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Roger Dingledine authoredfix log messages svn:r1725
Roger Dingledine authoredfix log messages svn:r1725
rendmid.c 8.83 KiB
/* Copyright 2004 Roger Dingledine */
/* See LICENSE for licensing information */
/* $Id$ */
#include "or.h"
/* Respond to an ESTABLISH_INTRO cell by setting the circuit's purpose and
* service pk digest..
*/
int
rend_mid_establish_intro(circuit_t *circ, const char *request, int request_len)
{
crypto_pk_env_t *pk = NULL;
char buf[DIGEST_LEN+9];
char expected_digest[DIGEST_LEN];
char pk_digest[DIGEST_LEN];
int asn1len;
circuit_t *c;
char serviceid[REND_SERVICE_ID_LEN+1];
log_fn(LOG_INFO,
"Received an ESTABLISH_INTRO request on circuit %d", circ->p_circ_id);
if (circ->purpose != CIRCUIT_PURPOSE_OR || circ->n_conn) {
log_fn(LOG_WARN, "Rejecting ESTABLISH_INTRO on non-OR or non-edge circuit");
goto err;
}
if (request_len < 2+DIGEST_LEN)
goto truncated;
/* First 2 bytes: length of asn1-encoded key. */
asn1len = ntohs(get_uint16(request));
/* Next asn1len bytes: asn1-encoded key. */
if (request_len < 2+DIGEST_LEN+asn1len)
goto truncated;
pk = crypto_pk_asn1_decode(request+2, asn1len);
if (!pk) {
log_fn(LOG_WARN, "Couldn't decode public key");
goto err;
}
/* Next 20 bytes: Hash of handshake_digest | "INTRODUCE" */
memcpy(buf, circ->handshake_digest, DIGEST_LEN);
memcpy(buf+DIGEST_LEN, "INTRODUCE", 9);
if (crypto_digest(buf, DIGEST_LEN+9, expected_digest)<0) {
log_fn(LOG_WARN, "Error computing digest");
goto err;
}
if (memcmp(expected_digest, request+2+asn1len, DIGEST_LEN)) {
log_fn(LOG_WARN, "Hash of session info was not as expected");
goto err;
}
/* Rest of body: signature of previous data */
if (crypto_pk_public_checksig_digest(pk, request, 2+asn1len+DIGEST_LEN,
request+2+DIGEST_LEN+asn1len,
request_len-(2+DIGEST_LEN+asn1len))<0) {
log_fn(LOG_WARN, "Incorrect signature on ESTABLISH_INTRO cell; rejecting");
goto err;
}
/* The request is valid. First, compute the hash of Bob's PK.*/
if (crypto_pk_get_digest(pk, pk_digest)<0) {
log_fn(LOG_WARN, "Couldn't hash public key.");
goto err;
}
if (base32_encode(serviceid, REND_SERVICE_ID_LEN+1,
pk_digest,10)) {
goto err;
}
/* Close any other intro circuits with the same pk. */
c = NULL;
while ((c = circuit_get_next_by_pk_and_purpose(
c,pk_digest,CIRCUIT_PURPOSE_INTRO_POINT))) {
log_fn(LOG_INFO, "Replacing old circuit %d for service %s",
c->p_circ_id, serviceid);
circuit_mark_for_close(c);
}
/* Acknlowedge the request. */
if (connection_edge_send_command(NULL,circ,
RELAY_COMMAND_INTRO_ESTABLISHED,
"", 0, NULL)<0) {
log_fn(LOG_WARN, "Couldn't send INTRO_ESTABLISHED cell");
goto err;
}
/* Now, set up this circuit. */
circ->purpose = CIRCUIT_PURPOSE_INTRO_POINT;
memcpy(circ->rend_pk_digest, pk_digest, DIGEST_LEN);
log_fn(LOG_INFO,
"Established introduction point on circuit %d for service %s",
circ->p_circ_id, serviceid);
return 0;
truncated:
log_fn(LOG_WARN, "Rejecting truncated ESTABLISH_INTRO cell");
err:
if (pk) crypto_free_pk_env(pk);
circuit_mark_for_close(circ);
return -1;
}
/* Process an INTRODUCE1 cell by finding the corresponding introduction
* circuit, and relaying the body of the INTRODUCE1 cell inside an
* INTRODUCE2 cell.
*/
int
rend_mid_introduce(circuit_t *circ, const char *request, int request_len)
{
circuit_t *intro_circ;
char serviceid[REND_SERVICE_ID_LEN+1];
char nak_body[1];
if (circ->purpose != CIRCUIT_PURPOSE_OR || circ->n_conn) {
log_fn(LOG_WARN, "Rejecting INTRODUCE1 on non-OR or non-edge circuit %d",
circ->p_circ_id);
goto err;
}
if (request_len < (DIGEST_LEN+(MAX_NICKNAME_LEN+1)+REND_COOKIE_LEN+
DH_KEY_LEN+CIPHER_KEY_LEN+PKCS1_OAEP_PADDING_OVERHEAD)) {
log_fn(LOG_WARN,
"Impossibly short INTRODUCE1 cell on circuit %d; responding with nack.",
circ->p_circ_id);
goto err;
}
if (base32_encode(serviceid, REND_SERVICE_ID_LEN+1, request,10)) {
goto err;
}
/* The first 20 bytes are all we look at: they have a hash of Bob's PK. */
intro_circ = circuit_get_next_by_pk_and_purpose(
NULL, request, CIRCUIT_PURPOSE_INTRO_POINT);
if (!intro_circ) {
log_fn(LOG_WARN,
"No intro circ found for INTRODUCE1 cell (%s) from circuit %d; responding with nack", serviceid, circ->p_circ_id);
goto err;
}
log_fn(LOG_INFO,
"Sending introduction request for service %s from circ %d to circ %d",
serviceid, circ->p_circ_id, intro_circ->p_circ_id);
/* Great. Now we just relay the cell down the circuit. */
if (connection_edge_send_command(NULL, intro_circ,
RELAY_COMMAND_INTRODUCE2,
request, request_len, NULL)) {
log_fn(LOG_WARN, "Unable to send INTRODUCE2 cell to OP.");
goto err;
}
/* And sent an ack down the cirecuit. Empty body->succeeded. */
if (connection_edge_send_command(NULL,circ,RELAY_COMMAND_INTRODUCE_ACK,
NULL,0,NULL)) {
log_fn(LOG_WARN, "Unable to send INTRODUCE_ACK cell to OP.");
circuit_mark_for_close(circ);
return -1;
}
return 0;
err:
/* Send the client an NACK */
nak_body[0] = 1;
if (connection_edge_send_command(NULL,circ,RELAY_COMMAND_INTRODUCE_ACK,
nak_body, 1, NULL)) {
log_fn(LOG_WARN, "Unable to send NAK to OP");
circuit_mark_for_close(circ); /* Is this right? */
}
return -1;
}
/* Process an ESTABLISH_RENDEZVOUS cell by settingthe circuit's purpose and
* rendezvous cookie.
*/
int
rend_mid_establish_rendezvous(circuit_t *circ, const char *request, int request_len)
{
char hexid[9];
if (circ->purpose != CIRCUIT_PURPOSE_OR || circ->n_conn) {
log_fn(LOG_WARN, "Tried to establish rendezvous on non-OR or non-edge circuit");
goto err;
}
if (request_len != REND_COOKIE_LEN) {
log_fn(LOG_WARN, "Invalid length on ESTABLISH_RENDEZVOUS");
goto err;
}
if (circuit_get_rendezvous(request)) {
log_fn(LOG_WARN, "Duplicate rendezvous cookie in ESTABLISH_RENDEZVOUS");
goto err;
}
/* Acknlowedge the request. */
if (connection_edge_send_command(NULL,circ,
RELAY_COMMAND_RENDEZVOUS_ESTABLISHED,
"", 0, NULL)<0) {
log_fn(LOG_WARN, "Couldn't send RENDEZVOUS_ESTABLISHED cell");
goto err;
}
circ->purpose = CIRCUIT_PURPOSE_REND_POINT_WAITING;
memcpy(circ->rend_cookie, request, REND_COOKIE_LEN);
hex_encode(request,4,hexid);
log_fn(LOG_INFO, "Established rendezvous point on circuit %d for cookie %s",
circ->p_circ_id, hexid);
return 0;
err:
circuit_mark_for_close(circ);
return -1;
}
/* Process a RENDEZVOUS1 cell by looking up the correct rendezvous circuit by its
* relaying the cell's body in a RENDEZVOUS2 cell, and connecting the two circuits.
*/
int
rend_mid_rendezvous(circuit_t *circ, const char *request, int request_len)
{
circuit_t *rend_circ;
char hexid[9];
if (request_len>=4) {
hex_encode(request,4,hexid);
log_fn(LOG_INFO, "Got request for rendezvous from circuit %d to cookie %s",
circ->p_circ_id, hexid);
}
if (circ->purpose != CIRCUIT_PURPOSE_OR || circ->n_conn) {
log_fn(LOG_WARN,
"Tried to complete rendezvous on non-OR or non-edge circuit %d",
circ->p_circ_id);
goto err;
}
if (request_len != REND_COOKIE_LEN+DH_KEY_LEN+DIGEST_LEN) {
log_fn(LOG_WARN,
"Rejecting RENDEZVOUS1 cell with bad length (%d) on circuit %d",
request_len, circ->p_circ_id);
goto err;
}
rend_circ = circuit_get_rendezvous(request);
if (!rend_circ) {
log_fn(LOG_WARN,
"Rejecting RENDEZVOUS1 cell with unrecognized rendezvous cookie %s",
hexid);
goto err;
}
/* Send the RENDEZVOUS2 cell to Alice. */
if (connection_edge_send_command(NULL, rend_circ,
RELAY_COMMAND_RENDEZVOUS2,
request+REND_COOKIE_LEN,
request_len-REND_COOKIE_LEN, NULL)) {
log_fn(LOG_WARN, "Unable to send RENDEZVOUS2 cell to OP on circuit %d",
rend_circ->p_circ_id);
goto err;
}
/* Join the circuits. */
log_fn(LOG_INFO,
"Completing rendezvous: circuit %d joins circuit %d (cookie %s)",
circ->p_circ_id, rend_circ->p_circ_id, hexid);
circ->purpose = CIRCUIT_PURPOSE_REND_ESTABLISHED;
rend_circ->purpose = CIRCUIT_PURPOSE_REND_ESTABLISHED;
memset(circ->rend_cookie, 0, REND_COOKIE_LEN);
rend_circ->rend_splice = circ;
circ->rend_splice = rend_circ;
return 0;
err:
circuit_mark_for_close(circ);
return -1;
}
/*
Local Variables:
mode:c
indent-tabs-mode:nil
c-basic-offset:2
End:
*/