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 <glib/gi18n-lib.h>

#include <libedataserver/libedataserver.h>

#include "e-mail-parser-extension.h"
#include "e-mail-part-utils.h"

typedef EMailParserExtension EMailParserMultipartSigned;
typedef EMailParserExtensionClass EMailParserMultipartSignedClass;

GType e_mail_parser_multipart_signed_get_type (void);

G_DEFINE_TYPE (
    EMailParserMultipartSigned,
    e_mail_parser_multipart_signed,
    E_TYPE_MAIL_PARSER_EXTENSION)

static const gchar *parser_mime_types[] = {
    "multipart/signed",
    "application/pgp-signature",
    NULL
};

static gboolean
empe_mp_signed_parse (EMailParserExtension *extension,
                      EMailParser *parser,
                      CamelMimePart *part,
                      GString *part_id,
                      GCancellable *cancellable,
                      GQueue *out_mail_parts)
{
    CamelMimePart *cpart = NULL;
    CamelMultipart *multipart;
    CamelCipherContext *cipher = NULL;
    CamelContentType *content_type;
    CamelSession *session;
    guint32 validity_type;
    CamelCipherValidity *valid;
    const gchar *protocol = NULL;
    GError *local_error = NULL;
    gint i, nparts, len;
    gboolean secured;

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

    multipart = (CamelMultipart *) camel_medium_get_content ((CamelMedium *) part);
    if (CAMEL_IS_MULTIPART_SIGNED (multipart)) {
        cpart = camel_multipart_get_part (
            multipart, CAMEL_MULTIPART_SIGNED_CONTENT);
    }

    if (cpart == NULL) {
        e_mail_parser_error (
            parser, out_mail_parts,
            _("Could not parse MIME message. "
            "Displaying as source."));
        e_mail_parser_parse_part_as (
            parser, part, part_id,
            "application/vnd.evolution.source",
            cancellable, out_mail_parts);

        return TRUE;
    }

    content_type = camel_data_wrapper_get_mime_type_field (
        CAMEL_DATA_WRAPPER (multipart));
    if (content_type != NULL)
        protocol = camel_content_type_param (content_type, "protocol");

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

    if (cipher == NULL) {
        e_mail_parser_error (
            parser, out_mail_parts,
            _("Unsupported signature format"));
        e_mail_parser_parse_part_as (
            parser, part, part_id, "multipart/mixed",
            cancellable, out_mail_parts);

        return TRUE;
    }

    valid = camel_cipher_context_verify_sync (
        cipher, part, cancellable, &local_error);

    if (local_error != NULL) {
        e_mail_parser_error (
            parser, out_mail_parts,
            _("Error verifying signature: %s"),
            local_error->message);
        e_mail_parser_parse_part_as (
            parser, part, part_id, "multipart/mixed",
            cancellable, out_mail_parts);

        g_object_unref (cipher);
        g_error_free (local_error);

        return TRUE;
    }

    nparts = camel_multipart_get_number (multipart);
    secured = FALSE;
    len = part_id->len;
    for (i = 0; i < nparts; i++) {
        GQueue work_queue = G_QUEUE_INIT;
        GList *head, *link;
        CamelMimePart *subpart;

        subpart = camel_multipart_get_part (multipart, i);

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

        e_mail_parser_parse_part (
            parser, subpart, part_id, cancellable, &work_queue);

        g_string_truncate (part_id, len);

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

        head = g_queue_peek_head_link (&work_queue);

        for (link = head; link != NULL; link = g_list_next (link)) {
            EMailPart *mail_part = link->data;

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

        e_queue_transfer (&work_queue, out_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) {
        GQueue work_queue = G_QUEUE_INIT;
        EMailPart *mail_part;

        g_string_append (part_id, ".signed.button");

        e_mail_parser_parse_part_as (
            parser, part, part_id,
            "application/vnd.evolution.widget.secure-button",
            cancellable, &work_queue);

        mail_part = g_queue_peek_head (&work_queue);

        if (mail_part != NULL)
            e_mail_part_update_validity (
                mail_part, valid,
                validity_type | E_MAIL_PART_VALIDITY_SIGNED);

        e_queue_transfer (&work_queue, out_mail_parts);

        g_string_truncate (part_id, len);
    }

    camel_cipher_validity_free (valid);

    g_object_unref (cipher);

    return TRUE;
}

static void
e_mail_parser_multipart_signed_class_init (EMailParserExtensionClass *class)
{
    class->mime_types = parser_mime_types;
    class->priority = G_PRIORITY_LOW;
    class->parse = empe_mp_signed_parse;
}

static void
e_mail_parser_multipart_signed_init (EMailParserExtension *extension)
{
}