/* ocsp_ht.c */
/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
 * project 2006.
 */
/* ====================================================================
 * Copyright (c) 2006 The OpenSSL Project.  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.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <openssl/asn1.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <openssl/ocsp.h>
#include <openssl/err.h>
#include <openssl/buffer.h>
#ifdef OPENSSL_SYS_SUNOS
#define strtoul (unsigned long)strtol
#endif /* OPENSSL_SYS_SUNOS */

/* Stateful OCSP request code, supporting non-blocking I/O */

/* Opaque OCSP request status structure */

struct ocsp_req_ctx_st {
	int state;		/* Current I/O state */
	unsigned char *iobuf;	/* Line buffer */
	int iobuflen;		/* Line buffer length */
	BIO *io;		/* BIO to perform I/O with */
	BIO *mem;		/* Memory BIO response is built into */
	unsigned long asn1_len;	/* ASN1 length of response */
	};

#define OCSP_MAX_REQUEST_LENGTH	(100 * 1024)
#define OCSP_MAX_LINE_LEN	4096;

/* OCSP states */

/* If set no reading should be performed */
#define OHS_NOREAD		0x1000
/* Error condition */
#define OHS_ERROR		(0 | OHS_NOREAD)
/* First line being read */
#define OHS_FIRSTLINE		1
/* MIME headers being read */
#define OHS_HEADERS		2
/* OCSP initial header (tag + length) being read */
#define OHS_ASN1_HEADER		3
/* OCSP content octets being read */
#define OHS_ASN1_CONTENT	4
/* Request being sent */
#define OHS_ASN1_WRITE		(6 | OHS_NOREAD)
/* Request being flushed */
#define OHS_ASN1_FLUSH		(7 | OHS_NOREAD)
/* Completed */
#define OHS_DONE		(8 | OHS_NOREAD)


static int parse_http_line1(char *line);

void OCSP_REQ_CTX_free(OCSP_REQ_CTX *rctx)
	{
	if (rctx->mem)
		BIO_free(rctx->mem);
	if (rctx->iobuf)
		OPENSSL_free(rctx->iobuf);
	OPENSSL_free(rctx);
	}

OCSP_REQ_CTX *OCSP_sendreq_new(BIO *io, char *path, OCSP_REQUEST *req,
								int maxline)
	{
	static char post_hdr[] = "POST %s HTTP/1.0\r\n"
	"Content-Type: application/ocsp-request\r\n"
	"Content-Length: %d\r\n\r\n";

	OCSP_REQ_CTX *rctx;
	rctx = OPENSSL_malloc(sizeof(OCSP_REQ_CTX));
	rctx->state = OHS_FIRSTLINE;
	rctx->mem = BIO_new(BIO_s_mem());
	rctx->io = io;
	if (maxline > 0)
		rctx->iobuflen = maxline;
	else
		rctx->iobuflen = OCSP_MAX_LINE_LEN;
	rctx->iobuf = OPENSSL_malloc(rctx->iobuflen);
	if (!path)
		path = "/";

        if (BIO_printf(rctx->mem, post_hdr, path,
				i2d_OCSP_REQUEST(req, NULL)) <= 0)
		{
		rctx->state = OHS_ERROR;
		return 0;
		}
        if (i2d_OCSP_REQUEST_bio(rctx->mem, req) <= 0)
		{
		rctx->state = OHS_ERROR;
		return 0;
		}
	rctx->state = OHS_ASN1_WRITE;
	rctx->asn1_len = BIO_get_mem_data(rctx->mem, NULL);

	return rctx;
	}

/* Parse the HTTP response. This will look like this:
 * "HTTP/1.0 200 OK". We need to obtain the numeric code and
 * (optional) informational message.
 */

static int parse_http_line1(char *line)
	{
	int retcode;
	char *p, *q, *r;
	/* Skip to first white space (passed protocol info) */

	for(p = line; *p && !isspace((unsigned char)*p); p++)
		continue;
	if(!*p)
		{
		OCSPerr(OCSP_F_PARSE_HTTP_LINE1,
					OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
		return 0;
		}

	/* Skip past white space to start of response code */
	while(*p && isspace((unsigned char)*p))
		p++;

	if(!*p)
		{
		OCSPerr(OCSP_F_PARSE_HTTP_LINE1,
					OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
		return 0;
		}

	/* Find end of response code: first whitespace after start of code */
	for(q = p; *q && !isspace((unsigned char)*q); q++)
		continue;

	if(!*q)
		{
		OCSPerr(OCSP_F_PARSE_HTTP_LINE1,
					OCSP_R_SERVER_RESPONSE_PARSE_ERROR);
		return 0;
		}

	/* Set end of response code and start of message */ 
	*q++ = 0;

	/* Attempt to parse numeric code */
	retcode = strtoul(p, &r, 10);

	if(*r)
		return 0;

	/* Skip over any leading white space in message */
	while(*q && isspace((unsigned char)*q))
		q++;

	if(*q)
		{
		/* Finally zap any trailing white space in message (include
		 * CRLF) */

		/* We know q has a non white space character so this is OK */
		for(r = q + strlen(q) - 1; isspace((unsigned char)*r); r--)
			*r = 0;
		}
	if(retcode != 200)
		{
		OCSPerr(OCSP_F_PARSE_HTTP_LINE1, OCSP_R_SERVER_RESPONSE_ERROR);
		if(!*q)
			ERR_add_error_data(2, "Code=", p);
		else
			ERR_add_error_data(4, "Code=", p, ",Reason=", q);
		return 0;
		}


	return 1;

	}

int OCSP_sendreq_nbio(OCSP_RESPONSE **presp, OCSP_REQ_CTX *rctx)
	{
	int i, n;
	const unsigned char *p;
	next_io:
	if (!(rctx->state & OHS_NOREAD))
		{
		n = BIO_read(rctx->io, rctx->iobuf, rctx->iobuflen);

		if (n <= 0)
			{
			if (BIO_should_retry(rctx->io))
				return -1;
			return 0;
			}

		/* Write data to memory BIO */

		if (BIO_write(rctx->mem, rctx->iobuf, n) != n)
			return 0;
		}

	switch(rctx->state)
		{

		case OHS_ASN1_WRITE:
		n = BIO_get_mem_data(rctx->mem, &p);

		i = BIO_write(rctx->io,
			p + (n - rctx->asn1_len), rctx->asn1_len);

		if (i <= 0)
			{
			if (BIO_should_retry(rctx->io))
				return -1;
			rctx->state = OHS_ERROR;
			return 0;
			}

		rctx->asn1_len -= i;

		if (rctx->asn1_len > 0)
			goto next_io;

		rctx->state = OHS_ASN1_FLUSH;

		(void)BIO_reset(rctx->mem);

		case OHS_ASN1_FLUSH:

		i = BIO_flush(rctx->io);

		if (i > 0)
			{
			rctx->state = OHS_FIRSTLINE;
			goto next_io;
			}

		if (BIO_should_retry(rctx->io))
			return -1;

		rctx->state = OHS_ERROR;
		return 0;

		case OHS_ERROR:
		return 0;

		case OHS_FIRSTLINE:
		case OHS_HEADERS:

		/* Attempt to read a line in */

		next_line:
		/* Due to &%^*$" memory BIO behaviour with BIO_gets we
		 * have to check there's a complete line in there before
		 * calling BIO_gets or we'll just get a partial read.
		 */
		n = BIO_get_mem_data(rctx->mem, &p);
		if ((n <= 0) || !memchr(p, '\n', n))
			{
			if (n >= rctx->iobuflen)
				{
				rctx->state = OHS_ERROR;
				return 0;
				}
			goto next_io;
			}
		n = BIO_gets(rctx->mem, (char *)rctx->iobuf, rctx->iobuflen);

		if (n <= 0)
			{
			if (BIO_should_retry(rctx->mem))
				goto next_io;
			rctx->state = OHS_ERROR;
			return 0;
			}

		/* Don't allow excessive lines */
		if (n == rctx->iobuflen)
			{
			rctx->state = OHS_ERROR;
			return 0;
			}

		/* First line */
		if (rctx->state == OHS_FIRSTLINE)
			{
			if (parse_http_line1((char *)rctx->iobuf))
				{
				rctx->state = OHS_HEADERS;
				goto next_line;
				}
			else
				{
				rctx->state = OHS_ERROR;
				return 0;
				}
			}
		else
			{
			/* Look for blank line: end of headers */
			for (p = rctx->iobuf; *p; p++)
				{
				if ((*p != '\r') && (*p != '\n'))
					break;
				}
			if (*p)
				goto next_line;

			rctx->state = OHS_ASN1_HEADER;

			}
 
		/* Fall thru */


		case OHS_ASN1_HEADER:
		/* Now reading ASN1 header: can read at least 6 bytes which
		 * is more than enough for any valid ASN1 SEQUENCE header
		 */
		n = BIO_get_mem_data(rctx->mem, &p);
		if (n < 6)
			goto next_io;

		/* Check it is an ASN1 SEQUENCE */
		if (*p++ != (V_ASN1_SEQUENCE|V_ASN1_CONSTRUCTED))
			{
			rctx->state = OHS_ERROR;
			return 0;
			}

		/* Check out length field */
		if (*p & 0x80)
			{
			n = *p & 0x7F;
			/* Not NDEF or excessive length */
			if (!n || (n > 4))
				{
				rctx->state = OHS_ERROR;
				return 0;
				}
			p++;
			rctx->asn1_len = 0;
			for (i = 0; i < n; i++)
				{
				rctx->asn1_len <<= 8;
				rctx->asn1_len |= *p++;
				}

			if (rctx->asn1_len > OCSP_MAX_REQUEST_LENGTH)
				{
				rctx->state = OHS_ERROR;
				return 0;
				}

			rctx->asn1_len += n + 2;
			}
		else
			rctx->asn1_len = *p + 2;

		rctx->state = OHS_ASN1_CONTENT;

		/* Fall thru */
		
		case OHS_ASN1_CONTENT:
		n = BIO_get_mem_data(rctx->mem, &p);
		if (n < (int)rctx->asn1_len)
			goto next_io;


		*presp = d2i_OCSP_RESPONSE(NULL, &p, rctx->asn1_len);
		if (*presp)
			{
			rctx->state = OHS_DONE;
			return 1;
			}

		rctx->state = OHS_ERROR;
		return 0;

		break;

		case OHS_DONE:
		return 1;

		}


	return 0;


	}

/* Blocking OCSP request handler: now a special case of non-blocking I/O */

OCSP_RESPONSE *OCSP_sendreq_bio(BIO *b, char *path, OCSP_REQUEST *req)
	{
	OCSP_RESPONSE *resp = NULL;
	OCSP_REQ_CTX *ctx;
	int rv;

	ctx = OCSP_sendreq_new(b, path, req, -1);

	do
		{
		rv = OCSP_sendreq_nbio(&resp, ctx);
		} while ((rv == -1) && BIO_should_retry(b));

	OCSP_REQ_CTX_free(ctx);

	if (rv)
		return resp;

	return NULL;
	}