Example #1
0
def test_verify_prefix_suffix(flask_client):
    user = login(flask_client)
    db.session.commit()

    CustomDomain.create(user_id=user.id, domain="test.com", verified=True)

    assert verify_prefix_suffix(user, "prefix", "@test.com")
    assert not verify_prefix_suffix(user, "prefix", "@abcd.com")

    word = random_word()
    suffix = f".{word}@{EMAIL_DOMAIN}"
    assert verify_prefix_suffix(user, "prefix", suffix)
Example #2
0
def new_custom_alias():
    """
    Create a new custom alias
    Input:
        alias_prefix, for ex "www_groupon_com"
        alias_suffix, either [email protected] or @my-domain.com
        optional "hostname" in args
        optional "note"
    Output:
        201 if success
        409 if the alias already exists

    """
    user: User = g.user
    if not user.can_create_new_alias():
        LOG.d("user %s cannot create any custom alias", user)
        return (
            jsonify(
                error="You have reached the limitation of a free account with the maximum of "
                f"{MAX_NB_EMAIL_FREE_PLAN} aliases, please upgrade your plan to create more aliases"
            ),
            400,
        )

    user_custom_domains = [cd.domain for cd in user.verified_custom_domains()]
    hostname = request.args.get("hostname")

    data = request.get_json()
    if not data:
        return jsonify(error="request body cannot be empty"), 400

    alias_prefix = data.get("alias_prefix", "").strip()
    alias_suffix = data.get("alias_suffix", "").strip()
    note = data.get("note")
    alias_prefix = convert_to_id(alias_prefix)

    if not verify_prefix_suffix(user, alias_prefix, alias_suffix, user_custom_domains):
        return jsonify(error="wrong alias prefix or suffix"), 400

    full_alias = alias_prefix + alias_suffix
    if GenEmail.get_by(email=full_alias):
        LOG.d("full alias already used %s", full_alias)
        return jsonify(error=f"alias {full_alias} already exists"), 409

    gen_email = GenEmail.create(
        user_id=user.id, email=full_alias, mailbox_id=user.default_mailbox_id, note=note
    )
    db.session.commit()

    if hostname:
        AliasUsedOn.create(gen_email_id=gen_email.id, hostname=hostname)
        db.session.commit()

    return jsonify(alias=full_alias), 201
Example #3
0
def new_custom_alias():
    """
    Currently used by Safari extension.
    Create a new custom alias
    Input:
        alias_prefix, for ex "www_groupon_com"
        alias_suffix, either [email protected] or @my-domain.com
        optional "hostname" in args
        optional "note"
    Output:
        201 if success
        409 if the alias already exists

    """
    LOG.warning("/alias/custom/new is obsolete")
    user: User = g.user
    if not user.can_create_new_alias():
        LOG.d("user %s cannot create any custom alias", user)
        return (
            jsonify(
                error=
                "You have reached the limitation of a free account with the maximum of "
                f"{MAX_NB_EMAIL_FREE_PLAN} aliases, please upgrade your plan to create more aliases"
            ),
            400,
        )

    hostname = request.args.get("hostname")

    data = request.get_json()
    if not data:
        return jsonify(error="request body cannot be empty"), 400

    alias_prefix = data.get("alias_prefix",
                            "").strip().lower().replace(" ", "")
    alias_suffix = data.get("alias_suffix",
                            "").strip().lower().replace(" ", "")
    note = data.get("note")
    alias_prefix = convert_to_id(alias_prefix)

    if not verify_prefix_suffix(user, alias_prefix, alias_suffix):
        return jsonify(error="wrong alias prefix or suffix"), 400

    full_alias = alias_prefix + alias_suffix
    if (Alias.get_by(email=full_alias) or DeletedAlias.get_by(email=full_alias)
            or DomainDeletedAlias.get_by(email=full_alias)):
        LOG.d("full alias already used %s", full_alias)
        return jsonify(error=f"alias {full_alias} already exists"), 409

    alias = Alias.create(user_id=user.id,
                         email=full_alias,
                         mailbox_id=user.default_mailbox_id,
                         note=note)

    if alias_suffix.startswith("@"):
        alias_domain = alias_suffix[1:]
        domain = CustomDomain.get_by(domain=alias_domain)
        if domain:
            LOG.d("set alias %s to domain %s", full_alias, domain)
            alias.custom_domain_id = domain.id

    db.session.commit()

    if hostname:
        AliasUsedOn.create(alias_id=alias.id,
                           hostname=hostname,
                           user_id=alias.user_id)
        db.session.commit()

    return jsonify(alias=full_alias,
                   **serialize_alias_info(get_alias_info(alias))), 201
Example #4
0
def new_custom_alias_v3():
    """
    Create a new custom alias
    Same as v2 but accept a list of mailboxes as input
    Input:
        alias_prefix, for ex "www_groupon_com"
        signed_suffix, either [email protected] or @my-domain.com
        mailbox_ids: list of int
        optional "hostname" in args
        optional "note"
        optional "name"

    Output:
        201 if success
        409 if the alias already exists

    """
    user: User = g.user
    if not user.can_create_new_alias():
        LOG.d("user %s cannot create any custom alias", user)
        return (
            jsonify(
                error=
                "You have reached the limitation of a free account with the maximum of "
                f"{MAX_NB_EMAIL_FREE_PLAN} aliases, please upgrade your plan to create more aliases"
            ),
            400,
        )

    hostname = request.args.get("hostname")

    data = request.get_json()
    if not data:
        return jsonify(error="request body cannot be empty"), 400

    alias_prefix = data.get("alias_prefix",
                            "").strip().lower().replace(" ", "")
    signed_suffix = data.get("signed_suffix", "").strip()
    mailbox_ids = data.get("mailbox_ids")
    note = data.get("note")
    name = data.get("name")
    if name:
        name = name.replace("\n", "")
    alias_prefix = convert_to_id(alias_prefix)

    if not check_alias_prefix(alias_prefix):
        return jsonify(error="alias prefix invalid format or too long"), 400

    # check if mailbox is not tempered with
    mailboxes = []
    for mailbox_id in mailbox_ids:
        mailbox = Mailbox.get(mailbox_id)
        if not mailbox or mailbox.user_id != user.id or not mailbox.verified:
            return jsonify(error="Errors with Mailbox"), 400
        mailboxes.append(mailbox)

    if not mailboxes:
        return jsonify(error="At least one mailbox must be selected"), 400

    # hypothesis: user will click on the button in the 600 secs
    try:
        alias_suffix = signer.unsign(signed_suffix, max_age=600).decode()
    except SignatureExpired:
        LOG.warning("Alias creation time expired for %s", user)
        return jsonify(
            error="Alias creation time is expired, please retry"), 412
    except Exception:
        LOG.warning("Alias suffix is tampered, user %s", user)
        return jsonify(error="Tampered suffix"), 400

    if not verify_prefix_suffix(user, alias_prefix, alias_suffix):
        return jsonify(error="wrong alias prefix or suffix"), 400

    full_alias = alias_prefix + alias_suffix
    if (Alias.get_by(email=full_alias) or DeletedAlias.get_by(email=full_alias)
            or DomainDeletedAlias.get_by(email=full_alias)):
        LOG.d("full alias already used %s", full_alias)
        return jsonify(error=f"alias {full_alias} already exists"), 409

    custom_domain_id = None
    if alias_suffix.startswith("@"):
        alias_domain = alias_suffix[1:]
        domain = CustomDomain.get_by(domain=alias_domain)
        if domain:
            custom_domain_id = domain.id

    alias = Alias.create(
        user_id=user.id,
        email=full_alias,
        note=note,
        name=name or None,
        mailbox_id=mailboxes[0].id,
        custom_domain_id=custom_domain_id,
    )
    db.session.flush()

    for i in range(1, len(mailboxes)):
        AliasMailbox.create(
            alias_id=alias.id,
            mailbox_id=mailboxes[i].id,
        )

    db.session.commit()

    if hostname:
        AliasUsedOn.create(alias_id=alias.id,
                           hostname=hostname,
                           user_id=alias.user_id)
        db.session.commit()

    return (
        jsonify(alias=full_alias,
                **serialize_alias_info_v2(get_alias_info_v2(alias))),
        201,
    )
Example #5
0
def new_custom_alias_v2():
    """
    Create a new custom alias
    Same as v1 but signed_suffix is actually the suffix with signature, e.g.
    [email protected]
    Input:
        alias_prefix, for ex "www_groupon_com"
        signed_suffix, either [email protected] or @my-domain.com
        optional "hostname" in args
        optional "note"
    Output:
        201 if success
        409 if the alias already exists

    """
    user: User = g.user
    if not user.can_create_new_alias():
        LOG.d("user %s cannot create any custom alias", user)
        return (
            jsonify(
                error=
                "You have reached the limitation of a free account with the maximum of "
                f"{MAX_NB_EMAIL_FREE_PLAN} aliases, please upgrade your plan to create more aliases"
            ),
            400,
        )

    hostname = request.args.get("hostname")

    data = request.get_json()
    if not data:
        return jsonify(error="request body cannot be empty"), 400

    alias_prefix = data.get("alias_prefix",
                            "").strip().lower().replace(" ", "")
    signed_suffix = data.get("signed_suffix", "").strip()
    note = data.get("note")
    alias_prefix = convert_to_id(alias_prefix)

    # hypothesis: user will click on the button in the 600 secs
    try:
        alias_suffix = signer.unsign(signed_suffix, max_age=600).decode()
    except SignatureExpired:
        LOG.warning("Alias creation time expired for %s", user)
        return jsonify(
            error="Alias creation time is expired, please retry"), 412
    except Exception:
        LOG.warning("Alias suffix is tampered, user %s", user)
        return jsonify(error="Tampered suffix"), 400

    if not verify_prefix_suffix(user, alias_prefix, alias_suffix):
        return jsonify(error="wrong alias prefix or suffix"), 400

    full_alias = alias_prefix + alias_suffix
    if (Alias.get_by(email=full_alias) or DeletedAlias.get_by(email=full_alias)
            or DomainDeletedAlias.get_by(email=full_alias)):
        LOG.d("full alias already used %s", full_alias)
        return jsonify(error=f"alias {full_alias} already exists"), 409

    custom_domain_id = None
    if alias_suffix.startswith("@"):
        alias_domain = alias_suffix[1:]
        domain = CustomDomain.get_by(domain=alias_domain)

        # check if the alias is currently in the domain trash
        if domain and DomainDeletedAlias.get_by(domain_id=domain.id,
                                                email=full_alias):
            LOG.d(
                f"Alias {full_alias} is currently in the {domain.domain} trash. "
            )
            return jsonify(error=f"alias {full_alias} in domain trash"), 409

        if domain:
            custom_domain_id = domain.id

    alias = Alias.create(
        user_id=user.id,
        email=full_alias,
        mailbox_id=user.default_mailbox_id,
        note=note,
        custom_domain_id=custom_domain_id,
    )

    db.session.commit()

    if hostname:
        AliasUsedOn.create(alias_id=alias.id,
                           hostname=hostname,
                           user_id=alias.user_id)
        db.session.commit()

    return (
        jsonify(alias=full_alias,
                **serialize_alias_info_v2(get_alias_info_v2(alias))),
        201,
    )
Example #6
0
def authorize():
    """
    Redirected from client when user clicks on "Login with Server".
    This is a GET request with the following field in url
    - client_id
    - (optional) state
    - response_type: must be code
    """
    oauth_client_id = request.args.get("client_id")
    state = request.args.get("state")
    scope = request.args.get("scope")
    redirect_uri = request.args.get("redirect_uri")
    response_mode = request.args.get("response_mode")
    nonce = request.args.get("nonce")

    try:
        response_types: [ResponseType] = get_response_types(request)
    except ValueError:
        return (
            "response_type must be code, token, id_token or certain combination of these."
            " Please see /.well-known/openid-configuration to see what response_type are supported ",
            400,
        )

    if set(response_types) not in SUPPORTED_OPENID_FLOWS:
        return (
            f"SimpleLogin only support the following OIDC flows: {SUPPORTED_OPENID_FLOWS_STR}",
            400,
        )

    if not redirect_uri:
        LOG.d("no redirect uri")
        return "redirect_uri must be set", 400

    client = Client.get_by(oauth_client_id=oauth_client_id)
    if not client:
        final_redirect_uri = (
            f"{redirect_uri}?error=invalid_client_id&client_id={oauth_client_id}"
        )
        return redirect(final_redirect_uri)

    # check if redirect_uri is valid
    # allow localhost by default
    hostname, scheme = get_host_name_and_scheme(redirect_uri)
    if hostname != "localhost" and hostname != "127.0.0.1":
        # support custom scheme for mobile app
        if scheme == "http":
            final_redirect_uri = f"{redirect_uri}?error=http_not_allowed"
            return redirect(final_redirect_uri)

        if not RedirectUri.get_by(client_id=client.id, uri=redirect_uri):
            final_redirect_uri = f"{redirect_uri}?error=unknown_redirect_uri"
            return redirect(final_redirect_uri)

    # redirect from client website
    if request.method == "GET":
        if current_user.is_authenticated:
            suggested_email, other_emails, email_suffix = None, [], None
            suggested_name, other_names = None, []

            # user has already allowed this client
            client_user: ClientUser = ClientUser.get_by(
                client_id=client.id, user_id=current_user.id)
            user_info = {}
            if client_user:
                LOG.debug("user %s has already allowed client %s",
                          current_user, client)
                user_info = client_user.get_user_info()
            else:
                suggested_email, other_emails = current_user.suggested_emails(
                    client.name)
                suggested_name, other_names = current_user.suggested_names()

                user_custom_domains = [
                    cd.domain for cd in current_user.verified_custom_domains()
                ]
                # List of (is_custom_domain, alias-suffix, time-signed alias-suffix)
                suffixes = available_suffixes(current_user)

            return render_template(
                "oauth/authorize.html",
                Scope=Scope,
                EMAIL_DOMAIN=EMAIL_DOMAIN,
                **locals(),
            )
        else:
            # after user logs in, redirect user back to this page
            return render_template(
                "oauth/authorize_nonlogin_user.html",
                client=client,
                next=request.url,
                Scope=Scope,
            )
    else:  # POST - user allows or denies
        if request.form.get("button") == "deny":
            LOG.debug("User %s denies Client %s", current_user, client)
            final_redirect_uri = f"{redirect_uri}?error=deny&state={state}"
            return redirect(final_redirect_uri)

        LOG.debug("User %s allows Client %s", current_user, client)
        client_user = ClientUser.get_by(client_id=client.id,
                                        user_id=current_user.id)

        # user has already allowed this client, user cannot change information
        if client_user:
            LOG.d("user %s has already allowed client %s", current_user,
                  client)
        else:
            alias_prefix = request.form.get("prefix")
            signed_suffix = request.form.get("suffix")

            alias = None

            # user creates a new alias, not using suggested alias
            if alias_prefix:
                # should never happen as this is checked on the front-end
                if not current_user.can_create_new_alias():
                    raise Exception(
                        f"User {current_user} cannot create custom email")

                # hypothesis: user will click on the button in the 600 secs
                try:
                    alias_suffix = signer.unsign(signed_suffix,
                                                 max_age=600).decode()
                except SignatureExpired:
                    LOG.warning("Alias creation time expired for %s",
                                current_user)
                    flash("Alias creation time is expired, please retry",
                          "warning")
                    return redirect(request.url)
                except Exception:
                    LOG.exception("Alias suffix is tampered, user %s",
                                  current_user)
                    flash("Unknown error, refresh the page", "error")
                    return redirect(request.url)

                user_custom_domains = [
                    cd.domain for cd in current_user.verified_custom_domains()
                ]

                from app.dashboard.views.custom_alias import verify_prefix_suffix

                if verify_prefix_suffix(current_user, alias_prefix,
                                        alias_suffix):
                    full_alias = alias_prefix + alias_suffix

                    if (Alias.get_by(email=full_alias)
                            or DeletedAlias.get_by(email=full_alias)
                            or DomainDeletedAlias.get_by(email=full_alias)):
                        LOG.exception("alias %s already used, very rare!",
                                      full_alias)
                        flash(f"Alias {full_alias} already used", "error")
                        return redirect(request.url)
                    else:
                        alias = Alias.create(
                            user_id=current_user.id,
                            email=full_alias,
                            mailbox_id=current_user.default_mailbox_id,
                        )

                        # get the custom_domain_id if alias is created with a custom domain
                        if alias_suffix.startswith("@"):
                            alias_domain = alias_suffix[1:]
                            domain = CustomDomain.get_by(domain=alias_domain)
                            if domain:
                                alias.custom_domain_id = domain.id

                        db.session.flush()
                        flash(f"Alias {full_alias} has been created",
                              "success")
                # only happen if the request has been "hacked"
                else:
                    flash("something went wrong", "warning")
                    return redirect(request.url)
            # User chooses one of the suggestions
            else:
                chosen_email = request.form.get("suggested-email")
                # todo: add some checks on chosen_email
                if chosen_email != current_user.email:
                    alias = Alias.get_by(email=chosen_email)
                    if not alias:
                        alias = Alias.create(
                            email=chosen_email,
                            user_id=current_user.id,
                            mailbox_id=current_user.default_mailbox_id,
                        )
                        db.session.flush()

            suggested_name = request.form.get("suggested-name")
            custom_name = request.form.get("custom-name")

            use_default_avatar = request.form.get("avatar-choice") == "default"

            client_user = ClientUser.create(client_id=client.id,
                                            user_id=current_user.id)
            if alias:
                client_user.alias_id = alias.id

            if custom_name:
                client_user.name = custom_name
            elif suggested_name != current_user.name:
                client_user.name = suggested_name

            if use_default_avatar:
                # use default avatar
                LOG.d("use default avatar for user %s client %s", current_user,
                      client)
                client_user.default_avatar = True

            db.session.flush()
            LOG.d("create client-user for client %s, user %s", client,
                  current_user)

        redirect_args = {}

        if state:
            redirect_args["state"] = state
        else:
            LOG.warning(
                "more security reason, state should be added. client %s",
                client)

        if scope:
            redirect_args["scope"] = scope

        auth_code = None
        if ResponseType.CODE in response_types:
            # Create authorization code
            auth_code = AuthorizationCode.create(
                client_id=client.id,
                user_id=current_user.id,
                code=random_string(),
                scope=scope,
                redirect_uri=redirect_uri,
                response_type=response_types_to_str(response_types),
            )
            db.session.add(auth_code)
            redirect_args["code"] = auth_code.code

        oauth_token = None
        if ResponseType.TOKEN in response_types:
            # create access-token
            oauth_token = OauthToken.create(
                client_id=client.id,
                user_id=current_user.id,
                scope=scope,
                redirect_uri=redirect_uri,
                access_token=generate_access_token(),
                response_type=response_types_to_str(response_types),
            )
            db.session.add(oauth_token)
            redirect_args["access_token"] = oauth_token.access_token

        if ResponseType.ID_TOKEN in response_types:
            redirect_args["id_token"] = make_id_token(
                client_user,
                nonce,
                oauth_token.access_token if oauth_token else None,
                auth_code.code if auth_code else None,
            )

        db.session.commit()

        # should all params appended the url using fragment (#) or query
        fragment = False

        if response_mode and response_mode == "fragment":
            fragment = True

        # if response_types contain "token" => implicit flow => should use fragment
        # except if client sets explicitly response_mode
        if not response_mode:
            if ResponseType.TOKEN in response_types:
                fragment = True

        # construct redirect_uri with redirect_args
        return redirect(construct_url(redirect_uri, redirect_args, fragment))
Example #7
0
def authorize():
    """
    Redirected from client when user clicks on "Login with Server".
    This is a GET request with the following field in url
    - client_id
    - (optional) state
    - response_type: must be code
    """
    oauth_client_id = request.args.get("client_id")
    state = request.args.get("state")
    scope = request.args.get("scope")
    redirect_uri = request.args.get("redirect_uri")
    response_mode = request.args.get("response_mode")
    nonce = request.args.get("nonce")

    try:
        response_types: [ResponseType] = get_response_types(request)
    except ValueError:
        return (
            "response_type must be code, token, id_token or certain combination of these."
            " Please see /.well-known/openid-configuration to see what response_type are supported ",
            400,
        )

    if set(response_types) not in SUPPORTED_OPENID_FLOWS:
        return (
            f"SimpleLogin only support the following OIDC flows: {SUPPORTED_OPENID_FLOWS_STR}",
            400,
        )

    if not redirect_uri:
        LOG.d("no redirect uri")
        return "redirect_uri must be set", 400

    client = Client.get_by(oauth_client_id=oauth_client_id)
    if not client:
        final_redirect_uri = (
            f"{redirect_uri}?error=invalid_client_id&client_id={oauth_client_id}"
        )
        return redirect(final_redirect_uri)

    # check if redirect_uri is valid
    # allow localhost by default
    # allow any redirect_uri if the app isn't approved
    hostname, scheme = get_host_name_and_scheme(redirect_uri)
    if hostname != "localhost" and hostname != "127.0.0.1" and client.approved:
        # support custom scheme for mobile app
        if scheme == "http":
            final_redirect_uri = f"{redirect_uri}?error=http_not_allowed"
            return redirect(final_redirect_uri)

        if not RedirectUri.get_by(client_id=client.id, uri=redirect_uri):
            final_redirect_uri = f"{redirect_uri}?error=unknown_redirect_uri"
            return redirect(final_redirect_uri)

    # redirect from client website
    if request.method == "GET":
        if current_user.is_authenticated:
            suggested_email, other_emails, email_suffix = None, [], None
            suggested_name, other_names = None, []

            # user has already allowed this client
            client_user: ClientUser = ClientUser.get_by(
                client_id=client.id, user_id=current_user.id)
            user_info = {}
            if client_user:
                LOG.d("user %s has already allowed client %s", current_user,
                      client)
                user_info = client_user.get_user_info()

                # redirect user to the client page
                redirect_args = construct_redirect_args(
                    client,
                    client_user,
                    nonce,
                    redirect_uri,
                    response_types,
                    scope,
                    state,
                )
                fragment = get_fragment(response_mode, response_types)

                # construct redirect_uri with redirect_args
                return redirect(
                    construct_url(redirect_uri, redirect_args, fragment))
            else:
                suggested_email, other_emails = current_user.suggested_emails(
                    client.name)
                suggested_name, other_names = current_user.suggested_names()

                user_custom_domains = [
                    cd.domain for cd in current_user.verified_custom_domains()
                ]
                suffixes = get_available_suffixes(current_user)

            return render_template(
                "oauth/authorize.html",
                Scope=Scope,
                EMAIL_DOMAIN=EMAIL_DOMAIN,
                **locals(),
            )
        else:
            # after user logs in, redirect user back to this page
            return render_template(
                "oauth/authorize_nonlogin_user.html",
                client=client,
                next=request.url,
                Scope=Scope,
            )
    else:  # POST - user allows or denies
        if not current_user.is_authenticated or not current_user.is_active:
            LOG.i(
                "Attempt to validate a OAUth allow request by an unauthenticated user"
            )
            return redirect(url_for("auth.login", next=request.url))

        if request.form.get("button") == "deny":
            LOG.d("User %s denies Client %s", current_user, client)
            final_redirect_uri = f"{redirect_uri}?error=deny&state={state}"
            return redirect(final_redirect_uri)

        LOG.d("User %s allows Client %s", current_user, client)
        client_user = ClientUser.get_by(client_id=client.id,
                                        user_id=current_user.id)

        # user has already allowed this client, user cannot change information
        if client_user:
            LOG.d("user %s has already allowed client %s", current_user,
                  client)
        else:
            alias_prefix = request.form.get("prefix")
            signed_suffix = request.form.get("suffix")

            alias = None

            # user creates a new alias, not using suggested alias
            if alias_prefix:
                # should never happen as this is checked on the front-end
                if not current_user.can_create_new_alias():
                    raise Exception(
                        f"User {current_user} cannot create custom email")

                alias_prefix = alias_prefix.strip().lower().replace(" ", "")

                if not check_alias_prefix(alias_prefix):
                    flash(
                        "Only lowercase letters, numbers, dashes (-), dots (.) and underscores (_) "
                        "are currently supported for alias prefix. Cannot be more than 40 letters",
                        "error",
                    )
                    return redirect(request.url)

                # hypothesis: user will click on the button in the 600 secs
                try:
                    alias_suffix = signer.unsign(signed_suffix,
                                                 max_age=600).decode()
                except SignatureExpired:
                    LOG.w("Alias creation time expired for %s", current_user)
                    flash("Alias creation time is expired, please retry",
                          "warning")
                    return redirect(request.url)
                except Exception:
                    LOG.w("Alias suffix is tampered, user %s", current_user)
                    flash("Unknown error, refresh the page", "error")
                    return redirect(request.url)

                user_custom_domains = [
                    cd.domain for cd in current_user.verified_custom_domains()
                ]

                from app.dashboard.views.custom_alias import verify_prefix_suffix

                if verify_prefix_suffix(current_user, alias_prefix,
                                        alias_suffix):
                    full_alias = alias_prefix + alias_suffix

                    if (Alias.get_by(email=full_alias)
                            or DeletedAlias.get_by(email=full_alias)
                            or DomainDeletedAlias.get_by(email=full_alias)):
                        LOG.e("alias %s already used, very rare!", full_alias)
                        flash(f"Alias {full_alias} already used", "error")
                        return redirect(request.url)
                    else:
                        alias = Alias.create(
                            user_id=current_user.id,
                            email=full_alias,
                            mailbox_id=current_user.default_mailbox_id,
                        )

                        Session.flush()
                        flash(f"Alias {full_alias} has been created",
                              "success")
                # only happen if the request has been "hacked"
                else:
                    flash("something went wrong", "warning")
                    return redirect(request.url)
            # User chooses one of the suggestions
            else:
                chosen_email = request.form.get("suggested-email")
                # todo: add some checks on chosen_email
                if chosen_email != current_user.email:
                    alias = Alias.get_by(email=chosen_email)
                    if not alias:
                        alias = Alias.create(
                            email=chosen_email,
                            user_id=current_user.id,
                            mailbox_id=current_user.default_mailbox_id,
                        )
                        Session.flush()

            suggested_name = request.form.get("suggested-name")
            custom_name = request.form.get("custom-name")

            use_default_avatar = request.form.get("avatar-choice") == "default"

            client_user = ClientUser.create(client_id=client.id,
                                            user_id=current_user.id)
            if alias:
                client_user.alias_id = alias.id

            if custom_name:
                client_user.name = custom_name
            elif suggested_name != current_user.name:
                client_user.name = suggested_name

            if use_default_avatar:
                # use default avatar
                LOG.d("use default avatar for user %s client %s", current_user,
                      client)
                client_user.default_avatar = True

            Session.flush()
            LOG.d("create client-user for client %s, user %s", client,
                  current_user)

        redirect_args = construct_redirect_args(client, client_user, nonce,
                                                redirect_uri, response_types,
                                                scope, state)
        fragment = get_fragment(response_mode, response_types)

        # construct redirect_uri with redirect_args
        return redirect(construct_url(redirect_uri, redirect_args, fragment))