[PATCH] LSM: allow an LSM to disable all hooks at once

Stephen Smalley sds at tycho.nsa.gov
Wed Dec 11 14:29:10 UTC 2019


On 12/11/19 9:08 AM, Ondrej Mosnacek wrote:
> Instead of deleting the hooks from each list one-by-one (which creates
> some bad race conditions), allow an LSM to provide a reference to its
> "enabled" variable and check this variable before calling the hook.
> 
> As a nice side effect, this allows marking the hooks (and other stuff)
> __ro_after_init unconditionally. Since SECURITY_WRITABLE_HOOKS no longer
> makes sense, remove it and instead use SECURITY_SELINUX_DISABLE directly
> for turning on the runtime disable functionality, to emphasize that this
> is only used by SELinux and is meant to be removed in the future.

Is this fundamentally different/better than adding if (!selinux_enabled) 
return 0; to the beginning of every SELinux hook function?  And as I 
noted to Casey in the earlier thread, that provides an additional easy 
target to kernel exploit writers for neutering SELinux with a single 
kernel write vulnerability. OTOH, they already have 
selinux_state.enforcing and friends, and this new one would only be if 
SECURITY_SELINUX_DISABLE=y.

> 
> Fixes: b1d9e6b0646d ("LSM: Switch to lists of hooks")
> Signed-off-by: Ondrej Mosnacek <omosnace at redhat.com>
> ---
> 
> This is an alternative to [1]. It turned out to be less simple than I
> had hoped, but OTOH the hook arrays can now be unconditionally made
> __ro_after_init so may be still worth it.
> 
> Compile- and boot- tested with SECURITY_SELINUX_DISABLE set to =y and
> =n; SELinux enabled. Changes to other LSMs only compile-tested (but
> those are trivial).
> 
> [1] https://lore.kernel.org/selinux/20191209075756.123157-1-omosnace@redhat.com/T/
> 
>   include/linux/lsm_hooks.h    | 46 +++++++++----------------------
>   security/Kconfig             |  5 ----
>   security/apparmor/lsm.c      | 14 ++++++----
>   security/commoncap.c         | 11 +++++---
>   security/loadpin/loadpin.c   | 10 +++++--
>   security/lockdown/lockdown.c | 11 +++++---
>   security/safesetid/lsm.c     |  9 +++++--
>   security/security.c          | 52 +++++++++++++++++++++---------------
>   security/selinux/Kconfig     |  5 ++--
>   security/selinux/hooks.c     | 28 ++++++++++++++-----
>   security/smack/smack_lsm.c   | 11 +++++---
>   security/tomoyo/tomoyo.c     | 13 ++++++---
>   security/yama/yama_lsm.c     | 10 +++++--
>   13 files changed, 133 insertions(+), 92 deletions(-)
> 
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index 20d8cf194fb7..91b77ebcb822 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -27,7 +27,6 @@
>   
>   #include <linux/security.h>
>   #include <linux/init.h>
> -#include <linux/rculist.h>
>   
>   /**
>    * union security_list_options - Linux Security Module hook function list
> @@ -2086,6 +2085,9 @@ struct security_hook_list {
>   	struct hlist_head		*head;
>   	union security_list_options	hook;
>   	char				*lsm;
> +#ifdef CONFIG_SECURITY_SELINUX_DISABLE
> +	const int			*enabled;
> +#endif
>   } __randomize_layout;
>   
>   /*
> @@ -2112,8 +2114,16 @@ struct lsm_blob_sizes {
>   extern struct security_hook_heads security_hook_heads;
>   extern char *lsm_names;
>   
> -extern void security_add_hooks(struct security_hook_list *hooks, int count,
> -				char *lsm);
> +struct security_hook_array {
> +	struct security_hook_list *hooks;
> +	int count;
> +	char *lsm;
> +#ifdef CONFIG_SECURITY_SELINUX_DISABLE
> +	const int *enabled;
> +#endif
> +};
> +
> +extern void security_add_hook_array(const struct security_hook_array *array);
>   
>   #define LSM_FLAG_LEGACY_MAJOR	BIT(0)
>   #define LSM_FLAG_EXCLUSIVE	BIT(1)
> @@ -2145,36 +2155,6 @@ extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[];
>   		__used __section(.early_lsm_info.init)			\
>   		__aligned(sizeof(unsigned long))
>   
> -#ifdef CONFIG_SECURITY_SELINUX_DISABLE
> -/*
> - * Assuring the safety of deleting a security module is up to
> - * the security module involved. This may entail ordering the
> - * module's hook list in a particular way, refusing to disable
> - * the module once a policy is loaded or any number of other
> - * actions better imagined than described.
> - *
> - * The name of the configuration option reflects the only module
> - * that currently uses the mechanism. Any developer who thinks
> - * disabling their module is a good idea needs to be at least as
> - * careful as the SELinux team.
> - */
> -static inline void security_delete_hooks(struct security_hook_list *hooks,
> -						int count)
> -{
> -	int i;
> -
> -	for (i = 0; i < count; i++)
> -		hlist_del_rcu(&hooks[i].list);
> -}
> -#endif /* CONFIG_SECURITY_SELINUX_DISABLE */
> -
> -/* Currently required to handle SELinux runtime hook disable. */
> -#ifdef CONFIG_SECURITY_WRITABLE_HOOKS
> -#define __lsm_ro_after_init
> -#else
> -#define __lsm_ro_after_init	__ro_after_init
> -#endif /* CONFIG_SECURITY_WRITABLE_HOOKS */
> -
>   extern int lsm_inode_alloc(struct inode *inode);
>   
>   #endif /* ! __LINUX_LSM_HOOKS_H */
> diff --git a/security/Kconfig b/security/Kconfig
> index 2a1a2d396228..456764990a13 100644
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -32,11 +32,6 @@ config SECURITY
>   
>   	  If you are unsure how to answer this question, answer N.
>   
> -config SECURITY_WRITABLE_HOOKS
> -	depends on SECURITY
> -	bool
> -	default n
> -
>   config SECURITYFS
>   	bool "Enable the securityfs filesystem"
>   	help
> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> index b621ad74f54a..a27f48670b37 100644
> --- a/security/apparmor/lsm.c
> +++ b/security/apparmor/lsm.c
> @@ -1158,13 +1158,13 @@ static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb,
>   /*
>    * The cred blob is a pointer to, not an instance of, an aa_task_ctx.
>    */
> -struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
> +struct lsm_blob_sizes apparmor_blob_sizes __ro_after_init = {
>   	.lbs_cred = sizeof(struct aa_task_ctx *),
>   	.lbs_file = sizeof(struct aa_file_ctx),
>   	.lbs_task = sizeof(struct aa_task_ctx),
>   };
>   
> -static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
> +static struct security_hook_list apparmor_hooks[] __ro_after_init = {
>   	LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
>   	LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
>   	LSM_HOOK_INIT(capget, apparmor_capget),
> @@ -1368,7 +1368,7 @@ static const struct kernel_param_ops param_ops_aaintbool = {
>   	.get = param_get_aaintbool
>   };
>   /* Boot time disable flag */
> -static int apparmor_enabled __lsm_ro_after_init = 1;
> +static int apparmor_enabled __ro_after_init = 1;
>   module_param_named(enabled, apparmor_enabled, aaintbool, 0444);
>   
>   static int __init apparmor_enabled_setup(char *str)
> @@ -1829,6 +1829,11 @@ __initcall(apparmor_nf_ip_init);
>   
>   static int __init apparmor_init(void)
>   {
> +	struct security_hook_array hook_array = {
> +		.hooks = apparmor_hooks,
> +		.count = ARRAY_SIZE(apparmor_hooks),
> +		.lsm = "apparmor",
> +	};
>   	int error;
>   
>   	aa_secids_init();
> @@ -1864,8 +1869,7 @@ static int __init apparmor_init(void)
>   		aa_free_root_ns();
>   		goto buffers_out;
>   	}
> -	security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),
> -				"apparmor");
> +	security_add_hook_array(&hook_array);
>   
>   	/* Report that AppArmor successfully initialized */
>   	apparmor_initialized = 1;
> diff --git a/security/commoncap.c b/security/commoncap.c
> index f4ee0ae106b2..6e9f4b6b6b1d 100644
> --- a/security/commoncap.c
> +++ b/security/commoncap.c
> @@ -1339,7 +1339,7 @@ int cap_mmap_file(struct file *file, unsigned long reqprot,
>   
>   #ifdef CONFIG_SECURITY
>   
> -static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
> +static struct security_hook_list capability_hooks[] __ro_after_init = {
>   	LSM_HOOK_INIT(capable, cap_capable),
>   	LSM_HOOK_INIT(settime, cap_settime),
>   	LSM_HOOK_INIT(ptrace_access_check, cap_ptrace_access_check),
> @@ -1362,8 +1362,13 @@ static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
>   
>   static int __init capability_init(void)
>   {
> -	security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks),
> -				"capability");
> +	struct security_hook_array hook_array = {
> +		.hooks = capability_hooks,
> +		.count = ARRAY_SIZE(capability_hooks),
> +		.lsm = "capability",
> +	};
> +
> +	security_add_hook_array(&hook_array);
>   	return 0;
>   }
>   
> diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
> index ee5cb944f4ad..5fadd4969d90 100644
> --- a/security/loadpin/loadpin.c
> +++ b/security/loadpin/loadpin.c
> @@ -180,7 +180,7 @@ static int loadpin_load_data(enum kernel_load_data_id id)
>   	return loadpin_read_file(NULL, (enum kernel_read_file_id) id);
>   }
>   
> -static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
> +static struct security_hook_list loadpin_hooks[] __ro_after_init = {
>   	LSM_HOOK_INIT(sb_free_security, loadpin_sb_free_security),
>   	LSM_HOOK_INIT(kernel_read_file, loadpin_read_file),
>   	LSM_HOOK_INIT(kernel_load_data, loadpin_load_data),
> @@ -224,10 +224,16 @@ static void __init parse_exclude(void)
>   
>   static int __init loadpin_init(void)
>   {
> +	struct security_hook_array hook_array = {
> +		.hooks = loadpin_hooks,
> +		.count = ARRAY_SIZE(loadpin_hooks),
> +		.lsm = "loadpin",
> +	};
> +
>   	pr_info("ready to pin (currently %senforcing)\n",
>   		enforce ? "" : "not ");
>   	parse_exclude();
> -	security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks), "loadpin");
> +	security_add_hook_array(&hook_array);
>   	return 0;
>   }
>   
> diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
> index 5a952617a0eb..bcfa0ff4ee63 100644
> --- a/security/lockdown/lockdown.c
> +++ b/security/lockdown/lockdown.c
> @@ -71,19 +71,24 @@ static int lockdown_is_locked_down(enum lockdown_reason what)
>   	return 0;
>   }
>   
> -static struct security_hook_list lockdown_hooks[] __lsm_ro_after_init = {
> +static struct security_hook_list lockdown_hooks[] __ro_after_init = {
>   	LSM_HOOK_INIT(locked_down, lockdown_is_locked_down),
>   };
>   
>   static int __init lockdown_lsm_init(void)
>   {
> +	struct security_hook_array hook_array = {
> +		.hooks = lockdown_hooks,
> +		.count = ARRAY_SIZE(lockdown_hooks),
> +		.lsm = "lockdown",
> +	};
> +
>   #if defined(CONFIG_LOCK_DOWN_KERNEL_FORCE_INTEGRITY)
>   	lock_kernel_down("Kernel configuration", LOCKDOWN_INTEGRITY_MAX);
>   #elif defined(CONFIG_LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY)
>   	lock_kernel_down("Kernel configuration", LOCKDOWN_CONFIDENTIALITY_MAX);
>   #endif
> -	security_add_hooks(lockdown_hooks, ARRAY_SIZE(lockdown_hooks),
> -			   "lockdown");
> +	security_add_hook_array(&hook_array);
>   	return 0;
>   }
>   
> diff --git a/security/safesetid/lsm.c b/security/safesetid/lsm.c
> index 7760019ad35d..4e36e53f033d 100644
> --- a/security/safesetid/lsm.c
> +++ b/security/safesetid/lsm.c
> @@ -156,8 +156,13 @@ static struct security_hook_list safesetid_security_hooks[] = {
>   
>   static int __init safesetid_security_init(void)
>   {
> -	security_add_hooks(safesetid_security_hooks,
> -			   ARRAY_SIZE(safesetid_security_hooks), "safesetid");
> +	struct security_hook_array hook_array = {
> +		.hooks = safesetid_security_hooks,
> +		.count = ARRAY_SIZE(safesetid_security_hooks),
> +		.lsm = "safesetid",
> +	};
> +
> +	security_add_hook_array(&hook_array);
>   
>   	/* Report that SafeSetID successfully initialized */
>   	safesetid_initialized = 1;
> diff --git a/security/security.c b/security/security.c
> index 2b5473d92416..a5dd348bd37e 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -68,14 +68,14 @@ const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
>   	[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
>   };
>   
> -struct security_hook_heads security_hook_heads __lsm_ro_after_init;
> +struct security_hook_heads security_hook_heads __ro_after_init;
>   static BLOCKING_NOTIFIER_HEAD(blocking_lsm_notifier_chain);
>   
>   static struct kmem_cache *lsm_file_cache;
>   static struct kmem_cache *lsm_inode_cache;
>   
>   char *lsm_names;
> -static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init;
> +static struct lsm_blob_sizes blob_sizes __ro_after_init;
>   
>   /* Boot-time LSM user choice */
>   static __initdata const char *chosen_lsm_order;
> @@ -467,20 +467,20 @@ static int lsm_append(const char *new, char **result)
>   
>   /**
>    * security_add_hooks - Add a modules hooks to the hook lists.
> - * @hooks: the hooks to add
> - * @count: the number of hooks to add
> - * @lsm: the name of the security module
> + * @array: the struct describing hooks to add
>    *
>    * Each LSM has to register its hooks with the infrastructure.
>    */
> -void __init security_add_hooks(struct security_hook_list *hooks, int count,
> -				char *lsm)
> +void __init security_add_hook_array(const struct security_hook_array *array)
>   {
>   	int i;
>   
> -	for (i = 0; i < count; i++) {
> -		hooks[i].lsm = lsm;
> -		hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
> +	for (i = 0; i < array->count; i++) {
> +		array->hooks[i].lsm = array->lsm;
> +#ifdef CONFIG_SECURITY_SELINUX_DISABLE
> +		array->hooks[i].enabled = array->enabled;
> +#endif
> +		hlist_add_tail_rcu(&array->hooks[i].list, array->hooks[i].head);
>   	}
>   
>   	/*
> @@ -488,7 +488,7 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
>   	 * and fix this up afterwards.
>   	 */
>   	if (slab_is_available()) {
> -		if (lsm_append(lsm, &lsm_names) < 0)
> +		if (lsm_append(array->lsm, &lsm_names) < 0)
>   			panic("%s - Cannot get early memory.\n", __func__);
>   	}
>   }
> @@ -679,11 +679,22 @@ static void __init lsm_early_task(struct task_struct *task)
>    *	This is a hook that returns a value.
>    */
>   
> +#define for_each_hook(p, func) \
> +	hlist_for_each_entry(p, &security_hook_heads.func, list)
> +
> +#ifdef CONFIG_SECURITY_SELINUX_DISABLE
> +#define for_each_enabled_hook(p, func) \
> +	for_each_hook(p, func) \
> +		if (!(p)->enabled || READ_ONCE(*(p)->enabled))
> +#else
> +#define for_each_enabled_hook for_each_hook
> +#endif
> +
>   #define call_void_hook(FUNC, ...)				\
>   	do {							\
>   		struct security_hook_list *P;			\
>   								\
> -		hlist_for_each_entry(P, &security_hook_heads.FUNC, list) \
> +		for_each_enabled_hook(P, FUNC)			\
>   			P->hook.FUNC(__VA_ARGS__);		\
>   	} while (0)
>   
> @@ -692,7 +703,7 @@ static void __init lsm_early_task(struct task_struct *task)
>   	do {							\
>   		struct security_hook_list *P;			\
>   								\
> -		hlist_for_each_entry(P, &security_hook_heads.FUNC, list) { \
> +		for_each_enabled_hook(P, FUNC) {		\
>   			RC = P->hook.FUNC(__VA_ARGS__);		\
>   			if (RC != 0)				\
>   				break;				\
> @@ -795,7 +806,7 @@ int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
>   	 * agree that it should be set it will. If any module
>   	 * thinks it should not be set it won't.
>   	 */
> -	hlist_for_each_entry(hp, &security_hook_heads.vm_enough_memory, list) {
> +	for_each_enabled_hook(hp, vm_enough_memory) {
>   		rc = hp->hook.vm_enough_memory(mm, pages);
>   		if (rc <= 0) {
>   			cap_sys_admin = 0;
> @@ -1343,7 +1354,7 @@ int security_inode_getsecurity(struct inode *inode, const char *name, void **buf
>   	/*
>   	 * Only one module will provide an attribute with a given name.
>   	 */
> -	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecurity, list) {
> +	for_each_enabled_hook(hp, inode_getsecurity) {
>   		rc = hp->hook.inode_getsecurity(inode, name, buffer, alloc);
>   		if (rc != -EOPNOTSUPP)
>   			return rc;
> @@ -1361,7 +1372,7 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void
>   	/*
>   	 * Only one module will provide an attribute with a given name.
>   	 */
> -	hlist_for_each_entry(hp, &security_hook_heads.inode_setsecurity, list) {
> +	for_each_enabled_hook(hp, inode_setsecurity) {
>   		rc = hp->hook.inode_setsecurity(inode, name, value, size,
>   								flags);
>   		if (rc != -EOPNOTSUPP)
> @@ -1744,7 +1755,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
>   	int rc = -ENOSYS;
>   	struct security_hook_list *hp;
>   
> -	hlist_for_each_entry(hp, &security_hook_heads.task_prctl, list) {
> +	for_each_enabled_hook(hp, task_prctl) {
>   		thisrc = hp->hook.task_prctl(option, arg2, arg3, arg4, arg5);
>   		if (thisrc != -ENOSYS) {
>   			rc = thisrc;
> @@ -1913,7 +1924,7 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
>   {
>   	struct security_hook_list *hp;
>   
> -	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
> +	for_each_enabled_hook(hp, getprocattr) {
>   		if (lsm != NULL && strcmp(lsm, hp->lsm))
>   			continue;
>   		return hp->hook.getprocattr(p, name, value);
> @@ -1926,7 +1937,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
>   {
>   	struct security_hook_list *hp;
>   
> -	hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
> +	for_each_enabled_hook(hp, setprocattr) {
>   		if (lsm != NULL && strcmp(lsm, hp->lsm))
>   			continue;
>   		return hp->hook.setprocattr(name, value, size);
> @@ -2327,8 +2338,7 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x,
>   	 * For speed optimization, we explicitly break the loop rather than
>   	 * using the macro
>   	 */
> -	hlist_for_each_entry(hp, &security_hook_heads.xfrm_state_pol_flow_match,
> -				list) {
> +	for_each_enabled_hook(hp, xfrm_state_pol_flow_match) {
>   		rc = hp->hook.xfrm_state_pol_flow_match(x, xp, fl);
>   		break;
>   	}
> diff --git a/security/selinux/Kconfig b/security/selinux/Kconfig
> index 996d35d950f7..f64290de1f8a 100644
> --- a/security/selinux/Kconfig
> +++ b/security/selinux/Kconfig
> @@ -26,7 +26,6 @@ config SECURITY_SELINUX_BOOTPARAM
>   config SECURITY_SELINUX_DISABLE
>   	bool "NSA SELinux runtime disable"
>   	depends on SECURITY_SELINUX
> -	select SECURITY_WRITABLE_HOOKS
>   	default n
>   	help
>   	  This option enables writing to a selinuxfs node 'disable', which
> @@ -37,8 +36,8 @@ config SECURITY_SELINUX_DISABLE
>   	  portability across platforms where boot parameters are difficult
>   	  to employ.
>   
> -	  NOTE: selecting this option will disable the '__ro_after_init'
> -	  kernel hardening feature for security hooks.   Please consider
> +	  NOTE: Selecting this option might cause memory leaks and random
> +	  crashes when the runtime disable is used. Please consider
>   	  using the selinux=0 boot parameter instead of enabling this
>   	  option.
>   
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 47626342b6e5..b76acd98dda5 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -123,7 +123,13 @@ __setup("enforcing=", enforcing_setup);
>   #define selinux_enforcing_boot 1
>   #endif
>   
> -int selinux_enabled __lsm_ro_after_init = 1;
> +/* Currently required to handle SELinux runtime hook disable. */
> +#ifdef CONFIG_SECURITY_SELINUX_DISABLE
> +int selinux_enabled = 1;
> +#else
> +int selinux_enabled __ro_after_init = 1;
> +#endif /* CONFIG_SECURITY_SELINUX_DISABLE */
> +
>   #ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
>   static int __init selinux_enabled_setup(char *str)
>   {
> @@ -6827,7 +6833,7 @@ static int selinux_lockdown(enum lockdown_reason what)
>   				    LOCKDOWN__CONFIDENTIALITY, &ad);
>   }
>   
> -struct lsm_blob_sizes selinux_blob_sizes __lsm_ro_after_init = {
> +struct lsm_blob_sizes selinux_blob_sizes __ro_after_init = {
>   	.lbs_cred = sizeof(struct task_security_struct),
>   	.lbs_file = sizeof(struct file_security_struct),
>   	.lbs_inode = sizeof(struct inode_security_struct),
> @@ -6896,7 +6902,7 @@ static int selinux_perf_event_write(struct perf_event *event)
>   }
>   #endif
>   
> -static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
> +static struct security_hook_list selinux_hooks[] __ro_after_init = {
>   	LSM_HOOK_INIT(binder_set_context_mgr, selinux_binder_set_context_mgr),
>   	LSM_HOOK_INIT(binder_transaction, selinux_binder_transaction),
>   	LSM_HOOK_INIT(binder_transfer_binder, selinux_binder_transfer_binder),
> @@ -7145,6 +7151,15 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
>   
>   static __init int selinux_init(void)
>   {
> +	struct security_hook_array hook_array = {
> +		.hooks = selinux_hooks,
> +		.count = ARRAY_SIZE(selinux_hooks),
> +		.lsm = "selinux",
> +#ifdef CONFIG_SECURITY_SELINUX_DISABLE
> +		.enabled = &selinux_enabled,
> +#endif
> +	};
> +
>   	pr_info("SELinux:  Initializing.\n");
>   
>   	memset(&selinux_state, 0, sizeof(selinux_state));
> @@ -7166,7 +7181,7 @@ static __init int selinux_init(void)
>   
>   	hashtab_cache_init();
>   
> -	security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks), "selinux");
> +	security_add_hook_array(&hook_array);
>   
>   	if (avc_add_callback(selinux_netcache_avc_callback, AVC_CALLBACK_RESET))
>   		panic("SELinux: Unable to register AVC netcache callback\n");
> @@ -7319,9 +7334,10 @@ int selinux_disable(struct selinux_state *state)
>   
>   	pr_info("SELinux:  Disabled at runtime.\n");
>   
> -	selinux_enabled = 0;
> +	/* Unregister netfilter hooks. */
> +	selinux_nf_ip_exit();
>   
> -	security_delete_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks));
> +	WRITE_ONCE(selinux_enabled, 0);
>   
>   	/* Try to destroy the avc node cache */
>   	avc_disable();
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index ecea41ce919b..c21dda12bc4b 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -4583,7 +4583,7 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode,
>   	return 0;
>   }
>   
> -struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
> +struct lsm_blob_sizes smack_blob_sizes __ro_after_init = {
>   	.lbs_cred = sizeof(struct task_smack),
>   	.lbs_file = sizeof(struct smack_known *),
>   	.lbs_inode = sizeof(struct inode_smack),
> @@ -4591,7 +4591,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
>   	.lbs_msg_msg = sizeof(struct smack_known *),
>   };
>   
> -static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
> +static struct security_hook_list smack_hooks[] __ro_after_init = {
>   	LSM_HOOK_INIT(ptrace_access_check, smack_ptrace_access_check),
>   	LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
>   	LSM_HOOK_INIT(syslog, smack_syslog),
> @@ -4765,6 +4765,11 @@ static __init void init_smack_known_list(void)
>    */
>   static __init int smack_init(void)
>   {
> +	struct security_hook_array hook_array = {
> +		.hooks = smack_hooks,
> +		.count = ARRAY_SIZE(smack_hooks),
> +		.lsm = "smack",
> +	};
>   	struct cred *cred = (struct cred *) current->cred;
>   	struct task_smack *tsp;
>   
> @@ -4787,7 +4792,7 @@ static __init int smack_init(void)
>   	/*
>   	 * Register with LSM
>   	 */
> -	security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), "smack");
> +	security_add_hook_array(&hook_array);
>   	smack_enabled = 1;
>   
>   	pr_info("Smack:  Initializing.\n");
> diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
> index 716c92ec941a..a4075379246d 100644
> --- a/security/tomoyo/tomoyo.c
> +++ b/security/tomoyo/tomoyo.c
> @@ -486,7 +486,7 @@ static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg,
>   	return tomoyo_socket_sendmsg_permission(sock, msg, size);
>   }
>   
> -struct lsm_blob_sizes tomoyo_blob_sizes __lsm_ro_after_init = {
> +struct lsm_blob_sizes tomoyo_blob_sizes __ro_after_init = {
>   	.lbs_task = sizeof(struct tomoyo_task),
>   };
>   
> @@ -533,7 +533,7 @@ static void tomoyo_task_free(struct task_struct *task)
>    * tomoyo_security_ops is a "struct security_operations" which is used for
>    * registering TOMOYO.
>    */
> -static struct security_hook_list tomoyo_hooks[] __lsm_ro_after_init = {
> +static struct security_hook_list tomoyo_hooks[] __ro_after_init = {
>   	LSM_HOOK_INIT(cred_prepare, tomoyo_cred_prepare),
>   	LSM_HOOK_INIT(bprm_committed_creds, tomoyo_bprm_committed_creds),
>   	LSM_HOOK_INIT(task_alloc, tomoyo_task_alloc),
> @@ -569,7 +569,7 @@ static struct security_hook_list tomoyo_hooks[] __lsm_ro_after_init = {
>   /* Lock for GC. */
>   DEFINE_SRCU(tomoyo_ss);
>   
> -int tomoyo_enabled __lsm_ro_after_init = 1;
> +int tomoyo_enabled __ro_after_init = 1;
>   
>   /**
>    * tomoyo_init - Register TOMOYO Linux as a LSM module.
> @@ -578,10 +578,15 @@ int tomoyo_enabled __lsm_ro_after_init = 1;
>    */
>   static int __init tomoyo_init(void)
>   {
> +	struct security_hook_array hook_array = {
> +		.hooks = tomoyo_hooks,
> +		.count = ARRAY_SIZE(tomoyo_hooks),
> +		.lsm = "tomoyo",
> +	};
>   	struct tomoyo_task *s = tomoyo_task(current);
>   
>   	/* register ourselves with the security framework */
> -	security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks), "tomoyo");
> +	security_add_hook_array(&hook_array);
>   	pr_info("TOMOYO Linux initialized\n");
>   	s->domain_info = &tomoyo_kernel_domain;
>   	atomic_inc(&tomoyo_kernel_domain.users);
> diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
> index 94dc346370b1..ed752f6eafcf 100644
> --- a/security/yama/yama_lsm.c
> +++ b/security/yama/yama_lsm.c
> @@ -421,7 +421,7 @@ static int yama_ptrace_traceme(struct task_struct *parent)
>   	return rc;
>   }
>   
> -static struct security_hook_list yama_hooks[] __lsm_ro_after_init = {
> +static struct security_hook_list yama_hooks[] __ro_after_init = {
>   	LSM_HOOK_INIT(ptrace_access_check, yama_ptrace_access_check),
>   	LSM_HOOK_INIT(ptrace_traceme, yama_ptrace_traceme),
>   	LSM_HOOK_INIT(task_prctl, yama_task_prctl),
> @@ -476,8 +476,14 @@ static inline void yama_init_sysctl(void) { }
>   
>   static int __init yama_init(void)
>   {
> +	struct security_hook_array hook_array = {
> +		.hooks = yama_hooks,
> +		.count = ARRAY_SIZE(yama_hooks),
> +		.lsm = "yama",
> +	};
> +
>   	pr_info("Yama: becoming mindful.\n");
> -	security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks), "yama");
> +	security_add_hook_array(&hook_array);
>   	yama_init_sysctl();
>   	return 0;
>   }
> 



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