3 * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
17 * sha1_prf - SHA1-based Pseudo-Random Function (PRF) (IEEE 802.11i, 8.5.1.1)
19 * @key_len: Length of the key in bytes
20 * @label: A unique label for each purpose of the PRF
21 * @data: Extra data to bind into the key
22 * @data_len: Length of the data
23 * @buf: Buffer for the generated pseudo-random key
24 * @buf_len: Number of bytes of key to generate
25 * Returns: 0 on success, -1 of failure
27 * This function is used to derive new, cryptographically separate keys from a
28 * given key (e.g., PMK in IEEE 802.11i).
30 int sha1_prf(const u8 *key, size_t key_len, const char *label,
31 const u8 *data, size_t data_len, u8 *buf, size_t buf_len)
35 u8 hash[SHA1_MAC_LEN];
36 size_t label_len = os_strlen(label) + 1;
37 const unsigned char *addr[3];
40 addr[0] = (u8 *) label;
48 while (pos < buf_len) {
50 if (plen >= SHA1_MAC_LEN) {
51 if (hmac_sha1_vector(key, key_len, 3, addr, len,
56 if (hmac_sha1_vector(key, key_len, 3, addr, len,
59 os_memcpy(&buf[pos], hash, plen);
64 os_memset(hash, 0, sizeof(hash));