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

/*
 * e-mail-parser-multipart-signed.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 _EMailParserMultipartSigned {
    GObject parent;
} EMailParserMultipartSigned;

typedef struct _EMailParserMultipartSignedClass {
    GObjectClass parent_class;
} EMailParserMultipartSignedClass;

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 (
    EMailParserMultipartSigned,
    e_mail_parser_multipart_signed,
    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/signed",
                        "application/pgp-signature",
                        NULL };

static GSList *
empe_mp_signed_parse (EMailParserExtension *extension,
                      EMailParser *parser,
                      CamelMimePart *part,
                      GString *part_id,
                      GCancellable *cancellable)
{
    CamelMimePart *cpart;
    CamelMultipartSigned *mps;
    CamelCipherContext *cipher = NULL;
    CamelSession *session;
    guint32 validity_type;
    GSList *parts;
    CamelCipherValidity *valid;
    GError *local_error = NULL;
    gint i, nparts, len;
    gboolean secured;

    if (g_cancellable_is_cancelled (cancellable))
        return NULL;

    /* If the part is application/pgp-signature sub-part then skip it. */
    if (!CAMEL_IS_MULTIPART (part)) {
        CamelContentType *ct;
        ct = camel_mime_part_get_content_type (CAMEL_MIME_PART (part));
        if (camel_content_type_is (ct, "application", "pgp-signature")) {
            return g_slist_alloc ();
        }
    }

    mps = (CamelMultipartSigned *) camel_medium_get_content ((CamelMedium *) part);
    if (!CAMEL_IS_MULTIPART_SIGNED (mps)
        || (cpart = camel_multipart_get_part ((CamelMultipart *) mps,
        CAMEL_MULTIPART_SIGNED_CONTENT)) == NULL) {
        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;
    }

    session = e_mail_parser_get_session (parser);
    /* FIXME: Should be done via a plugin interface */
    /* FIXME: duplicated in em-format-html-display.c */
    if (mps->protocol) {
#ifdef ENABLE_SMIME
        if (g_ascii_strcasecmp ("application/x-pkcs7-signature", mps->protocol) == 0
            || g_ascii_strcasecmp ("application/pkcs7-signature", mps->protocol) == 0) {
            cipher = camel_smime_context_new (session);
            validity_type = E_MAIL_PART_VALIDITY_SMIME;
        } else {
#endif
            if (g_ascii_strcasecmp ("application/pgp-signature", mps->protocol) == 0) {
                cipher = camel_gpg_context_new (session);
                validity_type = E_MAIL_PART_VALIDITY_PGP;
            }
#ifdef ENABLE_SMIME
        }
#endif
    }

    if (cipher == NULL) {
        parts = e_mail_parser_error (
                parser, cancellable,
                _("Unsupported signature format"));

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

        return parts;
    }

    valid = camel_cipher_context_verify_sync (
        cipher, part, cancellable, &local_error);
    if (valid == NULL) {
        parts = e_mail_parser_error (
                parser, cancellable,
                _("Error verifying signature: %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 (cipher);
        return parts;
    }

    nparts = camel_multipart_get_number (CAMEL_MULTIPART (mps));
    secured = FALSE;
    len = part_id->len;
    parts = NULL;
    for (i = 0; i < nparts; i++) {
        CamelMimePart *subpart;
        GSList *mail_parts, *iter;
        subpart = camel_multipart_get_part (CAMEL_MULTIPART (mps), i);

        g_string_append_printf (part_id, ".signed.%d", i);

        mail_parts = e_mail_parser_parse_part (
                parser, subpart, part_id, cancellable);

        g_string_truncate (part_id, len);

        if (!secured)
            secured = e_mail_part_is_secured (subpart);

        for (iter = mail_parts; iter; iter = iter->next) {
            EMailPart *mail_part;

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

            e_mail_part_update_validity (mail_part, valid,
                validity_type | E_MAIL_PART_VALIDITY_SIGNED);
        }

        parts = g_slist_concat (parts, mail_parts);
    }

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

        parts = g_slist_concat (parts, button);

        g_string_truncate (part_id, len);
    }

    camel_cipher_validity_free (valid);

    g_object_unref (cipher);

    return parts;
}

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

static void
e_mail_parser_multipart_signed_class_init (EMailParserMultipartSignedClass *class)
{
}

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

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

static void
e_mail_parser_multipart_signed_init (EMailParserMultipartSigned *parser)
{

}