/* $OpenBSD: prf.c,v 1.17 2026/06/24 09:57:32 hshoexer Exp $     */
/* $EOM: prf.c,v 1.7 1999/05/02 12:50:29 niklas Exp $    */

/*
 * Copyright (c) 1998 Niels Provos.  All rights reserved.
 * Copyright (c) 1999 Niklas Hallqvist.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <stdlib.h>
#include <string.h>

#include "hash.h"
#include "log.h"
#include "prf.h"

void    prf_hash_init(struct prf_hash_ctx *);
void    prf_hash_update(struct prf_hash_ctx *, unsigned char *, unsigned int);
void    prf_hash_final(unsigned char *, struct prf_hash_ctx *);

/* PRF behaves likes a hash */

void
prf_hash_init(struct prf_hash_ctx *ctx)
{
        memcpy(ctx->hash->ctx, ctx->ctx, ctx->hash->ctxsize);
        memcpy(ctx->hash->ctx2, ctx->ctx2, ctx->hash->ctxsize);
}

void
prf_hash_update(struct prf_hash_ctx *ctx, unsigned char *data,
    unsigned int len)
{
        ctx->hash->Update(ctx->hash->ctx, data, len);
}

void
prf_hash_final(unsigned char *digest, struct prf_hash_ctx *ctx)
{
        ctx->hash->HMACFinal(digest, ctx->hash);
}

/*
 * Obtain a Pseudo-Random Function for us. At the moment this is
 * the HMAC version of a hash. See RFC-2104 for reference.
 */
struct prf *
prf_alloc(enum prfs type, int subtype, unsigned char *shared,
    unsigned int sharedsize)
{
        struct hash    *hash;
        struct prf     *prf;
        struct prf_hash_ctx *prfctx;

        switch (type) {
        case PRF_HMAC:
                hash = hash_get(subtype);
                if (!hash) {
                        log_print("prf_alloc: unknown hash type %d", subtype);
                        return 0;
                }
                break;
        default:
                log_print("prf_alloc: unknown PRF type %d", type);
                return 0;
        }

        prf = malloc(sizeof *prf);
        if (!prf) {
                log_error("prf_alloc: malloc (%lu) failed",
                    (unsigned long)sizeof *prf);
                return 0;
        }
        if (type == PRF_HMAC) {
                /* Obtain needed memory.  */
                prfctx = malloc(sizeof *prfctx);
                if (!prfctx) {
                        log_error("prf_alloc: malloc (%lu) failed",
                            (unsigned long)sizeof *prfctx);
                        goto cleanprf;
                }
                prf->prfctx = prfctx;

                prfctx->ctx = malloc(hash->ctxsize);
                if (!prfctx->ctx) {
                        log_error("prf_alloc: malloc (%d) failed",
                            hash->ctxsize);
                        goto cleanprfctx;
                }
                prfctx->ctx2 = malloc(hash->ctxsize);
                if (!prfctx->ctx2) {
                        log_error("prf_alloc: malloc (%d) failed",
                            hash->ctxsize);
                        free(prfctx->ctx);      /* not used yet, thus just free */
                        goto cleanprfctx;
                }
                prf->type = PRF_HMAC;
                prf->blocksize = hash->hashsize;
                prfctx->hash = hash;

                /* Use the correct function pointers.  */
                prf->Init = (void(*)(void *))prf_hash_init;
                prf->Update = (void(*)(void *, unsigned char *,
                    unsigned int))prf_hash_update;
                prf->Final = (void(*)(unsigned char *, void *))prf_hash_final;

                /* Init HMAC contexts.  */
                hash->HMACInit(hash, shared, sharedsize);

                /* Save contexts.  */
                memcpy(prfctx->ctx, hash->ctx, hash->ctxsize);
                memcpy(prfctx->ctx2, hash->ctx2, hash->ctxsize);
        }
        return prf;

cleanprfctx:
        free(prf->prfctx);
cleanprf:
        free(prf);
        return 0;
}

/* Deallocate the PRF pointed to by PRF.  */
void
prf_free(struct prf *prf)
{
        struct prf_hash_ctx *prfctx = prf->prfctx;

        if (prf->type == PRF_HMAC) {
                freezero(prfctx->ctx2, prfctx->hash->ctxsize);
                freezero(prfctx->ctx, prfctx->hash->ctxsize);
        }
        free(prf->prfctx);
        free(prf);
}