/* $OpenBSD: bio_md.c,v 1.13 2014/06/12 15:49:29 deraadt Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * 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 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 OR CONTRIBUTORS 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.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include <errno.h>
#include "cryptlib.h"
#include <openssl/buffer.h>
#include <openssl/evp.h>

/* BIO_put and BIO_get both add to the digest,
 * BIO_gets returns the digest */

static int md_write(BIO *h, char const *buf, int num);
static int md_read(BIO *h, char *buf, int size);
/*static int md_puts(BIO *h, const char *str); */
static int md_gets(BIO *h, char *str, int size);
static long md_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int md_new(BIO *h);
static int md_free(BIO *data);
static long md_callback_ctrl(BIO *h, int cmd, bio_info_cb *fp);

static BIO_METHOD methods_md = {
	.type = BIO_TYPE_MD,
	.name = "message digest",
	.bwrite = md_write,
	.bread = md_read,
	.bgets = md_gets,
	.ctrl = md_ctrl,
	.create = md_new,
	.destroy = md_free,
	.callback_ctrl = md_callback_ctrl
};

BIO_METHOD *
BIO_f_md(void)
{
	return (&methods_md);
}

static int
md_new(BIO *bi)
{
	EVP_MD_CTX *ctx;

	ctx = EVP_MD_CTX_create();
	if (ctx == NULL)
		return (0);

	bi->init = 0;
	bi->ptr = (char *)ctx;
	bi->flags = 0;
	return (1);
}

static int
md_free(BIO *a)
{
	if (a == NULL)
		return (0);
	EVP_MD_CTX_destroy(a->ptr);
	a->ptr = NULL;
	a->init = 0;
	a->flags = 0;
	return (1);
}

static int
md_read(BIO *b, char *out, int outl)
{
	int ret = 0;
	EVP_MD_CTX *ctx;

	if (out == NULL)
		return (0);
	ctx = b->ptr;

	if ((ctx == NULL) || (b->next_bio == NULL))
		return (0);

	ret = BIO_read(b->next_bio, out, outl);
	if (b->init) {
		if (ret > 0) {
			if (EVP_DigestUpdate(ctx, (unsigned char *)out,
			    (unsigned int)ret) <= 0)
				return (-1);
		}
	}
	BIO_clear_retry_flags(b);
	BIO_copy_next_retry(b);
	return (ret);
}

static int
md_write(BIO *b, const char *in, int inl)
{
	int ret = 0;
	EVP_MD_CTX *ctx;

	if ((in == NULL) || (inl <= 0))
		return (0);
	ctx = b->ptr;

	if ((ctx != NULL) && (b->next_bio != NULL))
		ret = BIO_write(b->next_bio, in, inl);
	if (b->init) {
		if (ret > 0) {
			if (!EVP_DigestUpdate(ctx, (const unsigned char *)in,
			    (unsigned int)ret)) {
				BIO_clear_retry_flags(b);
				return 0;
			}
		}
	}
	if (b->next_bio != NULL) {
		BIO_clear_retry_flags(b);
		BIO_copy_next_retry(b);
	}
	return (ret);
}

static long
md_ctrl(BIO *b, int cmd, long num, void *ptr)
{
	EVP_MD_CTX *ctx, *dctx, **pctx;
	const EVP_MD **ppmd;
	EVP_MD *md;
	long ret = 1;
	BIO *dbio;

	ctx = b->ptr;

	switch (cmd) {
	case BIO_CTRL_RESET:
		if (b->init)
			ret = EVP_DigestInit_ex(ctx, ctx->digest, NULL);
		else
			ret = 0;
		if (ret > 0)
			ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		break;
	case BIO_C_GET_MD:
		if (b->init) {
			ppmd = ptr;
			*ppmd = ctx->digest;
		} else
			ret = 0;
		break;
	case BIO_C_GET_MD_CTX:
		pctx = ptr;
		*pctx = ctx;
		b->init = 1;
		break;
	case BIO_C_SET_MD_CTX:
		if (b->init)
			b->ptr = ptr;
		else
			ret = 0;
		break;
	case BIO_C_DO_STATE_MACHINE:
		BIO_clear_retry_flags(b);
		ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		BIO_copy_next_retry(b);
		break;

	case BIO_C_SET_MD:
		md = ptr;
		ret = EVP_DigestInit_ex(ctx, md, NULL);
		if (ret > 0)
			b->init = 1;
		break;
	case BIO_CTRL_DUP:
		dbio = ptr;
		dctx = dbio->ptr;
		if (!EVP_MD_CTX_copy_ex(dctx, ctx))
			return 0;
		b->init = 1;
		break;
	default:
		ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		break;
	}
	return (ret);
}

static long
md_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
{
	long ret = 1;

	if (b->next_bio == NULL)
		return (0);
	switch (cmd) {
	default:
		ret = BIO_callback_ctrl(b->next_bio, cmd, fp);
		break;
	}
	return (ret);
}

static int
md_gets(BIO *bp, char *buf, int size)
{
	EVP_MD_CTX *ctx;
	unsigned int ret;

	ctx = bp->ptr;
	if (size < ctx->digest->md_size)
		return (0);
	if (EVP_DigestFinal_ex(ctx, (unsigned char *)buf, &ret) <= 0)
		return -1;

	return ((int)ret);
}

/*
static int md_puts(bp,str)
BIO *bp;
char *str;
	{
	return(-1);
	}
*/