linux/security/tomoyo/load_policy.c
Randy Dunlap 39844b7e30 TOMOYO: fix __setup handlers return values
__setup() handlers should return 1 if the parameter is handled.
Returning 0 causes the entire string to be added to init's
environment strings (limited to 32 strings), unnecessarily polluting it.

Using the documented strings "TOMOYO_loader=string1" and
"TOMOYO_trigger=string2" causes an Unknown parameter message:
  Unknown kernel command line parameters
    "BOOT_IMAGE=/boot/bzImage-517rc5 TOMOYO_loader=string1 \
     TOMOYO_trigger=string2", will be passed to user space.

and these strings are added to init's environment string space:
  Run /sbin/init as init process
    with arguments:
     /sbin/init
    with environment:
     HOME=/
     TERM=linux
     BOOT_IMAGE=/boot/bzImage-517rc5
     TOMOYO_loader=string1
     TOMOYO_trigger=string2

With this change, these __setup handlers act as expected,
and init's environment is not polluted with these strings.

Fixes: 0e4ae0e0de ("TOMOYO: Make several options configurable.")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Link: https://lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Cc: James Morris <jmorris@namei.org>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: tomoyo-dev-en@lists.osdn.me
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
2022-02-24 07:45:07 +09:00

111 lines
2.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* security/tomoyo/load_policy.c
*
* Copyright (C) 2005-2011 NTT DATA CORPORATION
*/
#include "common.h"
#ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
/*
* Path to the policy loader. (default = CONFIG_SECURITY_TOMOYO_POLICY_LOADER)
*/
static const char *tomoyo_loader;
/**
* tomoyo_loader_setup - Set policy loader.
*
* @str: Program to use as a policy loader (e.g. /sbin/tomoyo-init ).
*
* Returns 0.
*/
static int __init tomoyo_loader_setup(char *str)
{
tomoyo_loader = str;
return 1;
}
__setup("TOMOYO_loader=", tomoyo_loader_setup);
/**
* tomoyo_policy_loader_exists - Check whether /sbin/tomoyo-init exists.
*
* Returns true if /sbin/tomoyo-init exists, false otherwise.
*/
static bool tomoyo_policy_loader_exists(void)
{
struct path path;
if (!tomoyo_loader)
tomoyo_loader = CONFIG_SECURITY_TOMOYO_POLICY_LOADER;
if (kern_path(tomoyo_loader, LOOKUP_FOLLOW, &path)) {
pr_info("Not activating Mandatory Access Control as %s does not exist.\n",
tomoyo_loader);
return false;
}
path_put(&path);
return true;
}
/*
* Path to the trigger. (default = CONFIG_SECURITY_TOMOYO_ACTIVATION_TRIGGER)
*/
static const char *tomoyo_trigger;
/**
* tomoyo_trigger_setup - Set trigger for activation.
*
* @str: Program to use as an activation trigger (e.g. /sbin/init ).
*
* Returns 0.
*/
static int __init tomoyo_trigger_setup(char *str)
{
tomoyo_trigger = str;
return 1;
}
__setup("TOMOYO_trigger=", tomoyo_trigger_setup);
/**
* tomoyo_load_policy - Run external policy loader to load policy.
*
* @filename: The program about to start.
*
* This function checks whether @filename is /sbin/init , and if so
* invoke /sbin/tomoyo-init and wait for the termination of /sbin/tomoyo-init
* and then continues invocation of /sbin/init.
* /sbin/tomoyo-init reads policy files in /etc/tomoyo/ directory and
* writes to /sys/kernel/security/tomoyo/ interfaces.
*
* Returns nothing.
*/
void tomoyo_load_policy(const char *filename)
{
static bool done;
char *argv[2];
char *envp[3];
if (tomoyo_policy_loaded || done)
return;
if (!tomoyo_trigger)
tomoyo_trigger = CONFIG_SECURITY_TOMOYO_ACTIVATION_TRIGGER;
if (strcmp(filename, tomoyo_trigger))
return;
if (!tomoyo_policy_loader_exists())
return;
done = true;
pr_info("Calling %s to load policy. Please wait.\n", tomoyo_loader);
argv[0] = (char *) tomoyo_loader;
argv[1] = NULL;
envp[0] = "HOME=/";
envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
envp[2] = NULL;
call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
tomoyo_check_profile();
}
#endif