1/* $OpenBSD: prf.c,v 1.16 2013/03/21 04:30:14 deraadt Exp $	 */
2/* $EOM: prf.c,v 1.7 1999/05/02 12:50:29 niklas Exp $	 */
3
4/*
5 * Copyright (c) 1998 Niels Provos.  All rights reserved.
6 * Copyright (c) 1999 Niklas Hallqvist.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/*
30 * This code was written under funding by Ericsson Radio Systems.
31 */
32
33#include <stdlib.h>
34#include <string.h>
35
36#include "hash.h"
37#include "log.h"
38#include "prf.h"
39
40void	prf_hash_init(struct prf_hash_ctx *);
41void	prf_hash_update(struct prf_hash_ctx *, unsigned char *, unsigned int);
42void	prf_hash_final(unsigned char *, struct prf_hash_ctx *);
43
44/* PRF behaves likes a hash */
45
46void
47prf_hash_init(struct prf_hash_ctx *ctx)
48{
49	memcpy(ctx->hash->ctx, ctx->ctx, ctx->hash->ctxsize);
50	memcpy(ctx->hash->ctx2, ctx->ctx2, ctx->hash->ctxsize);
51}
52
53void
54prf_hash_update(struct prf_hash_ctx *ctx, unsigned char *data,
55    unsigned int len)
56{
57	ctx->hash->Update(ctx->hash->ctx, data, len);
58}
59
60void
61prf_hash_final(unsigned char *digest, struct prf_hash_ctx *ctx)
62{
63	ctx->hash->HMACFinal(digest, ctx->hash);
64}
65
66/*
67 * Obtain a Pseudo-Random Function for us. At the moment this is
68 * the HMAC version of a hash. See RFC-2104 for reference.
69 */
70struct prf *
71prf_alloc(enum prfs type, int subtype, unsigned char *shared,
72    unsigned int sharedsize)
73{
74	struct hash    *hash;
75	struct prf     *prf;
76	struct prf_hash_ctx *prfctx;
77
78	switch (type) {
79	case PRF_HMAC:
80		hash = hash_get(subtype);
81		if (!hash) {
82			log_print("prf_alloc: unknown hash type %d", subtype);
83			return 0;
84		}
85		break;
86	default:
87		log_print("prf_alloc: unknown PRF type %d", type);
88		return 0;
89	}
90
91	prf = malloc(sizeof *prf);
92	if (!prf) {
93		log_error("prf_alloc: malloc (%lu) failed",
94		    (unsigned long)sizeof *prf);
95		return 0;
96	}
97	if (type == PRF_HMAC) {
98		/* Obtain needed memory.  */
99		prfctx = malloc(sizeof *prfctx);
100		if (!prfctx) {
101			log_error("prf_alloc: malloc (%lu) failed",
102			    (unsigned long)sizeof *prfctx);
103			goto cleanprf;
104		}
105		prf->prfctx = prfctx;
106
107		prfctx->ctx = malloc(hash->ctxsize);
108		if (!prfctx->ctx) {
109			log_error("prf_alloc: malloc (%d) failed",
110			    hash->ctxsize);
111			goto cleanprfctx;
112		}
113		prfctx->ctx2 = malloc(hash->ctxsize);
114		if (!prfctx->ctx2) {
115			log_error("prf_alloc: malloc (%d) failed",
116			    hash->ctxsize);
117			free(prfctx->ctx);
118			goto cleanprfctx;
119		}
120		prf->type = PRF_HMAC;
121		prf->blocksize = hash->hashsize;
122		prfctx->hash = hash;
123
124		/* Use the correct function pointers.  */
125		prf->Init = (void(*)(void *))prf_hash_init;
126		prf->Update = (void(*)(void *, unsigned char *,
127		    unsigned int))prf_hash_update;
128		prf->Final = (void(*)(unsigned char *, void *))prf_hash_final;
129
130		/* Init HMAC contexts.  */
131		hash->HMACInit(hash, shared, sharedsize);
132
133		/* Save contexts.  */
134		memcpy(prfctx->ctx, hash->ctx, hash->ctxsize);
135		memcpy(prfctx->ctx2, hash->ctx2, hash->ctxsize);
136	}
137	return prf;
138
139cleanprfctx:
140	free(prf->prfctx);
141cleanprf:
142	free(prf);
143	return 0;
144}
145
146/* Deallocate the PRF pointed to by PRF.  */
147void
148prf_free(struct prf *prf)
149{
150	struct prf_hash_ctx *prfctx = prf->prfctx;
151
152	if (prf->type == PRF_HMAC) {
153		free(prfctx->ctx2);
154		free(prfctx->ctx);
155	}
156	free(prf->prfctx);
157	free(prf);
158}
159