path: root/camel/camel-multipart-encrypted.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 *  Authors: Jeffrey Stedfast <fejj@ximian.com>
 *
 *  Copyright 2002 Ximian, Inc. (www.ximian.com)
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Street #330, Boston, MA 02111-1307, USA.
 *
 */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <string.h>

#include "camel-multipart-encrypted.h"
#include "camel-mime-filter-crlf.h"
#include "camel-stream-filter.h"
#include "camel-stream-mem.h"
#include "camel-stream-fs.h"
#include "camel-mime-utils.h"
#include "camel-mime-part.h"

static void camel_multipart_encrypted_class_init (CamelMultipartEncryptedClass *klass);
static void camel_multipart_encrypted_init (gpointer object, gpointer klass);
static void camel_multipart_encrypted_finalize (CamelObject *object);

static void set_mime_type_field (CamelDataWrapper *data_wrapper, CamelContentType *mime_type);


static CamelMultipartClass *parent_class = NULL;


CamelType
camel_multipart_encrypted_get_type (void)
{
    static CamelType type = CAMEL_INVALID_TYPE;
    
    if (type == CAMEL_INVALID_TYPE) {
        type = camel_type_register (camel_multipart_get_type (),
                        "CamelMultipartEncrypted",
                        sizeof (CamelMultipartEncrypted),
                        sizeof (CamelMultipartEncryptedClass),
                        (CamelObjectClassInitFunc) camel_multipart_encrypted_class_init,
                        NULL,
                        (CamelObjectInitFunc) camel_multipart_encrypted_init,
                        (CamelObjectFinalizeFunc) camel_multipart_encrypted_finalize);
    }
    
    return type;
}


static void
camel_multipart_encrypted_class_init (CamelMultipartEncryptedClass *klass)
{
    CamelDataWrapperClass *camel_data_wrapper_class = CAMEL_DATA_WRAPPER_CLASS (klass);
    
    parent_class = (CamelMultipartClass *) camel_multipart_get_type ();
    
    /* virtual method overload */
    camel_data_wrapper_class->set_mime_type_field = set_mime_type_field;
}

static void
camel_multipart_encrypted_init (gpointer object, gpointer klass)
{
    CamelMultipartEncrypted *multipart = (CamelMultipartEncrypted *) object;
    
    camel_data_wrapper_set_mime_type (CAMEL_DATA_WRAPPER (multipart), "multipart/encrypted");
    
    multipart->decrypted = NULL;
}

static void
camel_multipart_encrypted_finalize (CamelObject *object)
{
    CamelMultipartEncrypted *mpe = (CamelMultipartEncrypted *) object;
    
    g_free (mpe->protocol);
    
    if (mpe->decrypted)
        camel_object_unref (mpe->decrypted);
}

/* we snoop the mime type to get the protocol */
static void
set_mime_type_field (CamelDataWrapper *data_wrapper, CamelContentType *mime_type)
{
    CamelMultipartEncrypted *mpe = (CamelMultipartEncrypted *) data_wrapper;
    
    if (mime_type) {
        const char *protocol;
        
        protocol = camel_content_type_param (mime_type, "protocol");
        g_free (mpe->protocol);
        mpe->protocol = g_strdup (protocol);
    }
    
    ((CamelDataWrapperClass *) parent_class)->set_mime_type_field (data_wrapper, mime_type);
}


/**
 * camel_multipart_encrypted_new:
 *
 * Create a new CamelMultipartEncrypted object.
 *
 * A MultipartEncrypted should be used to store and create parts of
 * type "multipart/encrypted".
 *
 * Returns a new CamelMultipartEncrypted
 **/
CamelMultipartEncrypted *
camel_multipart_encrypted_new (void)
{
    CamelMultipartEncrypted *multipart;
    
    multipart = (CamelMultipartEncrypted *) camel_object_new (CAMEL_MULTIPART_ENCRYPTED_TYPE);
    
    return multipart;
}


int
camel_multipart_encrypted_encrypt (CamelMultipartEncrypted *mpe, CamelMimePart *content,
                   CamelCipherContext *cipher, const char *userid,
                   GPtrArray *recipients, CamelException *ex)
{
    CamelMimePart *version_part, *encrypted_part;
    CamelContentType *mime_type;
    CamelDataWrapper *wrapper;
    CamelStream *filtered_stream;
    CamelStream *stream, *ciphertext;
    CamelMimeFilter *crlf_filter;
    
    g_return_val_if_fail (CAMEL_IS_MULTIPART_ENCRYPTED (mpe), -1);
    g_return_val_if_fail (CAMEL_IS_CIPHER_CONTEXT (cipher), -1);
    g_return_val_if_fail (cipher->encrypt_protocol != NULL, -1);
    g_return_val_if_fail (CAMEL_IS_MIME_PART (content), -1);
    
    /* get the cleartext */
    stream = camel_stream_mem_new ();
    filtered_stream = (CamelStream *) camel_stream_filter_new_with_stream (stream);
    
    crlf_filter = camel_mime_filter_crlf_new (CAMEL_MIME_FILTER_CRLF_ENCODE,
                          CAMEL_MIME_FILTER_CRLF_MODE_CRLF_ONLY);
    camel_stream_filter_add (CAMEL_STREAM_FILTER (filtered_stream), crlf_filter);
    camel_object_unref (crlf_filter);
    
    camel_data_wrapper_write_to_stream ((CamelDataWrapper *) content, filtered_stream);
    camel_stream_flush (filtered_stream);
    camel_object_unref (filtered_stream);
    
    /* reset the content stream */
    camel_stream_reset (stream);
    
    /* encrypt the content stream */
    ciphertext = camel_stream_mem_new ();
    if (camel_cipher_encrypt (cipher, FALSE, userid, recipients, stream, ciphertext, ex) == -1) {
        camel_object_unref (ciphertext);
        camel_object_unref (stream);
        return -1;
    }
    
    camel_object_unref (stream);
    camel_stream_reset (ciphertext);
    
    /* construct the version part */
    stream = camel_stream_mem_new ();
    camel_stream_write_string (stream, "Version: 1\n");
    camel_stream_reset (stream);
    
    version_part = camel_mime_part_new ();
    wrapper = camel_data_wrapper_new ();
    camel_data_wrapper_set_mime_type (wrapper, cipher->encrypt_protocol);
    camel_data_wrapper_construct_from_stream (wrapper, stream);
    camel_object_unref (stream);
    camel_medium_set_content_object ((CamelMedium *) version_part, wrapper);
    camel_object_unref (wrapper);
    
    /* construct the encrypted mime part */
    encrypted_part = camel_mime_part_new ();
    wrapper = camel_data_wrapper_new ();
    camel_data_wrapper_set_mime_type (wrapper, "application/octet-stream; name=encrypted.asc");
    camel_data_wrapper_construct_from_stream (wrapper, ciphertext);
    camel_object_unref (ciphertext);
    camel_medium_set_content_object ((CamelMedium *) encrypted_part, wrapper);
    camel_object_unref (wrapper);
    
    /* save the version and encrypted parts */
    /* FIXME: make sure there aren't any other parts?? */
    camel_multipart_add_part (CAMEL_MULTIPART (mpe), version_part);
    camel_object_unref (version_part);
    camel_multipart_add_part (CAMEL_MULTIPART (mpe), encrypted_part);
    camel_object_unref (encrypted_part);
    
    /* cache the decrypted content */
    camel_object_ref (content);
    mpe->decrypted = content;
    
    /* set the content-type params for this multipart/encrypted part */
    mime_type = camel_content_type_new ("multipart", "encrypted");
    camel_content_type_set_param (mime_type, "protocol", cipher->encrypt_protocol);
    camel_data_wrapper_set_mime_type_field (CAMEL_DATA_WRAPPER (mpe), mime_type);
    camel_content_type_unref (mime_type);
    camel_multipart_set_boundary ((CamelMultipart *) mpe, NULL);
    
    return 0;
}


CamelMimePart *
camel_multipart_encrypted_decrypt (CamelMultipartEncrypted *mpe,
                   CamelCipherContext *cipher,
                   CamelException *ex)
{
    CamelMimePart *version_part, *encrypted_part, *decrypted_part;
    CamelContentType *mime_type;
    CamelDataWrapper *wrapper;
    CamelStream *filtered_stream;
    CamelMimeFilter *crlf_filter;
    CamelStream *ciphertext;
    CamelStream *stream;
    const char *protocol;
    char *content_type;
    
    g_return_val_if_fail (CAMEL_IS_MULTIPART_ENCRYPTED (mpe), NULL);
    g_return_val_if_fail (CAMEL_IS_CIPHER_CONTEXT (cipher), NULL);
    g_return_val_if_fail (cipher->encrypt_protocol != NULL, NULL);
    
    if (mpe->decrypted) {
        /* we seem to have already decrypted the part */
        camel_object_ref (mpe->decrypted);
        return mpe->decrypted;
    }
    
    protocol = mpe->protocol;
    
    if (protocol) {
        /* make sure the protocol matches the cipher encrypt protocol */
        if (strcasecmp (cipher->encrypt_protocol, protocol) != 0) {
            camel_exception_set (ex, CAMEL_EXCEPTION_SYSTEM,
                         _("Failed to decrypt MIME part: protocol error"));
            
            return NULL;
        }
    } else {
        /* *shrug* - I guess just go on as if they match? */
        protocol = cipher->encrypt_protocol;
    }
    
    /* make sure the protocol matches the version part's content-type */
    version_part = camel_multipart_get_part (CAMEL_MULTIPART (mpe), CAMEL_MULTIPART_ENCRYPTED_VERSION);
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (version_part));
    content_type = camel_data_wrapper_get_mime_type (wrapper);
    if (strcasecmp (content_type, protocol) != 0) {
        camel_exception_set (ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Failed to decrypt MIME part: protocol error"));
        
        g_free (content_type);
        
        return NULL;
    }
    g_free (content_type);
    
    /* get the encrypted part (second part) */
    encrypted_part = camel_multipart_get_part (CAMEL_MULTIPART (mpe), CAMEL_MULTIPART_ENCRYPTED_CONTENT);
    mime_type = camel_mime_part_get_content_type (encrypted_part);
    if (!camel_content_type_is (mime_type, "application", "octet-stream")) {
        camel_exception_set (ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Failed to decrypt MIME part: invalid structure"));
        return NULL;
    }
    
    /* get the ciphertext stream */
    ciphertext = camel_stream_mem_new ();
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (encrypted_part));
    camel_data_wrapper_write_to_stream (wrapper, ciphertext);
    camel_stream_reset (ciphertext);
    
    stream = camel_stream_mem_new ();
    filtered_stream = (CamelStream *) camel_stream_filter_new_with_stream (stream);
    crlf_filter = camel_mime_filter_crlf_new (CAMEL_MIME_FILTER_CRLF_DECODE,
                          CAMEL_MIME_FILTER_CRLF_MODE_CRLF_ONLY);
    camel_stream_filter_add (CAMEL_STREAM_FILTER (filtered_stream), crlf_filter);
    camel_object_unref (crlf_filter);
    
    /* get the cleartext */
    if (camel_cipher_decrypt (cipher, ciphertext, filtered_stream, ex) == -1) {
        camel_object_unref (filtered_stream);
        camel_object_unref (ciphertext);
        camel_object_unref (stream);
        
        return NULL;
    }
    
    camel_stream_flush (filtered_stream);
    camel_object_unref (filtered_stream);
    camel_object_unref (ciphertext);
    camel_stream_reset (stream);
    
    decrypted_part = camel_mime_part_new ();
    camel_data_wrapper_construct_from_stream (CAMEL_DATA_WRAPPER (decrypted_part), stream);
    
    if (decrypted_part) {
        /* cache the decrypted part */
        camel_object_ref (decrypted_part);
        mpe->decrypted = decrypted_part;
    } else {
        camel_exception_set (ex, CAMEL_EXCEPTION_SYSTEM,
                     _("Failed to decrypt MIME part: parse error"));
    }
    
    return decrypted_part;
}