security_kernel_act_as(9)

💅 security_kernel_act_as(9) — Kernel API Manual ✨

okay so bestie, listen up, because we're about to get into the credential side of the kernel LSM world and honestly? it's giving main character energy. this is a page from the Kernel API Manual, and it's a short one — one function, two args, one job. no cap.

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🌸 NAME 🌸

security_kernel_act_as — literally just "set the kernel credentials to act as secid". that's it. that's the whole vibe. 🫶

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🦋 SYNOPSIS 🦋

int security_kernel_act_as (struct cred *new , u32 secid );

like, copy-paste it exactly, don't @ me about the spaces around the commas, that's how the manpage does it. 💀

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🎀 ARGUMENTS 🎀

• new — the credentials. yes, that's the whole description. the manpage said "credentials" and honestly? it ate. that's the struct cred * you're about to fill in.
• secid — the secid. again. that's it. that's the text. it's a u32 security ID and we are NOT expanding on it because the original didn't. 🙈

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✨ DESCRIPTION ✨

so here's the tea ☕: this one sets the credentials for a kernel service to act as — and the original calls this the subjective context. so you're basically telling the kernel "hey, this service is gonna do stuff as this security ID now."

but — and this is the important bit, the ✨vibe check✨ of the whole page — the current task must be the one that nominated secid. that's a hard requirement, bestie, not a suggestion. don't be out here nominating secids from one task and then calling this from another one. that's not slay behaviour. 😭

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⭐ RETURN ⭐

returns 0 if successful. that's it. that's the whole return section. zero means we ate and left no crumbs 💅✨

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👑 SEE ALSO 👑

okay so this part is long. like, unreasonably long. this is the kernel's whole LSM friend group and they all showed up to the party. i'm keeping every single one, exactly as written, because i would never do you dirty like that. here's the full list, under ./security/security.c:

Kernel file ./security/security.c lsm_file_alloc(9),
lsm_backing_file_alloc(9), lsm_blob_alloc(9), lsm_cred_alloc(9),
lsm_inode_alloc(9), lsm_task_alloc(9), lsm_ipc_alloc(9),
lsm_key_alloc(9), lsm_msg_msg_alloc(9), lsm_bdev_alloc(9),
lsm_bpf_map_alloc(9), lsm_bpf_prog_alloc(9), lsm_bpf_token_alloc(9),
lsm_superblock_alloc(9), lsm_fill_user_ctx(9),
security_binder_set_context_mgr(9), security_binder_transaction(9),
security_binder_transfer_binder(9), security_binder_transfer_file(9),
security_ptrace_access_check(9), security_ptrace_traceme(9),
security_capget(9), security_capset(9), security_capable(9),
security_quotactl(9), security_quota_on(9), security_syslog(9),
security_settime64(9), security_vm_enough_memory_mm(9),
security_bprm_creds_for_exec(9), security_bprm_creds_from_file(9),
security_bprm_check(9), security_bprm_committing_creds(9),
security_bprm_committed_creds(9), security_fs_context_submount(9),
security_fs_context_dup(9), security_fs_context_parse_param(9),
security_sb_alloc(9), security_sb_delete(9), security_sb_free(9),
security_free_mnt_opts(9), security_sb_eat_lsm_opts(9),
security_sb_mnt_opts_compat(9), security_sb_remount(9),
security_sb_kern_mount(9), security_sb_show_options(9),
security_sb_statfs(9), security_sb_mount(9), security_sb_umount(9),
security_sb_pivotroot(9), security_sb_set_mnt_opts(9),
security_sb_clone_mnt_opts(9), security_move_mount(9),
security_path_notify(9), security_inode_alloc(9),
security_inode_free(9), security_dentry_init_security(9),
security_dentry_create_files_as(9), security_inode_init_security(9),
security_inode_init_security_anon(9), security_path_mknod(9),
security_path_post_mknod(9), security_path_mkdir(9),
security_path_rmdir(9), security_path_unlink(9),
security_path_symlink(9), security_path_link(9),
security_path_rename(9), security_path_truncate(9),
security_path_chmod(9), security_path_chown(9), security_path_chroot(9),
security_inode_create(9), security_inode_post_create_tmpfile(9),
security_inode_link(9), security_inode_unlink(9),
security_inode_symlink(9), security_inode_mkdir(9),
security_inode_rmdir(9), security_inode_mknod(9),
security_inode_rename(9), security_inode_readlink(9),
security_inode_follow_link(9), security_inode_permission(9),
security_inode_setattr(9), security_inode_post_setattr(9),
security_inode_getattr(9), security_inode_setxattr(9),
security_inode_set_acl(9), security_inode_post_set_acl(9),
security_inode_get_acl(9), security_inode_remove_acl(9),
security_inode_post_remove_acl(9), security_inode_post_setxattr(9),
security_inode_getxattr(9), security_inode_listxattr(9),
security_inode_removexattr(9), security_inode_post_removexattr(9),
security_inode_file_setattr(9), security_inode_file_getattr(9),
security_inode_need_killpriv(9), security_inode_killpriv(9),
security_inode_getsecurity(9), security_inode_setsecurity(9),
security_inode_listsecurity(9), security_inode_getlsmprop(9),
security_inode_copy_up(9), security_inode_copy_up_xattr(9),
security_inode_setintegrity(9), security_kernfs_init_security(9),
security_file_permission(9), security_file_alloc(9),
security_file_release(9), security_file_free(9),
security_backing_file_alloc(9), security_backing_file_free(9),
security_file_ioctl(9), security_file_ioctl_compat(9),
security_mmap_file(9), security_mmap_backing_file(9),
security_mmap_addr(9), security_file_mprotect(9), security_file_lock(9),
security_file_fcntl(9), security_file_set_fowner(9),
security_file_send_sigiotask(9), security_file_receive(9),
security_file_open(9), security_file_post_open(9),
security_file_truncate(9), security_task_alloc(9),
security_task_free(9), security_cred_alloc_blank(9),
security_cred_free(9), security_prepare_creds(9),
security_transfer_creds(9), security_cred_getsecid(9),
security_cred_getlsmprop(9), security_kernel_create_files_as(9),
security_kernel_module_request(9), security_kernel_read_file(9),
security_kernel_post_read_file(9), security_kernel_load_data(9),
security_kernel_post_load_data(9), security_task_fix_setuid(9),
security_task_fix_setgid(9), security_task_fix_setgroups(9),
security_task_setpgid(9), security_task_getpgid(9),
security_task_getsid(9), security_current_getlsmprop_subj(9),
security_task_getlsmprop_obj(9), security_task_setnice(9),
security_task_setioprio(9), security_task_getioprio(9),
security_task_prlimit(9), security_task_setrlimit(9),
security_task_setscheduler(9), security_task_getscheduler(9),
security_task_movememory(9), security_task_kill(9),
security_task_prctl(9), security_task_to_inode(9),
security_create_user_ns(9), security_ipc_permission(9),
security_ipc_getlsmprop(9), security_msg_msg_alloc(9),
security_msg_msg_free(9), security_msg_queue_alloc(9),
security_msg_queue_free(9), security_msg_queue_associate(9),
security_msg_queue_msgctl(9), security_msg_queue_msgsnd(9),
security_msg_queue_msgrcv(9), security_shm_alloc(9),
security_shm_free(9), security_shm_associate(9), security_shm_shmctl(9),
security_shm_shmat(9), security_sem_alloc(9), security_sem_free(9),
security_sem_associate(9), security_sem_semctl(9),
security_sem_semop(9), security_d_instantiate(9),
security_getselfattr(9), security_setselfattr(9),
security_getprocattr(9), security_setprocattr(9),
security_ismaclabel(9), security_secid_to_secctx(9),
security_lsmprop_to_secctx(9), security_secctx_to_secid(9),
security_release_secctx(9), security_inode_invalidate_secctx(9),
security_inode_notifysecctx(9), security_inode_setsecctx(9),
security_inode_getsecctx(9), security_post_notification(9),
security_watch_key(9), security_netlink_send(9),
security_unix_stream_connect(9), security_unix_may_send(9),
security_socket_create(9), security_socket_post_create(9),
security_socket_socketpair(9), security_socket_bind(9),
security_socket_connect(9), security_socket_listen(9),
security_socket_accept(9), security_socket_sendmsg(9),
security_socket_recvmsg(9), security_socket_getsockname(9),
security_socket_getpeername(9), security_socket_getsockopt(9),
security_socket_setsockopt(9), security_socket_shutdown(9),
security_sock_rcv_skb(9), security_socket_getpeersec_stream(9),
security_socket_getpeersec_dgram(9), lsm_sock_alloc(9),
security_sk_alloc(9), security_sk_free(9), security_sk_clone(9),
security_sk_classify_flow(9), security_req_classify_flow(9),
security_sock_graft(9), security_inet_conn_request(9),
security_inet_csk_clone(9), security_inet_conn_established(9),
security_secmark_relabel_packet(9), security_secmark_refcount_inc(9),
security_secmark_refcount_dec(9), security_tun_dev_alloc_security(9),
security_tun_dev_free_security(9), security_tun_dev_create(9),
security_tun_dev_attach_queue(9), security_tun_dev_attach(9),
security_tun_dev_open(9), security_sctp_assoc_request(9),
security_sctp_bind_connect(9), security_sctp_sk_clone(9),
security_sctp_assoc_established(9), security_mptcp_add_subflow(9),
security_unix_find(9), security_ib_pkey_access(9),
security_ib_endport_manage_subnet(9), security_ib_alloc_security(9),
security_ib_free_security(9), security_xfrm_policy_alloc(9),
security_xfrm_policy_clone(9), security_xfrm_policy_free(9),
security_xfrm_policy_delete(9), security_xfrm_state_alloc(9),
security_xfrm_state_alloc_acquire(9), security_xfrm_state_delete(9),
security_xfrm_state_free(9), security_xfrm_policy_lookup(9),
security_xfrm_state_pol_flow_match(9), security_xfrm_decode_session(9),
security_key_alloc(9), security_key_free(9), security_key_permission(9),
security_key_getsecurity(9), security_key_post_create_or_update(9),
security_audit_rule_init(9), security_audit_rule_known(9),
security_audit_rule_free(9), security_audit_rule_match(9),
security_bpf(9), security_bpf_map(9), security_bpf_prog(9),
security_bpf_map_create(9), security_bpf_prog_load(9),
security_bpf_token_create(9), security_bpf_token_cmd(9),
security_bpf_token_capable(9), security_bpf_map_free(9),
security_bpf_prog_free(9), security_bpf_token_free(9),
security_locked_down(9), security_bdev_alloc(9), security_bdev_free(9),
security_bdev_setintegrity(9), security_perf_event_open(9),
security_perf_event_alloc(9), security_perf_event_free(9),
security_perf_event_read(9), security_perf_event_write(9),
security_uring_override_creds(9), security_uring_sqpoll(9),
security_uring_cmd(9), security_uring_allowed(9),
security_initramfs_populated(9)

like i said. the whole friend group. iykyk 🧚💜

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💖 that's genuinely the whole page bestie — one function, two args, one requirement, and one absolute novel of a SEE ALSO. read the creds, respect the current task, and you're golden. periodt. 🎀

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this little cutie comes from the source tree path ./security, dated October 2026, and it lives in the Kernel API Manual (section 9, kernel developer land). mwah 💋 thanks for reading, bestie — go nominate a secid responsibly 🦋✨