/* asn_mime.c */

/*

 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL

 * project.

 */

/* ====================================================================

 * Copyright (c) 1999-2008 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.

 * ====================================================================

 *

 */

#include <stdio.h>

#include <ctype.h>

#include "cryptlib.h"

#include <openssl/rand.h>

#include <openssl/x509.h>

#include <openssl/asn1.h>

#include <openssl/asn1t.h>

#include "asn1_locl.h"

/*

 * Generalised MIME like utilities for streaming ASN1. Although many have a

 * PKCS7/CMS like flavour others are more general purpose.

 */

/*

 * MIME format structures Note that all are translated to lower case apart

 * from parameter values. Quotes are stripped off

 */

typedef struct {

    char *param_name;           /* Param name e.g. "micalg" */

    char *param_value;          /* Param value e.g. "sha1" */

} MIME_PARAM;

DECLARE_STACK_OF(MIME_PARAM)

IMPLEMENT_STACK_OF(MIME_PARAM)

typedef struct {

    char *name;                 /* Name of line e.g. "content-type" */

    char *value;                /* Value of line e.g. "text/plain" */

    STACK_OF(MIME_PARAM) *params; /* Zero or more parameters */

} MIME_HEADER;

DECLARE_STACK_OF(MIME_HEADER)

IMPLEMENT_STACK_OF(MIME_HEADER)

static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,

                            const ASN1_ITEM *it);

static char *strip_ends(char *name);

static char *strip_start(char *name);

static char *strip_end(char *name);

static MIME_HEADER *mime_hdr_new(char *name, char *value);

static int mime_hdr_addparam(MIME_HEADER *mhdr, char *name, char *value);

static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio);

static int mime_hdr_cmp(const MIME_HEADER *const *a,

                        const MIME_HEADER *const *b);

static int mime_param_cmp(const MIME_PARAM *const *a,

                          const MIME_PARAM *const *b);

static void mime_param_free(MIME_PARAM *param);

static int mime_bound_check(char *line, int linelen, char *bound, int blen);

static int multi_split(BIO *bio, char *bound, STACK_OF(BIO) **ret);

static int strip_eol(char *linebuf, int *plen);

static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, char *name);

static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, char *name);

static void mime_hdr_free(MIME_HEADER *hdr);

#define MAX_SMLEN 1024

#define mime_debug(x)           /* x */

/* Output an ASN1 structure in BER format streaming if necessary */

int i2d_ASN1_bio_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,

                        const ASN1_ITEM *it)

{

    /* If streaming create stream BIO and copy all content through it */

    if (flags & SMIME_STREAM) {

        BIO *bio, *tbio;

        bio = BIO_new_NDEF(out, val, it);

        if (!bio) {

            ASN1err(ASN1_F_I2D_ASN1_BIO_STREAM, ERR_R_MALLOC_FAILURE);

            return 0;

        }

        SMIME_crlf_copy(in, bio, flags);

        (void)BIO_flush(bio);

        /* Free up successive BIOs until we hit the old output BIO */

        do {

            tbio = BIO_pop(bio);

            BIO_free(bio);

            bio = tbio;

        } while (bio != out);

    }

    /*

     * else just write out ASN1 structure which will have all content stored

     * internally

     */

    else

        ASN1_item_i2d_bio(it, out, val);

    return 1;

}

/* Base 64 read and write of ASN1 structure */

static int B64_write_ASN1(BIO *out, ASN1_VALUE *val, BIO *in, int flags,

                          const ASN1_ITEM *it)

{

    BIO *b64;

    int r;

    b64 = BIO_new(BIO_f_base64());

    if (!b64) {

        ASN1err(ASN1_F_B64_WRITE_ASN1, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    /*

     * prepend the b64 BIO so all data is base64 encoded.

     */

    out = BIO_push(b64, out);

    r = i2d_ASN1_bio_stream(out, val, in, flags, it);

    (void)BIO_flush(out);

    BIO_pop(out);

    BIO_free(b64);

    return r;

}

/* Streaming ASN1 PEM write */

int PEM_write_bio_ASN1_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,

                              const char *hdr, const ASN1_ITEM *it)

{

    int r;

    BIO_printf(out, "-----BEGIN %s-----\n", hdr);

    r = B64_write_ASN1(out, val, in, flags, it);

    BIO_printf(out, "-----END %s-----\n", hdr);

    return r;

}

static ASN1_VALUE *b64_read_asn1(BIO *bio, const ASN1_ITEM *it)

{

    BIO *b64;

    ASN1_VALUE *val;

    if (!(b64 = BIO_new(BIO_f_base64()))) {

        ASN1err(ASN1_F_B64_READ_ASN1, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    bio = BIO_push(b64, bio);

    val = ASN1_item_d2i_bio(it, bio, NULL);

    if (!val)

        ASN1err(ASN1_F_B64_READ_ASN1, ASN1_R_DECODE_ERROR);

    (void)BIO_flush(bio);

    bio = BIO_pop(bio);

    BIO_free(b64);

    return val;

}

/* Generate the MIME "micalg" parameter from RFC3851, RFC4490 */

static int asn1_write_micalg(BIO *out, STACK_OF(X509_ALGOR) *mdalgs)

{

    const EVP_MD *md;

    int i, have_unknown = 0, write_comma, ret = 0, md_nid;

    have_unknown = 0;

    write_comma = 0;

    for (i = 0; i < sk_X509_ALGOR_num(mdalgs); i++) {

        if (write_comma)

            BIO_write(out, ",", 1);

        write_comma = 1;

        md_nid = OBJ_obj2nid(sk_X509_ALGOR_value(mdalgs, i)->algorithm);

        md = EVP_get_digestbynid(md_nid);

        if (md && md->md_ctrl) {

            int rv;

            char *micstr;

            rv = md->md_ctrl(NULL, EVP_MD_CTRL_MICALG, 0, &micstr);

            if (rv > 0) {

                BIO_puts(out, micstr);

                OPENSSL_free(micstr);

                continue;

            }

            if (rv != -2)

                goto err;

        }

        switch (md_nid) {

        case NID_sha1:

            BIO_puts(out, "sha1");

            break;

        case NID_md5:

            BIO_puts(out, "md5");

            break;

        case NID_sha256:

            BIO_puts(out, "sha-256");

            break;

        case NID_sha384:

            BIO_puts(out, "sha-384");

            break;

        case NID_sha512:

            BIO_puts(out, "sha-512");

            break;

        case NID_id_GostR3411_94:

            BIO_puts(out, "gostr3411-94");

            goto err;

            break;

        default:

            if (have_unknown)

                write_comma = 0;

            else {

                BIO_puts(out, "unknown");

                have_unknown = 1;

            }

            break;

        }

    }

    ret = 1;

 err:

    return ret;

}

/* SMIME sender */

int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,

                     int ctype_nid, int econt_nid,

                     STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)

{

    char bound[33], c;

    int i;

    const char *mime_prefix, *mime_eol, *cname = "smime.p7m";

    const char *msg_type = NULL;

    if (flags & SMIME_OLDMIME)

        mime_prefix = "application/x-pkcs7-";

    else

        mime_prefix = "application/pkcs7-";

    if (flags & SMIME_CRLFEOL)

        mime_eol = "\r\n";

    else

        mime_eol = "\n";

    if ((flags & SMIME_DETACHED) && data) {

        /* We want multipart/signed */

        /* Generate a random boundary */

        if (RAND_bytes((unsigned char *)bound, 32) <= 0)

            return 0;

        for (i = 0; i < 32; i++) {

            c = bound[i] & 0xf;

            if (c < 10)

                c += '0';

            else

                c += 'A' - 10;

            bound[i] = c;

        }

        bound[32] = 0;

        BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);

        BIO_printf(bio, "Content-Type: multipart/signed;");

        BIO_printf(bio, " protocol=\"%ssignature\";", mime_prefix);

        BIO_puts(bio, " micalg=\"");

        asn1_write_micalg(bio, mdalgs);

        BIO_printf(bio, "\"; boundary=\"----%s\"%s%s",

                   bound, mime_eol, mime_eol);

        BIO_printf(bio, "This is an S/MIME signed message%s%s",

                   mime_eol, mime_eol);

        /* Now write out the first part */

        BIO_printf(bio, "------%s%s", bound, mime_eol);

        if (!asn1_output_data(bio, data, val, flags, it))

            return 0;

        BIO_printf(bio, "%s------%s%s", mime_eol, bound, mime_eol);

        /* Headers for signature */

        BIO_printf(bio, "Content-Type: %ssignature;", mime_prefix);

        BIO_printf(bio, " name=\"smime.p7s\"%s", mime_eol);

        BIO_printf(bio, "Content-Transfer-Encoding: base64%s", mime_eol);

        BIO_printf(bio, "Content-Disposition: attachment;");

        BIO_printf(bio, " filename=\"smime.p7s\"%s%s", mime_eol, mime_eol);

        B64_write_ASN1(bio, val, NULL, 0, it);

        BIO_printf(bio, "%s------%s--%s%s", mime_eol, bound,

                   mime_eol, mime_eol);

        return 1;

    }

    /* Determine smime-type header */

    if (ctype_nid == NID_pkcs7_enveloped)

        msg_type = "enveloped-data";

    else if (ctype_nid == NID_pkcs7_signed) {

        if (econt_nid == NID_id_smime_ct_receipt)

            msg_type = "signed-receipt";

        else if (sk_X509_ALGOR_num(mdalgs) >= 0)

            msg_type = "signed-data";

        else

            msg_type = "certs-only";

    } else if (ctype_nid == NID_id_smime_ct_compressedData) {

        msg_type = "compressed-data";

        cname = "smime.p7z";

    }

    /* MIME headers */

    BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);

    BIO_printf(bio, "Content-Disposition: attachment;");

    BIO_printf(bio, " filename=\"%s\"%s", cname, mime_eol);

    BIO_printf(bio, "Content-Type: %smime;", mime_prefix);

    if (msg_type)

        BIO_printf(bio, " smime-type=%s;", msg_type);

    BIO_printf(bio, " name=\"%s\"%s", cname, mime_eol);

    BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",

               mime_eol, mime_eol);

    if (!B64_write_ASN1(bio, val, data, flags, it))

        return 0;

    BIO_printf(bio, "%s", mime_eol);

    return 1;

}

/* Handle output of ASN1 data */

static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,

                            const ASN1_ITEM *it)

{

    BIO *tmpbio;

    const ASN1_AUX *aux = it->funcs;

    ASN1_STREAM_ARG sarg;

    int rv = 1;

    /*

     * If data is not deteched or resigning then the output BIO is already

     * set up to finalise when it is written through.

     */

    if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {

        SMIME_crlf_copy(data, out, flags);

        return 1;

    }

    if (!aux || !aux->asn1_cb) {

        ASN1err(ASN1_F_ASN1_OUTPUT_DATA, ASN1_R_STREAMING_NOT_SUPPORTED);

        return 0;

    }

    sarg.out = out;

    sarg.ndef_bio = NULL;

    sarg.boundary = NULL;

    /* Let ASN1 code prepend any needed BIOs */

    if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)

        return 0;

    /* Copy data across, passing through filter BIOs for processing */

    SMIME_crlf_copy(data, sarg.ndef_bio, flags);

    /* Finalize structure */

    if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)

        rv = 0;

    /* Now remove any digests prepended to the BIO */

    while (sarg.ndef_bio != out) {

        tmpbio = BIO_pop(sarg.ndef_bio);

        BIO_free(sarg.ndef_bio);

        sarg.ndef_bio = tmpbio;

    }

    return rv;

}

/*

 * SMIME reader: handle multipart/signed and opaque signing. in multipart

 * case the content is placed in a memory BIO pointed to by "bcont". In

 * opaque this is set to NULL

 */

ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)

{

    BIO *asnin;

    STACK_OF(MIME_HEADER) *headers = NULL;

    STACK_OF(BIO) *parts = NULL;

    MIME_HEADER *hdr;

    MIME_PARAM *prm;

    ASN1_VALUE *val;

    int ret;

    if (bcont)

        *bcont = NULL;

    if (!(headers = mime_parse_hdr(bio))) {

        ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_PARSE_ERROR);

        return NULL;

    }

    if (!(hdr = mime_hdr_find(headers, "content-type")) || !hdr->value) {

        sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

        ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_CONTENT_TYPE);

        return NULL;

    }

    /* Handle multipart/signed */

    if (!strcmp(hdr->value, "multipart/signed")) {

        /* Split into two parts */

        prm = mime_param_find(hdr, "boundary");

        if (!prm || !prm->param_value) {

            sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

            ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BOUNDARY);

            return NULL;

        }

        ret = multi_split(bio, prm->param_value, &parts);

        sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

        if (!ret || (sk_BIO_num(parts) != 2)) {

            ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BODY_FAILURE);

            sk_BIO_pop_free(parts, BIO_vfree);

            return NULL;

        }

        /* Parse the signature piece */

        asnin = sk_BIO_value(parts, 1);

        if (!(headers = mime_parse_hdr(asnin))) {

            ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_SIG_PARSE_ERROR);

            sk_BIO_pop_free(parts, BIO_vfree);

            return NULL;

        }

        /* Get content type */

        if (!(hdr = mime_hdr_find(headers, "content-type")) || !hdr->value) {

            sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

            ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_SIG_CONTENT_TYPE);

            return NULL;

        }

        if (strcmp(hdr->value, "application/x-pkcs7-signature") &&

            strcmp(hdr->value, "application/pkcs7-signature")) {

            ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_SIG_INVALID_MIME_TYPE);

            ERR_add_error_data(2, "type: ", hdr->value);

            sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

            sk_BIO_pop_free(parts, BIO_vfree);

            return NULL;

        }

        sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

        /* Read in ASN1 */

        if (!(val = b64_read_asn1(asnin, it))) {

            ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_SIG_PARSE_ERROR);

            sk_BIO_pop_free(parts, BIO_vfree);

            return NULL;

        }

        if (bcont) {

            *bcont = sk_BIO_value(parts, 0);

            BIO_free(asnin);

            sk_BIO_free(parts);

        } else

            sk_BIO_pop_free(parts, BIO_vfree);

        return val;

    }

    /* OK, if not multipart/signed try opaque signature */

    if (strcmp(hdr->value, "application/x-pkcs7-mime") &&

        strcmp(hdr->value, "application/pkcs7-mime")) {

        ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_INVALID_MIME_TYPE);

        ERR_add_error_data(2, "type: ", hdr->value);

        sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

        return NULL;

    }

    sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

    if (!(val = b64_read_asn1(bio, it))) {

        ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_PARSE_ERROR);

        return NULL;

    }

    return val;

}

/* Copy text from one BIO to another making the output CRLF at EOL */

int SMIME_crlf_copy(BIO *in, BIO *out, int flags)

{

    BIO *bf;

    char eol;

    int len;

    char linebuf[MAX_SMLEN];

    /*

     * Buffer output so we don't write one line at a time. This is useful

     * when streaming as we don't end up with one OCTET STRING per line.

     */

    bf = BIO_new(BIO_f_buffer());

    if (!bf)

        return 0;

    out = BIO_push(bf, out);

    if (flags & SMIME_BINARY) {

        while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)

            BIO_write(out, linebuf, len);

    } else {

        if (flags & SMIME_TEXT)

            BIO_printf(out, "Content-Type: text/plain\r\n\r\n");

        while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {

            eol = strip_eol(linebuf, &len);

            if (len)

                BIO_write(out, linebuf, len);

            if (eol)

                BIO_write(out, "\r\n", 2);

        }

    }

    (void)BIO_flush(out);

    BIO_pop(out);

    BIO_free(bf);

    return 1;

}

/* Strip off headers if they are text/plain */

int SMIME_text(BIO *in, BIO *out)

{

    char iobuf[4096];

    int len;

    STACK_OF(MIME_HEADER) *headers;

    MIME_HEADER *hdr;

    if (!(headers = mime_parse_hdr(in))) {

        ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_PARSE_ERROR);

        return 0;

    }

    if (!(hdr = mime_hdr_find(headers, "content-type")) || !hdr->value) {

        ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_NO_CONTENT_TYPE);

        sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

        return 0;

    }

    if (strcmp(hdr->value, "text/plain")) {

        ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_INVALID_MIME_TYPE);

        ERR_add_error_data(2, "type: ", hdr->value);

        sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

        return 0;

    }

    sk_MIME_HEADER_pop_free(headers, mime_hdr_free);

    while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)

        BIO_write(out, iobuf, len);

    if (len < 0)

        return 0;

    return 1;

}

/*

 * Split a multipart/XXX message body into component parts: result is

 * canonical parts in a STACK of bios

 */

static int multi_split(BIO *bio, char *bound, STACK_OF(BIO) **ret)

{

    char linebuf[MAX_SMLEN];

    int len, blen;

    int eol = 0, next_eol = 0;

    BIO *bpart = NULL;

    STACK_OF(BIO) *parts;

    char state, part, first;

    blen = strlen(bound);

    part = 0;

    state = 0;

    first = 1;

    parts = sk_BIO_new_null();

    *ret = parts;

    while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {

        state = mime_bound_check(linebuf, len, bound, blen);

        if (state == 1) {

            first = 1;

            part++;

        } else if (state == 2) {

            sk_BIO_push(parts, bpart);

            return 1;

        } else if (part) {

            /* Strip CR+LF from linebuf */

            next_eol = strip_eol(linebuf, &len);

            if (first) {

                first = 0;

                if (bpart)

                    sk_BIO_push(parts, bpart);

                bpart = BIO_new(BIO_s_mem());

                if (bpart == NULL)

                    return 1;

                BIO_set_mem_eof_return(bpart, 0);

            } else if (eol)

                BIO_write(bpart, "\r\n", 2);

            eol = next_eol;

            if (len)

                BIO_write(bpart, linebuf, len);

        }

    }

    return 0;

}

/* This is the big one: parse MIME header lines up to message body */

#define MIME_INVALID    0

#define MIME_START      1

#define MIME_TYPE       2

#define MIME_NAME       3

#define MIME_VALUE      4

#define MIME_QUOTE      5

#define MIME_COMMENT    6

static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)

{

    char *p, *q, c;

    char *ntmp;

    char linebuf[MAX_SMLEN];

    MIME_HEADER *mhdr = NULL;

    STACK_OF(MIME_HEADER) *headers;

    int len, state, save_state = 0;

    headers = sk_MIME_HEADER_new(mime_hdr_cmp);

    if (!headers)

        return NULL;

    while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {

        /* If whitespace at line start then continuation line */

        if (mhdr && isspace((unsigned char)linebuf[0]))

            state = MIME_NAME;

        else

            state = MIME_START;

        ntmp = NULL;

        /* Go through all characters */

        for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');

             p++) {

            /*

             * State machine to handle MIME headers if this looks horrible

             * that's because it *is*

             */

            switch (state) {

            case MIME_START:

                if (c == ':') {

                    state = MIME_TYPE;

                    *p = 0;

                    ntmp = strip_ends(q);

                    q = p + 1;

                }

                break;

            case MIME_TYPE:

                if (c == ';') {

                    mime_debug("Found End Value\n");

                    *p = 0;

                    mhdr = mime_hdr_new(ntmp, strip_ends(q));

                    sk_MIME_HEADER_push(headers, mhdr);

                    ntmp = NULL;

                    q = p + 1;

                    state = MIME_NAME;

                } else if (c == '(') {

                    save_state = state;

                    state = MIME_COMMENT;

                }

                break;

            case MIME_COMMENT:

                if (c == ')') {

                    state = save_state;

                }

                break;

            case MIME_NAME:

                if (c == '=') {

                    state = MIME_VALUE;

                    *p = 0;

                    ntmp = strip_ends(q);

                    q = p + 1;

                }

                break;

            case MIME_VALUE:

                if (c == ';') {

                    state = MIME_NAME;

                    *p = 0;

                    mime_hdr_addparam(mhdr, ntmp, strip_ends(q));

                    ntmp = NULL;

                    q = p + 1;

                } else if (c == '"') {

                    mime_debug("Found Quote\n");

                    state = MIME_QUOTE;

                } else if (c == '(') {

                    save_state = state;

                    state = MIME_COMMENT;

                }

                break;

            case MIME_QUOTE:

                if (c == '"') {

                    mime_debug("Found Match Quote\n");

                    state = MIME_VALUE;

                }

                break;

            }

        }

        if (state == MIME_TYPE) {

            mhdr = mime_hdr_new(ntmp, strip_ends(q));

            sk_MIME_HEADER_push(headers, mhdr);

        } else if (state == MIME_VALUE)

            mime_hdr_addparam(mhdr, ntmp, strip_ends(q));

        if (p == linebuf)

            break;              /* Blank line means end of headers */

    }

    return headers;

}

static char *strip_ends(char *name)

{

    return strip_end(strip_start(name));

}

/* Strip a parameter of whitespace from start of param */

static char *strip_start(char *name)

{

    char *p, c;

    /* Look for first non white space or quote */

    for (p = name; (c = *p); p++) {

        if (c == '"') {

            /* Next char is start of string if non null */

            if (p[1])

                return p + 1;

            /* Else null string */

            return NULL;

        }

        if (!isspace((unsigned char)c))

            return p;

    }

    return NULL;

}

/* As above but strip from end of string : maybe should handle brackets? */

static char *strip_end(char *name)

{

    char *p, c;

    if (!name)

        return NULL;

    /* Look for first non white space or quote */

    for (p = name + strlen(name) - 1; p >= name; p--) {

        c = *p;

        if (c == '"') {

            if (p - 1 == name)

                return NULL;

            *p = 0;

            return name;

        }

        if (isspace((unsigned char)c))

            *p = 0;

        else

            return name;

    }

    return NULL;

}

static MIME_HEADER *mime_hdr_new(char *name, char *value)

{

    MIME_HEADER *mhdr;

    char *tmpname, *tmpval, *p;

    int c;

    if (name) {

        if (!(tmpname = BUF_strdup(name)))

            return NULL;

        for (p = tmpname; *p; p++) {

            c = (unsigned char)*p;

            if (isupper(c)) {

                c = tolower(c);

                *p = c;

            }

        }

    } else

        tmpname = NULL;

    if (value) {

        if (!(tmpval = BUF_strdup(value)))

            return NULL;

        for (p = tmpval; *p; p++) {

            c = (unsigned char)*p;

            if (isupper(c)) {

                c = tolower(c);

                *p = c;

            }

        }

    } else

        tmpval = NULL;

    mhdr = (MIME_HEADER *)OPENSSL_malloc(sizeof(MIME_HEADER));

    if (!mhdr)

        return NULL;

    mhdr->name = tmpname;

    mhdr->value = tmpval;

    if (!(mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)))

        return NULL;

    return mhdr;

}

static int mime_hdr_addparam(MIME_HEADER *mhdr, char *name, char *value)

{

    char *tmpname, *tmpval, *p;

    int c;

    MIME_PARAM *mparam;

    if (name) {

        tmpname = BUF_strdup(name);

        if (!tmpname)

            return 0;

        for (p = tmpname; *p; p++) {

            c = (unsigned char)*p;

            if (isupper(c)) {

                c = tolower(c);

                *p = c;

            }

        }

    } else

        tmpname = NULL;

    if (value) {

        tmpval = BUF_strdup(value);

        if (!tmpval)

            return 0;

    } else

        tmpval = NULL;

    /* Parameter values are case sensitive so leave as is */

    mparam = (MIME_PARAM *)OPENSSL_malloc(sizeof(MIME_PARAM));

    if (!mparam)

        return 0;

    mparam->param_name = tmpname;

    mparam->param_value = tmpval;

    sk_MIME_PARAM_push(mhdr->params, mparam);