From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Jeremy Cline <jcline@redhat.com>

Date: Mon, 30 Sep 2019 21:22:47 +0000

Subject: [PATCH] security: lockdown: expose a hook to lock the kernel down

In order to automatically lock down kernels running on UEFI machines

booted in Secure Boot mode, expose the lock_kernel_down() hook.

Upstream Status: RHEL only

Signed-off-by: Jeremy Cline <jcline@redhat.com>

---

 include/linux/lsm_hook_defs.h | 2 ++

 include/linux/lsm_hooks.h     | 6 ++++++

 include/linux/security.h      | 5 +++++

 security/lockdown/lockdown.c  | 1 +

 security/security.c           | 6 ++++++

 5 files changed, 20 insertions(+)

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h

index 2a8c74d99015..0d3129588b78 100644

--- a/include/linux/lsm_hook_defs.h

+++ b/include/linux/lsm_hook_defs.h

@@ -383,6 +383,8 @@ LSM_HOOK(void, LSM_RET_VOID, bpf_prog_free_security, struct bpf_prog_aux *aux)

 #endif /* CONFIG_BPF_SYSCALL */

 LSM_HOOK(int, 0, locked_down, enum lockdown_reason what)

+LSM_HOOK(int, 0, lock_kernel_down, const char *where, enum lockdown_reason level)

+

 #ifdef CONFIG_PERF_EVENTS

 LSM_HOOK(int, 0, perf_event_open, struct perf_event_attr *attr, int type)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h

index 9e2e3e63719d..317660f68b4f 100644

--- a/include/linux/lsm_hooks.h

+++ b/include/linux/lsm_hooks.h

@@ -1507,6 +1507,12 @@

  *

  *     @what: kernel feature being accessed

  *

+ * @lock_kernel_down

+ * 	Put the kernel into lock-down mode.

+ *

+ * 	@where: Where the lock-down is originating from (e.g. command line option)

+ * 	@level: The lock-down level (can only increase)

+ *

  * Security hooks for perf events

  *

  * @perf_event_open:

diff --git a/include/linux/security.h b/include/linux/security.h

index 0a0a03b36a3b..26869f44416b 100644

--- a/include/linux/security.h

+++ b/include/linux/security.h

@@ -451,6 +451,7 @@ int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);

 int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);

 int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);

 int security_locked_down(enum lockdown_reason what);

+int security_lock_kernel_down(const char *where, enum lockdown_reason level);

 #else /* CONFIG_SECURITY */

 static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)

@@ -1291,6 +1292,10 @@ static inline int security_locked_down(enum lockdown_reason what)

 {

 	return 0;

 }

+static inline int security_lock_kernel_down(const char *where, enum lockdown_reason level)

+{

+	return 0;

+}

 #endif	/* CONFIG_SECURITY */

 #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)

diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c

index 87cbdc64d272..18555cf18da7 100644

--- a/security/lockdown/lockdown.c

+++ b/security/lockdown/lockdown.c

@@ -73,6 +73,7 @@ static int lockdown_is_locked_down(enum lockdown_reason what)

 static struct security_hook_list lockdown_hooks[] __lsm_ro_after_init = {

 	LSM_HOOK_INIT(locked_down, lockdown_is_locked_down),

+	LSM_HOOK_INIT(lock_kernel_down, lock_kernel_down),

 };

 static int __init lockdown_lsm_init(void)

diff --git a/security/security.c b/security/security.c

index 70a7ad357bc6..23e16e773bc2 100644

--- a/security/security.c

+++ b/security/security.c

@@ -2516,6 +2516,12 @@ int security_locked_down(enum lockdown_reason what)

 }

 EXPORT_SYMBOL(security_locked_down);

+int security_lock_kernel_down(const char *where, enum lockdown_reason level)

+{

+	return call_int_hook(lock_kernel_down, 0, where, level);

+}

+EXPORT_SYMBOL(security_lock_kernel_down);

+

 #ifdef CONFIG_PERF_EVENTS

 int security_perf_event_open(struct perf_event_attr *attr, int type)

 {

-- 

2.28.0