/*
 * security/tomoyo/domain.c
 *
 * Domain transition functions for TOMOYO.
 *
 * Copyright (C) 2005-2010  NTT DATA CORPORATION
 */

#include "common.h"
#include <linux/binfmts.h>
#include <linux/slab.h>

/* Variables definitions.*/

/* The initial domain. */
struct tomoyo_domain_info tomoyo_kernel_domain;

/**
 * tomoyo_update_policy - Update an entry for exception policy.
 *
 * @new_entry:       Pointer to "struct tomoyo_acl_info".
 * @size:            Size of @new_entry in bytes.
 * @is_delete:       True if it is a delete request.
 * @list:            Pointer to "struct list_head".
 * @check_duplicate: Callback function to find duplicated entry.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_update_policy(struct tomoyo_acl_head *new_entry, const int size,
                         bool is_delete, struct list_head *list,
                         bool (*check_duplicate) (const struct tomoyo_acl_head
                                                  *,
                                                  const struct tomoyo_acl_head
                                                  *))
{
        int error = is_delete ? -ENOENT : -ENOMEM;
        struct tomoyo_acl_head *entry;

        if (mutex_lock_interruptible(&tomoyo_policy_lock))
                return -ENOMEM;
        list_for_each_entry_rcu(entry, list, list) {
                if (!check_duplicate(entry, new_entry))
                        continue;
                entry->is_deleted = is_delete;
                error = 0;
                break;
        }
        if (error && !is_delete) {
                entry = tomoyo_commit_ok(new_entry, size);
                if (entry) {
                        list_add_tail_rcu(&entry->list, list);
                        error = 0;
                }
        }
        mutex_unlock(&tomoyo_policy_lock);
        return error;
}

/**
 * tomoyo_update_domain - Update an entry for domain policy.
 *
 * @new_entry:       Pointer to "struct tomoyo_acl_info".
 * @size:            Size of @new_entry in bytes.
 * @is_delete:       True if it is a delete request.
 * @domain:          Pointer to "struct tomoyo_domain_info".
 * @check_duplicate: Callback function to find duplicated entry.
 * @merge_duplicate: Callback function to merge duplicated entry.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size,
                         bool is_delete, struct tomoyo_domain_info *domain,
                         bool (*check_duplicate) (const struct tomoyo_acl_info
                                                  *,
                                                  const struct tomoyo_acl_info
                                                  *),
                         bool (*merge_duplicate) (struct tomoyo_acl_info *,
                                                  struct tomoyo_acl_info *,
                                                  const bool))
{
        int error = is_delete ? -ENOENT : -ENOMEM;
        struct tomoyo_acl_info *entry;

        if (mutex_lock_interruptible(&tomoyo_policy_lock))
                return error;
        list_for_each_entry_rcu(entry, &domain->acl_info_list, list) {
                if (!check_duplicate(entry, new_entry))
                        continue;
                if (merge_duplicate)
                        entry->is_deleted = merge_duplicate(entry, new_entry,
                                                            is_delete);
                else
                        entry->is_deleted = is_delete;
                error = 0;
                break;
        }
        if (error && !is_delete) {
                entry = tomoyo_commit_ok(new_entry, size);
                if (entry) {
                        list_add_tail_rcu(&entry->list, &domain->acl_info_list);
                        error = 0;
                }
        }
        mutex_unlock(&tomoyo_policy_lock);
        return error;
}

void tomoyo_check_acl(struct tomoyo_request_info *r,
                      bool (*check_entry) (struct tomoyo_request_info *,
                                           const struct tomoyo_acl_info *))
{
        const struct tomoyo_domain_info *domain = r->domain;
        struct tomoyo_acl_info *ptr;

        list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
                if (ptr->is_deleted || ptr->type != r->param_type)
                        continue;
                if (check_entry(r, ptr)) {
                        r->granted = true;
                        return;
                }
        }
        r->granted = false;
}

/* The list for "struct tomoyo_domain_info". */
LIST_HEAD(tomoyo_domain_list);

struct list_head tomoyo_policy_list[TOMOYO_MAX_POLICY];
struct list_head tomoyo_group_list[TOMOYO_MAX_GROUP];

/**
 * tomoyo_last_word - Get last component of a domainname.
 *
 * @domainname: Domainname to check.
 *
 * Returns the last word of @domainname.
 */
static const char *tomoyo_last_word(const char *name)
{
        const char *cp = strrchr(name, ' ');
        if (cp)
                return cp + 1;
        return name;
}

static bool tomoyo_same_transition_control(const struct tomoyo_acl_head *a,
                                           const struct tomoyo_acl_head *b)
{
        const struct tomoyo_transition_control *p1 = container_of(a,
                                                                  typeof(*p1),
                                                                  head);
        const struct tomoyo_transition_control *p2 = container_of(b,
                                                                  typeof(*p2),
                                                                  head);
        return p1->type == p2->type && p1->is_last_name == p2->is_last_name
                && p1->domainname == p2->domainname
                && p1->program == p2->program;
}

/**
 * tomoyo_update_transition_control_entry - Update "struct tomoyo_transition_control" list.
 *
 * @domainname: The name of domain. Maybe NULL.
 * @program:    The name of program. Maybe NULL.
 * @type:       Type of transition.
 * @is_delete:  True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_update_transition_control_entry(const char *domainname,
                                                  const char *program,
                                                  const u8 type,
                                                  const bool is_delete)
{
        struct tomoyo_transition_control e = { .type = type };
        int error = is_delete ? -ENOENT : -ENOMEM;
        if (program) {
                if (!tomoyo_correct_path(program))
                        return -EINVAL;
                e.program = tomoyo_get_name(program);
                if (!e.program)
                        goto out;
        }
        if (domainname) {
                if (!tomoyo_correct_domain(domainname)) {
                        if (!tomoyo_correct_path(domainname))
                                goto out;
                        e.is_last_name = true;
                }
                e.domainname = tomoyo_get_name(domainname);
                if (!e.domainname)
                        goto out;
        }
        error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
                                     &tomoyo_policy_list
                                     [TOMOYO_ID_TRANSITION_CONTROL],
                                     tomoyo_same_transition_control);
 out:
        tomoyo_put_name(e.domainname);
        tomoyo_put_name(e.program);
        return error;
}

/**
 * tomoyo_write_transition_control - Write "struct tomoyo_transition_control" list.
 *
 * @data:      String to parse.
 * @is_delete: True if it is a delete request.
 * @type:      Type of this entry.
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_write_transition_control(char *data, const bool is_delete,
                                    const u8 type)
{
        char *domainname = strstr(data, " from ");
        if (domainname) {
                *domainname = '\0';
                domainname += 6;
        } else if (type == TOMOYO_TRANSITION_CONTROL_NO_KEEP ||
                   type == TOMOYO_TRANSITION_CONTROL_KEEP) {
                domainname = data;
                data = NULL;
        }
        return tomoyo_update_transition_control_entry(domainname, data, type,
                                                      is_delete);
}

/**
 * tomoyo_transition_type - Get domain transition type.
 *
 * @domainname: The name of domain.
 * @program:    The name of program.
 *
 * Returns TOMOYO_TRANSITION_CONTROL_INITIALIZE if executing @program
 * reinitializes domain transition, TOMOYO_TRANSITION_CONTROL_KEEP if executing
 * @program suppresses domain transition, others otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static u8 tomoyo_transition_type(const struct tomoyo_path_info *domainname,
                                 const struct tomoyo_path_info *program)
{
        const struct tomoyo_transition_control *ptr;
        const char *last_name = tomoyo_last_word(domainname->name);
        u8 type;
        for (type = 0; type < TOMOYO_MAX_TRANSITION_TYPE; type++) {
 next:
                list_for_each_entry_rcu(ptr, &tomoyo_policy_list
                                        [TOMOYO_ID_TRANSITION_CONTROL],
                                        head.list) {
                        if (ptr->head.is_deleted || ptr->type != type)
                                continue;
                        if (ptr->domainname) {
                                if (!ptr->is_last_name) {
                                        if (ptr->domainname != domainname)
                                                continue;
                                } else {
                                        /*
                                         * Use direct strcmp() since this is
                                         * unlikely used.
                                         */
                                        if (strcmp(ptr->domainname->name,
                                                   last_name))
                                                continue;
                                }
                        }
                        if (ptr->program &&
                            tomoyo_pathcmp(ptr->program, program))
                                continue;
                        if (type == TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE) {
                                /*
                                 * Do not check for initialize_domain if
                                 * no_initialize_domain matched.
                                 */
                                type = TOMOYO_TRANSITION_CONTROL_NO_KEEP;
                                goto next;
                        }
                        goto done;
                }
        }
 done:
        return type;
}

static bool tomoyo_same_aggregator(const struct tomoyo_acl_head *a,
                                   const struct tomoyo_acl_head *b)
{
        const struct tomoyo_aggregator *p1 = container_of(a, typeof(*p1), head);
        const struct tomoyo_aggregator *p2 = container_of(b, typeof(*p2), head);
        return p1->original_name == p2->original_name &&
                p1->aggregated_name == p2->aggregated_name;
}

/**
 * tomoyo_update_aggregator_entry - Update "struct tomoyo_aggregator" list.
 *
 * @original_name:   The original program's name.
 * @aggregated_name: The program name to use.
 * @is_delete:       True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_update_aggregator_entry(const char *original_name,
                                          const char *aggregated_name,
                                          const bool is_delete)
{
        struct tomoyo_aggregator e = { };
        int error = is_delete ? -ENOENT : -ENOMEM;

        if (!tomoyo_correct_path(original_name) ||
            !tomoyo_correct_path(aggregated_name))
                return -EINVAL;
        e.original_name = tomoyo_get_name(original_name);
        e.aggregated_name = tomoyo_get_name(aggregated_name);
        if (!e.original_name || !e.aggregated_name ||
            e.aggregated_name->is_patterned) /* No patterns allowed. */
                goto out;
        error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
                                     &tomoyo_policy_list[TOMOYO_ID_AGGREGATOR],
                                     tomoyo_same_aggregator);
 out:
        tomoyo_put_name(e.original_name);
        tomoyo_put_name(e.aggregated_name);
        return error;
}

/**
 * tomoyo_write_aggregator - Write "struct tomoyo_aggregator" list.
 *
 * @data:      String to parse.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_write_aggregator(char *data, const bool is_delete)
{
        char *cp = strchr(data, ' ');

        if (!cp)
                return -EINVAL;
        *cp++ = '\0';
        return tomoyo_update_aggregator_entry(data, cp, is_delete);
}

/**
 * tomoyo_assign_domain - Create a domain.
 *
 * @domainname: The name of domain.
 * @profile:    Profile number to assign if the domain was newly created.
 *
 * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
                                                const u8 profile)
{
        struct tomoyo_domain_info *entry;
        struct tomoyo_domain_info *domain = NULL;
        const struct tomoyo_path_info *saved_domainname;
        bool found = false;

        if (!tomoyo_correct_domain(domainname))
                return NULL;
        saved_domainname = tomoyo_get_name(domainname);
        if (!saved_domainname)
                return NULL;
        entry = kzalloc(sizeof(*entry), GFP_NOFS);
        if (mutex_lock_interruptible(&tomoyo_policy_lock))
                goto out;
        list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
                if (domain->is_deleted ||
                    tomoyo_pathcmp(saved_domainname, domain->domainname))
                        continue;
                found = true;
                break;
        }
        if (!found && tomoyo_memory_ok(entry)) {
                INIT_LIST_HEAD(&entry->acl_info_list);
                entry->domainname = saved_domainname;
                saved_domainname = NULL;
                entry->profile = profile;
                list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
                domain = entry;
                entry = NULL;
                found = true;
        }
        mutex_unlock(&tomoyo_policy_lock);
 out:
        tomoyo_put_name(saved_domainname);
        kfree(entry);
        return found ? domain : NULL;
}

/**
 * tomoyo_find_next_domain - Find a domain.
 *
 * @bprm: Pointer to "struct linux_binprm".
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_find_next_domain(struct linux_binprm *bprm)
{
        struct tomoyo_request_info r;
        char *tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
        struct tomoyo_domain_info *old_domain = tomoyo_domain();
        struct tomoyo_domain_info *domain = NULL;
        const char *original_name = bprm->filename;
        u8 mode;
        bool is_enforce;
        int retval = -ENOMEM;
        bool need_kfree = false;
        struct tomoyo_path_info rn = { }; /* real name */

        mode = tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE);
        is_enforce = (mode == TOMOYO_CONFIG_ENFORCING);
        if (!tmp)
                goto out;

 retry:
        if (need_kfree) {
                kfree(rn.name);
                need_kfree = false;
        }
        /* Get symlink's pathname of program. */
        retval = -ENOENT;
        rn.name = tomoyo_realpath_nofollow(original_name);
        if (!rn.name)
                goto out;
        tomoyo_fill_path_info(&rn);
        need_kfree = true;

        /* Check 'aggregator' directive. */
        {
                struct tomoyo_aggregator *ptr;
                list_for_each_entry_rcu(ptr, &tomoyo_policy_list
                                        [TOMOYO_ID_AGGREGATOR], head.list) {
                        if (ptr->head.is_deleted ||
                            !tomoyo_path_matches_pattern(&rn,
                                                         ptr->original_name))
                                continue;
                        kfree(rn.name);
                        need_kfree = false;
                        /* This is OK because it is read only. */
                        rn = *ptr->aggregated_name;
                        break;
                }
        }

        /* Check execute permission. */
        retval = tomoyo_path_permission(&r, TOMOYO_TYPE_EXECUTE, &rn);
        if (retval == TOMOYO_RETRY_REQUEST)
                goto retry;
        if (retval < 0)
                goto out;
        /*
         * To be able to specify domainnames with wildcards, use the
         * pathname specified in the policy (which may contain
         * wildcard) rather than the pathname passed to execve()
         * (which never contains wildcard).
         */
        if (r.param.path.matched_path) {
                if (need_kfree)
                        kfree(rn.name);
                need_kfree = false;
                /* This is OK because it is read only. */
                rn = *r.param.path.matched_path;
        }

        /* Calculate domain to transit to. */
        switch (tomoyo_transition_type(old_domain->domainname, &rn)) {
        case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
                /* Transit to the child of tomoyo_kernel_domain domain. */
                snprintf(tmp, TOMOYO_EXEC_TMPSIZE - 1, TOMOYO_ROOT_NAME " "
                         "%s", rn.name);
                break;
        case TOMOYO_TRANSITION_CONTROL_KEEP:
                /* Keep current domain. */
                domain = old_domain;
                break;
        default:
                if (old_domain == &tomoyo_kernel_domain &&
                    !tomoyo_policy_loaded) {
                        /*
                         * Needn't to transit from kernel domain before
                         * starting /sbin/init. But transit from kernel domain
                         * if executing initializers because they might start
                         * before /sbin/init.
                         */
                        domain = old_domain;
                } else {
                        /* Normal domain transition. */
                        snprintf(tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
                                 old_domain->domainname->name, rn.name);
                }
                break;
        }
        if (domain || strlen(tmp) >= TOMOYO_EXEC_TMPSIZE - 10)
                goto done;
        domain = tomoyo_find_domain(tmp);
        if (domain)
                goto done;
        if (is_enforce) {
                int error = tomoyo_supervisor(&r, "# wants to create domain\n"
                                              "%s\n", tmp);
                if (error == TOMOYO_RETRY_REQUEST)
                        goto retry;
                if (error < 0)
                        goto done;
        }
        domain = tomoyo_assign_domain(tmp, old_domain->profile);
 done:
        if (domain)
                goto out;
        printk(KERN_WARNING "TOMOYO-ERROR: Domain '%s' not defined.\n", tmp);
        if (is_enforce)
                retval = -EPERM;
        else
                old_domain->transition_failed = true;
 out:
        if (!domain)
                domain = old_domain;
        /* Update reference count on "struct tomoyo_domain_info". */
        atomic_inc(&domain->users);
        bprm->cred->security = domain;
        if (need_kfree)
                kfree(rn.name);
        kfree(tmp);
        return retval;
}