tpm2_start_auth_session(9)

📦 version 7.3.1, in nixpkgs unstable

✨ tpm2_start_auth_session(9) ✨

okay so bestie, we're in the Kernel API Manual today — like, the tpm2_start_auth_session(9) section specifically — and it's giving very much "kernel dev doing crypto things at 2am" energy 💅 don't worry tho, i got you 🫶

🌸 NAME 🌸

tpm2_start_auth_session — literally creates an HMAC authentication session 💖 yes, that's the whole vibe, that's what it does, periodt.

🎀 SYNOPSIS 🎀

int tpm2_start_auth_session (struct tpm_chip *chip );

that's it. that's the whole call. one arg, returns an int. iconic minimalism honestly ✨

🦋 ARGUMENTS 🦋

  • chip — a TPM chip 🧚 that's it, that's the parameter, it's your chip and she's a struct tpm_chip *

💜 DESCRIPTION 💜

okay so here's what actually happens, no cap:

she loads the ephemeral key — that's the null seed 🌱 — and then starts up an HMAC authenticated session 🔐 like, the session is now officially a thing, main character energy fr fr.

and then, the plot twist 😭: the null seed is flushed before the return. so by the time this function hands control back to you, that seed? gone. wiped. not invited to the afterparty 🙈 keep that in mind, it's lowkey important iykyk.

returns zero on success 🎉 or a POSIX error code if things went sideways 💀 (we love a clear error contract, highkey obsessed.)

bestie pls remember: zero = slay, anything else = check your error codes, don't just ignore the return value 🫶

🔥 SEE ALSO 🔥

all the siblings in the same kernel file, ./drivers/char/tpm/tpm2-sessions.c — go read the whole family, they're all connected:

🌸 mwah, that's the whole page 🌸

and that's a wrap on our little kernel session 💖 this one lives over in ./drivers/char/tpm, and the manual's dated October 2026 — so like, future-coded but make it TPM ⭐ go forth and authenticate responsibly, bestie 👑🎀

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