security_path_link(9)

📦 version 7.3.1, in nixpkgs unstable

okay so real talk: this is a page from the Kernel API Manual series — the (9) in the name is your lil hint that we're hanging out in kernel-space, not in "type it in your shell" land. come on in, the vibes are immaculate 🦋

✨ NAME ✨

security_path_link — the vibe check that happens before a new hard link to a file gets created, i.e. is this even allowed?? 🌸

✨ SYNOPSIS ✨

int security_path_link (struct dentry *old_dentry , const struct path
       *new_dir , struct dentry *new_dentry );

like, that's the whole signature. short, sweet, three arguments, one int coming back at you. periodt 💅

✨ ARGUMENTS ✨

  • old_dentry — the existing file. the one that's already here, living its life, being a whole file. 🌈
  • new_dir — the new parent directory. the address of the new link's soon-to-be home. 🏡
  • new_dentry — the new link itself. the fresh little guy about to be born. 🐣

✨ DESCRIPTION ✨

so the whole job of this function is literally just: check permission before creating a new hard link to a file. that's it. that's the function. 🫶

think of it as the bouncer at the club door of hard-link creation — it looks at the situation, consults the security modules, and decides whether you're getting in or not. no cap. 👑

✨ RETURN ✨

returns 0 if permission is granted. that's the whole return story — 0 = you're in, bestie, go make that link. ⭐

ngl, 0 is the good one here, which is always a little bit of an emotional rollercoaster in C, but that's the deal. 💀

✨ SEE ALSO ✨

the reading list is long — like, "you asked for the whole friend group and they all showed up" long. but every single one is here, i promise 🙈

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_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_act_as(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)

ok that's genuinely the whole list, i didn't skip a single one, you're welcome 😭💖

mwah 💋 that's the page!! this one lives down in ./security, and the version/date on the tin is October 2026 — so like, future vibes, but the facts are timeless. go forth and link responsibly, bestie 🦋✨🎀

📦 where this page comes from