|
@@ -6,7 +6,7 @@
|
|
|
|
|
|
extern or_options_t options; /* command-line and config-file options */
|
|
|
|
|
|
-static int relay_crypt(circuit_t *circ, char *in, char cell_direction,
|
|
|
+static int relay_crypt(circuit_t *circ, cell_t *cell, char cell_direction,
|
|
|
crypt_path_t **layer_hint, char *recognized);
|
|
|
static connection_t *relay_lookup_conn(circuit_t *circ, cell_t *cell, int cell_direction);
|
|
|
static void circuit_free_cpath_node(crypt_path_t *victim);
|
|
@@ -324,11 +324,15 @@ static void relay_set_digest(crypto_digest_env_t *digest, cell_t *cell) {
|
|
|
}
|
|
|
|
|
|
/* update digest from the payload of cell (with the integrity part set
|
|
|
- * to 0). If the integrity part is valid return 0, else return -1.
|
|
|
+ * to 0). If the integrity part is valid return 1, else restore digest
|
|
|
+ * and cell to their original state and return 0.
|
|
|
*/
|
|
|
-static int relay_check_digest(crypto_digest_env_t *digest, cell_t *cell) {
|
|
|
+static int relay_digest_matches(crypto_digest_env_t *digest, cell_t *cell) {
|
|
|
uint32_t received_integrity, calculated_integrity;
|
|
|
relay_header_t rh;
|
|
|
+ crypto_digest_env_t *backup_digest=NULL;
|
|
|
+
|
|
|
+ backup_digest = crypto_digest_dup(digest);
|
|
|
|
|
|
relay_header_unpack(&rh, cell->payload);
|
|
|
received_integrity = rh.integrity;
|
|
@@ -341,11 +345,18 @@ static int relay_check_digest(crypto_digest_env_t *digest, cell_t *cell) {
|
|
|
crypto_digest_get_digest(digest, (char *)&calculated_integrity, 4);
|
|
|
|
|
|
if(received_integrity != calculated_integrity) {
|
|
|
- log_fn(LOG_WARN,"Integrity check on cell payload failed. Bug or attack. (%d vs %d).",
|
|
|
+ log_fn(LOG_INFO,"Recognized=0 but bad digest. Not recognizing. (%d vs %d).",
|
|
|
received_integrity, calculated_integrity);
|
|
|
- return -1;
|
|
|
+ /* restore digest to its old form */
|
|
|
+ crypto_digest_assign(digest, backup_digest);
|
|
|
+ /* restore the relay header */
|
|
|
+ rh.integrity = received_integrity;
|
|
|
+ relay_header_pack(cell->payload, &rh);
|
|
|
+ crypto_free_digest_env(backup_digest);
|
|
|
+ return 0;
|
|
|
}
|
|
|
- return 0;
|
|
|
+ crypto_free_digest_env(backup_digest);
|
|
|
+ return 1;
|
|
|
}
|
|
|
|
|
|
static int relay_crypt_one_payload(crypto_cipher_env_t *cipher, char *in,
|
|
@@ -354,7 +365,7 @@ static int relay_crypt_one_payload(crypto_cipher_env_t *cipher, char *in,
|
|
|
relay_header_t rh;
|
|
|
|
|
|
relay_header_unpack(&rh, in);
|
|
|
- log_fn(LOG_INFO,"before crypt: %d",rh.recognized);
|
|
|
+ log_fn(LOG_DEBUG,"before crypt: %d",rh.recognized);
|
|
|
if(( encrypt_mode && crypto_cipher_encrypt(cipher, in, CELL_PAYLOAD_SIZE, out)) ||
|
|
|
(!encrypt_mode && crypto_cipher_decrypt(cipher, in, CELL_PAYLOAD_SIZE, out))) {
|
|
|
log_fn(LOG_WARN,"Error during crypt: %s", crypto_perror());
|
|
@@ -362,7 +373,7 @@ static int relay_crypt_one_payload(crypto_cipher_env_t *cipher, char *in,
|
|
|
}
|
|
|
memcpy(in,out,CELL_PAYLOAD_SIZE);
|
|
|
relay_header_unpack(&rh, in);
|
|
|
- log_fn(LOG_INFO,"after crypt: %d",rh.recognized);
|
|
|
+ log_fn(LOG_DEBUG,"after crypt: %d",rh.recognized);
|
|
|
return 0;
|
|
|
}
|
|
|
|
|
@@ -382,8 +393,7 @@ int circuit_receive_relay_cell(cell_t *cell, circuit_t *circ,
|
|
|
assert(cell && circ);
|
|
|
assert(cell_direction == CELL_DIRECTION_OUT || cell_direction == CELL_DIRECTION_IN);
|
|
|
|
|
|
- if(relay_crypt(circ, cell->payload, cell_direction,
|
|
|
- &layer_hint, &recognized) < 0) {
|
|
|
+ if(relay_crypt(circ, cell, cell_direction, &layer_hint, &recognized) < 0) {
|
|
|
log_fn(LOG_WARN,"relay crypt failed. Dropping connection.");
|
|
|
return -1;
|
|
|
}
|
|
@@ -391,10 +401,6 @@ int circuit_receive_relay_cell(cell_t *cell, circuit_t *circ,
|
|
|
if(recognized) {
|
|
|
conn = relay_lookup_conn(circ, cell, cell_direction);
|
|
|
if(cell_direction == CELL_DIRECTION_OUT) {
|
|
|
- if(relay_check_digest(circ->n_digest, cell) < 0) {
|
|
|
- log_fn(LOG_WARN,"outgoing cell failed integrity check. Closing circ.");
|
|
|
- return -1;
|
|
|
- }
|
|
|
++stats_n_relay_cells_delivered;
|
|
|
log_fn(LOG_DEBUG,"Sending to exit.");
|
|
|
if (connection_edge_process_relay_cell(cell, circ, conn, EDGE_EXIT, NULL) < 0) {
|
|
@@ -403,10 +409,6 @@ int circuit_receive_relay_cell(cell_t *cell, circuit_t *circ,
|
|
|
}
|
|
|
}
|
|
|
if(cell_direction == CELL_DIRECTION_IN) {
|
|
|
- if(relay_check_digest(layer_hint->b_digest, cell) < 0) {
|
|
|
- log_fn(LOG_WARN,"incoming cell failed integrity check. Closing circ.");
|
|
|
- return -1;
|
|
|
- }
|
|
|
++stats_n_relay_cells_delivered;
|
|
|
log_fn(LOG_DEBUG,"Sending to AP.");
|
|
|
if (connection_edge_process_relay_cell(cell, circ, conn, EDGE_AP, layer_hint) < 0) {
|
|
@@ -438,12 +440,12 @@ int circuit_receive_relay_cell(cell_t *cell, circuit_t *circ,
|
|
|
}
|
|
|
|
|
|
/* wrap this into receive_relay_cell one day */
|
|
|
-static int relay_crypt(circuit_t *circ, char *in, char cell_direction,
|
|
|
+static int relay_crypt(circuit_t *circ, cell_t *cell, char cell_direction,
|
|
|
crypt_path_t **layer_hint, char *recognized) {
|
|
|
crypt_path_t *thishop;
|
|
|
relay_header_t rh;
|
|
|
|
|
|
- assert(circ && in && recognized);
|
|
|
+ assert(circ && cell && recognized);
|
|
|
assert(cell_direction == CELL_DIRECTION_IN || cell_direction == CELL_DIRECTION_OUT);
|
|
|
|
|
|
if(cell_direction == CELL_DIRECTION_IN) {
|
|
@@ -457,14 +459,17 @@ static int relay_crypt(circuit_t *circ, char *in, char cell_direction,
|
|
|
do { /* Remember: cpath is in forward order, that is, first hop first. */
|
|
|
assert(thishop);
|
|
|
|
|
|
- if(relay_crypt_one_payload(thishop->b_crypto, in, 0) < 0)
|
|
|
+ if(relay_crypt_one_payload(thishop->b_crypto, cell->payload, 0) < 0)
|
|
|
return -1;
|
|
|
|
|
|
- relay_header_unpack(&rh, in);
|
|
|
+ relay_header_unpack(&rh, cell->payload);
|
|
|
if(rh.recognized == 0) {
|
|
|
- *recognized = 1;
|
|
|
- *layer_hint = thishop;
|
|
|
- return 0;
|
|
|
+ /* it's possibly recognized. have to check digest to be sure. */
|
|
|
+ if(relay_digest_matches(thishop->b_digest, cell)) {
|
|
|
+ *recognized = 1;
|
|
|
+ *layer_hint = thishop;
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
}
|
|
|
|
|
|
thishop = thishop->next;
|
|
@@ -472,93 +477,25 @@ static int relay_crypt(circuit_t *circ, char *in, char cell_direction,
|
|
|
log_fn(LOG_WARN,"in-cell at OP not recognized. Dropping.");
|
|
|
return 0;
|
|
|
} else { /* we're in the middle. Just one crypt. */
|
|
|
- if(relay_crypt_one_payload(circ->p_crypto, in, 1) < 0)
|
|
|
+ if(relay_crypt_one_payload(circ->p_crypto, cell->payload, 1) < 0)
|
|
|
return -1;
|
|
|
log_fn(LOG_DEBUG,"Skipping recognized check, because we're not the OP.");
|
|
|
}
|
|
|
} else /* cell_direction == CELL_DIRECTION_OUT */ {
|
|
|
/* we're in the middle. Just one crypt. */
|
|
|
|
|
|
- if(relay_crypt_one_payload(circ->n_crypto, in, 0) < 0)
|
|
|
- return -1;
|
|
|
-
|
|
|
- relay_header_unpack(&rh, in);
|
|
|
- if (rh.recognized == 0 ||
|
|
|
- (!circ->n_conn && rh.recognized == 11257)) {
|
|
|
- /* as a special exception, hops at the end of the circuit
|
|
|
- * recognize 01 as well. */
|
|
|
- log_fn(LOG_INFO,"Recognized '%d'", rh.recognized);
|
|
|
- *recognized = 1;
|
|
|
- return 0;
|
|
|
- }
|
|
|
- }
|
|
|
- return 0;
|
|
|
-}
|
|
|
-
|
|
|
-/* Helper function for circuit_package_relay_cell().
|
|
|
- * crypt the cell from layer_hint backward. if there's a conflict,
|
|
|
- * set *conflicthop to the nearest conflict, rewind all the ciphers,
|
|
|
- * and restore the digest state.
|
|
|
- *
|
|
|
- * Conflicthop is set to the node whose cipher is going to output
|
|
|
- * recognized=0. That is, the hop after conflicthop needs to receive
|
|
|
- * the dummy cell.
|
|
|
- */
|
|
|
-static int
|
|
|
-relay_try_all_crypts(cell_t *cell, circuit_t *circ, crypt_path_t *layer_hint,
|
|
|
- uint16_t recognized, crypt_path_t **conflicthop)
|
|
|
-{
|
|
|
- crypt_path_t *thishop; /* counter for repeated crypts */
|
|
|
- relay_header_t rh; /* to set/check 'recognized' */
|
|
|
- crypto_digest_env_t *backup_digest=NULL;
|
|
|
-
|
|
|
- backup_digest = crypto_digest_dup(layer_hint->f_digest);
|
|
|
- relay_header_unpack(&rh, cell->payload);
|
|
|
- rh.recognized = recognized;
|
|
|
- relay_header_pack(cell->payload, &rh);
|
|
|
- relay_set_digest(layer_hint->f_digest, cell);
|
|
|
-
|
|
|
- *conflicthop = NULL;
|
|
|
- thishop = layer_hint;
|
|
|
-
|
|
|
- /* moving from farthest to nearest hop */
|
|
|
- do {
|
|
|
- assert(thishop);
|
|
|
-
|
|
|
- log_fn(LOG_INFO,"crypting a layer of the relay cell.");
|
|
|
- if(relay_crypt_one_payload(thishop->f_crypto, cell->payload, 1) < 0) {
|
|
|
- crypto_free_digest_env(backup_digest);
|
|
|
+ if(relay_crypt_one_payload(circ->n_crypto, cell->payload, 0) < 0)
|
|
|
return -1;
|
|
|
- }
|
|
|
|
|
|
- if(thishop != circ->cpath) {
|
|
|
- /* if it's not the nearest hop, make sure it didn't accidentally
|
|
|
- * encrypt recognized to 00. For the nearest hop it doesn't matter
|
|
|
- * because it will be blindly decrypting whatever it gets. */
|
|
|
- relay_header_unpack(&rh, cell->payload);
|
|
|
-// if(rh.recognized == 0) {
|
|
|
- if(rh.recognized < 10000) {
|
|
|
- log_fn(LOG_INFO,"Found conflict");
|
|
|
- *conflicthop = thishop;
|
|
|
+ relay_header_unpack(&rh, cell->payload);
|
|
|
+ if (rh.recognized == 0) {
|
|
|
+ /* it's possibly recognized. have to check digest to be sure. */
|
|
|
+ if(relay_digest_matches(circ->n_digest, cell)) {
|
|
|
+ *recognized = 1;
|
|
|
+ return 0;
|
|
|
}
|
|
|
}
|
|
|
- thishop = thishop->prev;
|
|
|
- } while (thishop != circ->cpath->prev);
|
|
|
-
|
|
|
- if(*conflicthop) {
|
|
|
- /* 1. Restore the old digest state */
|
|
|
- crypto_digest_assign(layer_hint->f_digest, backup_digest);
|
|
|
-
|
|
|
- /* 2. Restore old state for the ciphers that changed. */
|
|
|
- thishop = layer_hint;
|
|
|
- do {
|
|
|
- log_fn(LOG_INFO,"Rewinding a cipher layer...");
|
|
|
- crypto_cipher_rewind(thishop->f_crypto, CELL_PAYLOAD_SIZE);
|
|
|
- thishop = thishop->prev;
|
|
|
- } while (thishop != circ->cpath->prev);
|
|
|
}
|
|
|
- /* else no conflict. success. */
|
|
|
- crypto_free_digest_env(backup_digest);
|
|
|
return 0;
|
|
|
}
|
|
|
|
|
@@ -575,11 +512,7 @@ circuit_package_relay_cell(cell_t *cell, circuit_t *circ,
|
|
|
crypt_path_t *layer_hint)
|
|
|
{
|
|
|
connection_t *conn; /* where to send the cell */
|
|
|
- crypt_path_t *conflicthop; /* for padding to prematurely recognized hops */
|
|
|
- crypt_path_t *tmpconflicthop;
|
|
|
- relay_header_t rh; /* to make the dummy cell */
|
|
|
- /* backup cell and digest if we need to send a dummy instead */
|
|
|
- cell_t backup_cell;
|
|
|
+ crypt_path_t *thishop; /* counter for repeated crypts */
|
|
|
|
|
|
if(cell_direction == CELL_DIRECTION_OUT) {
|
|
|
conn = circ->n_conn;
|
|
@@ -587,60 +520,21 @@ circuit_package_relay_cell(cell_t *cell, circuit_t *circ,
|
|
|
log_fn(LOG_INFO,"outgoing relay cell has n_conn==NULL. Dropping.");
|
|
|
return 0; /* just drop it */
|
|
|
}
|
|
|
+ relay_set_digest(layer_hint->f_digest, cell);
|
|
|
|
|
|
- again:
|
|
|
-
|
|
|
- /* copy cell in case we need to send a dummy relay cell instead */
|
|
|
- memcpy(&backup_cell, cell, sizeof(cell_t));
|
|
|
-
|
|
|
- log_fn(LOG_INFO,"Starting to crypt my relay cell.");
|
|
|
- if(relay_try_all_crypts(cell, circ, layer_hint, 0, &conflicthop) < 0) {
|
|
|
- log_fn(LOG_WARN,"relay_try_deliver_cell (1) failed. Closing.");
|
|
|
- return -1;
|
|
|
- }
|
|
|
- if(conflicthop) {
|
|
|
- log_fn(LOG_WARN,"'recognized' conflict found. Sending padding.");
|
|
|
- /* 1a. build and set_digest a padding cell. */
|
|
|
- cell->circ_id = backup_cell.circ_id;
|
|
|
- cell->command = CELL_RELAY;
|
|
|
- rh.command = RELAY_COMMAND_DROP;
|
|
|
- rh.recognized = rh.stream_id = rh.integrity = rh.length = 0;
|
|
|
- relay_header_pack(cell->payload, &rh);
|
|
|
- memset(cell->payload+RELAY_HEADER_SIZE, 0, RELAY_PAYLOAD_SIZE);
|
|
|
-
|
|
|
- /* if conflicthop is the last hop in the circuit... */
|
|
|
- if(conflicthop == circ->cpath->prev ||
|
|
|
- conflicthop->next->state == CPATH_STATE_CLOSED) {
|
|
|
- log_fn(LOG_WARN,"Got a conflict at the end of the circuit, using recognized=1");
|
|
|
- if(relay_try_all_crypts(cell, circ, conflicthop, 11257, &tmpconflicthop) < 0) {
|
|
|
- log_fn(LOG_WARN,"relay_try_deliver_cell (2) failed. Closing.");
|
|
|
- return -1;
|
|
|
- }
|
|
|
- } else {
|
|
|
- log_fn(LOG_WARN,"Got a conflict inside the circuit, using recognized=0");
|
|
|
- if(relay_try_all_crypts(cell, circ, conflicthop->next, 0, &tmpconflicthop) < 0) {
|
|
|
- log_fn(LOG_WARN,"relay_try_deliver_cell (3) failed. Closing.");
|
|
|
- return -1;
|
|
|
- }
|
|
|
- }
|
|
|
+ thishop = layer_hint;
|
|
|
+ /* moving from farthest to nearest hop */
|
|
|
+ do {
|
|
|
+ assert(thishop);
|
|
|
|
|
|
- if(tmpconflicthop) { /* conflict with this one too?! */
|
|
|
- log_fn(LOG_WARN,"Conflict with sending padding relay cell. Closing.");
|
|
|
+ log_fn(LOG_INFO,"crypting a layer of the relay cell.");
|
|
|
+ if(relay_crypt_one_payload(thishop->f_crypto, cell->payload, 1) < 0) {
|
|
|
return -1;
|
|
|
}
|
|
|
|
|
|
- /* send it. */
|
|
|
- ++stats_n_relay_cells_relayed;
|
|
|
- connection_or_write_cell_to_buf(cell, conn);
|
|
|
- log_fn(LOG_INFO,"Delivered my padding cell.");
|
|
|
-
|
|
|
- /* 2. Restore the original relay cell */
|
|
|
- memcpy(cell, &backup_cell, sizeof(cell_t));
|
|
|
+ thishop = thishop->prev;
|
|
|
+ } while (thishop != circ->cpath->prev);
|
|
|
|
|
|
- /* 3. Try again. */
|
|
|
- goto again;
|
|
|
- }
|
|
|
- /* no conflict, we succeeded. send it and be done. */
|
|
|
} else { /* incoming cell */
|
|
|
conn = circ->p_conn;
|
|
|
if(!conn) {
|