/* ocsp_ht.c */
/*
 * Written by Dr Stephen N Henson (steve@openssl.org) 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 <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include "e_os.h"
#include <openssl/asn1.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);
}

int OCSP_REQ_CTX_set1_req(OCSP_REQ_CTX *rctx, OCSP_REQUEST *req)
{
    static const char req_hdr[] =
        "Content-Type: application/ocsp-request\r\n"
        "Content-Length: %d\r\n\r\n";
    if (BIO_printf(rctx->mem, req_hdr, i2d_OCSP_REQUEST(req, NULL)) <= 0)
        return 0;
    if (i2d_OCSP_REQUEST_bio(rctx->mem, req) <= 0)
        return 0;
    rctx->state = OHS_ASN1_WRITE;
    rctx->asn1_len = BIO_get_mem_data(rctx->mem, NULL);
    return 1;
}

int OCSP_REQ_CTX_add1_header(OCSP_REQ_CTX *rctx,
                             const char *name, const char *value)
{
    if (!name)
        return 0;
    if (BIO_puts(rctx->mem, name) <= 0)
        return 0;
    if (value) {
        if (BIO_write(rctx->mem, ": ", 2) != 2)
            return 0;
        if (BIO_puts(rctx->mem, value) <= 0)
            return 0;
    }
    if (BIO_write(rctx->mem, "\r\n", 2) != 2)
        return 0;
    return 1;
}

OCSP_REQ_CTX *OCSP_sendreq_new(BIO *io, char *path, OCSP_REQUEST *req,
                               int maxline)
{
    static const char post_hdr[] = "POST %s HTTP/1.0\r\n";

    OCSP_REQ_CTX *rctx;
    rctx = OPENSSL_malloc(sizeof(OCSP_REQ_CTX));
    if (!rctx)
        return NULL;
    rctx->state = OHS_ERROR;
    rctx->mem = BIO_new(BIO_s_mem());
    rctx->io = io;
    rctx->asn1_len = 0;
    if (maxline > 0)
        rctx->iobuflen = maxline;
    else
        rctx->iobuflen = OCSP_MAX_LINE_LEN;
    rctx->iobuf = OPENSSL_malloc(rctx->iobuflen);
    if (!rctx->mem || !rctx->iobuf)
        goto err;
    if (!path)
        path = "/";

    if (BIO_printf(rctx->mem, post_hdr, path) <= 0)
        goto err;

    if (req && !OCSP_REQ_CTX_set1_req(rctx, req))
        goto err;

    return rctx;
 err:
    OCSP_REQ_CTX_free(rctx);
    return NULL;
}

/*
 * 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 2 bytes which is enough
         * for ASN1 SEQUENCE header and either length field or at least the
         * length of the length field.
         */
        n = BIO_get_mem_data(rctx->mem, &p);
        if (n < 2)
            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) {
            /*
             * If MSB set on initial length octet we can now always read 6
             * octets: make sure we have them.
             */
            if (n < 6)
                goto next_io;
            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);

    if (!ctx)
        return NULL;

    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;
}
