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Date:   Sun, 26 Nov 2017 22:16:07 +0000
From:   Sargun Dhillon <sargun@...gun.me>
To:     linux-security-module@...r.kernel.org
Cc:     keescook@...omium.org, igor.stoppa@...wei.com,
        casey@...aufler-ca.com, linux-kernel@...r.kernel.org
Subject: [RFC 1/3] security: Add safe, dynamic (runtime-loadable) hook support

This patch adds dynamic security hooks. These hooks are designed to allow
for safe runtime loading, and unloading. Each dynamic_security_hook is
protected by an SRCU, allowing for arbitrary computation inside of the
callback. Concurrency-control, loading, and unloading is done on a
per-dynamic_security_hook (per-callback) basis.

The primary purpose of this patchset is to facilitate the development of
out-of-tree minor LSMs. The recent developments around stacking LSMs
have results in a great many number of people being interested in
use-case specific minor LSMs, and this opens the door to automatically
generated custom LSMs.

These hooks are only run after all built-in, and major LSMs are run.
The LSMs enabled by this feature must be minor LSMs, but they can poke
at the security blobs, as they should be initialized by the time their
callback happens.

There should be little runtime performance overhead for this feature,
as it's protected behind static_keys, which are disabled by default,
and are only enabled per-hook at runtime, when a module is loaded.

It also uses an enum, as opposed to a set of list_heads for loading,
and unloading hooks. These are a new set of hooks that aren't protected
(currently) by the read-only memory allocator, but the patch is written
in the direction where the memory around the hooks could eventual be
written in a sealable manner.

Signed-off-by: Sargun Dhillon <sargun@...gun.me>
---
 include/linux/lsm_hooks.h | 254 +++++++++++++++++++++++++++++++++++++
 security/Kconfig          |   9 ++
 security/Makefile         |   1 +
 security/dynamic.c        | 316 ++++++++++++++++++++++++++++++++++++++++++++++
 security/dynamic.h        |  24 ++++
 security/security.c       |  66 +++++++++-
 6 files changed, 669 insertions(+), 1 deletion(-)
 create mode 100644 security/dynamic.c
 create mode 100644 security/dynamic.h

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 7161d8e..25f8749 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -28,6 +28,8 @@
 #include <linux/security.h>
 #include <linux/init.h>
 #include <linux/rculist.h>
+#include <linux/percpu_counter.h>
+#include <linux/percpu.h>
 
 /**
  * union security_list_options - Linux Security Module hook function list
@@ -1983,6 +1985,258 @@ extern char *lsm_names;
 extern void security_add_hooks(struct security_hook_list *hooks, int count,
 				char *lsm);
 
+#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
+enum dynamic_security_hook_type {
+	DYNAMIC_SECURITY_HOOK_binder_set_context_mgr,
+	DYNAMIC_SECURITY_HOOK_binder_transaction,
+	DYNAMIC_SECURITY_HOOK_binder_transfer_binder,
+	DYNAMIC_SECURITY_HOOK_binder_transfer_file,
+	DYNAMIC_SECURITY_HOOK_ptrace_access_check,
+	DYNAMIC_SECURITY_HOOK_ptrace_traceme,
+	DYNAMIC_SECURITY_HOOK_capget,
+	DYNAMIC_SECURITY_HOOK_capset,
+	DYNAMIC_SECURITY_HOOK_capable,
+	DYNAMIC_SECURITY_HOOK_quotactl,
+	DYNAMIC_SECURITY_HOOK_quota_on,
+	DYNAMIC_SECURITY_HOOK_syslog,
+	DYNAMIC_SECURITY_HOOK_settime,
+	DYNAMIC_SECURITY_HOOK_vm_enough_memory,
+	DYNAMIC_SECURITY_HOOK_bprm_set_creds,
+	DYNAMIC_SECURITY_HOOK_bprm_check_security,
+	DYNAMIC_SECURITY_HOOK_bprm_committing_creds,
+	DYNAMIC_SECURITY_HOOK_bprm_committed_creds,
+	DYNAMIC_SECURITY_HOOK_sb_alloc_security,
+	DYNAMIC_SECURITY_HOOK_sb_free_security,
+	DYNAMIC_SECURITY_HOOK_sb_copy_data,
+	DYNAMIC_SECURITY_HOOK_sb_remount,
+	DYNAMIC_SECURITY_HOOK_sb_kern_mount,
+	DYNAMIC_SECURITY_HOOK_sb_show_options,
+	DYNAMIC_SECURITY_HOOK_sb_statfs,
+	DYNAMIC_SECURITY_HOOK_sb_mount,
+	DYNAMIC_SECURITY_HOOK_sb_umount,
+	DYNAMIC_SECURITY_HOOK_sb_pivotroot,
+	DYNAMIC_SECURITY_HOOK_sb_set_mnt_opts,
+	DYNAMIC_SECURITY_HOOK_sb_clone_mnt_opts,
+	DYNAMIC_SECURITY_HOOK_sb_parse_opts_str,
+	DYNAMIC_SECURITY_HOOK_dentry_init_security,
+	DYNAMIC_SECURITY_HOOK_dentry_create_files_as,
+#ifdef CONFIG_SECURITY_PATH
+	DYNAMIC_SECURITY_HOOK_path_unlink,
+	DYNAMIC_SECURITY_HOOK_path_mkdir,
+	DYNAMIC_SECURITY_HOOK_path_rmdir,
+	DYNAMIC_SECURITY_HOOK_path_mknod,
+	DYNAMIC_SECURITY_HOOK_path_truncate,
+	DYNAMIC_SECURITY_HOOK_path_symlink,
+	DYNAMIC_SECURITY_HOOK_path_link,
+	DYNAMIC_SECURITY_HOOK_path_rename,
+	DYNAMIC_SECURITY_HOOK_path_chmod,
+	DYNAMIC_SECURITY_HOOK_path_chown,
+	DYNAMIC_SECURITY_HOOK_path_chroot,
+#endif
+	DYNAMIC_SECURITY_HOOK_inode_alloc_security,
+	DYNAMIC_SECURITY_HOOK_inode_free_security,
+	DYNAMIC_SECURITY_HOOK_inode_init_security,
+	DYNAMIC_SECURITY_HOOK_inode_create,
+	DYNAMIC_SECURITY_HOOK_inode_link,
+	DYNAMIC_SECURITY_HOOK_inode_unlink,
+	DYNAMIC_SECURITY_HOOK_inode_symlink,
+	DYNAMIC_SECURITY_HOOK_inode_mkdir,
+	DYNAMIC_SECURITY_HOOK_inode_rmdir,
+	DYNAMIC_SECURITY_HOOK_inode_mknod,
+	DYNAMIC_SECURITY_HOOK_inode_rename,
+	DYNAMIC_SECURITY_HOOK_inode_readlink,
+	DYNAMIC_SECURITY_HOOK_inode_follow_link,
+	DYNAMIC_SECURITY_HOOK_inode_permission,
+	DYNAMIC_SECURITY_HOOK_inode_setattr,
+	DYNAMIC_SECURITY_HOOK_inode_getattr,
+	DYNAMIC_SECURITY_HOOK_inode_setxattr,
+	DYNAMIC_SECURITY_HOOK_inode_post_setxattr,
+	DYNAMIC_SECURITY_HOOK_inode_getxattr,
+	DYNAMIC_SECURITY_HOOK_inode_listxattr,
+	DYNAMIC_SECURITY_HOOK_inode_removexattr,
+	DYNAMIC_SECURITY_HOOK_inode_need_killpriv,
+	DYNAMIC_SECURITY_HOOK_inode_killpriv,
+	DYNAMIC_SECURITY_HOOK_inode_getsecurity,
+	DYNAMIC_SECURITY_HOOK_inode_setsecurity,
+	DYNAMIC_SECURITY_HOOK_inode_listsecurity,
+	DYNAMIC_SECURITY_HOOK_inode_getsecid,
+	DYNAMIC_SECURITY_HOOK_inode_copy_up,
+	DYNAMIC_SECURITY_HOOK_inode_copy_up_xattr,
+	DYNAMIC_SECURITY_HOOK_file_permission,
+	DYNAMIC_SECURITY_HOOK_file_alloc_security,
+	DYNAMIC_SECURITY_HOOK_file_free_security,
+	DYNAMIC_SECURITY_HOOK_file_ioctl,
+	DYNAMIC_SECURITY_HOOK_mmap_addr,
+	DYNAMIC_SECURITY_HOOK_mmap_file,
+	DYNAMIC_SECURITY_HOOK_file_mprotect,
+	DYNAMIC_SECURITY_HOOK_file_lock,
+	DYNAMIC_SECURITY_HOOK_file_fcntl,
+	DYNAMIC_SECURITY_HOOK_file_set_fowner,
+	DYNAMIC_SECURITY_HOOK_file_send_sigiotask,
+	DYNAMIC_SECURITY_HOOK_file_receive,
+	DYNAMIC_SECURITY_HOOK_file_open,
+	DYNAMIC_SECURITY_HOOK_task_alloc,
+	DYNAMIC_SECURITY_HOOK_task_free,
+	DYNAMIC_SECURITY_HOOK_cred_alloc_blank,
+	DYNAMIC_SECURITY_HOOK_cred_free,
+	DYNAMIC_SECURITY_HOOK_cred_prepare,
+	DYNAMIC_SECURITY_HOOK_cred_transfer,
+	DYNAMIC_SECURITY_HOOK_kernel_act_as,
+	DYNAMIC_SECURITY_HOOK_kernel_create_files_as,
+	DYNAMIC_SECURITY_HOOK_kernel_read_file,
+	DYNAMIC_SECURITY_HOOK_kernel_post_read_file,
+	DYNAMIC_SECURITY_HOOK_kernel_module_request,
+	DYNAMIC_SECURITY_HOOK_task_fix_setuid,
+	DYNAMIC_SECURITY_HOOK_task_setpgid,
+	DYNAMIC_SECURITY_HOOK_task_getpgid,
+	DYNAMIC_SECURITY_HOOK_task_getsid,
+	DYNAMIC_SECURITY_HOOK_task_getsecid,
+	DYNAMIC_SECURITY_HOOK_task_setnice,
+	DYNAMIC_SECURITY_HOOK_task_setioprio,
+	DYNAMIC_SECURITY_HOOK_task_getioprio,
+	DYNAMIC_SECURITY_HOOK_task_prlimit,
+	DYNAMIC_SECURITY_HOOK_task_setrlimit,
+	DYNAMIC_SECURITY_HOOK_task_setscheduler,
+	DYNAMIC_SECURITY_HOOK_task_getscheduler,
+	DYNAMIC_SECURITY_HOOK_task_movememory,
+	DYNAMIC_SECURITY_HOOK_task_kill,
+	DYNAMIC_SECURITY_HOOK_task_prctl,
+	DYNAMIC_SECURITY_HOOK_task_to_inode,
+	DYNAMIC_SECURITY_HOOK_ipc_permission,
+	DYNAMIC_SECURITY_HOOK_ipc_getsecid,
+	DYNAMIC_SECURITY_HOOK_msg_msg_alloc_security,
+	DYNAMIC_SECURITY_HOOK_msg_msg_free_security,
+	DYNAMIC_SECURITY_HOOK_msg_queue_alloc_security,
+	DYNAMIC_SECURITY_HOOK_msg_queue_free_security,
+	DYNAMIC_SECURITY_HOOK_msg_queue_associate,
+	DYNAMIC_SECURITY_HOOK_msg_queue_msgctl,
+	DYNAMIC_SECURITY_HOOK_msg_queue_msgsnd,
+	DYNAMIC_SECURITY_HOOK_msg_queue_msgrcv,
+	DYNAMIC_SECURITY_HOOK_shm_alloc_security,
+	DYNAMIC_SECURITY_HOOK_shm_free_security,
+	DYNAMIC_SECURITY_HOOK_shm_associate,
+	DYNAMIC_SECURITY_HOOK_shm_shmctl,
+	DYNAMIC_SECURITY_HOOK_shm_shmat,
+	DYNAMIC_SECURITY_HOOK_sem_alloc_security,
+	DYNAMIC_SECURITY_HOOK_sem_free_security,
+	DYNAMIC_SECURITY_HOOK_sem_associate,
+	DYNAMIC_SECURITY_HOOK_sem_semctl,
+	DYNAMIC_SECURITY_HOOK_sem_semop,
+	DYNAMIC_SECURITY_HOOK_netlink_send,
+	DYNAMIC_SECURITY_HOOK_d_instantiate,
+	DYNAMIC_SECURITY_HOOK_getprocattr,
+	DYNAMIC_SECURITY_HOOK_setprocattr,
+	DYNAMIC_SECURITY_HOOK_ismaclabel,
+	DYNAMIC_SECURITY_HOOK_secid_to_secctx,
+	DYNAMIC_SECURITY_HOOK_secctx_to_secid,
+	DYNAMIC_SECURITY_HOOK_release_secctx,
+	DYNAMIC_SECURITY_HOOK_inode_invalidate_secctx,
+	DYNAMIC_SECURITY_HOOK_inode_notifysecctx,
+	DYNAMIC_SECURITY_HOOK_inode_setsecctx,
+	DYNAMIC_SECURITY_HOOK_inode_getsecctx,
+#ifdef CONFIG_SECURITY_NETWORK
+	DYNAMIC_SECURITY_HOOK_unix_stream_connect,
+	DYNAMIC_SECURITY_HOOK_unix_may_send,
+	DYNAMIC_SECURITY_HOOK_socket_create,
+	DYNAMIC_SECURITY_HOOK_socket_post_create,
+	DYNAMIC_SECURITY_HOOK_socket_bind,
+	DYNAMIC_SECURITY_HOOK_socket_connect,
+	DYNAMIC_SECURITY_HOOK_socket_listen,
+	DYNAMIC_SECURITY_HOOK_socket_accept,
+	DYNAMIC_SECURITY_HOOK_socket_sendmsg,
+	DYNAMIC_SECURITY_HOOK_socket_recvmsg,
+	DYNAMIC_SECURITY_HOOK_socket_getsockname,
+	DYNAMIC_SECURITY_HOOK_socket_getpeername,
+	DYNAMIC_SECURITY_HOOK_socket_getsockopt,
+	DYNAMIC_SECURITY_HOOK_socket_setsockopt,
+	DYNAMIC_SECURITY_HOOK_socket_shutdown,
+	DYNAMIC_SECURITY_HOOK_socket_sock_rcv_skb,
+	DYNAMIC_SECURITY_HOOK_socket_getpeersec_stream,
+	DYNAMIC_SECURITY_HOOK_socket_getpeersec_dgram,
+	DYNAMIC_SECURITY_HOOK_sk_alloc_security,
+	DYNAMIC_SECURITY_HOOK_sk_free_security,
+	DYNAMIC_SECURITY_HOOK_sk_clone_security,
+	DYNAMIC_SECURITY_HOOK_sk_getsecid,
+	DYNAMIC_SECURITY_HOOK_sock_graft,
+	DYNAMIC_SECURITY_HOOK_inet_conn_request,
+	DYNAMIC_SECURITY_HOOK_inet_csk_clone,
+	DYNAMIC_SECURITY_HOOK_inet_conn_established,
+	DYNAMIC_SECURITY_HOOK_secmark_relabel_packet,
+	DYNAMIC_SECURITY_HOOK_secmark_refcount_inc,
+	DYNAMIC_SECURITY_HOOK_secmark_refcount_dec,
+	DYNAMIC_SECURITY_HOOK_req_classify_flow,
+	DYNAMIC_SECURITY_HOOK_tun_dev_alloc_security,
+	DYNAMIC_SECURITY_HOOK_tun_dev_free_security,
+	DYNAMIC_SECURITY_HOOK_tun_dev_create,
+	DYNAMIC_SECURITY_HOOK_tun_dev_attach_queue,
+	DYNAMIC_SECURITY_HOOK_tun_dev_attach,
+	DYNAMIC_SECURITY_HOOK_tun_dev_open,
+#endif	/* CONFIG_SECURITY_NETWORK */
+#ifdef CONFIG_SECURITY_INFINIBAND
+	DYNAMIC_SECURITY_HOOK_ib_pkey_access,
+	DYNAMIC_SECURITY_HOOK_ib_endport_manage_subnet,
+	DYNAMIC_SECURITY_HOOK_ib_alloc_security,
+	DYNAMIC_SECURITY_HOOK_ib_free_security,
+#endif	/* CONFIG_SECURITY_INFINIBAND */
+#ifdef CONFIG_SECURITY_NETWORK_XFRM
+	DYNAMIC_SECURITY_HOOK_xfrm_policy_alloc_security,
+	DYNAMIC_SECURITY_HOOK_xfrm_policy_clone_security,
+	DYNAMIC_SECURITY_HOOK_xfrm_policy_free_security,
+	DYNAMIC_SECURITY_HOOK_xfrm_policy_delete_security,
+	DYNAMIC_SECURITY_HOOK_xfrm_state_alloc,
+	DYNAMIC_SECURITY_HOOK_xfrm_state_alloc_acquire,
+	DYNAMIC_SECURITY_HOOK_xfrm_state_free_security,
+	DYNAMIC_SECURITY_HOOK_xfrm_state_delete_security,
+	DYNAMIC_SECURITY_HOOK_xfrm_policy_lookup,
+	DYNAMIC_SECURITY_HOOK_xfrm_state_pol_flow_match,
+	DYNAMIC_SECURITY_HOOK_xfrm_decode_session,
+#endif	/* CONFIG_SECURITY_NETWORK_XFRM */
+#ifdef CONFIG_KEYS
+	DYNAMIC_SECURITY_HOOK_key_alloc,
+	DYNAMIC_SECURITY_HOOK_key_free,
+	DYNAMIC_SECURITY_HOOK_key_permission,
+	DYNAMIC_SECURITY_HOOK_key_getsecurity,
+#endif	/* CONFIG_KEYS */
+#ifdef CONFIG_AUDIT
+	DYNAMIC_SECURITY_HOOK_audit_rule_init,
+	DYNAMIC_SECURITY_HOOK_audit_rule_known,
+	DYNAMIC_SECURITY_HOOK_audit_rule_match,
+	DYNAMIC_SECURITY_HOOK_audit_rule_free,
+#endif /* CONFIG_AUDIT */
+#ifdef CONFIG_BPF_SYSCALL
+	DYNAMIC_SECURITY_HOOK_bpf,
+	DYNAMIC_SECURITY_HOOK_bpf_map,
+	DYNAMIC_SECURITY_HOOK_bpf_prog,
+	DYNAMIC_SECURITY_HOOK_bpf_map_alloc_security,
+	DYNAMIC_SECURITY_HOOK_bpf_map_free_security,
+	DYNAMIC_SECURITY_HOOK_bpf_prog_alloc_security,
+	DYNAMIC_SECURITY_HOOK_bpf_prog_free_security,
+#endif /* CONFIG_BPF_SYSCALL */
+	__MAX_DYNAMIC_SECURITY_HOOK,
+};
+
+struct dynamic_security_hook {
+	struct percpu_counter		invocation;
+	struct percpu_counter		deny;
+	struct list_head		list;
+	union security_list_options	hook;
+	enum dynamic_security_hook_type type;
+	const char			*lsm;
+};
+
+#define DYNAMIC_SECURITY_HOOK(NAME, LSM_NAME, TYPE, CALLBACK)	\
+static struct dynamic_security_hook NAME = {			\
+	.type		= DYNAMIC_SECURITY_HOOK_##TYPE,		\
+	.lsm		= LSM_NAME,				\
+	.hook.TYPE	= CALLBACK,				\
+}
+
+
+
+extern int security_add_dynamic_hook(struct dynamic_security_hook *hook);
+extern void security_remove_dynamic_hook(struct dynamic_security_hook *hook);
+#endif
+
 #ifdef CONFIG_SECURITY_SELINUX_DISABLE
 /*
  * Assuring the safety of deleting a security module is up to
diff --git a/security/Kconfig b/security/Kconfig
index e8e4494..77841bd 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -85,6 +85,15 @@ config SECURITY_PATH
 	  implement pathname based access controls.
 	  If you are unsure how to answer this question, answer N.
 
+config SECURITY_DYNAMIC_HOOKS
+	bool "Runtime loadable (minor) LSMs via LKMs"
+	depends on SECURITY && SRCU
+	help
+	  This enables LSMs which live in LKMs, and supports loading, and
+	  unloading them safely at runtime. These LSMs must be minor LSMs.
+	  They cannot circumvent the built-in LSMs.
+	  If you are unsure how to answer this question, answer N.
+
 config INTEL_TXT
 	bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
 	depends on HAVE_INTEL_TXT
diff --git a/security/Makefile b/security/Makefile
index 4d2d378..59e695a 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_MMU)			+= min_addr.o
 # Object file lists
 obj-$(CONFIG_SECURITY)			+= security.o
 obj-$(CONFIG_SECURITYFS)		+= inode.o
+obj-$(CONFIG_SECURITY_DYNAMIC_HOOKS)	+= dynamic.o
 obj-$(CONFIG_SECURITY_SELINUX)		+= selinux/
 obj-$(CONFIG_SECURITY_SMACK)		+= smack/
 obj-$(CONFIG_AUDIT)			+= lsm_audit.o
diff --git a/security/dynamic.c b/security/dynamic.c
new file mode 100644
index 0000000..14dd9f3
--- /dev/null
+++ b/security/dynamic.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/lsm_hooks.h>
+#include <linux/srcu.h>
+#include <linux/list.h>
+#include <linux/jump_label.h>
+#include <linux/percpu_counter.h>
+#include <linux/percpu.h>
+
+#include "dynamic.h"
+
+static DEFINE_MUTEX(dynamic_hook_lock);
+DEFINE_STATIC_KEY_ARRAY_FALSE(dynamic_hooks_keys, __MAX_DYNAMIC_SECURITY_HOOK);
+
+#define DYNAMIC_HOOK(FUNC) \
+[DYNAMIC_SECURITY_HOOK_##FUNC] = {					\
+	.name		= #FUNC,					\
+}
+
+
+struct dynamic_hook dynamic_hooks[__MAX_DYNAMIC_SECURITY_HOOK] = {
+	DYNAMIC_HOOK(binder_set_context_mgr),
+	DYNAMIC_HOOK(binder_transaction),
+	DYNAMIC_HOOK(binder_transfer_binder),
+	DYNAMIC_HOOK(binder_transfer_file),
+	DYNAMIC_HOOK(ptrace_access_check),
+	DYNAMIC_HOOK(ptrace_traceme),
+	DYNAMIC_HOOK(capget),
+	DYNAMIC_HOOK(capset),
+	DYNAMIC_HOOK(capable),
+	DYNAMIC_HOOK(quotactl),
+	DYNAMIC_HOOK(quota_on),
+	DYNAMIC_HOOK(syslog),
+	DYNAMIC_HOOK(settime),
+	DYNAMIC_HOOK(vm_enough_memory),
+	DYNAMIC_HOOK(bprm_set_creds),
+	DYNAMIC_HOOK(bprm_check_security),
+	DYNAMIC_HOOK(bprm_committing_creds),
+	DYNAMIC_HOOK(bprm_committed_creds),
+	DYNAMIC_HOOK(sb_alloc_security),
+	DYNAMIC_HOOK(sb_free_security),
+	DYNAMIC_HOOK(sb_copy_data),
+	DYNAMIC_HOOK(sb_remount),
+	DYNAMIC_HOOK(sb_kern_mount),
+	DYNAMIC_HOOK(sb_show_options),
+	DYNAMIC_HOOK(sb_statfs),
+	DYNAMIC_HOOK(sb_mount),
+	DYNAMIC_HOOK(sb_umount),
+	DYNAMIC_HOOK(sb_pivotroot),
+	DYNAMIC_HOOK(sb_set_mnt_opts),
+	DYNAMIC_HOOK(sb_clone_mnt_opts),
+	DYNAMIC_HOOK(sb_parse_opts_str),
+	DYNAMIC_HOOK(dentry_init_security),
+	DYNAMIC_HOOK(dentry_create_files_as),
+#ifdef CONFIG_SECURITY_PATH
+	DYNAMIC_HOOK(path_unlink),
+	DYNAMIC_HOOK(path_mkdir),
+	DYNAMIC_HOOK(path_rmdir),
+	DYNAMIC_HOOK(path_mknod),
+	DYNAMIC_HOOK(path_truncate),
+	DYNAMIC_HOOK(path_symlink),
+	DYNAMIC_HOOK(path_link),
+	DYNAMIC_HOOK(path_rename),
+	DYNAMIC_HOOK(path_chmod),
+	DYNAMIC_HOOK(path_chown),
+	DYNAMIC_HOOK(path_chroot),
+#endif
+	DYNAMIC_HOOK(inode_alloc_security),
+	DYNAMIC_HOOK(inode_free_security),
+	DYNAMIC_HOOK(inode_init_security),
+	DYNAMIC_HOOK(inode_create),
+	DYNAMIC_HOOK(inode_link),
+	DYNAMIC_HOOK(inode_unlink),
+	DYNAMIC_HOOK(inode_symlink),
+	DYNAMIC_HOOK(inode_mkdir),
+	DYNAMIC_HOOK(inode_rmdir),
+	DYNAMIC_HOOK(inode_mknod),
+	DYNAMIC_HOOK(inode_rename),
+	DYNAMIC_HOOK(inode_readlink),
+	DYNAMIC_HOOK(inode_follow_link),
+	DYNAMIC_HOOK(inode_permission),
+	DYNAMIC_HOOK(inode_setattr),
+	DYNAMIC_HOOK(inode_getattr),
+	DYNAMIC_HOOK(inode_setxattr),
+	DYNAMIC_HOOK(inode_post_setxattr),
+	DYNAMIC_HOOK(inode_getxattr),
+	DYNAMIC_HOOK(inode_listxattr),
+	DYNAMIC_HOOK(inode_removexattr),
+	DYNAMIC_HOOK(inode_need_killpriv),
+	DYNAMIC_HOOK(inode_killpriv),
+	DYNAMIC_HOOK(inode_getsecurity),
+	DYNAMIC_HOOK(inode_setsecurity),
+	DYNAMIC_HOOK(inode_listsecurity),
+	DYNAMIC_HOOK(inode_getsecid),
+	DYNAMIC_HOOK(inode_copy_up),
+	DYNAMIC_HOOK(inode_copy_up_xattr),
+	DYNAMIC_HOOK(file_permission),
+	DYNAMIC_HOOK(file_alloc_security),
+	DYNAMIC_HOOK(file_free_security),
+	DYNAMIC_HOOK(file_ioctl),
+	DYNAMIC_HOOK(mmap_addr),
+	DYNAMIC_HOOK(mmap_file),
+	DYNAMIC_HOOK(file_mprotect),
+	DYNAMIC_HOOK(file_lock),
+	DYNAMIC_HOOK(file_fcntl),
+	DYNAMIC_HOOK(file_set_fowner),
+	DYNAMIC_HOOK(file_send_sigiotask),
+	DYNAMIC_HOOK(file_receive),
+	DYNAMIC_HOOK(file_open),
+	DYNAMIC_HOOK(task_alloc),
+	DYNAMIC_HOOK(task_free),
+	DYNAMIC_HOOK(cred_alloc_blank),
+	DYNAMIC_HOOK(cred_free),
+	DYNAMIC_HOOK(cred_prepare),
+	DYNAMIC_HOOK(cred_transfer),
+	DYNAMIC_HOOK(kernel_act_as),
+	DYNAMIC_HOOK(kernel_create_files_as),
+	DYNAMIC_HOOK(kernel_read_file),
+	DYNAMIC_HOOK(kernel_post_read_file),
+	DYNAMIC_HOOK(kernel_module_request),
+	DYNAMIC_HOOK(task_fix_setuid),
+	DYNAMIC_HOOK(task_setpgid),
+	DYNAMIC_HOOK(task_getpgid),
+	DYNAMIC_HOOK(task_getsid),
+	DYNAMIC_HOOK(task_getsecid),
+	DYNAMIC_HOOK(task_setnice),
+	DYNAMIC_HOOK(task_setioprio),
+	DYNAMIC_HOOK(task_getioprio),
+	DYNAMIC_HOOK(task_prlimit),
+	DYNAMIC_HOOK(task_setrlimit),
+	DYNAMIC_HOOK(task_setscheduler),
+	DYNAMIC_HOOK(task_getscheduler),
+	DYNAMIC_HOOK(task_movememory),
+	DYNAMIC_HOOK(task_kill),
+	DYNAMIC_HOOK(task_prctl),
+	DYNAMIC_HOOK(task_to_inode),
+	DYNAMIC_HOOK(ipc_permission),
+	DYNAMIC_HOOK(ipc_getsecid),
+	DYNAMIC_HOOK(msg_msg_alloc_security),
+	DYNAMIC_HOOK(msg_msg_free_security),
+	DYNAMIC_HOOK(msg_queue_alloc_security),
+	DYNAMIC_HOOK(msg_queue_free_security),
+	DYNAMIC_HOOK(msg_queue_associate),
+	DYNAMIC_HOOK(msg_queue_msgctl),
+	DYNAMIC_HOOK(msg_queue_msgsnd),
+	DYNAMIC_HOOK(msg_queue_msgrcv),
+	DYNAMIC_HOOK(shm_alloc_security),
+	DYNAMIC_HOOK(shm_free_security),
+	DYNAMIC_HOOK(shm_associate),
+	DYNAMIC_HOOK(shm_shmctl),
+	DYNAMIC_HOOK(shm_shmat),
+	DYNAMIC_HOOK(sem_alloc_security),
+	DYNAMIC_HOOK(sem_free_security),
+	DYNAMIC_HOOK(sem_associate),
+	DYNAMIC_HOOK(sem_semctl),
+	DYNAMIC_HOOK(sem_semop),
+	DYNAMIC_HOOK(netlink_send),
+	DYNAMIC_HOOK(d_instantiate),
+	DYNAMIC_HOOK(getprocattr),
+	DYNAMIC_HOOK(setprocattr),
+	DYNAMIC_HOOK(ismaclabel),
+	DYNAMIC_HOOK(secid_to_secctx),
+	DYNAMIC_HOOK(secctx_to_secid),
+	DYNAMIC_HOOK(release_secctx),
+	DYNAMIC_HOOK(inode_invalidate_secctx),
+	DYNAMIC_HOOK(inode_notifysecctx),
+	DYNAMIC_HOOK(inode_setsecctx),
+	DYNAMIC_HOOK(inode_getsecctx),
+#ifdef CONFIG_SECURITY_NETWORK
+	DYNAMIC_HOOK(unix_stream_connect),
+	DYNAMIC_HOOK(unix_may_send),
+	DYNAMIC_HOOK(socket_create),
+	DYNAMIC_HOOK(socket_post_create),
+	DYNAMIC_HOOK(socket_bind),
+	DYNAMIC_HOOK(socket_connect),
+	DYNAMIC_HOOK(socket_listen),
+	DYNAMIC_HOOK(socket_accept),
+	DYNAMIC_HOOK(socket_sendmsg),
+	DYNAMIC_HOOK(socket_recvmsg),
+	DYNAMIC_HOOK(socket_getsockname),
+	DYNAMIC_HOOK(socket_getpeername),
+	DYNAMIC_HOOK(socket_getsockopt),
+	DYNAMIC_HOOK(socket_setsockopt),
+	DYNAMIC_HOOK(socket_shutdown),
+	DYNAMIC_HOOK(socket_sock_rcv_skb),
+	DYNAMIC_HOOK(socket_getpeersec_stream),
+	DYNAMIC_HOOK(socket_getpeersec_dgram),
+	DYNAMIC_HOOK(sk_alloc_security),
+	DYNAMIC_HOOK(sk_free_security),
+	DYNAMIC_HOOK(sk_clone_security),
+	DYNAMIC_HOOK(sk_getsecid),
+	DYNAMIC_HOOK(sock_graft),
+	DYNAMIC_HOOK(inet_conn_request),
+	DYNAMIC_HOOK(inet_csk_clone),
+	DYNAMIC_HOOK(inet_conn_established),
+	DYNAMIC_HOOK(secmark_relabel_packet),
+	DYNAMIC_HOOK(secmark_refcount_inc),
+	DYNAMIC_HOOK(secmark_refcount_dec),
+	DYNAMIC_HOOK(req_classify_flow),
+	DYNAMIC_HOOK(tun_dev_alloc_security),
+	DYNAMIC_HOOK(tun_dev_free_security),
+	DYNAMIC_HOOK(tun_dev_create),
+	DYNAMIC_HOOK(tun_dev_attach_queue),
+	DYNAMIC_HOOK(tun_dev_attach),
+	DYNAMIC_HOOK(tun_dev_open),
+#endif	/* CONFIG_SECURITY_NETWORK */
+#ifdef CONFIG_SECURITY_INFINIBAND
+	DYNAMIC_HOOK(ib_pkey_access),
+	DYNAMIC_HOOK(ib_endport_manage_subnet),
+	DYNAMIC_HOOK(ib_alloc_security),
+	DYNAMIC_HOOK(ib_free_security),
+#endif	/* CONFIG_SECURITY_INFINIBAND */
+#ifdef CONFIG_SECURITY_NETWORK_XFRM
+	DYNAMIC_HOOK(xfrm_policy_alloc_security),
+	DYNAMIC_HOOK(xfrm_policy_clone_security),
+	DYNAMIC_HOOK(xfrm_policy_free_security),
+	DYNAMIC_HOOK(xfrm_policy_delete_security),
+	DYNAMIC_HOOK(xfrm_state_alloc),
+	DYNAMIC_HOOK(xfrm_state_alloc_acquire),
+	DYNAMIC_HOOK(xfrm_state_free_security),
+	DYNAMIC_HOOK(xfrm_state_delete_security),
+	DYNAMIC_HOOK(xfrm_policy_lookup),
+	DYNAMIC_HOOK(xfrm_state_pol_flow_match),
+	DYNAMIC_HOOK(xfrm_decode_session),
+#endif	/* CONFIG_SECURITY_NETWORK_XFRM */
+#ifdef CONFIG_KEYS
+	DYNAMIC_HOOK(key_alloc),
+	DYNAMIC_HOOK(key_free),
+	DYNAMIC_HOOK(key_permission),
+	DYNAMIC_HOOK(key_getsecurity),
+#endif	/* CONFIG_KEYS */
+#ifdef CONFIG_AUDIT
+	DYNAMIC_HOOK(audit_rule_init),
+	DYNAMIC_HOOK(audit_rule_known),
+	DYNAMIC_HOOK(audit_rule_match),
+	DYNAMIC_HOOK(audit_rule_free),
+#endif /* CONFIG_AUDIT */
+#ifdef CONFIG_BPF_SYSCALL
+	DYNAMIC_HOOK(bpf),
+	DYNAMIC_HOOK(bpf_map),
+	DYNAMIC_HOOK(bpf_prog),
+	DYNAMIC_HOOK(bpf_map_alloc_security),
+	DYNAMIC_HOOK(bpf_map_free_security),
+	DYNAMIC_HOOK(bpf_prog_alloc_security),
+	DYNAMIC_HOOK(bpf_prog_free_security),
+#endif /* CONFIG_BPF_SYSCALL */
+};
+
+/**
+ * security_add_dynamic_hook - Add a dynamic hook to the dynamic hooks list
+ * @hook: A populated dynamic_security_hook object
+ *
+ * returns 0 if the hook was successfully installed
+ */
+int security_add_dynamic_hook(struct dynamic_security_hook *hook)
+{
+	int ret;
+
+	ret = percpu_counter_init(&hook->invocation, 0, GFP_KERNEL);
+	if (ret)
+		return ret;
+	ret = percpu_counter_init(&hook->deny, 0, GFP_KERNEL);
+	if (ret) {
+		percpu_counter_destroy(&hook->invocation);
+		return ret;
+	}
+
+	mutex_lock(&dynamic_hook_lock);
+	list_add_tail_rcu(&hook->list, &dynamic_hooks[hook->type].head);
+	static_branch_inc(&dynamic_hooks_keys[hook->type]);
+	mutex_unlock(&dynamic_hook_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(security_add_dynamic_hook);
+
+/**
+ * security_remove_dynamic_hook - Add a dynamic hook to the dynamic hooks list
+ * @hook: A populated dynamic_security_hook object, that's been previously added
+ */
+void security_remove_dynamic_hook(struct dynamic_security_hook *hook)
+{
+	mutex_lock(&dynamic_hook_lock);
+	list_del_rcu(&hook->list);
+	static_branch_dec(&dynamic_hooks_keys[hook->type]);
+	mutex_unlock(&dynamic_hook_lock);
+	synchronize_srcu(&dynamic_hooks[hook->type].srcu);
+
+	percpu_counter_destroy(&hook->invocation);
+	percpu_counter_destroy(&hook->deny);
+}
+EXPORT_SYMBOL_GPL(security_remove_dynamic_hook);
+
+void security_init_dynamic_hooks(void)
+{
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(dynamic_hooks); i++) {
+		INIT_LIST_HEAD(&dynamic_hooks[i].head);
+		ret = init_srcu_struct(&dynamic_hooks[i].srcu);
+		if (ret)
+			panic("%s - %d - Cannot initialize SRCU.\n",
+			      __func__, ret);
+		ret = percpu_counter_init(&dynamic_hooks[i].invocation, 0,
+					  GFP_KERNEL);
+		if (ret)
+			panic("%s - %d - Cannot Per CPU counter.\n",
+			      __func__, ret);
+		ret = percpu_counter_init(&dynamic_hooks[i].deny, 0,
+					  GFP_KERNEL);
+		if (ret)
+			panic("%s - %d - Cannot Per CPU counter.\n",
+			      __func__, ret);
+
+	}
+}
diff --git a/security/dynamic.h b/security/dynamic.h
new file mode 100644
index 0000000..6823e38
--- /dev/null
+++ b/security/dynamic.h
@@ -0,0 +1,24 @@
+#include <linux/lsm_hooks.h>
+#include <linux/srcu.h>
+#include <linux/list.h>
+#include <linux/jump_label.h>
+#include <linux/percpu_counter.h>
+#include <linux/percpu.h>
+#include <linux/fs.h>
+
+#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
+extern struct static_key_false dynamic_hooks_keys[];
+
+struct dynamic_hook {
+	struct percpu_counter	invocation;
+	struct percpu_counter	deny;
+	const char		*name;
+	struct list_head	head;
+	struct srcu_struct	srcu;
+};
+
+extern struct dynamic_hook dynamic_hooks[];
+extern void security_init_dynamic_hooks(void);
+#else
+static void security_init_dynamic_hooks(void) {}
+#endif
diff --git a/security/security.c b/security/security.c
index 1cd8526..b86d159 100644
--- a/security/security.c
+++ b/security/security.c
@@ -29,12 +29,14 @@
 #include <linux/backing-dev.h>
 #include <linux/string.h>
 #include <net/flow.h>
+#include <linux/percpu_counter.h>
+#include <linux/percpu.h>
+#include "dynamic.h"
 
 #define MAX_LSM_EVM_XATTR	2
 
 /* Maximum number of letters for an LSM name string */
 #define SECURITY_NAME_MAX	10
-
 struct security_hook_heads security_hook_heads __lsm_ro_after_init;
 static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
 
@@ -66,6 +68,8 @@ int __init security_init(void)
 	for (i = 0; i < sizeof(security_hook_heads) / sizeof(struct list_head);
 	     i++)
 		INIT_LIST_HEAD(&list[i]);
+
+	security_init_dynamic_hooks();
 	pr_info("Security Framework initialized\n");
 
 	/*
@@ -197,6 +201,64 @@ EXPORT_SYMBOL(unregister_lsm_notifier);
  *	This is a hook that returns a value.
  */
 
+#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
+#define call_void_hook(FUNC, ...)				\
+	do {							\
+		struct dynamic_security_hook *dsh;		\
+		struct security_hook_list *P;			\
+		struct dynamic_hook *dh;			\
+		int srcu_idx;					\
+		list_for_each_entry(P,				\
+				    &security_hook_heads.FUNC,	\
+				    list)			\
+			P->hook.FUNC(__VA_ARGS__);		\
+		if (static_branch_unlikely(&dynamic_hooks_keys[DYNAMIC_SECURITY_HOOK_##FUNC])) { \
+			dh = &dynamic_hooks[DYNAMIC_SECURITY_HOOK_##FUNC]; \
+			percpu_counter_inc(&dh->invocation);		\
+			srcu_idx = srcu_read_lock(&dh->srcu);		\
+			list_for_each_entry_rcu(dsh, &dh->head, list) {	\
+				dsh->hook.FUNC(__VA_ARGS__);		\
+				percpu_counter_inc(&dsh->invocation);	\
+			}						\
+			srcu_read_unlock(&dh->srcu, srcu_idx);		\
+		}							\
+	} while (0)
+
+#define call_int_hook(FUNC, IRC, ...) ({				\
+	int RC = IRC;							\
+	do {								\
+		struct dynamic_security_hook *dsh;			\
+		bool continue_iteration = true;				\
+		struct security_hook_list *P;				\
+		struct dynamic_hook *dh;				\
+		int srcu_idx;						\
+		list_for_each_entry(P, &security_hook_heads.FUNC, list) { \
+			RC = P->hook.FUNC(__VA_ARGS__);			\
+			if (RC != 0) {					\
+				continue_iteration = false;		\
+				break;					\
+			}						\
+		}							\
+		if (static_branch_unlikely(&dynamic_hooks_keys[DYNAMIC_SECURITY_HOOK_##FUNC]) && \
+		    continue_iteration) {				\
+			dh = &dynamic_hooks[DYNAMIC_SECURITY_HOOK_##FUNC]; \
+			percpu_counter_inc(&dh->invocation);		\
+			srcu_idx = srcu_read_lock(&dh->srcu);		\
+			list_for_each_entry_rcu(dsh, &dh->head, list) {	\
+				RC = dsh->hook.FUNC(__VA_ARGS__);	\
+				percpu_counter_inc(&dsh->invocation);	\
+				if (RC != 0) {				\
+					percpu_counter_inc(&dsh->deny);	\
+					percpu_counter_inc(&dh->deny);	\
+					break;				\
+				}					\
+			}						\
+			srcu_read_unlock(&dh->srcu, srcu_idx);		\
+		}							\
+	} while (0);							\
+	RC;								\
+})
+#else
 #define call_void_hook(FUNC, ...)				\
 	do {							\
 		struct security_hook_list *P;			\
@@ -218,6 +280,8 @@ EXPORT_SYMBOL(unregister_lsm_notifier);
 	} while (0);						\
 	RC;							\
 })
+#endif
+
 
 /* Security operations */
 
-- 
2.9.3

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