security_backing_file_alloc(9)

📦 version 7.3.1, in nixpkgs unstable

💅 security_backing_file_alloc(9) — Kernel API Manual energy ✨

okay so bestie, we're in the Kernel API Manual section today and this one is literally about giving a backing file its very own LSM blob 🎀 like, allocating it, setting it up, the whole glow-up. stay with me, it's not scary, i promise 🫶

✨ NAME ✨

security_backing_file_alloc — allocate and setup a backing file blob 💖

🦋 SYNOPSIS 🦋

int security_backing_file_alloc (struct file *backing_file , const
struct file *user_file );

🌸 ARGUMENTS 🌸

  • backing_file — the backing file 👑 (main character, honestly)
  • user_file — the associated user visible file, aka its plus-one 💅

🎀 DESCRIPTION 🎀

so what this does is: it allocates a backing file LSM blob and then does any necessary initialization of that LSM blob ✨ that's the whole job. no cap.

but here's the part you actually need to hear, bestie 👂 — there will be some operations where the LSM will not have access to user_file after this point 😭 so any important state that's associated with user_file and that matters to the LSM? capture it in the backing file's LSM blob right now. this is your moment. grab the lore while it's still in the room 🫶

and a very serious vibe check: LSM's should avoid taking a reference to user_file in this hook 🚫 because that will result in problems later when the system attempts to drop/put the file references — due to a circular dependency 💀 don't do it. fr fr. it's giving bad idea and we are NOT doing that.

⭐ RETURN ⭐

Return 0 if the hook is successful 🎉 negative values otherwise 🙈

🧚 SEE ALSO 🧚

the linked lore starts with Kernel file ./security/security.c and then, okay, deep breath, it's a lot but we list every single one because we don't skip ✨

and that's the page bestie, no notes 💅 this one lives under ./security and the docs are stamped October 2026 — go be a menace to circular dependencies and slay ✨🦋💖

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