ubifs_hmac_wkm(9)

💅 ubifs_hmac_wkm(9) — a Kernel API Manual moment 🎀

okay so bestie, this is ubifs_hmac_wkm from the kernel API manual, and honestly? it's giving "small function, big responsibility." let's get into it ✨

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🌸 NAME 🌸

ubifs_hmac_wkm — create a HMAC of the well known message 🫶

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⭐ SYNOPSIS ⭐

int ubifs_hmac_wkm (struct ubifs_info *c , u8 *hmac );

like, that's the whole signature. no notes. iconic. 👑

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🦋 ARGUMENTS 🦋

• c — the UBIFS file-system description object 💖 (yes, the whole file system is in this one little pointer, nbd)
• hmac — the HMAC of the well known message 🔥 that's the output, bestie, it lives here now

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🌈 DESCRIPTION 🌈

okay so what does this even do. this function creates a HMAC of a well known message. and why, you ask? because it's used to check if the key you handed it is actually suitable to authenticate a UBIFS image. vibe check for cryptographic keys, basically. 💅

but here's the tea — this is only a convenience to the user, so they get a better error message when the wrong key is provided. that's it. that's the whole gig. not me being the friendliest possible error path 😭🫶

and the return sitch:

this function returns 0 for success, or a negative error code otherwise. so like, 0 = slay, negative = not slay. 🍓

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✨ SEE ALSO ✨

the whole friend group, fr fr:

• Kernel file ./fs/ubifs/auth.c
• __ubifs_node_calc_hash(9)
• ubifs_hash_calc_hmac(9)
• ubifs_prepare_auth_node(9)
• __ubifs_hash_get_desc(9)
• ubifs_bad_hash(9)
• __ubifs_node_check_hash(9)
• ubifs_sb_verify_signature(9)
• ubifs_init_authentication(9)
• __ubifs_exit_authentication(9)
• ubifs_node_calc_hmac(9)
• __ubifs_node_insert_hmac(9)
• __ubifs_node_verify_hmac(9)

like, go read them. they're all in their authentication era together 💜🧚

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and that's the page, bestie! it lives over at ./fs/ubifs and this lil snapshot is dated October 2026 — main character documentation energy only, no cap. 💖🎀✨