16d49e1aeSJan Lentfer /*
26d49e1aeSJan Lentfer * SHA-256 hash implementation and interface functions
3*3ff40c12SJohn Marino * Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
46d49e1aeSJan Lentfer *
5*3ff40c12SJohn Marino * This software may be distributed under the terms of the BSD license.
6*3ff40c12SJohn Marino * See README for more details.
76d49e1aeSJan Lentfer */
86d49e1aeSJan Lentfer
96d49e1aeSJan Lentfer #include "includes.h"
106d49e1aeSJan Lentfer
116d49e1aeSJan Lentfer #include "common.h"
126d49e1aeSJan Lentfer #include "sha256.h"
136d49e1aeSJan Lentfer #include "crypto.h"
146d49e1aeSJan Lentfer
156d49e1aeSJan Lentfer
166d49e1aeSJan Lentfer /**
176d49e1aeSJan Lentfer * hmac_sha256_vector - HMAC-SHA256 over data vector (RFC 2104)
186d49e1aeSJan Lentfer * @key: Key for HMAC operations
196d49e1aeSJan Lentfer * @key_len: Length of the key in bytes
206d49e1aeSJan Lentfer * @num_elem: Number of elements in the data vector
216d49e1aeSJan Lentfer * @addr: Pointers to the data areas
226d49e1aeSJan Lentfer * @len: Lengths of the data blocks
236d49e1aeSJan Lentfer * @mac: Buffer for the hash (32 bytes)
24*3ff40c12SJohn Marino * Returns: 0 on success, -1 on failure
256d49e1aeSJan Lentfer */
hmac_sha256_vector(const u8 * key,size_t key_len,size_t num_elem,const u8 * addr[],const size_t * len,u8 * mac)26*3ff40c12SJohn Marino int hmac_sha256_vector(const u8 *key, size_t key_len, size_t num_elem,
276d49e1aeSJan Lentfer const u8 *addr[], const size_t *len, u8 *mac)
286d49e1aeSJan Lentfer {
296d49e1aeSJan Lentfer unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */
306d49e1aeSJan Lentfer unsigned char tk[32];
316d49e1aeSJan Lentfer const u8 *_addr[6];
326d49e1aeSJan Lentfer size_t _len[6], i;
336d49e1aeSJan Lentfer
346d49e1aeSJan Lentfer if (num_elem > 5) {
356d49e1aeSJan Lentfer /*
366d49e1aeSJan Lentfer * Fixed limit on the number of fragments to avoid having to
376d49e1aeSJan Lentfer * allocate memory (which could fail).
386d49e1aeSJan Lentfer */
39*3ff40c12SJohn Marino return -1;
406d49e1aeSJan Lentfer }
416d49e1aeSJan Lentfer
426d49e1aeSJan Lentfer /* if key is longer than 64 bytes reset it to key = SHA256(key) */
436d49e1aeSJan Lentfer if (key_len > 64) {
44*3ff40c12SJohn Marino if (sha256_vector(1, &key, &key_len, tk) < 0)
45*3ff40c12SJohn Marino return -1;
466d49e1aeSJan Lentfer key = tk;
476d49e1aeSJan Lentfer key_len = 32;
486d49e1aeSJan Lentfer }
496d49e1aeSJan Lentfer
506d49e1aeSJan Lentfer /* the HMAC_SHA256 transform looks like:
516d49e1aeSJan Lentfer *
526d49e1aeSJan Lentfer * SHA256(K XOR opad, SHA256(K XOR ipad, text))
536d49e1aeSJan Lentfer *
546d49e1aeSJan Lentfer * where K is an n byte key
556d49e1aeSJan Lentfer * ipad is the byte 0x36 repeated 64 times
566d49e1aeSJan Lentfer * opad is the byte 0x5c repeated 64 times
576d49e1aeSJan Lentfer * and text is the data being protected */
586d49e1aeSJan Lentfer
596d49e1aeSJan Lentfer /* start out by storing key in ipad */
606d49e1aeSJan Lentfer os_memset(k_pad, 0, sizeof(k_pad));
616d49e1aeSJan Lentfer os_memcpy(k_pad, key, key_len);
626d49e1aeSJan Lentfer /* XOR key with ipad values */
636d49e1aeSJan Lentfer for (i = 0; i < 64; i++)
646d49e1aeSJan Lentfer k_pad[i] ^= 0x36;
656d49e1aeSJan Lentfer
666d49e1aeSJan Lentfer /* perform inner SHA256 */
676d49e1aeSJan Lentfer _addr[0] = k_pad;
686d49e1aeSJan Lentfer _len[0] = 64;
696d49e1aeSJan Lentfer for (i = 0; i < num_elem; i++) {
706d49e1aeSJan Lentfer _addr[i + 1] = addr[i];
716d49e1aeSJan Lentfer _len[i + 1] = len[i];
726d49e1aeSJan Lentfer }
73*3ff40c12SJohn Marino if (sha256_vector(1 + num_elem, _addr, _len, mac) < 0)
74*3ff40c12SJohn Marino return -1;
756d49e1aeSJan Lentfer
766d49e1aeSJan Lentfer os_memset(k_pad, 0, sizeof(k_pad));
776d49e1aeSJan Lentfer os_memcpy(k_pad, key, key_len);
786d49e1aeSJan Lentfer /* XOR key with opad values */
796d49e1aeSJan Lentfer for (i = 0; i < 64; i++)
806d49e1aeSJan Lentfer k_pad[i] ^= 0x5c;
816d49e1aeSJan Lentfer
826d49e1aeSJan Lentfer /* perform outer SHA256 */
836d49e1aeSJan Lentfer _addr[0] = k_pad;
846d49e1aeSJan Lentfer _len[0] = 64;
856d49e1aeSJan Lentfer _addr[1] = mac;
866d49e1aeSJan Lentfer _len[1] = SHA256_MAC_LEN;
87*3ff40c12SJohn Marino return sha256_vector(2, _addr, _len, mac);
886d49e1aeSJan Lentfer }
896d49e1aeSJan Lentfer
906d49e1aeSJan Lentfer
916d49e1aeSJan Lentfer /**
926d49e1aeSJan Lentfer * hmac_sha256 - HMAC-SHA256 over data buffer (RFC 2104)
936d49e1aeSJan Lentfer * @key: Key for HMAC operations
946d49e1aeSJan Lentfer * @key_len: Length of the key in bytes
956d49e1aeSJan Lentfer * @data: Pointers to the data area
966d49e1aeSJan Lentfer * @data_len: Length of the data area
97*3ff40c12SJohn Marino * @mac: Buffer for the hash (32 bytes)
98*3ff40c12SJohn Marino * Returns: 0 on success, -1 on failure
996d49e1aeSJan Lentfer */
hmac_sha256(const u8 * key,size_t key_len,const u8 * data,size_t data_len,u8 * mac)100*3ff40c12SJohn Marino int hmac_sha256(const u8 *key, size_t key_len, const u8 *data,
1016d49e1aeSJan Lentfer size_t data_len, u8 *mac)
1026d49e1aeSJan Lentfer {
103*3ff40c12SJohn Marino return hmac_sha256_vector(key, key_len, 1, &data, &data_len, mac);
1046d49e1aeSJan Lentfer }
105