KEYCTL_INVALIDATE(2const)

💅 KEYCTL_INVALIDATE (it's a 2const page, bestie)

okay so welcome to the group chat, we're talking about KEYCTL_INVALIDATE from the linux/keyctl.h cinematic universe 🎀

✨ NAME ✨

KEYCTL_INVALIDATE — invalidate a key. that's it. that's the whole job. she ghosts the key 💀

📚 LIBRARY 📚

Standard C library (libc, -lc) — the classic, the icon, the one you already have 🫶

🌸 SYNOPSIS 🌸

#include <linux/keyctl.h>  /* Definition of KEY* constants */
#include <sys/syscall.h>   /* Definition of SYS_* constants */
#include <unistd.h>

long syscall(SYS_keyctl, KEYCTL_INVALIDATE, key_serial_t key);

no cap, that's the whole summoning circle 🔮

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🦋 DESCRIPTION 🦋

okay so picture this: you have a key, and you want it marked as invalid. That's the vibe. That's the function.

The ID of the key you're about to send to the shadow realm is specified in key ✨

But here's the thing, bestie — to invalidate a key, the caller must have search permission on the key. no permission, no invalidation, no exceptions. it's giving "you can't sit with us" 🚫

So when you do call it: this operation marks the key as invalid and schedules immediate garbage collection. The garbage collector then:

• removes the invalidated key from all keyrings 🌈
• deletes the key when its reference count reaches zero 💀

And after this operation, the key will be ignored by all searches, even if it hasn't actually been deleted yet. She's out of the search results already, she just hasn't finished packing her bags 🧳

Keys that are marked invalid become invisible to normal key operations immediately, though — plot twist — they are still visible in /proc/keys (marked with an 'i' flag) until they are actually removed. so she's gone but the receipts are still there 🙈

fr fr: invisible to operations ≠ deleted. the 'i' flag is your only warning in /proc/keys.

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🔥 RETURN VALUE 🔥

• On success, 0 is returned. slay. ✨
• On error, -1 is returned, and errno is set to indicate the error. 😭

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⭐ VERSIONS ⭐

A wrapper is provided in the libkeyutils library: keyctl_invalidate(3). use it if you don't wanna hand-roll the syscall, iykyk 💅

👑 STANDARDS 👑

Linux. just Linux. that's the standard. periodt 🫶

🎀 HISTORY 🎀

Linux 3.5 — she's been iconic since 2012-ish, we stan a legacy queen 🌸

💜 SEE ALSO 💜

• keyctl(2)
• keyctl_invalidate(3)

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and that's the page, bestie 💖 this came to you courtesy of Linux man-pages 6.20, dated 2026-02-08 — go invalidate something (respectfully), mwah 🫶✨