Blob Blame Raw
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