// SPDX-License-Identifier: GPL-2.0
/*
 * security/tomoyo/environ.c
 *
 * Copyright (C) 2005-2011  NTT DATA CORPORATION
 */

#include "common.h"

/**
 * tomoyo_check_env_acl - Check permission for environment variable's name.
 *
 * @r:   Pointer to "struct tomoyo_request_info".
 * @ptr: Pointer to "struct tomoyo_acl_info".
 *
 * Returns true if granted, false otherwise.
 */
static bool tomoyo_check_env_acl(struct tomoyo_request_info *r,
                                 const struct tomoyo_acl_info *ptr)
{
        const struct tomoyo_env_acl *acl =
                container_of(ptr, typeof(*acl), head);

        return tomoyo_path_matches_pattern(r->param.environ.name, acl->env);
}

/**
 * tomoyo_audit_env_log - Audit environment variable name log.
 *
 * @r: Pointer to "struct tomoyo_request_info".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_audit_env_log(struct tomoyo_request_info *r)
        __must_hold_shared(&tomoyo_ss)
{
        return tomoyo_supervisor(r, "misc env %s\n",
                                 r->param.environ.name->name);
}

/**
 * tomoyo_env_perm - Check permission for environment variable's name.
 *
 * @r:   Pointer to "struct tomoyo_request_info".
 * @env: The name of environment variable.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_env_perm(struct tomoyo_request_info *r, const char *env)
{
        struct tomoyo_path_info environ;
        int error;

        if (!env || !*env)
                return 0;
        environ.name = env;
        tomoyo_fill_path_info(&environ);
        r->param_type = TOMOYO_TYPE_ENV_ACL;
        r->param.environ.name = &environ;
        do {
                tomoyo_check_acl(r, tomoyo_check_env_acl);
                error = tomoyo_audit_env_log(r);
        } while (error == TOMOYO_RETRY_REQUEST);
        return error;
}

/**
 * tomoyo_same_env_acl - Check for duplicated "struct tomoyo_env_acl" entry.
 *
 * @a: Pointer to "struct tomoyo_acl_info".
 * @b: Pointer to "struct tomoyo_acl_info".
 *
 * Returns true if @a == @b, false otherwise.
 */
static bool tomoyo_same_env_acl(const struct tomoyo_acl_info *a,
                                const struct tomoyo_acl_info *b)
{
        const struct tomoyo_env_acl *p1 = container_of(a, typeof(*p1), head);
        const struct tomoyo_env_acl *p2 = container_of(b, typeof(*p2), head);

        return p1->env == p2->env;
}

/**
 * tomoyo_write_env - Write "struct tomoyo_env_acl" list.
 *
 * @param: Pointer to "struct tomoyo_acl_param".
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_write_env(struct tomoyo_acl_param *param)
{
        struct tomoyo_env_acl e = { .head.type = TOMOYO_TYPE_ENV_ACL };
        int error = -ENOMEM;
        const char *data = tomoyo_read_token(param);

        if (!tomoyo_correct_word(data) || strchr(data, '='))
                return -EINVAL;
        e.env = tomoyo_get_name(data);
        if (!e.env)
                return error;
        error = tomoyo_update_domain(&e.head, sizeof(e), param,
                                  tomoyo_same_env_acl, NULL);
        tomoyo_put_name(e.env);
        return error;
}

/**
 * tomoyo_write_misc - Update environment variable list.
 *
 * @param: Pointer to "struct tomoyo_acl_param".
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_write_misc(struct tomoyo_acl_param *param)
{
        if (tomoyo_str_starts(&param->data, "env "))
                return tomoyo_write_env(param);
        return -EINVAL;
}