src/kernel/linux/v4.19/security/tomoyo/environ.c

// 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)
{
	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;
}