[RFC v2 1/3] security: Add safe, dynamic (runtime-loadable) hook support
Casey Schaufler
casey at schaufler-ca.com
Fri Dec 8 16:27:10 UTC 2017
On 12/7/2017 8:24 PM, Sargun Dhillon wrote:
> This patch adds dynamic security hooks. These hooks are designed to allow
> for safe runtime loading. There are a few hooks that have custom
> conventions and are excluded from this list.
>
> 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 manner where the memory around the hooks could eventual be
> written in a sealable manner.
>
> Signed-off-by: Sargun Dhillon <sargun at sargun.me>
> ---
> include/linux/lsm_hooks.h | 250 ++++++++++++++++++++++++++++++++++++++++++
> security/Kconfig | 9 ++
> security/Makefile | 1 +
> security/dynamic.c | 269 ++++++++++++++++++++++++++++++++++++++++++++++
> security/dynamic.h | 18 ++++
> security/security.c | 135 +++++++++++++++++++++--
> 6 files changed, 675 insertions(+), 7 deletions(-)
> 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 7161d8e7ee79..9c44300fc1f8 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -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
> @@ -1983,6 +1984,255 @@ 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 {
Would it make sense to have lsm_dynamic.h ?
> + 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_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_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 list_head list;
> + union security_list_options hook;
> + enum dynamic_security_hook_type type;
> + const char *lsm;
> + struct module *owner;
> +};
> +
> +#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, \
> + .owner = THIS_MODULE, \
> +}
> +
> +
> +
> +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 e8e449444e65..77841bdb5bc5 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.
You'll want to fix this message since you've removed the unloading
facility.
> + 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 4d2d3782ddef..59e695a7e4b6 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 000000000000..cc2f5d232e9a
> --- /dev/null
> +++ b/security/dynamic.c
> @@ -0,0 +1,269 @@
> +// 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/module.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_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_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)
> +{
> + WARN_ON(!try_module_get(hook->owner));
> + mutex_lock(&dynamic_hook_lock);
> + list_add_tail_rcu(&hook->list, &dynamic_hooks[hook->type].head);
> + mutex_unlock(&dynamic_hook_lock);
> + static_branch_enable(&dynamic_hooks_keys[hook->type]);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(security_add_dynamic_hook);
> +
> +void __init security_init_dynamic_hooks(void)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(dynamic_hooks); i++)
> + INIT_LIST_HEAD(&dynamic_hooks[i].head);
> +}
> diff --git a/security/dynamic.h b/security/dynamic.h
> new file mode 100644
> index 000000000000..575bc4e3d370
> --- /dev/null
> +++ b/security/dynamic.h
> @@ -0,0 +1,18 @@
> +#include <linux/lsm_hooks.h>
> +#include <linux/srcu.h>
> +#include <linux/list.h>
> +#include <linux/jump_label.h>
> +
> +#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
> +extern struct static_key_false dynamic_hooks_keys[];
> +
> +struct dynamic_hook {
> + const char *name;
> + struct list_head head;
> +};
> +
> +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 1cd8526cb0b7..278f46ac8fc3 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -29,12 +29,12 @@
> #include <linux/backing-dev.h>
> #include <linux/string.h>
> #include <net/flow.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 +66,8 @@ 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");
>
> /*
> @@ -197,14 +199,61 @@ EXPORT_SYMBOL(unregister_lsm_notifier);
> * This is a hook that returns a value.
> */
>
> +#define call_void_hook_builtin(FUNC, ...) do { \
>
> + struct security_hook_list *P; \
> + list_for_each_entry(P, &security_hook_heads.FUNC, list) \
> + P->hook.FUNC(__VA_ARGS__); \
> +} while (0)
> +
> +#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
> +#define IS_DYNAMIC_HOOK_ENABLED(FUNC) \
> +static_branch_unlikely(&dynamic_hooks_keys[DYNAMIC_SECURITY_HOOK_##FUNC])
> +
> +#define call_void_hook_dynamic(FUNC, ...) ({ \
> + struct dynamic_security_hook *dsh; \
> + struct dynamic_hook *dh; \
> + dh = &dynamic_hooks[DYNAMIC_SECURITY_HOOK_##FUNC]; \
> + list_for_each_entry_rcu(dsh, &dh->head, list) \
> + dsh->hook.FUNC(__VA_ARGS__); \
> +})
> +
> #define call_void_hook(FUNC, ...) \
> do { \
> - struct security_hook_list *P; \
> - \
> - list_for_each_entry(P, &security_hook_heads.FUNC, list) \
> - P->hook.FUNC(__VA_ARGS__); \
> + call_void_hook_builtin(FUNC, __VA_ARGS__); \
> + if (!IS_DYNAMIC_HOOK_ENABLED(FUNC)) \
> + break; \
> + call_void_hook_dynamic(FUNC, __VA_ARGS__); \
> } 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; \
> + list_for_each_entry(P, &security_hook_heads.FUNC, list) { \
> + RC = P->hook.FUNC(__VA_ARGS__); \
> + if (RC != 0) { \
> + continue_iteration = false; \
> + break; \
> + } \
> + } \
> + if (!IS_DYNAMIC_HOOK_ENABLED(FUNC)) \
> + break; \
> + if (!continue_iteration) \
> + break; \
> + dh = &dynamic_hooks[DYNAMIC_SECURITY_HOOK_##FUNC]; \
> + list_for_each_entry(dsh, &dh->head, list) { \
> + RC = dsh->hook.FUNC(__VA_ARGS__); \
> + if (RC != 0) \
> + break; \
> + } \
> + } while (0); \
> + RC; \
> +})
> +
> +#else
> #define call_int_hook(FUNC, IRC, ...) ({ \
> int RC = IRC; \
> do { \
> @@ -219,6 +268,10 @@ EXPORT_SYMBOL(unregister_lsm_notifier);
> RC; \
> })
>
> +#define call_void_hook call_void_hook_builtin
> +#endif
> +
> +
> /* Security operations */
>
> int security_binder_set_context_mgr(struct task_struct *mgr)
> @@ -304,6 +357,31 @@ int security_settime64(const struct timespec64 *ts, const struct timezone *tz)
> return call_int_hook(settime, 0, ts, tz);
> }
>
> +#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
> +static int dynamic_vm_enough_memory_mm(struct mm_struct *mm, long pages)
> +{
> + struct dynamic_security_hook *dsh;
> + struct dynamic_hook *dh;
> + int rc = 1;
> +
> + if (!IS_DYNAMIC_HOOK_ENABLED(vm_enough_memory))
> + return 1;
> +
> + dh = &dynamic_hooks[DYNAMIC_SECURITY_HOOK_vm_enough_memory];
> + list_for_each_entry(dsh, &dh->head, list) {
> + rc = dsh->hook.vm_enough_memory(mm, pages);
> + if (rc <= 0)
> + break;
> + }
> + return rc;
> +}
> +#else
> +static int dynamic_vm_enough_memory_mm(struct mm_struct *mm, long pages)
> +{
> + return 1;
> +}
> +#endif
> +
> int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
> {
> struct security_hook_list *hp;
> @@ -321,9 +399,13 @@ int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
> rc = hp->hook.vm_enough_memory(mm, pages);
> if (rc <= 0) {
> cap_sys_admin = 0;
> - break;
> + goto out;
> }
> }
> +
> + if (dynamic_vm_enough_memory_mm(mm, pages) <= 0)
> + cap_sys_admin = 0;
> +out:
> return __vm_enough_memory(mm, pages, cap_sys_admin);
> }
>
> @@ -1119,6 +1201,42 @@ int security_task_kill(struct task_struct *p, struct siginfo *info,
> return call_int_hook(task_kill, 0, p, info, sig, secid);
> }
>
> +#ifdef CONFIG_SECURITY_DYNAMIC_HOOKS
> +static int dynamic_task_prctl(int option, unsigned long arg2,
> + unsigned long arg3, unsigned long arg4,
> + unsigned long arg5)
> +{
> + struct dynamic_security_hook *dsh;
> + struct dynamic_hook *dh;
> + int rc = -ENOSYS;
> + int thisrc;
> +
> + if (!IS_DYNAMIC_HOOK_ENABLED(task_prctl))
> + goto out;
> +
> + dh = &dynamic_hooks[DYNAMIC_SECURITY_HOOK_task_prctl];
> + list_for_each_entry(dsh, &dh->head, list) {
> + thisrc = dsh->hook.task_prctl(option, arg2, arg3, arg4, arg5);
> + if (thisrc != -ENOSYS) {
> + rc = thisrc;
> + if (thisrc != 0)
> + break;
> + }
> + }
> +
> +out:
> + return rc;
> +}
> +#else
> +static int dynamic_task_prctl(int option, unsigned long arg2,
> + unsigned long arg3, unsigned long arg4,
> + unsigned long arg5)
> +{
> + return -ENOSYS;
> +}
> +
> +#endif
> +
> int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
> unsigned long arg4, unsigned long arg5)
> {
> @@ -1131,9 +1249,12 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
> if (thisrc != -ENOSYS) {
> rc = thisrc;
> if (thisrc != 0)
> - break;
> + goto out;
> }
> }
> +
> + rc = dynamic_task_prctl(option, arg2, arg3, arg4, arg5);
> +out:
> return rc;
> }
>
--
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