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

/* * SHA1 T-PRF for EAP-FAST * 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_t_prf - EAP-FAST Pseudo-Random Function (T-PRF) * @key: Key for PRF * @key_len: Length of the key in bytes * @label: A unique label for each purpose of the PRF * @seed: Seed value to bind into the key * @seed_len: Length of the seed * @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 for EAP-FAST. T-PRF is defined in RFC 4851, Section 5.5. */ int sha1_t_prf(const u8 *key, size_t key_len, const char *label, const u8 *seed, size_t seed_len, u8 *buf, size_t buf_len) { unsigned char counter = 0; size_t pos, plen; u8 hash[SHA1_MAC_LEN]; size_t label_len = os_strlen(label); u8 output_len[2]; const unsigned char *addr[5]; size_t len[5]; addr[0] = hash; len[0] = 0; addr[1] = (unsigned char *) label; len[1] = label_len + 1; addr[2] = seed; len[2] = seed_len; addr[3] = output_len; len[3] = 2; addr[4] = &counter; len[4] = 1; output_len[0] = (buf_len >> 8) & 0xff; output_len[1] = buf_len & 0xff; pos = 0; while (pos < buf_len) { counter++; plen = buf_len - pos; if (hmac_sha1_vector(key, key_len, 5, addr, len, hash)) return -1; if (plen >= SHA1_MAC_LEN) { os_memcpy(&buf[pos], hash, SHA1_MAC_LEN); pos += SHA1_MAC_LEN; } else { os_memcpy(&buf[pos], hash, plen); break; } len[0] = SHA1_MAC_LEN; } forced_memzero(hash, SHA1_MAC_LEN); return 0; }