* Key Exhange protocol functions
*/
+static bool
+silc_verify_public_key_internal(SilcServer server, SilcSocketConnection sock,
+ SilcSocketType conn_type,
+ unsigned char *pk, uint32 pk_len,
+ SilcSKEPKType pk_type)
+{
+ char file[256], filename[256], *fingerprint;
+ struct stat st;
+
+ if (pk_type != SILC_SKE_PK_TYPE_SILC) {
+ SILC_LOG_WARNING(("We don't support %s (%s) port %d public key type %d",
+ sock->hostname, sock->ip, sock->port, pk_type));
+ return FALSE;
+ }
+
+ /* Accept client keys without verification */
+ if (conn_type == SILC_SOCKET_TYPE_CLIENT) {
+ SILC_LOG_DEBUG(("Accepting client public key without verification"));
+ return TRUE;
+ }
+
+ memset(filename, 0, sizeof(filename));
+ memset(file, 0, sizeof(file));
+ snprintf(file, sizeof(file) - 1, "serverkey_%s_%d.pub", sock->hostname,
+ sock->port);
+ snprintf(filename, sizeof(filename) - 1, SILC_ETCDIR "/serverkeys/%s",
+ file);
+
+ /* Create serverkeys directory if it doesn't exist. */
+ if (stat(SILC_ETCDIR "/serverkeys", &st) < 0) {
+ /* If dir doesn't exist */
+ if (errno == ENOENT) {
+ if (mkdir(SILC_ETCDIR "/serverkeys", 0755) < 0) {
+ SILC_LOG_ERROR(("Couldn't create `%s' directory\n",
+ SILC_ETCDIR "/serverkeys"));
+ return TRUE;
+ }
+ } else {
+ SILC_LOG_ERROR(("%s\n", strerror(errno)));
+ return TRUE;
+ }
+ }
+
+ /* Take fingerprint of the public key */
+ fingerprint = silc_hash_fingerprint(NULL, pk, pk_len);
+ SILC_LOG_DEBUG(("Received server %s (%s) port %d public key (%s)",
+ sock->hostname, sock->ip, sock->port, fingerprint));
+ silc_free(fingerprint);
+
+ /* Check whether this key already exists */
+ if (stat(filename, &st) < 0) {
+ /* We don't have it, then cache it. */
+ SILC_LOG_DEBUG(("New public key from server"));
+
+ silc_pkcs_save_public_key_data(filename, pk, pk_len,
+ SILC_PKCS_FILE_PEM);
+ return TRUE;
+ } else {
+ /* The key already exists, verify it. */
+ SilcPublicKey public_key;
+ unsigned char *encpk;
+ uint32 encpk_len;
+
+ SILC_LOG_DEBUG(("We have the public key saved locally"));
+
+ /* Load the key file */
+ if (!silc_pkcs_load_public_key(filename, &public_key,
+ SILC_PKCS_FILE_PEM))
+ if (!silc_pkcs_load_public_key(filename, &public_key,
+ SILC_PKCS_FILE_BIN)) {
+ SILC_LOG_WARNING(("Could not load local copy of the %s (%s) port %d "
+ "server public key", sock->hostname, sock->ip,
+ sock->port));
+
+ /* Save the key for future checking */
+ unlink(filename);
+ silc_pkcs_save_public_key_data(filename, pk, pk_len,
+ SILC_PKCS_FILE_PEM);
+ return TRUE;
+ }
+
+ /* Encode the key data */
+ encpk = silc_pkcs_public_key_encode(public_key, &encpk_len);
+ if (!encpk) {
+ SILC_LOG_WARNING(("Local copy of the server %s (%s) port %d public key "
+ "is malformed", sock->hostname, sock->ip, sock->port));
+
+ /* Save the key for future checking */
+ unlink(filename);
+ silc_pkcs_save_public_key_data(filename, pk, pk_len,
+ SILC_PKCS_FILE_PEM);
+ return TRUE;
+ }
+
+ if (memcmp(encpk, pk, encpk_len)) {
+ SILC_LOG_WARNING(("%s (%s) port %d server public key does not match "
+ "with local copy", sock->hostname, sock->ip,
+ sock->port));
+ SILC_LOG_WARNING(("It is possible that the key has expired or changed"));
+ SILC_LOG_WARNING(("It is also possible that some one is performing "
+ "man-in-the-middle attack"));
+ SILC_LOG_WARNING(("Will not accept the server %s (%s) port %d public "
+ "key",
+ sock->hostname, sock->ip, sock->port));
+ return FALSE;
+ }
+
+ /* Local copy matched */
+ return TRUE;
+ }
+}
+
+/* Callback that is called when we have received KE2 payload from
+ responder. We try to verify the public key now. */
+
+static void
+silc_server_protocol_ke_verify_key(SilcSKE ske,
+ unsigned char *pk_data,
+ uint32 pk_len,
+ SilcSKEPKType pk_type,
+ void *context,
+ SilcSKEVerifyCbCompletion completion,
+ void *completion_context)
+{
+ SilcProtocol protocol = (SilcProtocol)context;
+ SilcServerKEInternalContext *ctx =
+ (SilcServerKEInternalContext *)protocol->context;
+ SilcServer server = (SilcServer)ctx->server;
+
+ SILC_LOG_DEBUG(("Start"));
+
+ if (silc_verify_public_key_internal(server, ctx->sock,
+ (ctx->responder == FALSE ?
+ SILC_SOCKET_TYPE_ROUTER:
+ ctx->sconfig ? SILC_SOCKET_TYPE_SERVER :
+ ctx->rconfig ? SILC_SOCKET_TYPE_ROUTER :
+ SILC_SOCKET_TYPE_CLIENT),
+ pk_data, pk_len, pk_type))
+ completion(ske, SILC_SKE_STATUS_OK, completion_context);
+ else
+ completion(ske, SILC_SKE_STATUS_UNSUPPORTED_PUBLIC_KEY,
+ completion_context);
+}
+
/* Packet sending callback. This function is provided as packet sending
routine to the Key Exchange functions. */
/* Callback that is called by the SKE to indicate that it is safe to
continue the execution of the protocol. This is used only if we are
- initiator. Is given as argument to the silc_ske_initiator_finish
- function. This is called due to the fact that the public key verification
- process is asynchronous and we must not continue the protocl until
- the public key has been verified and this callback is called. */
+ initiator. Is given as argument to the silc_ske_initiator_finish or
+ silc_ske_responder_phase_2 functions. This is called due to the fact
+ that the public key verification process is asynchronous and we must
+ not continue the protocl until the public key has been verified and
+ this callback is called. */
-static void silc_server_protocol_ke_finish(SilcSKE ske, void *context)
+static void silc_server_protocol_ke_continue(SilcSKE ske, void *context)
{
SilcProtocol protocol = (SilcProtocol)context;
SilcServerKEInternalContext *ctx =
/* Send Ok to the other end. We will end the protocol as responder
sends Ok to us when we will take the new keys into use. */
- if (ctx->responder == FALSE)
+ if (ctx->responder == FALSE) {
silc_ske_end(ctx->ske, silc_server_protocol_ke_send_packet, context);
- /* End the protocol on the next round */
- protocol->state = SILC_PROTOCOL_STATE_END;
+ /* End the protocol on the next round */
+ protocol->state = SILC_PROTOCOL_STATE_END;
+ }
+
+ /* Advance protocol state and call the next state if we are responder.
+ This happens when this callback was sent to silc_ske_responder_phase_2
+ function. */
+ if (ctx->responder == TRUE) {
+ protocol->state++;
+ silc_protocol_execute(protocol, server->timeout_queue, 0, 100000);
+ }
}
/* Performs key exchange protocol. This is used for both initiator
if (ctx->responder == TRUE) {
/* Process the received Key Exchange 1 Payload packet from
the initiator. This also creates our parts of the Diffie
- Hellman algorithm. */
- /* XXX TODO: If mutual authentication flag is set then the
- verify_key callback should be set to verify the remote ends
- public key!! */
- /* XXX TODO: when the verify_key is set then the `callback'
- must be set as well as the verify_key is asynchronous
- (take a look to silc_ske_initiator_finish for example. */
- status = silc_ske_responder_phase_2(ctx->ske, ctx->packet->buffer,
- NULL, NULL, NULL, NULL);
+ Hellman algorithm. The silc_server_protocol_ke_continue
+ will be called after the public key has been verified. */
+ status =
+ silc_ske_responder_phase_2(ctx->ske, ctx->packet->buffer,
+ silc_server_protocol_ke_verify_key,
+ context,
+ silc_server_protocol_ke_continue,
+ context);
} else {
/* Call the Phase-2 function. This creates Diffie Hellman
key exchange parameters and sends our public part inside
server->private_key,
silc_server_protocol_ke_send_packet,
context);
+ protocol->state++;
}
/* Return now if the procedure is pending. */
silc_protocol_execute(protocol, server->timeout_queue, 0, 300000);
return;
}
-
- /* Advance protocol state and call the next state if we are responder */
- protocol->state++;
- if (ctx->responder == TRUE)
- silc_protocol_execute(protocol, server->timeout_queue, 0, 100000);
}
break;
case 4:
protocol->state = SILC_PROTOCOL_STATE_END;
} else {
/* Finish the protocol. This verifies the Key Exchange 2 payload
- sent by responder. */
- /* XXX TODO: the verify_key callback is not set!!! */
+ sent by responder. The silc_server_protocol_ke_continue will
+ be called after the public key has been verified. */
status = silc_ske_initiator_finish(ctx->ske, ctx->packet->buffer,
- NULL, NULL,
- silc_server_protocol_ke_finish,
+ silc_server_protocol_ke_verify_key,
+ context,
+ silc_server_protocol_ke_continue,
context);
}
projects / silc.git / commitdiff