/** * sha384_prf_bits - IEEE Std 802.11ac-2013, 11.6.1.7.2 Key derivation function * @key: Key for KDF * @key_len: Length of the key in bytes * @label: A unique label for each purpose of the PRF * @data: Extra data to bind into the key * @data_len: Length of the data * @buf: Buffer for the generated pseudo-random key * @buf_len: Number of bits of key to generate * * This function is used to derive new, cryptographically separate keys from a * given key. If the requested buf_len is not divisible by eight, the least * significant 1-7 bits of the last octet in the output are not part of the * requested output. */ void sha384_prf_bits(const u8 *key, size_t key_len, const char *label, const u8 *data, size_t data_len, u8 *buf, size_t buf_len_bits) { u16 counter = 1; size_t pos, plen; u8 hash[SHA384_MAC_LEN]; const u8 *addr[4]; size_t len[4]; u8 counter_le[2], length_le[2]; size_t buf_len = (buf_len_bits + 7) / 8; addr[0] = counter_le; len[0] = 2; addr[1] = (u8 *) label; len[1] = os_strlen(label); addr[2] = data; len[2] = data_len; addr[3] = length_le; len[3] = sizeof(length_le); WPA_PUT_LE16(length_le, buf_len_bits); pos = 0; while (pos < buf_len) { plen = buf_len - pos; WPA_PUT_LE16(counter_le, counter); if (plen >= SHA384_MAC_LEN) { hmac_sha384_vector(key, key_len, 4, addr, len, &buf[pos]); pos += SHA384_MAC_LEN; } else { hmac_sha384_vector(key, key_len, 4, addr, len, hash); os_memcpy(&buf[pos], hash, plen); pos += plen; break; } counter++; } /* * Mask out unused bits in the last octet if it does not use all the * bits. */ if (buf_len_bits % 8) { u8 mask = 0xff << (8 - buf_len_bits % 8); buf[pos - 1] &= mask; } os_memset(hash, 0, sizeof(hash)); }
/** * rsn_pmkid_suite_b_192 - Calculate PMK identifier for Suite B AKM * @kck: Key confirmation key * @kck_len: Length of kck in bytes * @aa: Authenticator address * @spa: Supplicant address * @pmkid: Buffer for PMKID * Returns: 0 on success, -1 on failure * * IEEE Std 802.11ac-2013 - 11.6.1.3 Pairwise key hierarchy * PMKID = Truncate(HMAC-SHA-384(KCK, "PMK Name" || AA || SPA)) */ int rsn_pmkid_suite_b_192(const u8 *kck, size_t kck_len, const u8 *aa, const u8 *spa, u8 *pmkid) { char *title = "PMK Name"; const u8 *addr[3]; const size_t len[3] = { 8, ETH_ALEN, ETH_ALEN }; unsigned char hash[SHA384_MAC_LEN]; addr[0] = (u8 *) title; addr[1] = aa; addr[2] = spa; if (hmac_sha384_vector(kck, kck_len, 3, addr, len, hash) < 0) return -1; os_memcpy(pmkid, hash, PMKID_LEN); return 0; }