path: root/em-format/e-mail-parser-multipart-encrypted.c

/*
 * e-mail-parser-multipart-encrypted.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 */

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

#include "e-mail-format-extensions.h"

#include <em-format/e-mail-parser-extension.h>
#include <em-format/e-mail-parser.h>
#include <em-format/e-mail-part-utils.h>

#include <glib/gi18n-lib.h>
#include <camel/camel.h>

typedef struct _EMailParserMultipartEncrypted {
    GObject parent;
} EMailParserMultipartEncrypted;

typedef struct _EMailParserMultipartEncryptedClass {
    GObjectClass parent_class;
} EMailParserMultipartEncryptedClass;

static void e_mail_parser_parser_extension_interface_init (EMailParserExtensionInterface *iface);
static void e_mail_parser_mail_extension_interface_init (EMailExtensionInterface *iface);

G_DEFINE_TYPE_EXTENDED (
    EMailParserMultipartEncrypted,
    e_mail_parser_multipart_encrypted,
    G_TYPE_OBJECT,
    0,
    G_IMPLEMENT_INTERFACE (
        E_TYPE_MAIL_EXTENSION,
        e_mail_parser_mail_extension_interface_init)
    G_IMPLEMENT_INTERFACE (
        E_TYPE_MAIL_PARSER_EXTENSION,
        e_mail_parser_parser_extension_interface_init))

static const gchar* parser_mime_types[] = { "multipart/encrypted", NULL };

static GSList *
empe_mp_encrypted_parse (EMailParserExtension *extension,
                         EMailParser *parser,
                         CamelMimePart *part,
                         GString *part_id,
                         GCancellable *cancellable)
{
    CamelCipherContext *context;
    const gchar *protocol;
    CamelMimePart *opart;
    CamelCipherValidity *valid;
    CamelMultipartEncrypted *mpe;
    GError *local_error = NULL;
    GSList *parts;
    gint len;
    GSList *iter;

    if (g_cancellable_is_cancelled (cancellable))
        return NULL;

    mpe = (CamelMultipartEncrypted *) camel_medium_get_content ((CamelMedium *) part);
    if (!CAMEL_IS_MULTIPART_ENCRYPTED (mpe)) {
        parts = e_mail_parser_error (
                parser, cancellable,
                _("Could not parse MIME message. "
                  "Displaying as source."));
        parts = g_slist_concat (
                parts,
                e_mail_parser_parse_part_as (
                    parser, part, part_id,
                    "application/vnd.evolution/source",
                    cancellable));

        return parts;
    }

    /* Currently we only handle RFC2015-style PGP encryption. */
    protocol = camel_content_type_param (
        ((CamelDataWrapper *)mpe)->mime_type, "protocol");
    if (!protocol || g_ascii_strcasecmp (protocol, "application/pgp-encrypted") != 0) {
        parts = e_mail_parser_error (
                parser, cancellable,
                   _("Unsupported encryption type for multipart/encrypted"));

        parts = g_slist_concat (
                parts,
                e_mail_parser_parse_part_as (
                    parser, part, part_id,
                    "multipart/mixed", cancellable));
        return parts;
    }

    context = camel_gpg_context_new (e_mail_parser_get_session (parser));

    opart = camel_mime_part_new ();
    valid = camel_cipher_context_decrypt_sync (
            context, part, opart, cancellable, &local_error);

    e_mail_part_preserve_charset_in_content_type (part, opart);
    if (valid == NULL) {
        parts = e_mail_parser_error (
                parser, cancellable,
                _("Could not parse PGP/MIME message: %s"),
                local_error->message ?
                    local_error->message :
                    _("Unknown error"));

        g_clear_error (&local_error);

        parts = g_slist_concat (parts,
                e_mail_parser_parse_part_as (
                    parser, part, part_id,
                    "multipart/mixed", cancellable));

        g_object_unref (opart);
        g_object_unref (context);

        return parts;
    }

    len = part_id->len;
    g_string_append (part_id, ".encrypted");

    parts = e_mail_parser_parse_part (
            parser, opart, part_id, cancellable);

    g_string_truncate (part_id, len);

    /* Update validity of all encrypted sub-parts */
    for (iter = parts; iter; iter = iter->next) {
        EMailPart *mail_part;

        mail_part = iter->data;
        if (!mail_part)
            continue;

        e_mail_part_update_validity (mail_part, valid,
            E_MAIL_PART_VALIDITY_ENCRYPTED |
            E_MAIL_PART_VALIDITY_PGP);
    }

    /* Add a widget with details about the encryption, but only when
        * the decrypted part isn't itself secured, in that case it has created
        * the button itself */
    if (!e_mail_part_is_secured (opart)) {
        GSList *button;
        EMailPart *mail_part;
        g_string_append (part_id, ".encrypted.button");

        button = e_mail_parser_parse_part_as (
                parser, part, part_id,
                "application/vnd.evolution.widget.secure-button",
                cancellable);
        if (button && button->data) {
            mail_part = button->data;

            e_mail_part_update_validity (mail_part, valid,
                E_MAIL_PART_VALIDITY_ENCRYPTED |
                E_MAIL_PART_VALIDITY_PGP);
        }

        parts = g_slist_concat (parts, button);

        g_string_truncate (part_id, len);
    }

    camel_cipher_validity_free (valid);

    /* TODO: Make sure when we finalize this part, it is zero'd out */
    g_object_unref (opart);
    g_object_unref (context);

    return parts;
}

static const gchar **
empe_mp_encrypted_mime_types (EMailExtension *extension)
{
    return parser_mime_types;
}

static void
e_mail_parser_multipart_encrypted_class_init (EMailParserMultipartEncryptedClass *class)
{
}

static void
e_mail_parser_parser_extension_interface_init (EMailParserExtensionInterface *iface)
{
    iface->parse = empe_mp_encrypted_parse;
}

static void
e_mail_parser_mail_extension_interface_init (EMailExtensionInterface *iface)
{
    iface->mime_types = empe_mp_encrypted_mime_types;
}

static void
e_mail_parser_multipart_encrypted_init (EMailParserMultipartEncrypted *parser)
{

}