/* * SHA1 hash implementation and interface functions * Copyright (c) 2003-2005, Jouni Malinen * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Alternatively, this software may be distributed under the terms of BSD * license. * * See README and COPYING for more details. */ #include "common.h" #include "sha1.h" #include "crypto.h" /** * hmac_sha1_vector - HMAC-SHA1 over data vector (RFC 2104) * @key: Key for HMAC operations * @key_len: Length of the key in bytes * @num_elem: Number of elements in the data vector * @addr: Pointers to the data areas * @len: Lengths of the data blocks * @mac: Buffer for the hash (20 bytes) * Returns: 0 on success, -1 on failure */ int hmac_sha1_vector(const u8 *key, size_t key_len, size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac) { unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */ unsigned char tk[20]; const u8 *_addr[6]; size_t _len[6], i; if (num_elem > 5) { /* * Fixed limit on the number of fragments to avoid having to * allocate memory (which could fail). */ return -1; } /* if key is longer than 64 bytes reset it to key = SHA1(key) */ if (key_len > 64) { if (sha1_vector(1, &key, &key_len, tk)) return -1; key = tk; key_len = 20; } /* the HMAC_SHA1 transform looks like: * * SHA1(K XOR opad, SHA1(K XOR ipad, text)) * * where K is an n byte key * ipad is the byte 0x36 repeated 64 times * opad is the byte 0x5c repeated 64 times * and text is the data being protected */ /* start out by storing key in ipad */ os_memset(k_pad, 0, sizeof(k_pad)); os_memcpy(k_pad, key, key_len); /* XOR key with ipad values */ for (i = 0; i < 64; i++) k_pad[i] ^= 0x36; /* perform inner SHA1 */ _addr[0] = k_pad; _len[0] = 64; for (i = 0; i < num_elem; i++) { _addr[i + 1] = addr[i]; _len[i + 1] = len[i]; } if (sha1_vector(1 + num_elem, _addr, _len, mac)) return -1; os_memset(k_pad, 0, sizeof(k_pad)); os_memcpy(k_pad, key, key_len); /* XOR key with opad values */ for (i = 0; i < 64; i++) k_pad[i] ^= 0x5c; /* perform outer SHA1 */ _addr[0] = k_pad; _len[0] = 64; _addr[1] = mac; _len[1] = SHA1_MAC_LEN; return sha1_vector(2, _addr, _len, mac); } /** * hmac_sha1 - HMAC-SHA1 over data buffer (RFC 2104) * @key: Key for HMAC operations * @key_len: Length of the key in bytes * @data: Pointers to the data area * @data_len: Length of the data area * @mac: Buffer for the hash (20 bytes) * Returns: 0 on success, -1 of failure */ int hmac_sha1(const u8 *key, size_t key_len, const u8 *data, size_t data_len, u8 *mac) { return hmac_sha1_vector(key, key_len, 1, &data, &data_len, mac); } /** * 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++; } return 0; }