ima_kernel_module_request(9)

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

okay so bestie, welcome to the glow-up of ima_kernel_module_request, straight out of the Kernel API Manual. she's a tiny function with one very specific job and honestly? she ate. let's get into it 💖

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✨ NAME ✨

ima_kernel_module_request — literally here to Prevent crypto-pkcs1(rsa,*) requests 🛑🔐

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🌸 SYNOPSIS 🌸

int ima_kernel_module_request (char *kmod_name );

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🦋 ARGUMENTS 🦋

• kmod_name — the kernel module name, bestie. that's it, that's the whole parameter 🫶

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👑 DESCRIPTION 👑

so here's the situation, and it's giving "infinite loop but make it a deadlock" 😭

the whole point of this function is to avoid a verification loop: verifying the signature of the modprobe binary would itself require executing modprobe. and like… that's a problem. because the modprobe iint->mutex is already held when the signature verification is performed, so a deadlock occurs the moment modprobe gets executed inside that critical region — the same lock simply cannot be taken again. periodt. 💀

when does this cursed scenario even happen? ok so: public_key_verify_signature, in the case of the RSA algorithm, uses alg_name to store internal information so it can construct an algorithm on the fly ✨ — but then crypto_larval_lookup will try to use that same alg_name to load a kernel module with that same name. and that's the vibe check failing, bestie 🚩

and here's the slay part: since we don't have any real "crypto-pkcs1(rsa,*)" kernel modules, it is safe to fail such a module request from crypto_larval_lookup — which conveniently avoids the verification loop entirely. icon behavior, no cap 👑🔥

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⭐ RETURN ⭐

• Zero — it is safe to load the kernel module, we're so back 🟢
• -EINVAL — otherwise, and no we're not okay 😭

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🌈 SEE ALSO 🌈

Kernel file ./security/integrity/ima/ima_main.c 💖 and the whole friend group:

• ima_file_free(9)
• ima_file_mmap(9)
• ima_file_mprotect(9)
• ima_bprm_check(9)
• ima_creds_check(9)
• ima_bprm_creds_for_exec(9)
• ima_file_check(9)
• ima_file_hash(9)
• ima_inode_hash(9)
• ima_post_create_tmpfile(9)
• ima_post_path_mknod(9)
• ima_read_file(9)
• ima_post_read_file(9)
• ima_load_data(9)
• ima_post_load_data(9)
• process_buffer_measurement(9)
• ima_kexec_cmdline(9)
• ima_measure_critical_data(9)
• ima_measure_raw_policy(9)

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okay that's the whole page, you're officially smarter than you were five minutes ago, i'm so proud of you 🥹🫶 this lil entry lives in ./security/integrity/ima and it's stamped October 2026 — go off, calendar icon 💅✨ mwah, bye bestie 🎀💜