fsverity_prepare_hash_state(9)

💅 fsverity_prepare_hash_state(9)

okay so this page lives in the Kernel API Manual (yes bestie, we're in kernel territory, drink some water 💖) and it's all about one little function that does your hashing homework before the hashing even starts. iconic behaviour, honestly.

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🌸 NAME 🌸

fsverity_prepare_hash_state — precompute the initial hash state ✨

like, get the hash state ready ahead of time so nobody's scrambling later. main character prep energy.

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🎀 SYNOPSIS 🎀

union fsverity_hash_ctx * fsverity_prepare_hash_state (const struct
fsverity_hash_alg *alg , const u8 *salt , size_t salt_size );

that's the whole signature, copy it exactly, no editing the source code because you think it'd look cuter with a different name 💅

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🦋 ARGUMENTS 🦋

• alg — the hash algorithm. which one we're using. that's it, that's the vibe.
• salt — a salt which is to be prepended to all data to be hashed 🧂 literally gets sprinkled on the front of everything before it goes through the hash.
• salt_size — salt size in bytes. how many bytes of salt we're working with.

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🔥 RETURN 🔥

the kmalloc'ed initial hash state, or NULL if out of memory 😭

so like… check for NULL, bestie. if memory says no, this function says NULL, and you gotta handle that. no cap.

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🌈 SEE ALSO 🌈

• Kernel file ./fs/verity/hash_algs.c
• fsverity_get_hash_alg(9)
• fsverity_hash_block(9)
• fsverity_hash_buffer(9)

go read those too, iykyk 🫶

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and that's the page!! source: ./fs/verity, dated October 2026 — so go forth, precompute that hash state, and slay 💜🎀🦋