/*

 * Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include "e_os.h"

#include <stdio.h>

#include <stdlib.h>

#include "crypto/ctype.h"

#include <string.h>

#include <openssl/asn1.h>

#include <openssl/ocsp.h>

#include <openssl/err.h>

#include <openssl/buffer.h>

/* 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 */

    unsigned long max_resp_len; /* Maximum length of response */

};

#define OCSP_MAX_RESP_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

/* First call: ready to start I/O */

#define OHS_ASN1_WRITE_INIT     (5 | OHS_NOREAD)

/* 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)

/* Headers set, no final \r\n included */

#define OHS_HTTP_HEADER         (9 | OHS_NOREAD)

static int parse_http_line1(char *line);

OCSP_REQ_CTX *OCSP_REQ_CTX_new(BIO *io, int maxline)

{

    OCSP_REQ_CTX *rctx = OPENSSL_zalloc(sizeof(*rctx));

    if (rctx == NULL)

        return NULL;

    rctx->state = OHS_ERROR;

    rctx->max_resp_len = OCSP_MAX_RESP_LENGTH;

    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 (rctx->iobuf == NULL || rctx->mem == NULL) {

        OCSP_REQ_CTX_free(rctx);

        return NULL;

    }

    return rctx;

}

void OCSP_REQ_CTX_free(OCSP_REQ_CTX *rctx)

{

    if (!rctx)

        return;

    BIO_free(rctx->mem);

    OPENSSL_free(rctx->iobuf);

    OPENSSL_free(rctx);

}

BIO *OCSP_REQ_CTX_get0_mem_bio(OCSP_REQ_CTX *rctx)

{

    return rctx->mem;

}

void OCSP_set_max_response_length(OCSP_REQ_CTX *rctx, unsigned long len)

{

    if (len == 0)

        rctx->max_resp_len = OCSP_MAX_RESP_LENGTH;

    else

        rctx->max_resp_len = len;

}

int OCSP_REQ_CTX_i2d(OCSP_REQ_CTX *rctx, const ASN1_ITEM *it, ASN1_VALUE *val)

{

    static const char req_hdr[] =

        "Content-Type: application/ocsp-request\r\n"

        "Content-Length: %d\r\n\r\n";

    int reqlen = ASN1_item_i2d(val, NULL, it);

    if (BIO_printf(rctx->mem, req_hdr, reqlen) <= 0)

        return 0;

    if (ASN1_item_i2d_bio(it, rctx->mem, val) <= 0)

        return 0;

    rctx->state = OHS_ASN1_WRITE_INIT;

    return 1;

}

int OCSP_REQ_CTX_nbio_d2i(OCSP_REQ_CTX *rctx,

                          ASN1_VALUE **pval, const ASN1_ITEM *it)

{

    int rv, len;

    const unsigned char *p;

    rv = OCSP_REQ_CTX_nbio(rctx);

    if (rv != 1)

        return rv;

    len = BIO_get_mem_data(rctx->mem, &p);

    *pval = ASN1_item_d2i(NULL, &p, len, it);

    if (*pval == NULL) {

        rctx->state = OHS_ERROR;

        return 0;

    }

    return 1;

}

int OCSP_REQ_CTX_http(OCSP_REQ_CTX *rctx, const char *op, const char *path)

{

    static const char http_hdr[] = "%s %s HTTP/1.0\r\n";

    if (!path)

        path = "/";

    if (BIO_printf(rctx->mem, http_hdr, op, path) <= 0)

        return 0;

    rctx->state = OHS_HTTP_HEADER;

    return 1;

}

int OCSP_REQ_CTX_set1_req(OCSP_REQ_CTX *rctx, OCSP_REQUEST *req)

{

    return OCSP_REQ_CTX_i2d(rctx, ASN1_ITEM_rptr(OCSP_REQUEST),

                            (ASN1_VALUE *)req);

}

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;

    rctx->state = OHS_HTTP_HEADER;

    return 1;

}

OCSP_REQ_CTX *OCSP_sendreq_new(BIO *io, const char *path, OCSP_REQUEST *req,

                               int maxline)

{

    OCSP_REQ_CTX *rctx = NULL;

    rctx = OCSP_REQ_CTX_new(io, maxline);

    if (rctx == NULL)

        return NULL;

    if (!OCSP_REQ_CTX_http(rctx, "POST", path))

        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 && !ossl_isspace(*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 && ossl_isspace(*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 && !ossl_isspace(*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 && ossl_isspace(*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; ossl_isspace(*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_REQ_CTX_nbio(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_HTTP_HEADER:

        /* Last operation was adding headers: need a final \r\n */

        if (BIO_write(rctx->mem, "\r\n", 2) != 2) {

            rctx->state = OHS_ERROR;

            return 0;

        }

        rctx->state = OHS_ASN1_WRITE_INIT;

        /* fall thru */

    case OHS_ASN1_WRITE_INIT:

        rctx->asn1_len = BIO_get_mem_data(rctx->mem, NULL);

        rctx->state = OHS_ASN1_WRITE;

        /* fall thru */

    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);

        /* fall thru */

    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 > rctx->max_resp_len) {

                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, NULL);

        if (n < (int)rctx->asn1_len)

            goto next_io;

        rctx->state = OHS_DONE;

        return 1;

    case OHS_DONE:

        return 1;

    }

    return 0;

}

int OCSP_sendreq_nbio(OCSP_RESPONSE **presp, OCSP_REQ_CTX *rctx)

{

    return OCSP_REQ_CTX_nbio_d2i(rctx,

                                 (ASN1_VALUE **)presp,

                                 ASN1_ITEM_rptr(OCSP_RESPONSE));

}

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

OCSP_RESPONSE *OCSP_sendreq_bio(BIO *b, const 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 == NULL)

        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;

}