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TOMOYO: Make several options configurable.

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To be able to start using enforcing mode from the early stage of boot sequence,
this patch adds support for activating access control without calling external
policy loader program. This will be useful for systems where operations which
can lead to the hijacking of the boot sequence are needed before loading the
policy. For example, you can activate immediately after loading the fixed part
of policy which will allow only operations needed for mounting a partition
which contains the variant part of policy and verifying (e.g. running GPG
check) and loading the variant part of policy. Since you can start using
enforcing mode from the beginning, you can reduce the possibility of hijacking
the boot sequence.

This patch makes several variables configurable on build time. This patch also
adds TOMOYO_loader= and TOMOYO_trigger= kernel command line option to boot the
same kernel in two different init systems (BSD-style init and systemd).

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Tetsuo Handa 2011-06-26 23:22:59 +09:00 committed by James Morris
parent efe836ab2b
commit 0e4ae0e0de
3 changed files with 117 additions and 23 deletions
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61
security/tomoyo/Kconfig
View File

@ -9,3 +9,64 @@ config SECURITY_TOMOYO
Required userspace tools and further information may be
found at <http://tomoyo.sourceforge.jp/>.
If you are unsure how to answer this question, answer N.
config SECURITY_TOMOYO_MAX_ACCEPT_ENTRY
int "Default maximal count for learning mode"
default 2048
range 0 2147483647
depends on SECURITY_TOMOYO
help
This is the default value for maximal ACL entries
that are automatically appended into policy at "learning mode".
Some programs access thousands of objects, so running
such programs in "learning mode" dulls the system response
and consumes much memory.
This is the safeguard for such programs.
config SECURITY_TOMOYO_MAX_AUDIT_LOG
int "Default maximal count for audit log"
default 1024
range 0 2147483647
depends on SECURITY_TOMOYO
help
This is the default value for maximal entries for
audit logs that the kernel can hold on memory.
You can read the log via /sys/kernel/security/tomoyo/audit.
If you don't need audit logs, you may set this value to 0.
config SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
bool "Activate without calling userspace policy loader."
default n
depends on SECURITY_TOMOYO
---help---
Say Y here if you want to activate access control as soon as built-in
policy was loaded. This option will be useful for systems where
operations which can lead to the hijacking of the boot sequence are
needed before loading the policy. For example, you can activate
immediately after loading the fixed part of policy which will allow
only operations needed for mounting a partition which contains the
variant part of policy and verifying (e.g. running GPG check) and
loading the variant part of policy. Since you can start using
enforcing mode from the beginning, you can reduce the possibility of
hijacking the boot sequence.
config SECURITY_TOMOYO_POLICY_LOADER
string "Location of userspace policy loader"
default "/sbin/tomoyo-init"
depends on SECURITY_TOMOYO
depends on !SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
---help---
This is the default pathname of policy loader which is called before
activation. You can override this setting via TOMOYO_loader= kernel
command line option.
config SECURITY_TOMOYO_ACTIVATION_TRIGGER
string "Trigger for calling userspace policy loader"
default "/sbin/init"
depends on SECURITY_TOMOYO
depends on !SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
---help---
This is the default pathname of activation trigger.
You can override this setting via TOMOYO_trigger= kernel command line
option. For example, if you pass init=/bin/systemd option, you may
want to also pass TOMOYO_trigger=/bin/systemd option.

3
security/tomoyo/common.c
View File

@ -2420,4 +2420,7 @@ void __init tomoyo_load_builtin_policy(void)
}
}
tomoyo_read_unlock(idx);
#ifdef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
tomoyo_check_profile();
#endif
}

76
security/tomoyo/load_policy.c
View File

@ -8,8 +8,27 @@
#include "common.h"
/* path to policy loader */
static const char *tomoyo_loader = "/sbin/tomoyo-init";
#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 0;
}
__setup("TOMOYO_loader=", tomoyo_loader_setup);
/**
* tomoyo_policy_loader_exists - Check whether /sbin/tomoyo-init exists.
@ -18,24 +37,38 @@ static const char *tomoyo_loader = "/sbin/tomoyo-init";
*/
static bool tomoyo_policy_loader_exists(void)
{
/*
* Don't activate MAC if the policy loader doesn't exist.
* If the initrd includes /sbin/init but real-root-dev has not
* mounted on / yet, activating MAC will block the system since
* policies are not loaded yet.
* Thus, let do_execve() call this function every time.
*/
struct path path;
if (!tomoyo_loader)
tomoyo_loader = CONFIG_SECURITY_TOMOYO_POLICY_LOADER;
if (kern_path(tomoyo_loader, LOOKUP_FOLLOW, &path)) {
printk(KERN_INFO "Not activating Mandatory Access Control now "
"since %s doesn't exist.\n", tomoyo_loader);
printk(KERN_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 0;
}
__setup("TOMOYO_trigger=", tomoyo_trigger_setup);
/**
* tomoyo_load_policy - Run external policy loader to load policy.
*
@ -51,24 +84,19 @@ static bool tomoyo_policy_loader_exists(void)
*/
void tomoyo_load_policy(const char *filename)
{
static bool done;
char *argv[2];
char *envp[3];
if (tomoyo_policy_loaded)
if (tomoyo_policy_loaded || done)
return;
/*
* Check filename is /sbin/init or /sbin/tomoyo-start.
* /sbin/tomoyo-start is a dummy filename in case where /sbin/init can't
* be passed.
* You can create /sbin/tomoyo-start by
* "ln -s /bin/true /sbin/tomoyo-start".
*/
if (strcmp(filename, "/sbin/init") &&
strcmp(filename, "/sbin/tomoyo-start"))
if (!tomoyo_trigger)
tomoyo_trigger = CONFIG_SECURITY_TOMOYO_ACTIVATION_TRIGGER;
if (strcmp(filename, tomoyo_trigger))
return;
if (!tomoyo_policy_loader_exists())
return;
done = true;
printk(KERN_INFO "Calling %s to load policy. Please wait.\n",
tomoyo_loader);
argv[0] = (char *) tomoyo_loader;
@ -79,3 +107,5 @@ void tomoyo_load_policy(const char *filename)
call_usermodehelper(argv[0], argv, envp, 1);
tomoyo_check_profile();
}
#endif