[PATCH v1 2/8] LSM: Add an LSM identifier for external use

Casey Schaufler
2022-10-25T18:46:01Z

Add an integer member "id" to the struct lsm_id. This value is
a unique identifier associated with each security module. The
values are defined in a new UAPI header file. Each existing LSM
has been updated to include it's LSMID in the lsm_id.

The LSM ID values are sequential, with the oldest module
LSM_ID_CAPABILITY being the lowest value and the existing
modules numbered in the order they were included in the
main line kernel. The first 32 values (0 - 31) are reserved
for some as yet unknown but important use.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
include/linux/lsm_hooks.h | 1 +
include/uapi/linux/lsm.h | 32 ++++++++++++++++++++++++++++++++
security/apparmor/lsm.c | 2 ++
security/bpf/hooks.c | 2 ++
security/commoncap.c | 2 ++
security/landlock/setup.c | 2 ++
security/loadpin/loadpin.c | 2 ++
security/lockdown/lockdown.c | 2 ++
security/safesetid/lsm.c | 2 ++
security/selinux/hooks.c | 2 ++
security/smack/smack_lsm.c | 2 ++
security/tomoyo/tomoyo.c | 2 ++
security/yama/yama_lsm.c | 2 ++
13 files changed, 55 insertions(+)
create mode 100644 include/uapi/linux/lsm.h

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index e383e468f742..dd4b4d95a172 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1607,6 +1607,7 @@ struct security_hook_heads {
*/
struct lsm_id {
const char *lsm; /* Name of the LSM */
+ int id; /* LSM ID */
};

/*
diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
new file mode 100644
index 000000000000..d5bcbb9375df
--- /dev/null
+++ b/include/uapi/linux/lsm.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Linus Security Modules (LSM) - User space API
+ *
+ * Copyright (C) 2022 Casey Schaufler <casey@schaufler-ca.com>
+ * Copyright (C) Intel Corporation
+ */
+
+#ifndef _UAPI_LINUX_LSM_H
+#define _UAPI_LINUX_LSM_H
+
+/*
+ * ID values to identify security modules.
+ * A system may use more than one security module.
+ *
+ * LSM_ID_XXX values 0 - 31 are reserved for future use
+ */
+#define LSM_ID_INVALID -1
+#define LSM_ID_CAPABILITY 32
+#define LSM_ID_SELINUX 33
+#define LSM_ID_SMACK 34
+#define LSM_ID_TOMOYO 35
+#define LSM_ID_IMA 36
+#define LSM_ID_APPARMOR 37
+#define LSM_ID_YAMA 38
+#define LSM_ID_LOADPIN 39
+#define LSM_ID_SAFESETID 40
+#define LSM_ID_LOCKDOWN 41
+#define LSM_ID_BPF 42
+#define LSM_ID_LANDLOCK 43
+
+#endif /* _UAPI_LINUX_LSM_H */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index e708c1ad7267..b859b1af6c75 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -24,6 +24,7 @@
#include <linux/zlib.h>
#include <net/sock.h>
#include <uapi/linux/mount.h>
+#include <uapi/linux/lsm.h>

#include "include/apparmor.h"
#include "include/apparmorfs.h"
@@ -1204,6 +1205,7 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {

static struct lsm_id apparmor_lsmid __lsm_ro_after_init = {
.lsm = "apparmor",
+ .id = LSM_ID_APPARMOR,
};

static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c
index ef9b1d983665..20983ae8d31f 100644
--- a/security/bpf/hooks.c
+++ b/security/bpf/hooks.c
@@ -5,6 +5,7 @@
*/
#include <linux/lsm_hooks.h>
#include <linux/bpf_lsm.h>
+#include <uapi/linux/lsm.h>

static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
@@ -21,6 +22,7 @@ static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
*/
struct lsm_id bpf_lsmid __lsm_ro_after_init = {
.lsm = "bpf",
+ .id = LSM_ID_BPF,
};

static int __init bpf_lsm_init(void)
diff --git a/security/commoncap.c b/security/commoncap.c
index 986920da0c26..940e36d8503d 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -25,6 +25,7 @@
#include <linux/binfmts.h>
#include <linux/personality.h>
#include <linux/mnt_idmapping.h>
+#include <uapi/linux/lsm.h>

/*
* If a non-root user executes a setuid-root binary in
@@ -1448,6 +1449,7 @@ int cap_mmap_file(struct file *file, unsigned long reqprot,

static struct lsm_id capability_lsmid __lsm_ro_after_init = {
.lsm = "capability",
+ .id = LSM_ID_CAPABILITY,
};

static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
diff --git a/security/landlock/setup.c b/security/landlock/setup.c
index 4a12666a4090..5b32c087e34b 100644
--- a/security/landlock/setup.c
+++ b/security/landlock/setup.c
@@ -8,6 +8,7 @@

#include <linux/init.h>
#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>

#include "common.h"
#include "cred.h"
@@ -25,6 +26,7 @@ struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {

struct lsm_id landlock_lsmid __lsm_ro_after_init = {
.lsm = LANDLOCK_NAME,
+ .id = LSM_ID_LANDLOCK,
};

static int __init landlock_init(void)
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 24d041a888b8..32bdf7294a6f 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -20,6 +20,7 @@
#include <linux/string_helpers.h>
#include <linux/dm-verity-loadpin.h>
#include <uapi/linux/loadpin.h>
+#include <uapi/linux/lsm.h>

#define VERITY_DIGEST_FILE_HEADER "# LOADPIN_TRUSTED_VERITY_ROOT_DIGESTS"

@@ -199,6 +200,7 @@ static int loadpin_load_data(enum kernel_load_data_id id, bool contents)

static struct lsm_id loadpin_lsmid __lsm_ro_after_init = {
.lsm = "loadpin",
+ .id = LSM_ID_LOADPIN,
};

static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index 2004d67f7201..e8c41a0caf7d 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -13,6 +13,7 @@
#include <linux/security.h>
#include <linux/export.h>
#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>

static enum lockdown_reason kernel_locked_down;

@@ -77,6 +78,7 @@ static struct security_hook_list lockdown_hooks[] __lsm_ro_after_init = {

static struct lsm_id lockdown_lsmid __lsm_ro_after_init = {
.lsm = "lockdown",
+ .id = LSM_ID_LOCKDOWN,
};

static int __init lockdown_lsm_init(void)
diff --git a/security/safesetid/lsm.c b/security/safesetid/lsm.c
index d9af1d04d293..8d0742ba045d 100644
--- a/security/safesetid/lsm.c
+++ b/security/safesetid/lsm.c
@@ -19,6 +19,7 @@
#include <linux/ptrace.h>
#include <linux/sched/task_stack.h>
#include <linux/security.h>
+#include <uapi/linux/lsm.h>
#include "lsm.h"

/* Flag indicating whether initialization completed */
@@ -263,6 +264,7 @@ static int safesetid_task_fix_setgroups(struct cred *new, const struct cred *old

static struct lsm_id safesetid_lsmid __lsm_ro_after_init = {
.lsm = "safesetid",
+ .id = LSM_ID_SAFESETID,
};

static struct security_hook_list safesetid_security_hooks[] = {
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index aee20bb1778d..5fcce36267bd 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -92,6 +92,7 @@
#include <linux/fsnotify.h>
#include <linux/fanotify.h>
#include <linux/io_uring.h>
+#include <uapi/linux/lsm.h>

#include "avc.h"
#include "objsec.h"
@@ -7016,6 +7017,7 @@ static int selinux_uring_cmd(struct io_uring_cmd *ioucmd)

static struct lsm_id selinux_lsmid __lsm_ro_after_init = {
.lsm = "selinux",
+ .id = LSM_ID_SELINUX,
};

/*
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 0c0fea933bbd..c7ba80e20b8d 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -43,6 +43,7 @@
#include <linux/fs_parser.h>
#include <linux/watch_queue.h>
#include <linux/io_uring.h>
+#include <uapi/linux/lsm.h>
#include "smack.h"

#define TRANS_TRUE "TRUE"
@@ -4789,6 +4790,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {

static struct lsm_id smack_lsmid __lsm_ro_after_init = {
.lsm = "smack",
+ .id = LSM_ID_SMACK,
};

static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index 80fbab5d2d7e..1916eb6216f7 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -6,6 +6,7 @@
*/

#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>
#include "common.h"

/**
@@ -532,6 +533,7 @@ static void tomoyo_task_free(struct task_struct *task)

static struct lsm_id tomoyo_lsmid __lsm_ro_after_init = {
.lsm = "tomoyo",
+ .id = LSM_ID_TOMOYO,
};

/*
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index 4f60158850a7..2487b8f847f3 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -18,6 +18,7 @@
#include <linux/task_work.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
+#include <uapi/linux/lsm.h>

#define YAMA_SCOPE_DISABLED 0
#define YAMA_SCOPE_RELATIONAL 1
@@ -423,6 +424,7 @@ static int yama_ptrace_traceme(struct task_struct *parent)

static struct lsm_id yama_lsmid __lsm_ro_after_init = {
.lsm = "yama",
+ .id = LSM_ID_YAMA,
};

static struct security_hook_list yama_hooks[] __lsm_ro_after_init = {
--
2.37.3