL) {
+ kmem_cache_free(avtab_node_cachep, newnode);
+ return NULL;
+ }
+ *xperms = *(datum->u.xperms);
+ newnode->datum.u.xperms = xperms;
+ } else {
+ newnode->datum.u.data = datum->u.data;
+ }
+
+ if (prev) {
+ newnode->next = prev->next;
+ prev->next = newnode;
+ } else {
+ struct avtab_node **n = &h->htable[hvalue];
+
+ newnode->next = *n;
+ *n = newnode;
+ }
+
+ h->nel++;
+ return newnode;
+}
+
+static int avtab_insert(struct avtab *h, const struct avtab_key *key,
+ const struct avtab_datum *datum)
+{
+ int hvalue;
+ struct avtab_node *prev, *cur, *newnode;
+ u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+
+ if (!h || !h->nslot)
+ return -EINVAL;
+
+ hvalue = avtab_hash(key, h->mask);
+ for (prev = NULL, cur = h->htable[hvalue];
+ cur;
+ prev = cur, cur = cur->next) {
+ if (key->source_type == cur->key.source_type &&
+ key->target_type == cur->key.target_type &&
+ key->target_class == cur->key.target_class &&
+ (specified & cur->key.specified)) {
+ /* extended perms may not be unique */
+ if (specified & AVTAB_XPERMS)
+ break;
+ return -EEXIST;
+ }
+ if (key->source_type < cur->key.source_type)
+ break;
+ if (key->source_type == cur->key.source_type &&
+ key->target_type < cur->key.target_type)
+ break;
+ if (key->source_type == cur->key.source_type &&
+ key->target_type == cur->key.target_type &&
+ key->target_class < cur->key.target_class)
+ break;
+ }
+
+ newnode = avtab_insert_node(h, hvalue, prev, key, datum);
+ if (!newnode)
+ return -ENOMEM;
+
+ return 0;
+}
+
+/* Unlike avtab_insert(), this function allow multiple insertions of the same
+ * key/specified mask into the table, as needed by the conditional avtab.
+ * It also returns a pointer to the node inserted.
+ */
+struct avtab_node *avtab_insert_nonunique(struct avtab *h,
+ const struct avtab_key *key,
+ const struct avtab_datum *datum)
+{
+ int hvalue;
+ struct avtab_node *prev, *cur;
+ u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+
+ if (!h || !h->nslot)
+ return NULL;
+ hvalue = avtab_hash(key, h->mask);
+ for (prev = NULL, cur = h->htable[hvalue];
+ cur;
+ prev = cur, cur = cur->next) {
+ if (key->source_type == cur->key.source_type &&
+ key->target_type == cur->key.target_type &&
+ key->target_class == cur->key.target_class &&
+ (specified & cur->key.specified))
+ break;
+ if (key->source_type < cur->key.source_type)
+ break;
+ if (key->source_type == cur->key.source_type &&
+ key->target_type < cur->key.target_type)
+ break;
+ if (key->source_type == cur->key.source_type &&
+ key->target_type == cur->key.target_type &&
+ key->target_class < cur->key.target_class)
+ break;
+ }
+ return avtab_insert_node(h, hvalue, prev, key, datum);
+}
+
+struct avtab_datum *avtab_search(struct avtab *h, const struct avtab_key *key)
+{
+ int hvalue;
+ struct avtab_node *cur;
+ u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+
+ if (!h || !h->nslot)
+ return NULL;
+
+ hvalue = avtab_hash(key, h->mask);
+ for (cur = h->htable[hvalue]; cur;
+ cur = cur->next) {
+ if (key->source_type == cur->key.source_type &&
+ key->target_type == cur->key.target_type &&
+ key->target_class == cur->key.target_class &&
+ (specified & cur->key.specified))
+ return &cur->datum;
+
+ if (key->source_type < cur->key.source_type)
+ break;
+ if (key->source_type == cur->key.source_type &&
+ key->target_type < cur->key.target_type)
+ break;
+ if (key->source_type == cur->key.source_type &&
+ key->target_type == cur->key.target_type &&
+ key->target_class < cur->key.target_class)
+ break;
+ }
+
+ return NULL;
+}
+
+/* This search function returns a node pointer, and can be used in
+ * conjunction with avtab_search_next_node()
+ */
+struct avtab_node *avtab_search_node(struct avtab *h,
+ const struct avtab_key *key)
+{
+ int hvalue;
+ struct avtab_node *cur;
+ u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+
+ if (!h || !h->nslot)
+ return NULL;
+
+ hvalue = avtab_hash(key, h->mask);
+ for (cur = h->htable[hvalue]; cur;
+ cur = cur->next) {
+ if (key->source_type == cur->key.source_type &&
+ key->target_type == cur->key.target_type &&
+ key->target_class == cur->key.target_class &&
+ (specified & cur->key.specified))
+ return cur;
+
+ if (key->source_type < cur->key.source_type)
+ break;
+ if (key->source_type == cur->key.source_type &&
+ key->target_type < cur->key.target_type)
+ break;
+ if (key->source_type == cur->key.source_type &&
+ key->target_type == cur->key.target_type &&
+ key->target_class < cur->key.target_class)
+ break;
+ }
+ return NULL;
+}
+
+struct avtab_node*
+avtab_search_node_next(struct avtab_node *node, int specified)
+{
+ struct avtab_node *cur;
+
+ if (!node)
+ return NULL;
+
+ specified &= ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+ for (cur = node->next; cur; cur = cur->next) {
+ if (node->key.source_type == cur->key.source_type &&
+ node->key.target_type == cur->key.target_type &&
+ node->key.target_class == cur->key.target_class &&
+ (specified & cur->key.specified))
+ return cur;
+
+ if (node->key.source_type < cur->key.source_type)
+ break;
+ if (node->key.source_type == cur->key.source_type &&
+ node->key.target_type < cur->key.target_type)
+ break;
+ if (node->key.source_type == cur->key.source_type &&
+ node->key.target_type == cur->key.target_type &&
+ node->key.target_class < cur->key.target_class)
+ break;
+ }
+ return NULL;
+}
+
+void avtab_destroy(struct avtab *h)
+{
+ int i;
+ struct avtab_node *cur, *temp;
+
+ if (!h)
+ return;
+
+ for (i = 0; i < h->nslot; i++) {
+ cur = h->htable[i];
+ while (cur) {
+ temp = cur;
+ cur = cur->next;
+ if (temp->key.specified & AVTAB_XPERMS)
+ kmem_cache_free(avtab_xperms_cachep,
+ temp->datum.u.xperms);
+ kmem_cache_free(avtab_node_cachep, temp);
+ }
+ }
+ kvfree(h->htable);
+ h->htable = NULL;
+ h->nel = 0;
+ h->nslot = 0;
+ h->mask = 0;
+}
+
+void avtab_init(struct avtab *h)
+{
+ h->htable = NULL;
+ h->nel = 0;
+ h->nslot = 0;
+ h->mask = 0;
+}
+
+static int avtab_alloc_common(struct avtab *h, u32 nslot)
+{
+ if (!nslot)
+ return 0;
+
+ h->htable = kvcalloc(nslot, sizeof(void *), GFP_KERNEL);
+ if (!h->htable)
+ return -ENOMEM;
+
+ h->nslot = nslot;
+ h->mask = nslot - 1;
+ return 0;
+}
+
+int avtab_alloc(struct avtab *h, u32 nrules)
+{
+ int rc;
+ u32 nslot = 0;
+
+ if (nrules != 0) {
+ u32 shift = 1;
+ u32 work = nrules >> 3;
+ while (work) {
+ work >>= 1;
+ shift++;
+ }
+ nslot = 1 << shift;
+ if (nslot > MAX_AVTAB_HASH_BUCKETS)
+ nslot = MAX_AVTAB_HASH_BUCKETS;
+
+ rc = avtab_alloc_common(h, nslot);
+ if (rc)
+ return rc;
+ }
+
+ pr_debug("SELinux: %d avtab hash slots, %d rules.\n", nslot, nrules);
+ return 0;
+}
+
+int avtab_alloc_dup(struct avtab *new, const struct avtab *orig)
+{
+ return avtab_alloc_common(new, orig->nslot);
+}
+
+void avtab_hash_eval(struct avtab *h, char *tag)
+{
+ int i, chain_len, slots_used, max_chain_len;
+ unsigned long long chain2_len_sum;
+ struct avtab_node *cur;
+
+ slots_used = 0;
+ max_chain_len = 0;
+ chain2_len_sum = 0;
+ for (i = 0; i < h->nslot; i++) {
+ cur = h->htable[i];
+ if (cur) {
+ slots_used++;
+ chain_len = 0;
+ while (cur) {
+ chain_len++;
+ cur = cur->next;
+ }
+
+ if (chain_len > max_chain_len)
+ max_chain_len = chain_len;
+ chain2_len_sum += chain_len * chain_len;
+ }
+ }
+
+ pr_debug("SELinux: %s: %d entries and %d/%d buckets used, "
+ "longest chain length %d sum of chain length^2 %llu\n",
+ tag, h->nel, slots_used, h->nslot, max_chain_len,
+ chain2_len_sum);
+}
+
+static const uint16_t spec_order[] = {
+ AVTAB_ALLOWED,
+ AVTAB_AUDITDENY,
+ AVTAB_AUDITALLOW,
+ AVTAB_TRANSITION,
+ AVTAB_CHANGE,
+ AVTAB_MEMBER,
+ AVTAB_XPERMS_ALLOWED,
+ AVTAB_XPERMS_AUDITALLOW,
+ AVTAB_XPERMS_DONTAUDIT
+};
+
+int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
+ int (*insertf)(struct avtab *a, const struct avtab_key *k,
+ const struct avtab_datum *d, void *p),
+ void *p)
+{
+ __le16 buf16[4];
+ u16 enabled;
+ u32 items, items2, val, vers = pol->policyvers;
+ struct avtab_key key;
+ struct avtab_datum datum;
+ struct avtab_extended_perms xperms;
+ __le32 buf32[ARRAY_SIZE(xperms.perms.p)];
+ int i, rc;
+ unsigned set;
+
+ memset(&key, 0, sizeof(struct avtab_key));
+ memset(&datum, 0, sizeof(struct avtab_datum));
+
+ if (vers < POLICYDB_VERSION_AVTAB) {
+ rc = next_entry(buf32, fp, sizeof(u32));
+ if (rc) {
+ pr_err("SELinux: avtab: truncated entry\n");
+ return rc;
+ }
+ items2 = le32_to_cpu(buf32[0]);
+ if (items2 > ARRAY_SIZE(buf32)) {
+ pr_err("SELinux: avtab: entry overflow\n");
+ return -EINVAL;
+
+ }
+ rc = next_entry(buf32, fp, sizeof(u32)*items2);
+ if (rc) {
+ pr_err("SELinux: avtab: truncated entry\n");
+ return rc;
+ }
+ items = 0;
+
+ val = le32_to_cpu(buf32[items++]);
+ key.source_type = (u16)val;
+ if (key.source_type != val) {
+ pr_err("SELinux: avtab: truncated source type\n");
+ return -EINVAL;
+ }
+ val = le32_to_cpu(buf32[items++]);
+ key.target_type = (u16)val;
+ if (key.target_type != val) {
+ pr_err("SELinux: avtab: truncated target type\n");
+ return -EINVAL;
+ }
+ val = le32_to_cpu(buf32[items++]);
+ key.target_class = (u16)val;
+ if (key.target_class != val) {
+ pr_err("SELinux: avtab: truncated target class\n");
+ return -EINVAL;
+ }
+
+ val = le32_to_cpu(buf32[items++]);
+ enabled = (val & AVTAB_ENABLED_OLD) ? AVTAB_ENABLED : 0;
+
+ if (!(val & (AVTAB_AV | AVTAB_TYPE))) {
+ pr_err("SELinux: avtab: null entry\n");
+ return -EINVAL;
+ }
+ if ((val & AVTAB_AV) &&
+ (val & AVTAB_TYPE)) {
+ pr_err("SELinux: avtab: entry has both access vectors and types\n");
+ return -EINVAL;
+ }
+ if (val & AVTAB_XPERMS) {
+ pr_err("SELinux: avtab: entry has extended permissions\n");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(spec_order); i++) {
+ if (val & spec_order[i]) {
+ key.specified = spec_order[i] | enabled;
+ datum.u.data = le32_to_cpu(buf32[items++]);
+ rc = insertf(a, &key, &datum, p);
+ if (rc)
+ return rc;
+ }
+ }
+
+ if (items != items2) {
+ pr_err("SELinux: avtab: entry only had %d items, expected %d\n",
+ items2, items);
+ return -EINVAL;
+ }
+ return 0;
+ }
+
+ rc = next_entry(buf16, fp, sizeof(u16)*4);
+ if (rc) {
+ pr_err("SELinux: avtab: truncated entry\n");
+ return rc;
+ }
+
+ items = 0;
+ key.source_type = le16_to_cpu(buf16[items++]);
+ key.target_type = le16_to_cpu(buf16[items++]);
+ key.target_class = le16_to_cpu(buf16[items++]);
+ key.specified = le16_to_cpu(buf16[items++]);
+
+ if (!policydb_type_isvalid(pol, key.source_type) ||
+ !policydb_type_isvalid(pol, key.target_type) ||
+ !policydb_class_isvalid(pol, key.target_class)) {
+ pr_err("SELinux: avtab: invalid type or class\n");
+ return -EINVAL;
+ }
+
+ set = 0;
+ for (i = 0; i < ARRAY_SIZE(spec_order); i++) {
+ if (key.specified & spec_order[i])
+ set++;
+ }
+ if (!set || set > 1) {
+ pr_err("SELinux: avtab: more than one specifier\n");
+ return -EINVAL;
+ }
+
+ if ((vers < POLICYDB_VERSION_XPERMS_IOCTL) &&
+ (key.specified & AVTAB_XPERMS)) {
+ pr_err("SELinux: avtab: policy version %u does not "
+ "support extended permissions rules and one "
+ "was specified\n", vers);
+ return -EINVAL;
+ } else if (key.specified & AVTAB_XPERMS) {
+ memset(&xperms, 0, sizeof(struct avtab_extended_perms));
+ rc = next_entry(&xperms.specified, fp, sizeof(u8));
+ if (rc) {
+ pr_err("SELinux: avtab: truncated entry\n");
+ return rc;
+ }
+ rc = next_entry(&xperms.driver, fp, sizeof(u8));
+ if (rc) {
+ pr_err("SELinux: avtab: truncated entry\n");
+ return rc;
+ }
+ rc = next_entry(buf32, fp, sizeof(u32)*ARRAY_SIZE(xperms.perms.p));
+ if (rc) {
+ pr_err("SELinux: avtab: truncated entry\n");
+ return rc;
+ }
+ for (i = 0; i < ARRAY_SIZE(xperms.perms.p); i++)
+ xperms.perms.p[i] = le32_to_cpu(buf32[i]);
+ datum.u.xperms = &xperms;
+ } else {
+ rc = next_entry(buf32, fp, sizeof(u32));
+ if (rc) {
+ pr_err("SELinux: avtab: truncated entry\n");
+ return rc;
+ }
+ datum.u.data = le32_to_cpu(*buf32);
+ }
+ if ((key.specified & AVTAB_TYPE) &&
+ !policydb_type_isvalid(pol, datum.u.data)) {
+ pr_err("SELinux: avtab: invalid type\n");
+ return -EINVAL;
+ }
+ return insertf(a, &key, &datum, p);
+}
+
+static int avtab_insertf(struct avtab *a, const struct avtab_key *k,
+ const struct avtab_datum *d, void *p)
+{
+ return avtab_insert(a, k, d);
+}
+
+int avtab_read(struct avtab *a, void *fp, struct policydb *pol)
+{
+ int rc;
+ __le32 buf[1];
+ u32 nel, i;
+
+
+ rc = next_entry(buf, fp, sizeof(u32));
+ if (rc < 0) {
+ pr_err("SELinux: avtab: truncated table\n");
+ goto bad;
+ }
+ nel = le32_to_cpu(buf[0]);
+ if (!nel) {
+ pr_err("SELinux: avtab: table is empty\n");
+ rc = -EINVAL;
+ goto bad;
+ }
+
+ rc = avtab_alloc(a, nel);
+ if (rc)
+ goto bad;
+
+ for (i = 0; i < nel; i++) {
+ rc = avtab_read_item(a, fp, pol, avtab_insertf, NULL);
+ if (rc) {
+ if (rc == -ENOMEM)
+ pr_err("SELinux: avtab: out of memory\n");
+ else if (rc == -EEXIST)
+ pr_err("SELinux: avtab: duplicate entry\n");
+
+ goto bad;
+ }
+ }
+
+ rc = 0;
+out:
+ return rc;
+
+bad:
+ avtab_destroy(a);
+ goto out;
+}
+
+int avtab_write_item(struct policydb *p, const struct avtab_node *cur, void *fp)
+{
+ __le16 buf16[4];
+ __le32 buf32[ARRAY_SIZE(cur->datum.u.xperms->perms.p)];
+ int rc;
+ unsigned int i;
+
+ buf16[0] = cpu_to_le16(cur->key.source_type);
+ buf16[1] = cpu_to_le16(cur->key.target_type);
+ buf16[2] = cpu_to_le16(cur->key.target_class);
+ buf16[3] = cpu_to_le16(cur->key.specified);
+ rc = put_entry(buf16, sizeof(u16), 4, fp);
+ if (rc)
+ return rc;
+
+ if (cur->key.specified & AVTAB_XPERMS) {
+ rc = put_entry(&cur->datum.u.xperms->specified, sizeof(u8), 1, fp);
+ if (rc)
+ return rc;
+ rc = put_entry(&cur->datum.u.xperms->driver, sizeof(u8), 1, fp);
+ if (rc)
+ return rc;
+ for (i = 0; i < ARRAY_SIZE(cur->datum.u.xperms->perms.p); i++)
+ buf32[i] = cpu_to_le32(cur->datum.u.xperms->perms.p[i]);
+ rc = put_entry(buf32, sizeof(u32),
+ ARRAY_SIZE(cur->datum.u.xperms->perms.p), fp);
+ } else {
+ buf32[0] = cpu_to_le32(cur->datum.u.data);
+ rc = put_entry(buf32, sizeof(u32), 1, fp);
+ }
+ if (rc)
+ return rc;
+ return 0;
+}
+
+int avtab_write(struct policydb *p, struct avtab *a, void *fp)
+{
+ unsigned int i;
+ int rc = 0;
+ struct avtab_node *cur;
+ __le32 buf[1];
+
+ buf[0] = cpu_to_le32(a->nel);
+ rc = put_entry(buf, sizeof(u32), 1, fp);
+ if (rc)
+ return rc;
+
+ for (i = 0; i < a->nslot; i++) {
+ for (cur = a->htable[i]; cur;
+ cur = cur->next) {
+ rc = avtab_write_item(p, cur, fp);
+ if (rc)
+ return rc;
+ }
+ }
+
+ return rc;
+}
+
+void __init avtab_cache_init(void)
+{
+ avtab_node_cachep = kmem_cache_create("avtab_node",
+ sizeof(struct avtab_node),
+ 0, SLAB_PANIC, NULL);
+ avtab_xperms_cachep = kmem_cache_create("avtab_extended_perms",
+ sizeof(struct avtab_extended_perms),
+ 0, SLAB_PANIC, NULL);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 16:00:12 +0000