security_file_open(9)

📦 version 7.3.1, in nixpkgs unstable

💅 security_file_open — like, the manual page bestie

okay so real talk, this one is from the Kernel API Manual, section 9, and it's called security_file_open. It's giving "quiet little LSM hook that does so much" and honestly? Obsessed. 🎀

✨ NAME ✨

security_file_open — saves all that open()-time state so the LSM can come back to it later, no cap

🌸 SYNOPSIS 🌸

int security_file_open (struct file *file );

💖 ARGUMENTS 💖

  • file — the file, obviously 💅 the struct you're doing all this saving-for-later business on

🦋 DESCRIPTION 🦋

So what it actually does: it saves the open-time permission-checking state so it can be pulled back out later at file_permission time, and then it rechecks access if literally anything has changed since inode_permission. Lowkey thorough of it. ✨

And here's the cute trick — you can check whether a file is opened for execution (think an execve(2) call) either directly or indirectly (hi, ELF's ld.so 👋) by checking:

file->f_flags & __FMODE_EXEC

That's the whole vibe check right there. iykyk. 🔥

👑 RETURN 👑

Returns 0 if permission is granted. That's it, that's the answer, slay. ✅

🌈 SEE ALSO 🌈

Kernel file ./security/security.c — plus the whole entire extended friend group, and no I'm not skipping a single one of them, we don't do that here 💜

🫶 and that's the whole page, bestie. this lil icon comes from the ./security source tree and it's dated October 2026 — go forth and check your file->f_flags, ily, bye!! 💖

📦 where this page comes from