/* $OpenBSD: tls_peer.c,v 1.1 2015/09/11 11:28:01 jsing Exp $ */
/*
 * Copyright (c) 2015 Joel Sing <jsing@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdio.h>

#include <openssl/x509.h>

#include <tls.h>
#include "tls_internal.h"

static int
tls_hex_string(const unsigned char *in, size_t inlen, char **out,
    size_t *outlen)
{
	static const char hex[] = "0123456789abcdef";
	size_t i, len;
	char *p;

	if (outlen != NULL)
		*outlen = 0;

	if (inlen >= SIZE_MAX)
		return (-1);
	if ((*out = reallocarray(NULL, inlen + 1, 2)) == NULL)
		return (-1);

	p = *out;
	len = 0;
	for (i = 0; i < inlen; i++) {
		p[len++] = hex[(in[i] >> 4) & 0x0f];
		p[len++] = hex[in[i] & 0x0f];
	}
	p[len++] = 0;

	if (outlen != NULL)
		*outlen = len;

	return (0);
}

int
tls_peer_cert_hash(struct tls *ctx, char **hash)
{
	char d[EVP_MAX_MD_SIZE], *dhex = NULL;
	int dlen, rv = -1;

	*hash = NULL;
	if (ctx->ssl_peer_cert == NULL)
		return (0);

	if (X509_digest(ctx->ssl_peer_cert, EVP_sha256(), d, &dlen) != 1) {
		tls_set_errorx(ctx, "digest failed");
		goto err;
	}

	if (tls_hex_string(d, dlen, &dhex, NULL) != 0) {
		tls_set_errorx(ctx, "digest hex string failed");
		goto err;
	}

	if (asprintf(hash, "SHA256:%s", dhex) == -1) {
		tls_set_errorx(ctx, "out of memory");
		*hash = NULL;
		goto err;
	}

	rv = 0;

err:
	free(dhex);

	return (rv);
}