[RFC PATCH v11 01/19] security: add ipe lsm

Fan Wu
2023-10-04T22:09:54Z

From: Deven Bowers <deven.desai@linux.microsoft.com>

Integrity Policy Enforcement (IPE) is an LSM that provides an
complimentary approach to Mandatory Access Control than existing LSMs
today.

Existing LSMs have centered around the concept of access to a resource
should be controlled by the current user's credentials. IPE's approach,
is that access to a resource should be controlled by the system's trust
of a current resource.

The basis of this approach is defining a global policy to specify which
resource can be trusted.

Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
---
v2:
+ Split evaluation loop, access control hooks,
and evaluation loop from policy parser and userspace
interface to pass mailing list character limit

v3:
+ Move ipe_load_properties to patch 04.
+ Remove useless 0-initializations
+ Prefix extern variables with ipe_
+ Remove kernel module parameters, as these are
exposed through sysctls.
+ Add more prose to the IPE base config option
help text.
+ Use GFP_KERNEL for audit_log_start.
+ Remove unnecessary caching system.
+ Remove comments from headers
+ Use rcu_access_pointer for rcu-pointer null check
+ Remove usage of reqprot; use prot only.
+ Move policy load and activation audit event to 03/12

v4:
+ Remove sysctls in favor of securityfs nodes
+ Re-add kernel module parameters, as these are now
exposed through securityfs.
+ Refactor property audit loop to a separate function.

v5:
+ fix minor grammatical errors
+ do not group rule by curly-brace in audit record,
reconstruct the exact rule.

v6:
+ No changes

v7:
+ Further split lsm creation into a separate commit from the
evaluation loop and audit system, for easier review.

+ Introduce the concept of an ipe_context, a scoped way to
introduce execution policies, used initially for allowing for
kunit tests in isolation.

v8:
+ Follow lsmname_hook_name convention for lsm hooks.
+ Move LSM blob accessors to ipe.c and mark LSM blobs as static.

v9:
+ Remove ipe_context for simplification

v10:
+ Add github url

v11:
+ Correct github url
+ Move ipe before bpf
---
MAINTAINERS | 7 +++++++
security/Kconfig | 11 ++++++-----
security/Makefile | 1 +
security/ipe/Kconfig | 17 +++++++++++++++++
security/ipe/Makefile | 9 +++++++++
security/ipe/ipe.c | 35 +++++++++++++++++++++++++++++++++++
security/ipe/ipe.h | 16 ++++++++++++++++
7 files changed, 91 insertions(+), 5 deletions(-)
create mode 100644 security/ipe/Kconfig
create mode 100644 security/ipe/Makefile
create mode 100644 security/ipe/ipe.c
create mode 100644 security/ipe/ipe.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 35977b269d5e..b898f2f8f9c4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10389,6 +10389,13 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git
F: security/integrity/
F: security/integrity/ima/

+INTEGRITY POLICY ENFORCEMENT (IPE)
+M: Fan Wu <wufan@linux.microsoft.com>
+L: linux-security-module@vger.kernel.org
+S: Supported
+T: git https://github.com/microsoft/ipe.git
+F: security/ipe/
+
INTEL 810/815 FRAMEBUFFER DRIVER
M: Antonino Daplas <adaplas@gmail.com>
L: linux-fbdev@vger.kernel.org
diff --git a/security/Kconfig b/security/Kconfig
index 52c9af08ad35..cc7adfbb6b96 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -194,6 +194,7 @@ source "security/yama/Kconfig"
source "security/safesetid/Kconfig"
source "security/lockdown/Kconfig"
source "security/landlock/Kconfig"
+source "security/ipe/Kconfig"

source "security/integrity/Kconfig"

@@ -233,11 +234,11 @@ endchoice

config LSM
string "Ordered list of enabled LSMs"
- default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
- default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
- default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
- default "landlock,lockdown,yama,loadpin,safesetid,bpf" if DEFAULT_SECURITY_DAC
- default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,bpf"
+ default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,ipe,bpf" if DEFAULT_SECURITY_SMACK
+ default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,ipe,bpf" if DEFAULT_SECURITY_APPARMOR
+ default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,ipe,bpf" if DEFAULT_SECURITY_TOMOYO
+ default "landlock,lockdown,yama,loadpin,safesetid,ipe,bpf" if DEFAULT_SECURITY_DAC
+ default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,ipe,bpf"
help
A comma-separated list of LSMs, in initialization order.
Any LSMs left off this list, except for those with order
diff --git a/security/Makefile b/security/Makefile
index 18121f8f85cd..527b1864d96c 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown/
obj-$(CONFIG_CGROUPS) += device_cgroup.o
obj-$(CONFIG_BPF_LSM) += bpf/
obj-$(CONFIG_SECURITY_LANDLOCK) += landlock/
+obj-$(CONFIG_SECURITY_IPE) += ipe/

# Object integrity file lists
obj-$(CONFIG_INTEGRITY) += integrity/
diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig
new file mode 100644
index 000000000000..e4875fb04883
--- /dev/null
+++ b/security/ipe/Kconfig
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Integrity Policy Enforcement (IPE) configuration
+#
+
+menuconfig SECURITY_IPE
+ bool "Integrity Policy Enforcement (IPE)"
+ depends on SECURITY && SECURITYFS
+ select PKCS7_MESSAGE_PARSER
+ select SYSTEM_DATA_VERIFICATION
+ help
+ This option enables the Integrity Policy Enforcement LSM
+ allowing users to define a policy to enforce a trust-based access
+ control. A key feature of IPE is a customizable policy to allow
+ admins to reconfigure trust requirements on the fly.
+
+ If unsure, answer N.
diff --git a/security/ipe/Makefile b/security/ipe/Makefile
new file mode 100644
index 000000000000..f7a80d0f18f8
--- /dev/null
+++ b/security/ipe/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) Microsoft Corporation. All rights reserved.
+#
+# Makefile for building the IPE module as part of the kernel tree.
+#
+
+obj-$(CONFIG_SECURITY_IPE) += \
+ ipe.o \
diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c
new file mode 100644
index 000000000000..ba5526f9d527
--- /dev/null
+++ b/security/ipe/ipe.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ */
+
+#include "ipe.h"
+
+static struct lsm_blob_sizes ipe_blobs __ro_after_init = {
+};
+
+static struct security_hook_list ipe_hooks[] __ro_after_init = {
+};
+
+/**
+ * ipe_init - Entry point of IPE.
+ *
+ * This is called at LSM init, which happens occurs early during kernel
+ * start up. During this phase, IPE registers its hooks and loads the
+ * builtin boot policy.
+ * Return:
+ * * 0 - OK
+ * * -ENOMEM - Out of memory
+ */
+static int __init ipe_init(void)
+{
+ security_add_hooks(ipe_hooks, ARRAY_SIZE(ipe_hooks), "ipe");
+
+ return 0;
+}
+
+DEFINE_LSM(ipe) = {
+ .name = "ipe",
+ .init = ipe_init,
+ .blobs = &ipe_blobs,
+};
diff --git a/security/ipe/ipe.h b/security/ipe/ipe.h
new file mode 100644
index 000000000000..a1c68d0fc2e0
--- /dev/null
+++ b/security/ipe/ipe.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ */
+
+#ifndef _IPE_H
+#define _IPE_H
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+#define pr_fmt(fmt) "IPE: " fmt
+
+#include <linux/lsm_hooks.h>
+
+#endif /* _IPE_H */
--
2.25.1