components/wpa_supplicant/src/crypto/sha1-prf.c (ESP-IDF)

/* * SHA1-based PRF * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi> * * This software may be distributed under the terms of the BSD license. * See README for more details. */ #include "includes.h" #include "common.h" #include "sha1.h" #include "crypto.h" /** * sha1_prf - SHA1-based Pseudo-Random Function (PRF) (IEEE 802.11i, 8.5.1.1) * @key: Key for PRF * @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 bytes of key to generate * Returns: 0 on success, -1 of failure * * This function is used to derive new, cryptographically separate keys from a * given key (e.g., PMK in IEEE 802.11i). */ int sha1_prf(const u8 *key, size_t key_len, const char *label, const u8 *data, size_t data_len, u8 *buf, size_t buf_len) { u8 counter = 0; size_t pos, plen; u8 hash[SHA1_MAC_LEN]; size_t label_len = os_strlen(label) + 1; const unsigned char *addr[3]; size_t len[3]; addr[0] = (u8 *) label; len[0] = label_len; addr[1] = data; len[1] = data_len; addr[2] = &counter; len[2] = 1; pos = 0; while (pos < buf_len) { plen = buf_len - pos; if (plen >= SHA1_MAC_LEN) { if (hmac_sha1_vector(key, key_len, 3, addr, len, &buf[pos])) return -1; pos += SHA1_MAC_LEN; } else { if (hmac_sha1_vector(key, key_len, 3, addr, len, hash)) return -1; os_memcpy(&buf[pos], hash, plen); break; } counter++; } forced_memzero(hash, sizeof(hash)); return 0; }