--- /dev/null
+/*
+ * NetLabel Domain Hash Table
+ *
+ * This file manages the domain hash table that NetLabel uses to determine
+ * which network labeling protocol to use for a given domain. The NetLabel
+ * system manages static and dynamic label mappings for network protocols such
+ * as CIPSO and RIPSO.
+ *
+ * Author: Paul Moore <paul.moore@hp.com>
+ *
+ */
+
+/*
+ * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/rcupdate.h>
+#include <linux/list.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/audit.h>
+#include <net/netlabel.h>
+#include <net/cipso_ipv4.h>
+#include <asm/bug.h>
+
+#include "netlabel_mgmt.h"
+#include "netlabel_domainhash.h"
+#include "netlabel_user.h"
+
+struct netlbl_domhsh_tbl {
+ struct list_head *tbl;
+ u32 size;
+};
+
+/* Domain hash table */
+/* XXX - updates should be so rare that having one spinlock for the entire
+ * hash table should be okay */
+static DEFINE_SPINLOCK(netlbl_domhsh_lock);
+static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL;
+
+/* Default domain mapping */
+static DEFINE_SPINLOCK(netlbl_domhsh_def_lock);
+static struct netlbl_dom_map *netlbl_domhsh_def = NULL;
+
+/*
+ * Domain Hash Table Helper Functions
+ */
+
+/**
+ * netlbl_domhsh_free_entry - Frees a domain hash table entry
+ * @entry: the entry's RCU field
+ *
+ * Description:
+ * This function is designed to be used as a callback to the call_rcu()
+ * function so that the memory allocated to a hash table entry can be released
+ * safely.
+ *
+ */
+static void netlbl_domhsh_free_entry(struct rcu_head *entry)
+{
+ struct netlbl_dom_map *ptr;
+
+ ptr = container_of(entry, struct netlbl_dom_map, rcu);
+ kfree(ptr->domain);
+ kfree(ptr);
+}
+
+/**
+ * netlbl_domhsh_hash - Hashing function for the domain hash table
+ * @domain: the domain name to hash
+ *
+ * Description:
+ * This is the hashing function for the domain hash table, it returns the
+ * correct bucket number for the domain. The caller is responsibile for
+ * calling the rcu_read_[un]lock() functions.
+ *
+ */
+static u32 netlbl_domhsh_hash(const char *key)
+{
+ u32 iter;
+ u32 val;
+ u32 len;
+
+ /* This is taken (with slight modification) from
+ * security/selinux/ss/symtab.c:symhash() */
+
+ for (iter = 0, val = 0, len = strlen(key); iter < len; iter++)
+ val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter];
+ return val & (rcu_dereference(netlbl_domhsh)->size - 1);
+}
+
+/**
+ * netlbl_domhsh_search - Search for a domain entry
+ * @domain: the domain
+ * @def: return default if no match is found
+ *
+ * Description:
+ * Searches the domain hash table and returns a pointer to the hash table
+ * entry if found, otherwise NULL is returned. If @def is non-zero and a
+ * match is not found in the domain hash table the default mapping is returned
+ * if it exists. The caller is responsibile for the rcu hash table locks
+ * (i.e. the caller much call rcu_read_[un]lock()).
+ *
+ */
+static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain, u32 def)
+{
+ u32 bkt;
+ struct netlbl_dom_map *iter;
+
+ if (domain != NULL) {
+ bkt = netlbl_domhsh_hash(domain);
+ list_for_each_entry_rcu(iter, &netlbl_domhsh->tbl[bkt], list)
+ if (iter->valid && strcmp(iter->domain, domain) == 0)
+ return iter;
+ }
+
+ if (def != 0) {
+ iter = rcu_dereference(netlbl_domhsh_def);
+ if (iter != NULL && iter->valid)
+ return iter;
+ }
+
+ return NULL;
+}
+
+/*
+ * Domain Hash Table Functions
+ */
+
+/**
+ * netlbl_domhsh_init - Init for the domain hash
+ * @size: the number of bits to use for the hash buckets
+ *
+ * Description:
+ * Initializes the domain hash table, should be called only by
+ * netlbl_user_init() during initialization. Returns zero on success, non-zero
+ * values on error.
+ *
+ */
+int netlbl_domhsh_init(u32 size)
+{
+ u32 iter;
+ struct netlbl_domhsh_tbl *hsh_tbl;
+
+ if (size == 0)
+ return -EINVAL;
+
+ hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL);
+ if (hsh_tbl == NULL)
+ return -ENOMEM;
+ hsh_tbl->size = 1 << size;
+ hsh_tbl->tbl = kcalloc(hsh_tbl->size,
+ sizeof(struct list_head),
+ GFP_KERNEL);
+ if (hsh_tbl->tbl == NULL) {
+ kfree(hsh_tbl);
+ return -ENOMEM;
+ }
+ for (iter = 0; iter < hsh_tbl->size; iter++)
+ INIT_LIST_HEAD(&hsh_tbl->tbl[iter]);
+
+ rcu_read_lock();
+ spin_lock(&netlbl_domhsh_lock);
+ rcu_assign_pointer(netlbl_domhsh, hsh_tbl);
+ spin_unlock(&netlbl_domhsh_lock);
+ rcu_read_unlock();
+
+ return 0;
+}
+
+/**
+ * netlbl_domhsh_add - Adds a entry to the domain hash table
+ * @entry: the entry to add
+ * @audit_info: NetLabel audit information
+ *
+ * Description:
+ * Adds a new entry to the domain hash table and handles any updates to the
+ * lower level protocol handler (i.e. CIPSO). Returns zero on success,
+ * negative on failure.
+ *
+ */
+int netlbl_domhsh_add(struct netlbl_dom_map *entry,
+ struct netlbl_audit *audit_info)
+{
+ int ret_val;
+ u32 bkt;
+ struct audit_buffer *audit_buf;
+
+ switch (entry->type) {
+ case NETLBL_NLTYPE_UNLABELED:
+ ret_val = 0;
+ break;
+ case NETLBL_NLTYPE_CIPSOV4:
+ ret_val = cipso_v4_doi_domhsh_add(entry->type_def.cipsov4,
+ entry->domain);
+ break;
+ default:
+ return -EINVAL;
+ }
+ if (ret_val != 0)
+ return ret_val;
+
+ entry->valid = 1;
+ INIT_RCU_HEAD(&entry->rcu);
+
+ ret_val = 0;
+ rcu_read_lock();
+ if (entry->domain != NULL) {
+ bkt = netlbl_domhsh_hash(entry->domain);
+ spin_lock(&netlbl_domhsh_lock);
+ if (netlbl_domhsh_search(entry->domain, 0) == NULL)
+ list_add_tail_rcu(&entry->list,
+ &netlbl_domhsh->tbl[bkt]);
+ else
+ ret_val = -EEXIST;
+ spin_unlock(&netlbl_domhsh_lock);
+ } else if (entry->domain == NULL) {
+ INIT_LIST_HEAD(&entry->list);
+ spin_lock(&netlbl_domhsh_def_lock);
+ if (rcu_dereference(netlbl_domhsh_def) == NULL)
+ rcu_assign_pointer(netlbl_domhsh_def, entry);
+ else
+ ret_val = -EEXIST;
+ spin_unlock(&netlbl_domhsh_def_lock);
+ } else
+ ret_val = -EINVAL;
+
+ audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info);
+ if (audit_buf != NULL) {
+ audit_log_format(audit_buf,
+ " nlbl_domain=%s",
+ entry->domain ? entry->domain : "(default)");
+ switch (entry->type) {
+ case NETLBL_NLTYPE_UNLABELED:
+ audit_log_format(audit_buf, " nlbl_protocol=unlbl");
+ break;
+ case NETLBL_NLTYPE_CIPSOV4:
+ audit_log_format(audit_buf,
+ " nlbl_protocol=cipsov4 cipso_doi=%u",
+ entry->type_def.cipsov4->doi);
+ break;
+ }
+ audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
+ audit_log_end(audit_buf);
+ }
+
+ rcu_read_unlock();
+
+ if (ret_val != 0) {
+ switch (entry->type) {
+ case NETLBL_NLTYPE_CIPSOV4:
+ if (cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4,
+ entry->domain) != 0)
+ BUG();
+ break;
+ }
+ }
+
+ return ret_val;
+}
+
+/**
+ * netlbl_domhsh_add_default - Adds the default entry to the domain hash table
+ * @entry: the entry to add
+ * @audit_info: NetLabel audit information
+ *
+ * Description:
+ * Adds a new default entry to the domain hash table and handles any updates
+ * to the lower level protocol handler (i.e. CIPSO). Returns zero on success,
+ * negative on failure.
+ *
+ */
+int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
+ struct netlbl_audit *audit_info)
+{
+ return netlbl_domhsh_add(entry, audit_info);
+}
+
+/**
+ * netlbl_domhsh_remove - Removes an entry from the domain hash table
+ * @domain: the domain to remove
+ * @audit_info: NetLabel audit information
+ *
+ * Description:
+ * Removes an entry from the domain hash table and handles any updates to the
+ * lower level protocol handler (i.e. CIPSO). Returns zero on success,
+ * negative on failure.
+ *
+ */
+int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info)
+{
+ int ret_val = -ENOENT;
+ struct netlbl_dom_map *entry;
+ struct audit_buffer *audit_buf;
+
+ rcu_read_lock();
+ if (domain != NULL)
+ entry = netlbl_domhsh_search(domain, 0);
+ else
+ entry = netlbl_domhsh_search(domain, 1);
+ if (entry == NULL)
+ goto remove_return;
+ switch (entry->type) {
+ case NETLBL_NLTYPE_UNLABELED:
+ break;
+ case NETLBL_NLTYPE_CIPSOV4:
+ ret_val = cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4,
+ entry->domain);
+ if (ret_val != 0)
+ goto remove_return;
+ break;
+ }
+ ret_val = 0;
+ if (entry != rcu_dereference(netlbl_domhsh_def)) {
+ spin_lock(&netlbl_domhsh_lock);
+ if (entry->valid) {
+ entry->valid = 0;
+ list_del_rcu(&entry->list);
+ } else
+ ret_val = -ENOENT;
+ spin_unlock(&netlbl_domhsh_lock);
+ } else {
+ spin_lock(&netlbl_domhsh_def_lock);
+ if (entry->valid) {
+ entry->valid = 0;
+ rcu_assign_pointer(netlbl_domhsh_def, NULL);
+ } else
+ ret_val = -ENOENT;
+ spin_unlock(&netlbl_domhsh_def_lock);
+ }
+
+ audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info);
+ if (audit_buf != NULL) {
+ audit_log_format(audit_buf,
+ " nlbl_domain=%s res=%u",
+ entry->domain ? entry->domain : "(default)",
+ ret_val == 0 ? 1 : 0);
+ audit_log_end(audit_buf);
+ }
+
+ if (ret_val == 0)
+ call_rcu(&entry->rcu, netlbl_domhsh_free_entry);
+
+remove_return:
+ rcu_read_unlock();
+ return ret_val;
+}
+
+/**
+ * netlbl_domhsh_remove_default - Removes the default entry from the table
+ * @audit_info: NetLabel audit information
+ *
+ * Description:
+ * Removes/resets the default entry for the domain hash table and handles any
+ * updates to the lower level protocol handler (i.e. CIPSO). Returns zero on
+ * success, non-zero on failure.
+ *
+ */
+int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info)
+{
+ return netlbl_domhsh_remove(NULL, audit_info);
+}
+
+/**
+ * netlbl_domhsh_getentry - Get an entry from the domain hash table
+ * @domain: the domain name to search for
+ *
+ * Description:
+ * Look through the domain hash table searching for an entry to match @domain,
+ * return a pointer to a copy of the entry or NULL. The caller is responsibile
+ * for ensuring that rcu_read_[un]lock() is called.
+ *
+ */
+struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain)
+{
+ return netlbl_domhsh_search(domain, 1);
+}
+
+/**
+ * netlbl_domhsh_walk - Iterate through the domain mapping hash table
+ * @skip_bkt: the number of buckets to skip at the start
+ * @skip_chain: the number of entries to skip in the first iterated bucket
+ * @callback: callback for each entry
+ * @cb_arg: argument for the callback function
+ *
+ * Description:
+ * Interate over the domain mapping hash table, skipping the first @skip_bkt
+ * buckets and @skip_chain entries. For each entry in the table call
+ * @callback, if @callback returns a negative value stop 'walking' through the
+ * table and return. Updates the values in @skip_bkt and @skip_chain on
+ * return. Returns zero on succcess, negative values on failure.
+ *
+ */
+int netlbl_domhsh_walk(u32 *skip_bkt,
+ u32 *skip_chain,
+ int (*callback) (struct netlbl_dom_map *entry, void *arg),
+ void *cb_arg)
+{
+ int ret_val = -ENOENT;
+ u32 iter_bkt;
+ struct netlbl_dom_map *iter_entry;
+ u32 chain_cnt = 0;
+
+ rcu_read_lock();
+ for (iter_bkt = *skip_bkt;
+ iter_bkt < rcu_dereference(netlbl_domhsh)->size;
+ iter_bkt++, chain_cnt = 0) {
+ list_for_each_entry_rcu(iter_entry,
+ &netlbl_domhsh->tbl[iter_bkt],
+ list)
+ if (iter_entry->valid) {
+ if (chain_cnt++ < *skip_chain)
+ continue;
+ ret_val = callback(iter_entry, cb_arg);
+ if (ret_val < 0) {
+ chain_cnt--;
+ goto walk_return;
+ }
+ }
+ }
+
+walk_return:
+ rcu_read_unlock();
+ *skip_bkt = iter_bkt;
+ *skip_chain = chain_cnt;
+ return ret_val;
+}
git://git.onelab.eu / linux-2.6.git / blobdiff