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-rw-r--r--xmpp-vala/src/module/sasl.vala203
1 files changed, 157 insertions, 46 deletions
diff --git a/xmpp-vala/src/module/sasl.vala b/xmpp-vala/src/module/sasl.vala
index 4a427ce0..2e87e590 100644
--- a/xmpp-vala/src/module/sasl.vala
+++ b/xmpp-vala/src/module/sasl.vala
@@ -1,9 +1,27 @@
-namespace Xmpp.PlainSasl {
+namespace Xmpp.Sasl {
private const string NS_URI = "urn:ietf:params:xml:ns:xmpp-sasl";
+ public class Flag : XmppStreamFlag {
+ public static FlagIdentity<Flag> IDENTITY = new FlagIdentity<Flag>(NS_URI, "sasl");
+ public string mechanism;
+ public string name;
+ public string password;
+ public string client_nonce;
+ public uint8[] server_signature;
+ public bool finished = false;
+
+ public override string get_ns() { return NS_URI; }
+ public override string get_id() { return IDENTITY.id; }
+ }
+
+ namespace Mechanism {
+ public const string PLAIN = "PLAIN";
+ public const string SCRAM_SHA_1 = "SCRAM-SHA-1";
+ public const string SCRAM_SHA_1_PLUS = "SCRAM-SHA-1-PLUS";
+ }
+
public class Module : XmppStreamNegotiationModule {
- public static ModuleIdentity<Module> IDENTITY = new ModuleIdentity<Module>(NS_URI, "plain_module");
- private const string MECHANISM = "PLAIN";
+ public static ModuleIdentity<Module> IDENTITY = new ModuleIdentity<Module>(NS_URI, "sasl");
public string name { get; set; }
public string password { get; set; }
@@ -26,14 +44,109 @@ namespace Xmpp.PlainSasl {
stream.received_nonza.disconnect(this.received_nonza);
}
+ private static size_t SHA1_SIZE = 20;
+
+ private static uint8[] sha1(uint8[] data) {
+ Checksum checksum = new Checksum(ChecksumType.SHA1);
+ checksum.update(data, data.length);
+ uint8[] res = new uint8[SHA1_SIZE];
+ checksum.get_digest(res, ref SHA1_SIZE);
+ return res;
+ }
+
+ private static uint8[] hmac_sha1(uint8[] key, uint8[] data) {
+ Hmac hmac = new Hmac(ChecksumType.SHA1, key);
+ hmac.update(data);
+ uint8[] res = new uint8[SHA1_SIZE];
+ hmac.get_digest(res, ref SHA1_SIZE);
+ return res;
+ }
+
+ private static uint8[] pbkdf2_sha1(string password, uint8[] salt, uint iterations) {
+ uint8[] res = new uint8[SHA1_SIZE];
+ uint8[] last = new uint8[salt.length + 4];
+ for(int i = 0; i < salt.length; i++) {
+ last[i] = salt[i];
+ }
+ last[salt.length + 3] = 1;
+ for(int i = 0; i < iterations; i++) {
+ last = hmac_sha1((uint8[]) password.to_utf8(), last);
+ xor_inplace(res, last);
+ }
+ return res;
+ }
+
+ private static void xor_inplace(uint8[] mix, uint8[] a2) {
+ for(int i = 0; i < mix.length; i++) {
+ mix[i] = mix[i] ^ a2[i];
+ }
+ }
+
+ private static uint8[] xor(uint8[] a1, uint8[] a2) {
+ uint8[] mix = new uint8[a1.length];
+ for(int i = 0; i < a1.length; i++) {
+ mix[i] = a1[i] ^ a2[i];
+ }
+ return mix;
+ }
+
public void received_nonza(XmppStream stream, StanzaNode node) {
if (node.ns_uri == NS_URI) {
if (node.name == "success") {
+ Flag flag = stream.get_flag(Flag.IDENTITY);
+ if (flag.mechanism == Mechanism.SCRAM_SHA_1) {
+ string confirm = (string) Base64.decode(node.get_string_content());
+ uint8[] server_signature = null;
+ foreach(string c in confirm.split(",")) {
+ string[] split = c.split("=", 2);
+ if (split.length != 2) continue;
+ switch(split[0]) {
+ case "v": server_signature = Base64.decode(split[1]); break;
+ }
+ }
+ if (server_signature == null) return;
+ if (server_signature.length != flag.server_signature.length) return;
+ for(int i = 0; i < server_signature.length; i++) {
+ if (server_signature[i] != flag.server_signature[i]) return;
+ }
+ }
stream.require_setup();
- stream.get_flag(Flag.IDENTITY).finished = true;
+ flag.password = null; // Remove password from memory
+ flag.finished = true;
} else if (node.name == "failure") {
stream.remove_flag(stream.get_flag(Flag.IDENTITY));
received_auth_failure(stream, node);
+ } else if (node.name == "challenge" && stream.has_flag(Flag.IDENTITY)) {
+ Flag flag = stream.get_flag(Flag.IDENTITY);
+ if (flag.mechanism == Mechanism.SCRAM_SHA_1) {
+ string challenge = (string) Base64.decode(node.get_string_content());
+ string? server_nonce = null;
+ uint8[] salt = null;
+ uint iterations = 0;
+ foreach(string c in challenge.split(",")) {
+ string[] split = c.split("=", 2);
+ if (split.length != 2) continue;
+ switch(split[0]) {
+ case "r": server_nonce = split[1]; break;
+ case "s": salt = Base64.decode(split[1]); break;
+ case "i": iterations = int.parse(split[1]); break;
+ }
+ }
+ if (server_nonce == null || salt == null || iterations == 0) return;
+ if (!server_nonce.has_prefix(flag.client_nonce)) return;
+ string client_final_message_bare = @"c=biws,r=$server_nonce";
+ uint8[] salted_password = pbkdf2_sha1(flag.password, salt, iterations);
+ uint8[] client_key = hmac_sha1(salted_password, (uint8[]) "Client Key".to_utf8());
+ uint8[] stored_key = sha1(client_key);
+ string auth_message = @"n=$(flag.name),r=$(flag.client_nonce),$challenge,$client_final_message_bare";
+ uint8[] client_signature = hmac_sha1(stored_key, (uint8[]) auth_message.to_utf8());
+ uint8[] client_proof = xor(client_key, client_signature);
+ uint8[] server_key = hmac_sha1(salted_password, (uint8[]) "Server Key".to_utf8());
+ flag.server_signature = hmac_sha1(server_key, (uint8[]) auth_message.to_utf8());
+ string client_final_message = @"$client_final_message_bare,p=$(Base64.encode(client_proof))";
+ stream.write(new StanzaNode.build("response", NS_URI).add_self_xmlns()
+ .put_node(new StanzaNode.text(Base64.encode((uchar[]) (client_final_message).to_utf8()))));
+ }
}
}
}
@@ -44,45 +157,53 @@ namespace Xmpp.PlainSasl {
if (!stream.has_flag(Tls.Flag.IDENTITY) || !stream.get_flag(Tls.Flag.IDENTITY).finished) return;
var mechanisms = stream.features.get_subnode("mechanisms", NS_URI);
- if (mechanisms != null) {
- bool supportsPlain = false;
- foreach (var mechanism in mechanisms.sub_nodes) {
- if (mechanism.name != "mechanism" || mechanism.ns_uri != NS_URI) continue;
- var text = mechanism.get_subnode("#text");
- if (text != null && text.val == MECHANISM) {
- supportsPlain = true;
- }
- }
- if (!supportsPlain) {
- stderr.printf("Server at %s does not support %s auth, use full-features Sasl implementation!\n", stream.remote_name.to_string(), MECHANISM);
- return;
- }
-
- if (!name.contains("@")) {
- name = "%s@%s".printf(name, stream.remote_name.to_string());
- }
- if (!use_full_name && name.contains("@")) {
- var split = name.split("@");
- if (split[1] == stream.remote_name.to_string()) {
- name = split[0];
- } else {
- use_full_name = true;
- }
+ string[] supported_mechanisms = {};
+ foreach (var mechanism in mechanisms.sub_nodes) {
+ if (mechanism.name != "mechanism" || mechanism.ns_uri != NS_URI) continue;
+ supported_mechanisms += mechanism.get_string_content();
+ }
+ if (!name.contains("@")) {
+ name = "%s@%s".printf(name, stream.remote_name.to_string());
+ }
+ if (!use_full_name && name.contains("@")) {
+ var split = name.split("@");
+ if (split[1] == stream.remote_name.to_string()) {
+ name = split[0];
+ } else {
+ use_full_name = true;
}
- var name = this.name;
- if (!use_full_name && name.contains("@")) {
- var split = name.split("@");
- if (split[1] == stream.remote_name.to_string()) {
- name = split[0];
- }
+ }
+ string name = this.name;
+ if (!use_full_name && name.contains("@")) {
+ var split = name.split("@");
+ if (split[1] == stream.remote_name.to_string()) {
+ name = split[0];
}
+ }
+ if (Mechanism.SCRAM_SHA_1 in supported_mechanisms) {
+ string normalized_password = password.normalize(-1, NormalizeMode.NFKC);
+ string client_nonce = Random.next_int().to_string("%.8x") + Random.next_int().to_string("%.8x") + Random.next_int().to_string("%.8x");
+ string initial_message = @"n=$name,r=$client_nonce";
stream.write(new StanzaNode.build("auth", NS_URI).add_self_xmlns()
- .put_attribute("mechanism", MECHANISM)
+ .put_attribute("mechanism", Mechanism.SCRAM_SHA_1)
+ .put_node(new StanzaNode.text(Base64.encode((uchar[]) ("n,,"+initial_message).to_utf8()))));
+ var flag = new Flag();
+ flag.mechanism = Mechanism.SCRAM_SHA_1;
+ flag.name = name;
+ flag.password = normalized_password;
+ flag.client_nonce = client_nonce;
+ stream.add_flag(flag);
+ } else if (Mechanism.PLAIN in supported_mechanisms) {
+ stream.write(new StanzaNode.build("auth", NS_URI).add_self_xmlns()
+ .put_attribute("mechanism", Mechanism.PLAIN)
.put_node(new StanzaNode.text(Base64.encode(get_plain_bytes(name, password)))));
var flag = new Flag();
- flag.mechanism = MECHANISM;
+ flag.mechanism = Mechanism.PLAIN;
flag.name = name;
stream.add_flag(flag);
+ } else {
+ stderr.printf("No supported mechanism provided by server at %s\n", stream.remote_name.to_string());
+ return;
}
}
@@ -108,14 +229,4 @@ namespace Xmpp.PlainSasl {
public override string get_ns() { return NS_URI; }
public override string get_id() { return IDENTITY.id; }
}
-
- public class Flag : XmppStreamFlag {
- public static FlagIdentity<Flag> IDENTITY = new FlagIdentity<Flag>(NS_URI, "sasl");
- public string mechanism;
- public string name;
- public bool finished = false;
-
- public override string get_ns() { return NS_URI; }
- public override string get_id() { return IDENTITY.id; }
- }
}