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517 lines
13 KiB
517 lines
13 KiB
/*
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* Implementation of the access vector table type.
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*
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* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
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*/
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/* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
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*
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* Added conditional policy language extensions
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*
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* Copyright (C) 2003 Tresys Technology, LLC
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 2.
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*
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* Updated: Yuichi Nakamura <ynakam@hitachisoft.jp>
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* Tuned number of hash slots for avtab to reduce memory usage
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include "avtab.h"
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#include "policydb.h"
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static struct kmem_cache *avtab_node_cachep;
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static inline int avtab_hash(struct avtab_key *keyp, u16 mask)
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{
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return ((keyp->target_class + (keyp->target_type << 2) +
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(keyp->source_type << 9)) & mask);
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}
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static struct avtab_node*
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avtab_insert_node(struct avtab *h, int hvalue,
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struct avtab_node *prev, struct avtab_node *cur,
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struct avtab_key *key, struct avtab_datum *datum)
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{
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struct avtab_node *newnode;
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newnode = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL);
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if (newnode == NULL)
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return NULL;
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newnode->key = *key;
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newnode->datum = *datum;
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if (prev) {
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newnode->next = prev->next;
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prev->next = newnode;
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} else {
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newnode->next = h->htable[hvalue];
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h->htable[hvalue] = newnode;
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}
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h->nel++;
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return newnode;
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}
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static int avtab_insert(struct avtab *h, struct avtab_key *key, struct avtab_datum *datum)
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{
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int hvalue;
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struct avtab_node *prev, *cur, *newnode;
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u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
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if (!h || !h->htable)
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return -EINVAL;
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hvalue = avtab_hash(key, h->mask);
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for (prev = NULL, cur = h->htable[hvalue];
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cur;
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prev = cur, cur = cur->next) {
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if (key->source_type == cur->key.source_type &&
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key->target_type == cur->key.target_type &&
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key->target_class == cur->key.target_class &&
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(specified & cur->key.specified))
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return -EEXIST;
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if (key->source_type < cur->key.source_type)
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break;
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if (key->source_type == cur->key.source_type &&
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key->target_type < cur->key.target_type)
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break;
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if (key->source_type == cur->key.source_type &&
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key->target_type == cur->key.target_type &&
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key->target_class < cur->key.target_class)
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break;
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}
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newnode = avtab_insert_node(h, hvalue, prev, cur, key, datum);
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if (!newnode)
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return -ENOMEM;
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return 0;
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}
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/* Unlike avtab_insert(), this function allow multiple insertions of the same
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* key/specified mask into the table, as needed by the conditional avtab.
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* It also returns a pointer to the node inserted.
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*/
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struct avtab_node *
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avtab_insert_nonunique(struct avtab *h, struct avtab_key *key, struct avtab_datum *datum)
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{
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int hvalue;
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struct avtab_node *prev, *cur, *newnode;
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u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
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if (!h || !h->htable)
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return NULL;
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hvalue = avtab_hash(key, h->mask);
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for (prev = NULL, cur = h->htable[hvalue];
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cur;
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prev = cur, cur = cur->next) {
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if (key->source_type == cur->key.source_type &&
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key->target_type == cur->key.target_type &&
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key->target_class == cur->key.target_class &&
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(specified & cur->key.specified))
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break;
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if (key->source_type < cur->key.source_type)
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break;
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if (key->source_type == cur->key.source_type &&
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key->target_type < cur->key.target_type)
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break;
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if (key->source_type == cur->key.source_type &&
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key->target_type == cur->key.target_type &&
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key->target_class < cur->key.target_class)
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break;
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}
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newnode = avtab_insert_node(h, hvalue, prev, cur, key, datum);
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return newnode;
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}
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struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key)
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{
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int hvalue;
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struct avtab_node *cur;
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u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
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if (!h || !h->htable)
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return NULL;
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hvalue = avtab_hash(key, h->mask);
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for (cur = h->htable[hvalue]; cur; cur = cur->next) {
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if (key->source_type == cur->key.source_type &&
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key->target_type == cur->key.target_type &&
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key->target_class == cur->key.target_class &&
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(specified & cur->key.specified))
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return &cur->datum;
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if (key->source_type < cur->key.source_type)
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break;
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if (key->source_type == cur->key.source_type &&
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key->target_type < cur->key.target_type)
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break;
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if (key->source_type == cur->key.source_type &&
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key->target_type == cur->key.target_type &&
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key->target_class < cur->key.target_class)
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break;
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}
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return NULL;
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}
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/* This search function returns a node pointer, and can be used in
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* conjunction with avtab_search_next_node()
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*/
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struct avtab_node*
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avtab_search_node(struct avtab *h, struct avtab_key *key)
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{
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int hvalue;
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struct avtab_node *cur;
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u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
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if (!h || !h->htable)
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return NULL;
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hvalue = avtab_hash(key, h->mask);
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for (cur = h->htable[hvalue]; cur; cur = cur->next) {
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if (key->source_type == cur->key.source_type &&
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key->target_type == cur->key.target_type &&
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key->target_class == cur->key.target_class &&
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(specified & cur->key.specified))
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return cur;
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if (key->source_type < cur->key.source_type)
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break;
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if (key->source_type == cur->key.source_type &&
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key->target_type < cur->key.target_type)
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break;
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if (key->source_type == cur->key.source_type &&
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key->target_type == cur->key.target_type &&
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key->target_class < cur->key.target_class)
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break;
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}
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return NULL;
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}
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struct avtab_node*
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avtab_search_node_next(struct avtab_node *node, int specified)
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{
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struct avtab_node *cur;
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if (!node)
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return NULL;
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specified &= ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
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for (cur = node->next; cur; cur = cur->next) {
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if (node->key.source_type == cur->key.source_type &&
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node->key.target_type == cur->key.target_type &&
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node->key.target_class == cur->key.target_class &&
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(specified & cur->key.specified))
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return cur;
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if (node->key.source_type < cur->key.source_type)
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break;
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if (node->key.source_type == cur->key.source_type &&
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node->key.target_type < cur->key.target_type)
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break;
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if (node->key.source_type == cur->key.source_type &&
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node->key.target_type == cur->key.target_type &&
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node->key.target_class < cur->key.target_class)
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break;
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}
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return NULL;
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}
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void avtab_destroy(struct avtab *h)
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{
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int i;
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struct avtab_node *cur, *temp;
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if (!h || !h->htable)
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return;
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for (i = 0; i < h->nslot; i++) {
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cur = h->htable[i];
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while (cur != NULL) {
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temp = cur;
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cur = cur->next;
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kmem_cache_free(avtab_node_cachep, temp);
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}
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h->htable[i] = NULL;
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}
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kfree(h->htable);
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h->htable = NULL;
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h->nslot = 0;
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h->mask = 0;
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}
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int avtab_init(struct avtab *h)
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{
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h->htable = NULL;
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h->nel = 0;
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return 0;
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}
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int avtab_alloc(struct avtab *h, u32 nrules)
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{
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u16 mask = 0;
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u32 shift = 0;
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u32 work = nrules;
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u32 nslot = 0;
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if (nrules == 0)
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goto avtab_alloc_out;
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while (work) {
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work = work >> 1;
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shift++;
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}
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if (shift > 2)
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shift = shift - 2;
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nslot = 1 << shift;
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if (nslot > MAX_AVTAB_SIZE)
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nslot = MAX_AVTAB_SIZE;
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mask = nslot - 1;
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h->htable = kcalloc(nslot, sizeof(*(h->htable)), GFP_KERNEL);
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if (!h->htable)
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return -ENOMEM;
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avtab_alloc_out:
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h->nel = 0;
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h->nslot = nslot;
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h->mask = mask;
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printk(KERN_DEBUG "SELinux: %d avtab hash slots, %d rules.\n",
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h->nslot, nrules);
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return 0;
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}
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void avtab_hash_eval(struct avtab *h, char *tag)
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{
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int i, chain_len, slots_used, max_chain_len;
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unsigned long long chain2_len_sum;
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struct avtab_node *cur;
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slots_used = 0;
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max_chain_len = 0;
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chain2_len_sum = 0;
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for (i = 0; i < h->nslot; i++) {
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cur = h->htable[i];
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if (cur) {
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slots_used++;
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chain_len = 0;
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while (cur) {
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chain_len++;
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cur = cur->next;
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}
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if (chain_len > max_chain_len)
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max_chain_len = chain_len;
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chain2_len_sum += chain_len * chain_len;
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}
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}
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printk(KERN_DEBUG "SELinux: %s: %d entries and %d/%d buckets used, "
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"longest chain length %d sum of chain length^2 %Lu\n",
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tag, h->nel, slots_used, h->nslot, max_chain_len,
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chain2_len_sum);
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}
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static uint16_t spec_order[] = {
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AVTAB_ALLOWED,
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AVTAB_AUDITDENY,
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AVTAB_AUDITALLOW,
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AVTAB_TRANSITION,
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AVTAB_CHANGE,
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AVTAB_MEMBER
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};
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int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
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int (*insertf)(struct avtab *a, struct avtab_key *k,
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struct avtab_datum *d, void *p),
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void *p)
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{
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__le16 buf16[4];
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u16 enabled;
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__le32 buf32[7];
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u32 items, items2, val, vers = pol->policyvers;
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struct avtab_key key;
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struct avtab_datum datum;
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int i, rc;
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unsigned set;
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memset(&key, 0, sizeof(struct avtab_key));
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memset(&datum, 0, sizeof(struct avtab_datum));
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if (vers < POLICYDB_VERSION_AVTAB) {
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rc = next_entry(buf32, fp, sizeof(u32));
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if (rc < 0) {
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printk(KERN_ERR "SELinux: avtab: truncated entry\n");
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return -1;
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}
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items2 = le32_to_cpu(buf32[0]);
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if (items2 > ARRAY_SIZE(buf32)) {
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printk(KERN_ERR "SELinux: avtab: entry overflow\n");
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return -1;
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}
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rc = next_entry(buf32, fp, sizeof(u32)*items2);
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if (rc < 0) {
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printk(KERN_ERR "SELinux: avtab: truncated entry\n");
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return -1;
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}
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items = 0;
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val = le32_to_cpu(buf32[items++]);
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key.source_type = (u16)val;
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if (key.source_type != val) {
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printk(KERN_ERR "SELinux: avtab: truncated source type\n");
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return -1;
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}
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val = le32_to_cpu(buf32[items++]);
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key.target_type = (u16)val;
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if (key.target_type != val) {
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printk(KERN_ERR "SELinux: avtab: truncated target type\n");
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return -1;
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}
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val = le32_to_cpu(buf32[items++]);
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key.target_class = (u16)val;
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if (key.target_class != val) {
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printk(KERN_ERR "SELinux: avtab: truncated target class\n");
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return -1;
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}
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val = le32_to_cpu(buf32[items++]);
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enabled = (val & AVTAB_ENABLED_OLD) ? AVTAB_ENABLED : 0;
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if (!(val & (AVTAB_AV | AVTAB_TYPE))) {
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printk(KERN_ERR "SELinux: avtab: null entry\n");
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return -1;
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}
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if ((val & AVTAB_AV) &&
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(val & AVTAB_TYPE)) {
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printk(KERN_ERR "SELinux: avtab: entry has both access vectors and types\n");
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return -1;
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}
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for (i = 0; i < ARRAY_SIZE(spec_order); i++) {
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if (val & spec_order[i]) {
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key.specified = spec_order[i] | enabled;
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datum.data = le32_to_cpu(buf32[items++]);
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rc = insertf(a, &key, &datum, p);
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if (rc)
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return rc;
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}
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}
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if (items != items2) {
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printk(KERN_ERR "SELinux: avtab: entry only had %d items, expected %d\n", items2, items);
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return -1;
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}
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return 0;
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}
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rc = next_entry(buf16, fp, sizeof(u16)*4);
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if (rc < 0) {
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printk(KERN_ERR "SELinux: avtab: truncated entry\n");
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return -1;
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}
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items = 0;
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key.source_type = le16_to_cpu(buf16[items++]);
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key.target_type = le16_to_cpu(buf16[items++]);
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key.target_class = le16_to_cpu(buf16[items++]);
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key.specified = le16_to_cpu(buf16[items++]);
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if (!policydb_type_isvalid(pol, key.source_type) ||
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!policydb_type_isvalid(pol, key.target_type) ||
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!policydb_class_isvalid(pol, key.target_class)) {
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printk(KERN_ERR "SELinux: avtab: invalid type or class\n");
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return -1;
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}
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set = 0;
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for (i = 0; i < ARRAY_SIZE(spec_order); i++) {
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if (key.specified & spec_order[i])
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set++;
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}
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if (!set || set > 1) {
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printk(KERN_ERR "SELinux: avtab: more than one specifier\n");
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return -1;
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}
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rc = next_entry(buf32, fp, sizeof(u32));
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if (rc < 0) {
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printk(KERN_ERR "SELinux: avtab: truncated entry\n");
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return -1;
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}
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datum.data = le32_to_cpu(*buf32);
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if ((key.specified & AVTAB_TYPE) &&
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!policydb_type_isvalid(pol, datum.data)) {
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printk(KERN_ERR "SELinux: avtab: invalid type\n");
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return -1;
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}
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return insertf(a, &key, &datum, p);
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}
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|
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static int avtab_insertf(struct avtab *a, struct avtab_key *k,
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struct avtab_datum *d, void *p)
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{
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return avtab_insert(a, k, d);
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}
|
|
|
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int avtab_read(struct avtab *a, void *fp, struct policydb *pol)
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{
|
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int rc;
|
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__le32 buf[1];
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u32 nel, i;
|
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|
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rc = next_entry(buf, fp, sizeof(u32));
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if (rc < 0) {
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printk(KERN_ERR "SELinux: avtab: truncated table\n");
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goto bad;
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}
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nel = le32_to_cpu(buf[0]);
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if (!nel) {
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printk(KERN_ERR "SELinux: avtab: table is empty\n");
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rc = -EINVAL;
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goto bad;
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}
|
|
|
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rc = avtab_alloc(a, nel);
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if (rc)
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goto bad;
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|
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for (i = 0; i < nel; i++) {
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rc = avtab_read_item(a, fp, pol, avtab_insertf, NULL);
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if (rc) {
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if (rc == -ENOMEM)
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printk(KERN_ERR "SELinux: avtab: out of memory\n");
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else if (rc == -EEXIST)
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printk(KERN_ERR "SELinux: avtab: duplicate entry\n");
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else
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rc = -EINVAL;
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goto bad;
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}
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}
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rc = 0;
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out:
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return rc;
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|
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bad:
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avtab_destroy(a);
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goto out;
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}
|
|
|
|
void avtab_cache_init(void)
|
|
{
|
|
avtab_node_cachep = kmem_cache_create("avtab_node",
|
|
sizeof(struct avtab_node),
|
|
0, SLAB_PANIC, NULL);
|
|
}
|
|
|
|
void avtab_cache_destroy(void)
|
|
{
|
|
kmem_cache_destroy(avtab_node_cachep);
|
|
}
|
|
|