Safe, dynamically loadable LSM hooks

index 7161d8e7ee79..d28c7f5b01c1 100644
@@ -1729,241 +1729,243 @@ union security_list_options {
 #endif /* CONFIG_BPF_SYSCALL */
 };
 
-struct security_hook_heads {
-	struct list_head binder_set_context_mgr;
-	struct list_head binder_transaction;
-	struct list_head binder_transfer_binder;
-	struct list_head binder_transfer_file;
-	struct list_head ptrace_access_check;
-	struct list_head ptrace_traceme;
-	struct list_head capget;
-	struct list_head capset;
-	struct list_head capable;
-	struct list_head quotactl;
-	struct list_head quota_on;
-	struct list_head syslog;
-	struct list_head settime;
-	struct list_head vm_enough_memory;
-	struct list_head bprm_set_creds;
-	struct list_head bprm_check_security;
-	struct list_head bprm_committing_creds;
-	struct list_head bprm_committed_creds;
-	struct list_head sb_alloc_security;
-	struct list_head sb_free_security;
-	struct list_head sb_copy_data;
-	struct list_head sb_remount;
-	struct list_head sb_kern_mount;
-	struct list_head sb_show_options;
-	struct list_head sb_statfs;
-	struct list_head sb_mount;
-	struct list_head sb_umount;
-	struct list_head sb_pivotroot;
-	struct list_head sb_set_mnt_opts;
-	struct list_head sb_clone_mnt_opts;
-	struct list_head sb_parse_opts_str;
-	struct list_head dentry_init_security;
-	struct list_head dentry_create_files_as;
+enum lsm_hook {
+	LSM_HOOK_binder_set_context_mgr,
+	LSM_HOOK_binder_transaction,
+	LSM_HOOK_binder_transfer_binder,
+	LSM_HOOK_binder_transfer_file,
+	LSM_HOOK_ptrace_access_check,
+	LSM_HOOK_ptrace_traceme,
+	LSM_HOOK_capget,
+	LSM_HOOK_capset,
+	LSM_HOOK_capable,
+	LSM_HOOK_quotactl,
+	LSM_HOOK_quota_on,
+	LSM_HOOK_syslog,
+	LSM_HOOK_settime,
+	LSM_HOOK_vm_enough_memory,
+	LSM_HOOK_bprm_set_creds,
+	LSM_HOOK_bprm_check_security,
+	LSM_HOOK_bprm_committing_creds,
+	LSM_HOOK_bprm_committed_creds,
+	LSM_HOOK_sb_alloc_security,
+	LSM_HOOK_sb_free_security,
+	LSM_HOOK_sb_copy_data,
+	LSM_HOOK_sb_remount,
+	LSM_HOOK_sb_kern_mount,
+	LSM_HOOK_sb_show_options,
+	LSM_HOOK_sb_statfs,
+	LSM_HOOK_sb_mount,
+	LSM_HOOK_sb_umount,
+	LSM_HOOK_sb_pivotroot,
+	LSM_HOOK_sb_set_mnt_opts,
+	LSM_HOOK_sb_clone_mnt_opts,
+	LSM_HOOK_sb_parse_opts_str,
+	LSM_HOOK_dentry_init_security,
+	LSM_HOOK_dentry_create_files_as,
 #ifdef CONFIG_SECURITY_PATH
-	struct list_head path_unlink;
-	struct list_head path_mkdir;
-	struct list_head path_rmdir;
-	struct list_head path_mknod;
-	struct list_head path_truncate;
-	struct list_head path_symlink;
-	struct list_head path_link;
-	struct list_head path_rename;
-	struct list_head path_chmod;
-	struct list_head path_chown;
-	struct list_head path_chroot;
+	LSM_HOOK_path_unlink,
+	LSM_HOOK_path_mkdir,
+	LSM_HOOK_path_rmdir,
+	LSM_HOOK_path_mknod,
+	LSM_HOOK_path_truncate,
+	LSM_HOOK_path_symlink,
+	LSM_HOOK_path_link,
+	LSM_HOOK_path_rename,
+	LSM_HOOK_path_chmod,
+	LSM_HOOK_path_chown,
+	LSM_HOOK_path_chroot,
 #endif
-	struct list_head inode_alloc_security;
-	struct list_head inode_free_security;
-	struct list_head inode_init_security;
-	struct list_head inode_create;
-	struct list_head inode_link;
-	struct list_head inode_unlink;
-	struct list_head inode_symlink;
-	struct list_head inode_mkdir;
-	struct list_head inode_rmdir;
-	struct list_head inode_mknod;
-	struct list_head inode_rename;
-	struct list_head inode_readlink;
-	struct list_head inode_follow_link;
-	struct list_head inode_permission;
-	struct list_head inode_setattr;
-	struct list_head inode_getattr;
-	struct list_head inode_setxattr;
-	struct list_head inode_post_setxattr;
-	struct list_head inode_getxattr;
-	struct list_head inode_listxattr;
-	struct list_head inode_removexattr;
-	struct list_head inode_need_killpriv;
-	struct list_head inode_killpriv;
-	struct list_head inode_getsecurity;
-	struct list_head inode_setsecurity;
-	struct list_head inode_listsecurity;
-	struct list_head inode_getsecid;
-	struct list_head inode_copy_up;
-	struct list_head inode_copy_up_xattr;
-	struct list_head file_permission;
-	struct list_head file_alloc_security;
-	struct list_head file_free_security;
-	struct list_head file_ioctl;
-	struct list_head mmap_addr;
-	struct list_head mmap_file;
-	struct list_head file_mprotect;
-	struct list_head file_lock;
-	struct list_head file_fcntl;
-	struct list_head file_set_fowner;
-	struct list_head file_send_sigiotask;
-	struct list_head file_receive;
-	struct list_head file_open;
-	struct list_head task_alloc;
-	struct list_head task_free;
-	struct list_head cred_alloc_blank;
-	struct list_head cred_free;
-	struct list_head cred_prepare;
-	struct list_head cred_transfer;
-	struct list_head kernel_act_as;
-	struct list_head kernel_create_files_as;
-	struct list_head kernel_read_file;
-	struct list_head kernel_post_read_file;
-	struct list_head kernel_module_request;
-	struct list_head task_fix_setuid;
-	struct list_head task_setpgid;
-	struct list_head task_getpgid;
-	struct list_head task_getsid;
-	struct list_head task_getsecid;
-	struct list_head task_setnice;
-	struct list_head task_setioprio;
-	struct list_head task_getioprio;
-	struct list_head task_prlimit;
-	struct list_head task_setrlimit;
-	struct list_head task_setscheduler;
-	struct list_head task_getscheduler;
-	struct list_head task_movememory;
-	struct list_head task_kill;
-	struct list_head task_prctl;
-	struct list_head task_to_inode;
-	struct list_head ipc_permission;
-	struct list_head ipc_getsecid;
-	struct list_head msg_msg_alloc_security;
-	struct list_head msg_msg_free_security;
-	struct list_head msg_queue_alloc_security;
-	struct list_head msg_queue_free_security;
-	struct list_head msg_queue_associate;
-	struct list_head msg_queue_msgctl;
-	struct list_head msg_queue_msgsnd;
-	struct list_head msg_queue_msgrcv;
-	struct list_head shm_alloc_security;
-	struct list_head shm_free_security;
-	struct list_head shm_associate;
-	struct list_head shm_shmctl;
-	struct list_head shm_shmat;
-	struct list_head sem_alloc_security;
-	struct list_head sem_free_security;
-	struct list_head sem_associate;
-	struct list_head sem_semctl;
-	struct list_head sem_semop;
-	struct list_head netlink_send;
-	struct list_head d_instantiate;
-	struct list_head getprocattr;
-	struct list_head setprocattr;
-	struct list_head ismaclabel;
-	struct list_head secid_to_secctx;
-	struct list_head secctx_to_secid;
-	struct list_head release_secctx;
-	struct list_head inode_invalidate_secctx;
-	struct list_head inode_notifysecctx;
-	struct list_head inode_setsecctx;
-	struct list_head inode_getsecctx;
+	LSM_HOOK_inode_alloc_security,
+	LSM_HOOK_inode_free_security,
+	LSM_HOOK_inode_init_security,
+	LSM_HOOK_inode_create,
+	LSM_HOOK_inode_link,
+	LSM_HOOK_inode_unlink,
+	LSM_HOOK_inode_symlink,
+	LSM_HOOK_inode_mkdir,
+	LSM_HOOK_inode_rmdir,
+	LSM_HOOK_inode_mknod,
+	LSM_HOOK_inode_rename,
+	LSM_HOOK_inode_readlink,
+	LSM_HOOK_inode_follow_link,
+	LSM_HOOK_inode_permission,
+	LSM_HOOK_inode_setattr,
+	LSM_HOOK_inode_getattr,
+	LSM_HOOK_inode_setxattr,
+	LSM_HOOK_inode_post_setxattr,
+	LSM_HOOK_inode_getxattr,
+	LSM_HOOK_inode_listxattr,
+	LSM_HOOK_inode_removexattr,
+	LSM_HOOK_inode_need_killpriv,
+	LSM_HOOK_inode_killpriv,
+	LSM_HOOK_inode_getsecurity,
+	LSM_HOOK_inode_setsecurity,
+	LSM_HOOK_inode_listsecurity,
+	LSM_HOOK_inode_getsecid,
+	LSM_HOOK_inode_copy_up,
+	LSM_HOOK_inode_copy_up_xattr,
+	LSM_HOOK_file_permission,
+	LSM_HOOK_file_alloc_security,
+	LSM_HOOK_file_free_security,
+	LSM_HOOK_file_ioctl,
+	LSM_HOOK_mmap_addr,
+	LSM_HOOK_mmap_file,
+	LSM_HOOK_file_mprotect,
+	LSM_HOOK_file_lock,
+	LSM_HOOK_file_fcntl,
+	LSM_HOOK_file_set_fowner,
+	LSM_HOOK_file_send_sigiotask,
+	LSM_HOOK_file_receive,
+	LSM_HOOK_file_open,
+	LSM_HOOK_task_alloc,
+	LSM_HOOK_task_free,
+	LSM_HOOK_cred_alloc_blank,
+	LSM_HOOK_cred_free,
+	LSM_HOOK_cred_prepare,
+	LSM_HOOK_cred_transfer,
+	LSM_HOOK_kernel_act_as,
+	LSM_HOOK_kernel_create_files_as,
+	LSM_HOOK_kernel_read_file,
+	LSM_HOOK_kernel_post_read_file,
+	LSM_HOOK_kernel_module_request,
+	LSM_HOOK_task_fix_setuid,
+	LSM_HOOK_task_setpgid,
+	LSM_HOOK_task_getpgid,
+	LSM_HOOK_task_getsid,
+	LSM_HOOK_task_getsecid,
+	LSM_HOOK_task_setnice,
+	LSM_HOOK_task_setioprio,
+	LSM_HOOK_task_getioprio,
+	LSM_HOOK_task_prlimit,
+	LSM_HOOK_task_setrlimit,
+	LSM_HOOK_task_setscheduler,
+	LSM_HOOK_task_getscheduler,
+	LSM_HOOK_task_movememory,
+	LSM_HOOK_task_kill,
+	LSM_HOOK_task_prctl,
+	LSM_HOOK_task_to_inode,
+	LSM_HOOK_ipc_permission,
+	LSM_HOOK_ipc_getsecid,
+	LSM_HOOK_msg_msg_alloc_security,
+	LSM_HOOK_msg_msg_free_security,
+	LSM_HOOK_msg_queue_alloc_security,
+	LSM_HOOK_msg_queue_free_security,
+	LSM_HOOK_msg_queue_associate,
+	LSM_HOOK_msg_queue_msgctl,
+	LSM_HOOK_msg_queue_msgsnd,
+	LSM_HOOK_msg_queue_msgrcv,
+	LSM_HOOK_shm_alloc_security,
+	LSM_HOOK_shm_free_security,
+	LSM_HOOK_shm_associate,
+	LSM_HOOK_shm_shmctl,
+	LSM_HOOK_shm_shmat,
+	LSM_HOOK_sem_alloc_security,
+	LSM_HOOK_sem_free_security,
+	LSM_HOOK_sem_associate,
+	LSM_HOOK_sem_semctl,
+	LSM_HOOK_sem_semop,
+	LSM_HOOK_netlink_send,
+	LSM_HOOK_d_instantiate,
+	LSM_HOOK_getprocattr,
+	LSM_HOOK_setprocattr,
+	LSM_HOOK_ismaclabel,
+	LSM_HOOK_secid_to_secctx,
+	LSM_HOOK_secctx_to_secid,
+	LSM_HOOK_release_secctx,
+	LSM_HOOK_inode_invalidate_secctx,
+	LSM_HOOK_inode_notifysecctx,
+	LSM_HOOK_inode_setsecctx,
+	LSM_HOOK_inode_getsecctx,
 #ifdef CONFIG_SECURITY_NETWORK
-	struct list_head unix_stream_connect;
-	struct list_head unix_may_send;
-	struct list_head socket_create;
-	struct list_head socket_post_create;
-	struct list_head socket_bind;
-	struct list_head socket_connect;
-	struct list_head socket_listen;
-	struct list_head socket_accept;
-	struct list_head socket_sendmsg;
-	struct list_head socket_recvmsg;
-	struct list_head socket_getsockname;
-	struct list_head socket_getpeername;
-	struct list_head socket_getsockopt;
-	struct list_head socket_setsockopt;
-	struct list_head socket_shutdown;
-	struct list_head socket_sock_rcv_skb;
-	struct list_head socket_getpeersec_stream;
-	struct list_head socket_getpeersec_dgram;
-	struct list_head sk_alloc_security;
-	struct list_head sk_free_security;
-	struct list_head sk_clone_security;
-	struct list_head sk_getsecid;
-	struct list_head sock_graft;
-	struct list_head inet_conn_request;
-	struct list_head inet_csk_clone;
-	struct list_head inet_conn_established;
-	struct list_head secmark_relabel_packet;
-	struct list_head secmark_refcount_inc;
-	struct list_head secmark_refcount_dec;
-	struct list_head req_classify_flow;
-	struct list_head tun_dev_alloc_security;
-	struct list_head tun_dev_free_security;
-	struct list_head tun_dev_create;
-	struct list_head tun_dev_attach_queue;
-	struct list_head tun_dev_attach;
-	struct list_head tun_dev_open;
+	LSM_HOOK_unix_stream_connect,
+	LSM_HOOK_unix_may_send,
+	LSM_HOOK_socket_create,
+	LSM_HOOK_socket_post_create,
+	LSM_HOOK_socket_bind,
+	LSM_HOOK_socket_connect,
+	LSM_HOOK_socket_listen,
+	LSM_HOOK_socket_accept,
+	LSM_HOOK_socket_sendmsg,
+	LSM_HOOK_socket_recvmsg,
+	LSM_HOOK_socket_getsockname,
+	LSM_HOOK_socket_getpeername,
+	LSM_HOOK_socket_getsockopt,
+	LSM_HOOK_socket_setsockopt,
+	LSM_HOOK_socket_shutdown,
+	LSM_HOOK_socket_sock_rcv_skb,
+	LSM_HOOK_socket_getpeersec_stream,
+	LSM_HOOK_socket_getpeersec_dgram,
+	LSM_HOOK_sk_alloc_security,
+	LSM_HOOK_sk_free_security,
+	LSM_HOOK_sk_clone_security,
+	LSM_HOOK_sk_getsecid,
+	LSM_HOOK_sock_graft,
+	LSM_HOOK_inet_conn_request,
+	LSM_HOOK_inet_csk_clone,
+	LSM_HOOK_inet_conn_established,
+	LSM_HOOK_secmark_relabel_packet,
+	LSM_HOOK_secmark_refcount_inc,
+	LSM_HOOK_secmark_refcount_dec,
+	LSM_HOOK_req_classify_flow,
+	LSM_HOOK_tun_dev_alloc_security,
+	LSM_HOOK_tun_dev_free_security,
+	LSM_HOOK_tun_dev_create,
+	LSM_HOOK_tun_dev_attach_queue,
+	LSM_HOOK_tun_dev_attach,
+	LSM_HOOK_tun_dev_open,
 #endif	/* CONFIG_SECURITY_NETWORK */
 #ifdef CONFIG_SECURITY_INFINIBAND
-	struct list_head ib_pkey_access;
-	struct list_head ib_endport_manage_subnet;
-	struct list_head ib_alloc_security;
-	struct list_head ib_free_security;
+	LSM_HOOK_ib_pkey_access,
+	LSM_HOOK_ib_endport_manage_subnet,
+	LSM_HOOK_ib_alloc_security,
+	LSM_HOOK_ib_free_security,
 #endif	/* CONFIG_SECURITY_INFINIBAND */
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
-	struct list_head xfrm_policy_alloc_security;
-	struct list_head xfrm_policy_clone_security;
-	struct list_head xfrm_policy_free_security;
-	struct list_head xfrm_policy_delete_security;
-	struct list_head xfrm_state_alloc;
-	struct list_head xfrm_state_alloc_acquire;
-	struct list_head xfrm_state_free_security;
-	struct list_head xfrm_state_delete_security;
-	struct list_head xfrm_policy_lookup;
-	struct list_head xfrm_state_pol_flow_match;
-	struct list_head xfrm_decode_session;
+	LSM_HOOK_xfrm_policy_alloc_security,
+	LSM_HOOK_xfrm_policy_clone_security,
+	LSM_HOOK_xfrm_policy_free_security,
+	LSM_HOOK_xfrm_policy_delete_security,
+	LSM_HOOK_xfrm_state_alloc,
+	LSM_HOOK_xfrm_state_alloc_acquire,
+	LSM_HOOK_xfrm_state_free_security,
+	LSM_HOOK_xfrm_state_delete_security,
+	LSM_HOOK_xfrm_policy_lookup,
+	LSM_HOOK_xfrm_state_pol_flow_match,
+	LSM_HOOK_xfrm_decode_session,
 #endif	/* CONFIG_SECURITY_NETWORK_XFRM */
 #ifdef CONFIG_KEYS
-	struct list_head key_alloc;
-	struct list_head key_free;
-	struct list_head key_permission;
-	struct list_head key_getsecurity;
+	LSM_HOOK_key_alloc,
+	LSM_HOOK_key_free,
+	LSM_HOOK_key_permission,
+	LSM_HOOK_key_getsecurity,
 #endif	/* CONFIG_KEYS */
 #ifdef CONFIG_AUDIT
-	struct list_head audit_rule_init;
-	struct list_head audit_rule_known;
-	struct list_head audit_rule_match;
-	struct list_head audit_rule_free;
+	LSM_HOOK_audit_rule_init,
+	LSM_HOOK_audit_rule_known,
+	LSM_HOOK_audit_rule_match,
+	LSM_HOOK_audit_rule_free,
 #endif /* CONFIG_AUDIT */
 #ifdef CONFIG_BPF_SYSCALL
-	struct list_head bpf;
-	struct list_head bpf_map;
-	struct list_head bpf_prog;
-	struct list_head bpf_map_alloc_security;
-	struct list_head bpf_map_free_security;
-	struct list_head bpf_prog_alloc_security;
-	struct list_head bpf_prog_free_security;
+	LSM_HOOK_bpf,
+	LSM_HOOK_bpf_map,
+	LSM_HOOK_bpf_prog,
+	LSM_HOOK_bpf_map_alloc_security,
+	LSM_HOOK_bpf_map_free_security,
+	LSM_HOOK_bpf_prog_alloc_security,
+	LSM_HOOK_bpf_prog_free_security,
 #endif /* CONFIG_BPF_SYSCALL */
-} __randomize_layout;
+	__MAX_LSM_HOOK,
+};
 
+#define HOOK_IDX(NAME)	LSM_HOOK_##NAME
 /*
  * Security module hook list structure.
  * For use with generic list macros for common operations.
  */
 struct security_hook_list {
 	struct list_head		list;
-	struct list_head		*head;
+	enum lsm_hook			head_idx;
 	union security_list_options	hook;
 	char				*lsm;
 } __randomize_layout;

@@ -1975,9 +1977,8 @@ struct security_hook_list {
  * text involved.
  */
 #define LSM_HOOK_INIT(HEAD, HOOK) \
-	{ .head = &security_hook_heads.HEAD, .hook = { .HEAD = HOOK } }
+	{ .head_idx = HOOK_IDX(HEAD), .hook = { .HEAD = HOOK } }
 
-extern struct security_hook_heads security_hook_heads;
 extern char *lsm_names;
 
 extern void security_add_hooks(struct security_hook_list *hooks, int count,

index 1cd8526cb0b7..b9fb297b824e 100644
@@ -35,9 +35,11 @@
 /* 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 struct list_head security_hook_heads[__MAX_LSM_HOOK] __lsm_ro_after_init;
 static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
 
+#define HOOK_HEAD(NAME)	(&security_hook_heads[HOOK_IDX(NAME)])
+
 char *lsm_names;
 /* Boot-time LSM user choice */
 static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =

@@ -61,11 +63,9 @@ static void __init do_security_initcalls(void)
 int __init security_init(void)
 {
 	int i;
-	struct list_head *list = (struct list_head *) &security_hook_heads;
 
-	for (i = 0; i < sizeof(security_hook_heads) / sizeof(struct list_head);
-	     i++)
-		INIT_LIST_HEAD(&list[i]);
+	for (i = 0; i < ARRAY_SIZE(security_hook_heads); i++)
+		INIT_LIST_HEAD(&security_hook_heads[i]);
 	pr_info("Security Framework initialized\n");
 
 	/*

@@ -159,11 +159,14 @@ int __init security_module_enable(const char *module)
 void __init security_add_hooks(struct security_hook_list *hooks, int count,
 				char *lsm)
 {
+	enum lsm_hook hook_idx;
 	int i;
 
 	for (i = 0; i < count; i++) {
 		hooks[i].lsm = lsm;
-		list_add_tail_rcu(&hooks[i].list, hooks[i].head);
+		hook_idx = hooks[i].head_idx;
+		list_add_tail_rcu(&hooks[i].list,
+				  &security_hook_heads[hook_idx]);
 	}
 	if (lsm_append(lsm, &lsm_names) < 0)
 		panic("%s - Cannot get early memory.\n", __func__);

@@ -201,7 +204,7 @@ EXPORT_SYMBOL(unregister_lsm_notifier);
 	do {							\
 		struct security_hook_list *P;			\
 								\
-		list_for_each_entry(P, &security_hook_heads.FUNC, list)	\
+		list_for_each_entry(P, HOOK_HEAD(FUNC), list)	\
 			P->hook.FUNC(__VA_ARGS__);		\
 	} while (0)
 

@@ -210,7 +213,7 @@ EXPORT_SYMBOL(unregister_lsm_notifier);
 	do {							\
 		struct security_hook_list *P;			\
 								\
-		list_for_each_entry(P, &security_hook_heads.FUNC, list) { \
+		list_for_each_entry(P, HOOK_HEAD(FUNC), list) { \
 			RC = P->hook.FUNC(__VA_ARGS__);		\
 			if (RC != 0)				\
 				break;				\

@@ -317,7 +320,7 @@ 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.
 	 */
-	list_for_each_entry(hp, &security_hook_heads.vm_enough_memory, list) {
+	list_for_each_entry(hp, HOOK_HEAD(vm_enough_memory), list) {
 		rc = hp->hook.vm_enough_memory(mm, pages);
 		if (rc <= 0) {
 			cap_sys_admin = 0;

@@ -805,7 +808,7 @@ int security_inode_getsecurity(struct inode *inode, const char *name, void **buf
 	/*
 	 * Only one module will provide an attribute with a given name.
 	 */
-	list_for_each_entry(hp, &security_hook_heads.inode_getsecurity, list) {
+	list_for_each_entry(hp, HOOK_HEAD(inode_getsecurity), list) {
 		rc = hp->hook.inode_getsecurity(inode, name, buffer, alloc);
 		if (rc != -EOPNOTSUPP)
 			return rc;

@@ -823,7 +826,7 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void
 	/*
 	 * Only one module will provide an attribute with a given name.
 	 */
-	list_for_each_entry(hp, &security_hook_heads.inode_setsecurity, list) {
+	list_for_each_entry(hp, HOOK_HEAD(inode_setsecurity), list) {
 		rc = hp->hook.inode_setsecurity(inode, name, value, size,
 								flags);
 		if (rc != -EOPNOTSUPP)

@@ -1126,7 +1129,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 	int rc = -ENOSYS;
 	struct security_hook_list *hp;
 
-	list_for_each_entry(hp, &security_hook_heads.task_prctl, list) {
+	list_for_each_entry(hp, HOOK_HEAD(task_prctl), list) {
 		thisrc = hp->hook.task_prctl(option, arg2, arg3, arg4, arg5);
 		if (thisrc != -ENOSYS) {
 			rc = thisrc;

@@ -1629,8 +1632,7 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x,
 	 * For speed optimization, we explicitly break the loop rather than
 	 * using the macro
 	 */
-	list_for_each_entry(hp, &security_hook_heads.xfrm_state_pol_flow_match,
-				list) {
+	list_for_each_entry(hp, HOOK_HEAD(xfrm_state_pol_flow_match), list) {
 		rc = hp->hook.xfrm_state_pol_flow_match(x, xp, fl);
 		break;
 	}

index d28c7f5b01c1..6fda1ebc565c 100644
@@ -28,6 +28,7 @@
 #include <linux/security.h>
 #include <linux/init.h>
 #include <linux/rculist.h>
+#include <linux/module.h>
 
 /**
  * union security_list_options - Linux Security Module hook function list

@@ -1968,6 +1969,9 @@ struct security_hook_list {
 	enum lsm_hook			head_idx;
 	union security_list_options	hook;
 	char				*lsm;
+#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
+	struct module			*owner;
+#endif
 } __randomize_layout;
 
 /*

@@ -1976,11 +1980,24 @@ struct security_hook_list {
  * care of the common case and reduces the amount of
  * text involved.
  */
+#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
+#define LSM_HOOK_INIT(HEAD, HOOK)		\
+	{					\
+		.head_idx = HOOK_IDX(HEAD),	\
+		.hook = { .HEAD = HOOK },	\
+		.owner = THIS_MODULE,		\
+	}
+
+#else
 #define LSM_HOOK_INIT(HEAD, HOOK) \
 	{ .head_idx = HOOK_IDX(HEAD), .hook = { .HEAD = HOOK } }
+#endif
 
-extern char *lsm_names;
-
+#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
+extern void security_add_dynamic_hooks(struct security_hook_list *hooks,
+					int count,
+					char *lsm);
+#endif
 extern void security_add_hooks(struct security_hook_list *hooks, int count,
 				char *lsm);
 

index 8dd9ca8848e4..89be07b044a5 100644
@@ -22,6 +22,10 @@
 #include <linux/security.h>
 #include <linux/lsm_hooks.h>
 #include <linux/magic.h>
+#include <linux/mutex.h>
+
+extern char *lsm_names;
+extern struct mutex lsm_lock;
 
 static struct vfsmount *mount;
 static int mount_count;

@@ -312,8 +316,13 @@ static struct dentry *lsm_dentry;
 static ssize_t lsm_read(struct file *filp, char __user *buf, size_t count,
 			loff_t *ppos)
 {
-	return simple_read_from_buffer(buf, count, ppos, lsm_names,
-		strlen(lsm_names));
+	ssize_t ret;
+
+	mutex_lock(&lsm_lock);
+	ret = simple_read_from_buffer(buf, count, ppos, lsm_names,
+				      strlen(lsm_names));
+	mutex_unlock(&lsm_lock);
+	return ret;
 }
 
 static const struct file_operations lsm_ops = {

341 lines not on this page · raw message

new file mode 100644
index 000000000000..f29fddb7cae0
@@ -0,0 +1,33 @@
+/*
+ * This sample hooks into the "path_chroot"
+ *
+ * Once you run it, the following will not be allowed:
+ * date --set="October 21 2015 16:29:00 PDT"
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/lsm_hooks.h>
+
+static int settime_cb(const struct timespec *ts, const struct timezone *tz)
+{
+	/* We aren't allowed to travel to October 21 2015 16:29 PDT */
+	if (ts->tv_sec >= 1445470140 && ts->tv_sec < 1445470200)
+		return -EPERM;
+
+	return 0;
+}
+
+static struct security_hook_list sample_hooks[] = {
+	LSM_HOOK_INIT(settime, settime_cb),
+};
+
+static int __init lsm_init(void)
+{
+	security_add_dynamic_hooks(sample_hooks, ARRAY_SIZE(sample_hooks),
+				   "sample");
+	return 0;
+}
+
+module_init(lsm_init)
+MODULE_LICENSE("GPL");