1 files changed, 513 insertions, 0 deletions

diff --git a/net/netlabel/netlabel_domainhash.c b/net/netlabel/netlabel_domainhash.c
new file mode 100644
index 000000000000..5bb3fad4a115
--- /dev/null
+++ b/net/netlabel/netlabel_domainhash.c
@@ -0,0 +1,513 @@
+/*
+ * 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 <net/netlabel.h>
+#include <net/cipso_ipv4.h>
+#include <asm/bug.h>
+
+#include "netlabel_mgmt.h"
+#include "netlabel_domainhash.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 */
+DEFINE_SPINLOCK(netlbl_domhsh_lock);
+static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL;
+
+/* Default domain mapping */
+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
+ *
+ * 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)
+{
+        int ret_val;
+        u32 bkt;
+
+        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;
+        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
+ *
+ * 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)
+{
+        return netlbl_domhsh_add(entry);
+}
+
+/**
+ * netlbl_domhsh_remove - Removes an entry from the domain hash table
+ * @domain: the domain to remove
+ *
+ * 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)
+{
+        int ret_val = -ENOENT;
+        struct netlbl_dom_map *entry;
+
+        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);
+        }
+        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
+ *
+ * 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(void)
+{
+        return netlbl_domhsh_remove(NULL);
+}
+
+/**
+ * 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_dump - Dump the domain hash table into a sk_buff
+ *
+ * Description:
+ * Dump the domain hash table into a buffer suitable for returning to an
+ * application in response to a NetLabel management DOMAIN message.  This
+ * function may fail if another process is growing the hash table at the same
+ * time.  The returned sk_buff has room at the front of the sk_buff for
+ * @headroom bytes.  See netlabel.h for the DOMAIN message format.  Returns a
+ * pointer to a sk_buff on success, NULL on error.
+ *
+ */
+struct sk_buff *netlbl_domhsh_dump(size_t headroom)
+{
+        struct sk_buff *skb = NULL;
+        ssize_t buf_len;
+        u32 bkt_iter;
+        u32 dom_cnt = 0;
+        struct netlbl_domhsh_tbl *hsh_tbl;
+        struct netlbl_dom_map *list_iter;
+        ssize_t tmp_len;
+
+        buf_len = NETLBL_LEN_U32;
+        rcu_read_lock();
+        hsh_tbl = rcu_dereference(netlbl_domhsh);
+        for (bkt_iter = 0; bkt_iter < hsh_tbl->size; bkt_iter++)
+                list_for_each_entry_rcu(list_iter,
+                                        &hsh_tbl->tbl[bkt_iter], list) {
+                        buf_len += NETLBL_LEN_U32 +
+                                nla_total_size(strlen(list_iter->domain) + 1);
+                        switch (list_iter->type) {
+                        case NETLBL_NLTYPE_UNLABELED:
+                                break;
+                        case NETLBL_NLTYPE_CIPSOV4:
+                                buf_len += 2 * NETLBL_LEN_U32;
+                                break;
+                        }
+                        dom_cnt++;
+                }
+
+        skb = netlbl_netlink_alloc_skb(headroom, buf_len, GFP_ATOMIC);
+        if (skb == NULL)
+                goto dump_failure;
+
+        if (nla_put_u32(skb, NLA_U32, dom_cnt) != 0)
+                goto dump_failure;
+        buf_len -= NETLBL_LEN_U32;
+        hsh_tbl = rcu_dereference(netlbl_domhsh);
+        for (bkt_iter = 0; bkt_iter < hsh_tbl->size; bkt_iter++)
+                list_for_each_entry_rcu(list_iter,
+                                        &hsh_tbl->tbl[bkt_iter], list) {
+                        tmp_len = nla_total_size(strlen(list_iter->domain) +
+                                                 1);
+                        if (buf_len < NETLBL_LEN_U32 + tmp_len)
+                                goto dump_failure;
+                        if (nla_put_string(skb,
+                                           NLA_STRING,
+                                           list_iter->domain) != 0)
+                                goto dump_failure;
+                        if (nla_put_u32(skb, NLA_U32, list_iter->type) != 0)
+                                goto dump_failure;
+                        buf_len -= NETLBL_LEN_U32 + tmp_len;
+                        switch (list_iter->type) {
+                        case NETLBL_NLTYPE_UNLABELED:
+                                break;
+                        case NETLBL_NLTYPE_CIPSOV4:
+                                if (buf_len < 2 * NETLBL_LEN_U32)
+                                        goto dump_failure;
+                                if (nla_put_u32(skb,
+                                       NLA_U32,
+                                       list_iter->type_def.cipsov4->type) != 0)
+                                        goto dump_failure;
+                                if (nla_put_u32(skb,
+                                       NLA_U32,
+                                       list_iter->type_def.cipsov4->doi) != 0)
+                                        goto dump_failure;
+                                buf_len -= 2 * NETLBL_LEN_U32;
+                                break;
+                        }
+                }
+        rcu_read_unlock();
+
+        return skb;
+
+dump_failure:
+        rcu_read_unlock();
+        kfree_skb(skb);
+        return NULL;
+}
+
+/**
+ * netlbl_domhsh_dump_default - Dump the default domain mapping into a sk_buff
+ *
+ * Description:
+ * Dump the default domain mapping into a buffer suitable for returning to an
+ * application in response to a NetLabel management DEFDOMAIN message.  This
+ * function may fail if another process is changing the default domain mapping
+ * at the same time.  The returned sk_buff has room at the front of the
+ * skb_buff for @headroom bytes.  See netlabel.h for the DEFDOMAIN message
+ * format.  Returns a pointer to a sk_buff on success, NULL on error.
+ *
+ */
+struct sk_buff *netlbl_domhsh_dump_default(size_t headroom)
+{
+        struct sk_buff *skb;
+        ssize_t buf_len;
+        struct netlbl_dom_map *entry;
+
+        buf_len = NETLBL_LEN_U32;
+        rcu_read_lock();
+        entry = rcu_dereference(netlbl_domhsh_def);
+        if (entry != NULL)
+                switch (entry->type) {
+                case NETLBL_NLTYPE_UNLABELED:
+                        break;
+                case NETLBL_NLTYPE_CIPSOV4:
+                        buf_len += 2 * NETLBL_LEN_U32;
+                        break;
+                }
+
+        skb = netlbl_netlink_alloc_skb(headroom, buf_len, GFP_ATOMIC);
+        if (skb == NULL)
+                goto dump_default_failure;
+
+        if (entry != rcu_dereference(netlbl_domhsh_def))
+                goto dump_default_failure;
+        if (entry != NULL) {
+                if (nla_put_u32(skb, NLA_U32, entry->type) != 0)
+                        goto dump_default_failure;
+                buf_len -= NETLBL_LEN_U32;
+                switch (entry->type) {
+                case NETLBL_NLTYPE_UNLABELED:
+                        break;
+                case NETLBL_NLTYPE_CIPSOV4:
+                        if (buf_len < 2 * NETLBL_LEN_U32)
+                                goto dump_default_failure;
+                        if (nla_put_u32(skb,
+                                        NLA_U32,
+                                        entry->type_def.cipsov4->type) != 0)
+                                goto dump_default_failure;
+                        if (nla_put_u32(skb,
+                                        NLA_U32,
+                                        entry->type_def.cipsov4->doi) != 0)
+                                goto dump_default_failure;
+                        buf_len -= 2 * NETLBL_LEN_U32;
+                        break;
+                }
+        } else
+                nla_put_u32(skb, NLA_U32, NETLBL_NLTYPE_NONE);
+        rcu_read_unlock();
+
+        return skb;
+
+dump_default_failure:
+        rcu_read_unlock();
+        kfree_skb(skb);
+        return NULL;
+}