evm_write_key(9)

💖 evm_write_key(9) 💖

hii bestie!! welcome to the Kernel API Manual — this is the page for evm_write_key(9), and we are gonna make it make sense, i promise 🫶✨

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✨ NAME ✨

• evm_write_key — the write() for <securityfs>/evm, periodt 💅

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🎀 SYNOPSIS 🎀

okay so here's the signature, copied exactly so u can trust it:

ssize_t evm_write_key (struct file *file , const char __user *buf ,
       size_t count , loff_t *ppos );

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🧚 ARGUMENTS 🧚

• file — file pointer, not actually used 🙈
• buf — where to get the data from
• count — bytes sent
• ppos — where to start

bestie note: file is literally not actually used here, no cap 💀

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🌸 DESCRIPTION 🌸

okay so the whole vibe is: this is used to signal that key is on the kernel key ring 🔑

here's the little to-do list it's giving:

• get the integrity hmac key from the kernel key ring
• create list of hmac protected extended attributes

and then — Returns number of bytes written or error code, as appropriate ✨

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🦋 SEE ALSO 🦋

• Kernel file: ./security/integrity/evm/evm_secfs.c
• evm_read_key(9)
• evm_read_xattrs(9)
• evm_write_xattrs(9)

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xoxo 💋 this page's source/version is ./security/integrity/evm, and its date is October 2026. now go slay those hmac protected extended attributes, bestie 💅✨