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using Gee;
namespace Xmpp.Xep.EntityCapabilities {
private const string NS_URI = "http://jabber.org/protocol/caps";
private Regex? sha1_base64_regex = null;
private Regex get_sha1_base64_regex() {
if (sha1_base64_regex == null) {
sha1_base64_regex = /^[A-Za-z0-9+\/]{27}=$/;
}
return sha1_base64_regex;
}
public string? get_caps_hash(Presence.Stanza presence) {
Regex sha1_base64_regex = get_sha1_base64_regex();
StanzaNode? c_node = presence.stanza.get_subnode("c", NS_URI);
if (c_node == null) return null;
string? ver_attribute = c_node.get_attribute("ver", NS_URI);
if (ver_attribute == null || !sha1_base64_regex.match(ver_attribute)) return null;
return ver_attribute;
}
public class Module : XmppStreamModule {
public static ModuleIdentity<Module> IDENTITY = new ModuleIdentity<Module>(NS_URI, "0115_entity_capabilities");
private string own_ver_hash;
private Storage storage;
public Module(Storage storage) {
this.storage = storage;
}
private string get_own_hash(XmppStream stream) {
if (own_ver_hash == null) {
own_ver_hash = compute_hash(stream.get_flag(ServiceDiscovery.Flag.IDENTITY).own_identities, stream.get_flag(ServiceDiscovery.Flag.IDENTITY).own_features, new ArrayList<DataForms.DataForm>());
}
return own_ver_hash;
}
public override void attach(XmppStream stream) {
stream.get_module(Presence.Module.IDENTITY).pre_send_presence_stanza.connect(on_pre_send_presence_stanza);
stream.get_module(Presence.Module.IDENTITY).received_presence.connect(on_received_presence);
stream.get_module(ServiceDiscovery.Module.IDENTITY).add_feature(stream, NS_URI);
check_features_node_ver(stream);
}
public override void detach(XmppStream stream) {
stream.get_module(Presence.Module.IDENTITY).pre_send_presence_stanza.disconnect(on_pre_send_presence_stanza);
stream.get_module(Presence.Module.IDENTITY).received_presence.disconnect(on_received_presence);
stream.get_module(ServiceDiscovery.Module.IDENTITY).remove_feature(stream, NS_URI);
}
public override string get_ns() { return NS_URI; }
public override string get_id() { return IDENTITY.id; }
private void on_pre_send_presence_stanza(XmppStream stream, Presence.Stanza presence) {
if (presence.type_ == Presence.Stanza.TYPE_AVAILABLE) {
presence.stanza.put_node(new StanzaNode.build("c", NS_URI).add_self_xmlns()
.put_attribute("hash", "sha-1")
.put_attribute("node", "https://dino.im")
.put_attribute("ver", get_own_hash(stream)));
}
}
private void on_received_presence(XmppStream stream, Presence.Stanza presence) {
string? caps_hash = get_caps_hash(presence);
if (caps_hash == null) return;
process_hash.begin(stream, presence.from, caps_hash);
}
private void check_features_node_ver(XmppStream stream) {
StanzaNode? node = stream.features.get_subnode("c", NS_URI);
if (node == null) return;
string? ver_attribute = node.get_attribute("ver", NS_URI);
if (ver_attribute == null) return;
process_hash.begin(stream, stream.remote_name, ver_attribute);
}
private async void process_hash(XmppStream stream, Jid jid_from, string caps_hash) {
Gee.List<string> capabilities = storage.get_features(caps_hash);
ServiceDiscovery.Identity identity = storage.get_identities(caps_hash);
if (identity == null) {
ServiceDiscovery.InfoResult? info_result = yield stream.get_module(ServiceDiscovery.Module.IDENTITY).request_info(stream, jid_from);
if (info_result == null) return;
store_entity_result(stream, caps_hash, info_result);
} else {
stream.get_flag(ServiceDiscovery.Flag.IDENTITY).set_entity_features(jid_from, capabilities);
}
}
private void store_entity_result(XmppStream stream, string entity, ServiceDiscovery.InfoResult? query_result) {
if (query_result == null) return;
Gee.List<DataForms.DataForm> data_forms = new ArrayList<DataForms.DataForm>();
foreach (StanzaNode node in query_result.iq.stanza.get_deep_subnodes(ServiceDiscovery.NS_URI_INFO + ":query", DataForms.NS_URI + ":x")) {
data_forms.add(DataForms.DataForm.create_from_node(node));
}
if (compute_hash(query_result.identities, query_result.features, data_forms) == entity) {
storage.store_identities(entity, query_result.identities);
storage.store_features(entity, query_result.features);
stream.get_flag(ServiceDiscovery.Flag.IDENTITY).set_entity_features(query_result.iq.from, query_result.features);
}
}
private static string compute_hash(Gee.Set<ServiceDiscovery.Identity> identities_set, Gee.List<string> features, Gee.List<DataForms.DataForm> data_forms) {
var identities = new ArrayList<ServiceDiscovery.Identity>();
foreach (var identity in identities_set) identities.add(identity);
identities.sort(compare_identities);
features.sort();
StringBuilder sb = new StringBuilder();
foreach (ServiceDiscovery.Identity identity in identities) {
sb.append(sanitize(identity.category))
.append("/")
.append(sanitize(identity.type_))
.append("//");
if (identity.name != null) {
sb.append(sanitize(identity.name));
}
sb.append("<");
}
foreach (string feature in features) {
sb.append(sanitize(feature))
.append("<");
}
data_forms.sort(compare_data_forms);
foreach (DataForms.DataForm data_form in data_forms) {
if (data_form.form_type == null) {
// If [..] the FORM_TYPE field is not of type "hidden" or the form does not include a FORM_TYPE field, ignore the form but continue processing. (XEP-0115 5.4)
continue;
}
sb.append(sanitize(data_form.form_type))
.append("<");
data_form.fields.sort(compare_data_fields);
foreach (DataForms.DataForm.Field field in data_form.fields) {
sb.append(sanitize(field.var))
.append("<");
Gee.List<string> values = field.get_values();
values.sort();
foreach (string value in values) {
sb.append(sanitize(value ?? ""))
.append("<");
}
}
}
Checksum c = new Checksum(ChecksumType.SHA1);
c.update(sb.str.data, -1);
size_t size = 20;
uint8[] buf = new uint8[size];
c.get_digest(buf, ref size);
return Base64.encode(buf);
}
/*
* If the four characters '&', 'l', 't', ';' appear consecutively in any of the factors of the verification
* string S [...] then that string of characters MUST be treated as literally '<' and MUST NOT be converted to
* the character '<', because completing such a conversion would open the protocol to trivial attacks. (XEP-0115 5.1)
*/
private static string sanitize(string s) {
return s.replace("<", "<");
}
private static int compare_identities(ServiceDiscovery.Identity a, ServiceDiscovery.Identity b) {
int category_comp = a.category.collate(b.category);
if (category_comp != 0) return category_comp;
int type_comp = a.type_.collate(b.type_);
if (type_comp != 0) return type_comp;
// TODO lang
return 0;
}
private static int compare_data_forms(DataForms.DataForm a, DataForms.DataForm b) {
if (a.form_type != null && b.form_type != null) {
return a.form_type.collate(b.form_type);
}
return 0;
}
private static int compare_data_fields(DataForms.DataForm.Field a, DataForms.DataForm.Field b) {
if (a.var != null && b.var != null) {
return a.var.collate(b.var);
}
return 0;
}
}
public interface Storage : Object {
public abstract void store_identities(string entity, Gee.Set<ServiceDiscovery.Identity> identities);
public abstract void store_features(string entity, Gee.List<string> capabilities);
public abstract ServiceDiscovery.Identity? get_identities(string entity);
public abstract Gee.List<string> get_features(string entity);
}
}
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