Add a KUnit test suite for the AES-CCM library API. It consists of: - All the shared test cases from aead-test-template.h. These include extensive consistency tests, a "Monte-Carlo test", and a benchmark. - Tests against hardcoded AES-CCM test vectors from external sources. - Tests for CCM-specific message length validation. To generate the expected aes_ccm_monte_carlo_checksum[] value, add a script gen-aead-testvecs.py which computes it using python-cryptography.
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| 1 | +#!/usr/bin/env python3 | |
| 2 | +# SPDX-License-Identifier: GPL-2.0-or-later | |
| 3 | +# | |
| 4 | +# Script that generates known-good data used in the AEAD tests. | |
| 5 | +# | |
| 6 | +# Requires that python-cryptography be installed. | |
| 7 | +# | |
| 8 | +# Copyright 2026 Google LLC | |
| 9 | + | |
| 10 | +import hashlib | |
| 11 | +import sys | |
| 12 | +import cryptography.hazmat.primitives.ciphers.aead | |
| 13 | + | |
| 14 | + | |
| 15 | +# Deterministically generate 'length' random bytes. | |
| 16 | +def rand_bytes(length): | |
| 17 | + seed = length | |
| 18 | + out = [] | |
| 19 | + for _ in range(length): | |
| 20 | + seed = (seed * 25214903917 + 11) % 2**48 | |
| 21 | + out.append((seed >> 16) % 256) | |
| 22 | + return bytes(out) | |
| 23 | + | |
| 24 | + | |
| 25 | +# Deterministically generate many different AEAD inputs using exactly the same | |
| 26 | +# method that the test uses; encrypt them using an independent implementation of | |
| 27 | +# the algorithm; compute the checksum of all the resulting (ciphertext, authtag) | |
| 28 | +# pairs concatenated to each other; and print the checksum as a C struct. | |
| 29 | +def gen_monte_carlo_checksum(alg): | |
| 30 | + blake2s = hashlib.blake2s() | |
| 31 | + for data_len in range(1025): | |
| 32 | + ad_len = data_len % 293 | |
| 33 | + pt = rand_bytes(data_len) | |
| 34 | + ad = rand_bytes(ad_len) | |
| 35 | + if alg == "aes-ccm": | |
| 36 | + key_len = [16, 24, 32][data_len % 3] | |
| 37 | + key = rand_bytes(key_len) | |
| 38 | + nonce = rand_bytes([7, 8, 9, 10, 11, 12, 13][data_len % 7]) | |
| 39 | + tag_len = [4, 6, 8, 10, 12, 14, 16][data_len % 7] | |
| 40 | + ccm = cryptography.hazmat.primitives.ciphers.aead.AESCCM( | |
| 41 | + key, tag_length=tag_len | |
| 42 | + ) | |
| 43 | + ct_and_tag = ccm.encrypt(nonce, pt, ad) | |
| 44 | + | |
| 45 | + blake2s.update(ct_and_tag) | |
| 46 | + | |
| 47 | + name = f"{alg.replace('-', '_')}_monte_carlo_checksum" | |
| 48 | + value = blake2s.digest() | |
| 49 | + print(f"static const u8 {name}[BLAKE2S_HASH_SIZE] = {{") | |
| 50 | + for i in range(0, len(value), 11): | |
| 51 | + line = "\t" + "".join(f"0x{b:02x}, " for b in value[i : i + 11]) | |
| 52 | + print(f"{line.rstrip()}") | |
| 53 | + print("};") | |
| 54 | + | |
| 55 | + | |
| 56 | +if len(sys.argv) != 2 or sys.argv[1] not in ("aes-ccm"): | |
| 57 | + sys.stderr.write("Usage: gen-aead-testvecs.py [aes-ccm]\n") | |
| 58 | + sys.exit(1) | |
| 59 | + | |
| 60 | +gen_monte_carlo_checksum(sys.argv[1]) | |