nihilist/tor
1
0
Fork 0
mirror of https://gitlab.torproject.org/tpo/core/tor.git synced 2024-11-11 05:33:47 +01:00
Code Issues Packages Projects Releases Wiki Activity

Use new wrappers for making,sending,processing create/extend cells

Browse Source
This commit is contained in:
Nick Mathewson 2012-12-05 23:07:49 -05:00
parent 2802ccaeb6
commit 6c69b16c93
3 changed files with 93 additions and 91 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

169
src/or/circuitbuild.c
View File

@ -55,9 +55,7 @@ static channel_t * channel_connect_for_circuit(const tor_addr_t *addr,
uint16_t port,
const char *id_digest);
static int circuit_deliver_create_cell(circuit_t *circ,
uint8_t cell_type,
const uint8_t *payload,
size_t payload_len);
const create_cell_t *create_cell);
static int onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit);
static crypt_path_t *onion_next_hop_in_cpath(crypt_path_t *cpath);
static int onion_extend_cpath(origin_circuit_t *circ);
@ -474,15 +472,13 @@ circuit_n_chan_done(channel_t *chan, int status)
* died? */
}
} else {
/* pull the create cell out of circ->onionskin, and send it */
tor_assert(circ->n_chan_onionskin);
if (circuit_deliver_create_cell(circ,CELL_CREATE,
(const uint8_t*)circ->n_chan_onionskin,
circ->n_chan_onionskin_len)<0) {
/* pull the create cell out of circ->n_chan_create_cell, and send it */
tor_assert(circ->n_chan_create_cell);
if (circuit_deliver_create_cell(circ, circ->n_chan_create_cell)<0) {
circuit_mark_for_close(circ, END_CIRC_REASON_RESOURCELIMIT);
continue;
}
tor_free(circ->n_chan_onionskin);
tor_free(circ->n_chan_create_cell);
circuit_set_state(circ, CIRCUIT_STATE_OPEN);
}
}
@ -499,16 +495,17 @@ circuit_n_chan_done(channel_t *chan, int status)
* Return -1 if we failed to find a suitable circid, else return 0.
*/
static int
circuit_deliver_create_cell(circuit_t *circ, uint8_t cell_type,
const uint8_t *payload, size_t payload_len)
circuit_deliver_create_cell(circuit_t *circ, const create_cell_t *create_cell)
{
cell_t cell;
circid_t id;
tor_assert(circ);
tor_assert(circ->n_chan);
tor_assert(payload);
tor_assert(cell_type == CELL_CREATE || cell_type == CELL_CREATE_FAST);
tor_assert(create_cell);
tor_assert(create_cell->cell_type == CELL_CREATE ||
create_cell->cell_type == CELL_CREATE_FAST ||
create_cell->cell_type == CELL_CREATE2);
id = get_unique_circ_id_by_chan(circ->n_chan);
if (!id) {
@ -519,10 +516,12 @@ circuit_deliver_create_cell(circuit_t *circ, uint8_t cell_type,
circuit_set_n_circid_chan(circ, id, circ->n_chan);
memset(&cell, 0, sizeof(cell_t));
cell.command = cell_type;
if (create_cell_format(&cell, create_cell) < 0) {
log_warn(LD_CIRC,"Couldn't format create cell");
return -1;
}
cell.circ_id = circ->n_circ_id;
memcpy(cell.payload, payload, payload_len);
append_cell_to_circuit_queue(circ, circ->n_chan, &cell,
CELL_DIRECTION_OUT, 0);
@ -615,18 +614,16 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
{
crypt_path_t *hop;
const node_t *node;
uint8_t payload[2+4+DIGEST_LEN+MAX_ONIONSKIN_CHALLENGE_LEN];
uint8_t *onionskin;
uint16_t handshake_type;
int onionskin_len;
size_t payload_len;
tor_assert(circ);
if (circ->cpath->state == CPATH_STATE_CLOSED) {
/* This is the first hop. */
create_cell_t cc;
int fast;
uint8_t cell_type;
int len;
log_debug(LD_CIRC,"First skin; sending create cell.");
memset(&cc, 0, sizeof(cc));
if (circ->build_state->onehop_tunnel)
control_event_bootstrap(BOOTSTRAP_STATUS_ONEHOP_CREATE, 0);
else
@ -638,30 +635,29 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
/* We are an OR and we know the right onion key: we should
* send an old slow create cell.
*/
cell_type = CELL_CREATE;
handshake_type = ONION_HANDSHAKE_TYPE_TAP;
cc.cell_type = CELL_CREATE;
cc.handshake_type = ONION_HANDSHAKE_TYPE_TAP;
note_request("cell: create", 1);
} else {
/* We are not an OR, and we're building the first hop of a circuit to a
* new OR: we can be speedy and use CREATE_FAST to save an RSA operation
* and a DH operation. */
cell_type = CELL_CREATE_FAST;
handshake_type = ONION_HANDSHAKE_TYPE_FAST;
cc.cell_type = CELL_CREATE_FAST;
cc.handshake_type = ONION_HANDSHAKE_TYPE_FAST;
note_request("cell: create fast", 1);
}
memset(payload, 0, sizeof(payload));
onionskin_len = onion_skin_create(handshake_type,
circ->cpath->extend_info,
&circ->cpath->handshake_state,
payload);
if (onionskin_len < 0) {
len = onion_skin_create(cc.handshake_type,
circ->cpath->extend_info,
&circ->cpath->handshake_state,
cc.onionskin);
if (len < 0) {
log_warn(LD_CIRC,"onion_skin_create (first hop) failed.");
return - END_CIRC_REASON_INTERNAL;
}
cc.handshake_len = len;
if (circuit_deliver_create_cell(TO_CIRCUIT(circ), cell_type, payload,
onionskin_len) < 0)
if (circuit_deliver_create_cell(TO_CIRCUIT(circ), &cc) < 0)
return - END_CIRC_REASON_RESOURCELIMIT;
circ->cpath->state = CPATH_STATE_AWAITING_KEYS;
@ -670,10 +666,13 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
fast ? "CREATE_FAST" : "CREATE",
node ? node_describe(node) : "<unnamed>");
} else {
extend_cell_t ec;
int len;
tor_assert(circ->cpath->state == CPATH_STATE_OPEN);
tor_assert(circ->base_.state == CIRCUIT_STATE_BUILDING);
log_debug(LD_CIRC,"starting to send subsequent skin.");
hop = onion_next_hop_in_cpath(circ->cpath);
memset(&ec, 0, sizeof(ec));
if (!hop) {
/* done building the circuit. whew. */
circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN);
@ -743,34 +742,44 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
return - END_CIRC_REASON_INTERNAL;
}
set_uint32(payload, tor_addr_to_ipv4n(&hop->extend_info->addr));
set_uint16(payload+4, htons(hop->extend_info->port));
ec.cell_type = RELAY_COMMAND_EXTEND;
tor_addr_copy(&ec.orport_ipv4.addr, &hop->extend_info->addr);
ec.orport_ipv4.port = hop->extend_info->port;
tor_addr_make_unspec(&ec.orport_ipv6.addr);
memcpy(ec.node_id, hop->extend_info->identity_digest, DIGEST_LEN);
onionskin = payload+2+4;
memcpy(payload+2+4+TAP_ONIONSKIN_CHALLENGE_LEN,
hop->extend_info->identity_digest, DIGEST_LEN);
payload_len = 2+4+TAP_ONIONSKIN_CHALLENGE_LEN+DIGEST_LEN;
ec.create_cell.handshake_type = ONION_HANDSHAKE_TYPE_TAP;
ec.create_cell.cell_type = CELL_CREATE;
handshake_type = ONION_HANDSHAKE_TYPE_TAP;
if (onion_skin_create(handshake_type,
hop->extend_info,
&hop->handshake_state,
onionskin) < 0) {
len = onion_skin_create(ec.create_cell.handshake_type,
hop->extend_info,
&hop->handshake_state,
ec.create_cell.onionskin);
if (len < 0) {
log_warn(LD_CIRC,"onion_skin_create failed.");
return - END_CIRC_REASON_INTERNAL;
}
ec.create_cell.handshake_len = len;
log_info(LD_CIRC,"Sending extend relay cell.");
note_request("cell: extend", 1);
/* send it to hop->prev, because it will transfer
* it to a create cell and then send to hop */
if (relay_send_command_from_edge(0, TO_CIRCUIT(circ),
RELAY_COMMAND_EXTEND,
(char*)payload, payload_len,
hop->prev) < 0)
return 0; /* circuit is closed */
{
uint8_t command = 0;
uint16_t payload_len=0;
uint8_t payload[RELAY_PAYLOAD_SIZE];
if (extend_cell_format(&command, &payload_len, payload, &ec)<0) {
log_warn(LD_CIRC,"Couldn't format extend cell");
return -END_CIRC_REASON_INTERNAL;
}
/* send it to hop->prev, because it will transfer
* it to a create cell and then send to hop */
if (relay_send_command_from_edge(0, TO_CIRCUIT(circ),
command,
(char*)payload, payload_len,
hop->prev) < 0)
return 0; /* circuit is closed */
}
hop->state = CPATH_STATE_AWAITING_KEYS;
}
return 0;
@ -809,11 +818,7 @@ circuit_extend(cell_t *cell, circuit_t *circ)
{
channel_t *n_chan;
relay_header_t rh;
char *onionskin;
char *id_digest=NULL;
uint32_t n_addr32;
uint16_t n_port;
tor_addr_t n_addr;
extend_cell_t ec;
const char *msg = NULL;
int should_launch = 0;
@ -836,27 +841,21 @@ circuit_extend(cell_t *cell, circuit_t *circ)
relay_header_unpack(&rh, cell->payload);
if (rh.length < 4+2+TAP_ONIONSKIN_CHALLENGE_LEN+DIGEST_LEN) {
if (extend_cell_parse(&ec, rh.command,
cell->payload+RELAY_HEADER_SIZE,
rh.length) < 0) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Wrong length %d on extend cell. Closing circuit.",
rh.length);
"Can't parse extend cell. Closing circuit.");
return -1;
}
n_addr32 = ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE));
n_port = ntohs(get_uint16(cell->payload+RELAY_HEADER_SIZE+4));
onionskin = (char*) cell->payload+RELAY_HEADER_SIZE+4+2;
id_digest = (char*) cell->payload+RELAY_HEADER_SIZE+4+2+
TAP_ONIONSKIN_CHALLENGE_LEN;
tor_addr_from_ipv4h(&n_addr, n_addr32);
if (!n_port || !n_addr32) {
if (!ec.orport_ipv4.port || tor_addr_is_null(&ec.orport_ipv4.addr)) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Client asked me to extend to zero destination port or addr.");
return -1;
}
if (tor_addr_is_internal(&n_addr, 0) &&
if (tor_addr_is_internal(&ec.orport_ipv4.addr, 0) &&
!get_options()->ExtendAllowPrivateAddresses) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Client asked me to extend to a private address");
@ -869,7 +868,7 @@ circuit_extend(cell_t *cell, circuit_t *circ)
* fingerprints -- a) because it opens the user up to a mitm attack,
* and b) because it lets an attacker force the relay to hold open a
* new TLS connection for each extend request. */
if (tor_digest_is_zero(id_digest)) {
if (tor_digest_is_zero((const char*)ec.node_id)) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Client asked me to extend without specifying an id_digest.");
return -1;
@ -878,7 +877,7 @@ circuit_extend(cell_t *cell, circuit_t *circ)
/* Next, check if we're being asked to connect to the hop that the
* extend cell came from. There isn't any reason for that, and it can
* assist circular-path attacks. */
if (tor_memeq(id_digest,
if (tor_memeq(ec.node_id,
TO_OR_CIRCUIT(circ)->p_chan->identity_digest,
DIGEST_LEN)) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
@ -886,29 +885,34 @@ circuit_extend(cell_t *cell, circuit_t *circ)
return -1;
}
n_chan = channel_get_for_extend(id_digest,
&n_addr,
n_chan = channel_get_for_extend((const char*)ec.node_id,
&ec.orport_ipv4.addr,
&msg,
&should_launch);
if (!n_chan) {
log_debug(LD_CIRC|LD_OR,"Next router (%s): %s",
fmt_addrport(&n_addr, n_port), msg?msg:"????");
fmt_addrport(&ec.orport_ipv4.addr,ec.orport_ipv4.port),
msg?msg:"????");
circ->n_hop = extend_info_new(NULL /*nickname*/,
id_digest,
NULL /*onion_key*/,
&n_addr, n_port);
(const char*)ec.node_id,
NULL /*onion_key*/,
&ec.orport_ipv4.addr,
ec.orport_ipv4.port);
circ->n_chan_onionskin = tor_malloc(TAP_ONIONSKIN_CHALLENGE_LEN);
memcpy(circ->n_chan_onionskin, onionskin, TAP_ONIONSKIN_CHALLENGE_LEN);
circ->n_chan_onionskin_len = TAP_ONIONSKIN_CHALLENGE_LEN;
/* XXXX Make sure we can eventually deliver create cell with weird
* content */
circ->n_chan_create_cell = tor_memdup(&ec.create_cell,
sizeof(ec.create_cell));
circuit_set_state(circ, CIRCUIT_STATE_CHAN_WAIT);
if (should_launch) {
/* we should try to open a connection */
n_chan = channel_connect_for_circuit(&n_addr, n_port, id_digest);
n_chan = channel_connect_for_circuit(&ec.orport_ipv4.addr,
ec.orport_ipv4.port,
(const char*)ec.node_id);
if (!n_chan) {
log_info(LD_CIRC,"Launching n_chan failed. Closing circuit.");
circuit_mark_for_close(circ, END_CIRC_REASON_CONNECTFAILED);
@ -929,8 +933,7 @@ circuit_extend(cell_t *cell, circuit_t *circ)
"n_chan is %s",
channel_get_canonical_remote_descr(n_chan));
if (circuit_deliver_create_cell(circ, CELL_CREATE, (uint8_t*)onionskin,
TAP_ONIONSKIN_CHALLENGE_LEN) < 0)
if (circuit_deliver_create_cell(circ, &ec.create_cell) < 0)
return -1;
return 0;
}

6
src/or/circuitlist.c
View File

@ -252,7 +252,7 @@ circuit_set_state(circuit_t *circ, uint8_t state)
smartlist_add(circuits_pending_chans, circ);
}
if (state == CIRCUIT_STATE_OPEN)
tor_assert(!circ->n_chan_onionskin);
tor_assert(!circ->n_chan_create_cell);
circ->state = state;
}
@ -674,7 +674,7 @@ circuit_free(circuit_t *circ)
}
extend_info_free(circ->n_hop);
tor_free(circ->n_chan_onionskin);
tor_free(circ->n_chan_create_cell);
/* Remove from map. */
circuit_set_n_circid_chan(circ, 0, NULL);
@ -1582,7 +1582,7 @@ assert_circuit_ok(const circuit_t *c)
tor_assert(c->deliver_window >= 0);
tor_assert(c->package_window >= 0);
if (c->state == CIRCUIT_STATE_OPEN) {
tor_assert(!c->n_chan_onionskin);
tor_assert(!c->n_chan_create_cell);
if (or_circ) {
tor_assert(or_circ->n_crypto);
tor_assert(or_circ->p_crypto);

9
src/or/or.h
View File

@ -2645,6 +2645,8 @@ typedef struct {
#define ORIGIN_CIRCUIT_MAGIC 0x35315243u
#define OR_CIRCUIT_MAGIC 0x98ABC04Fu
struct create_cell_t;
/**
* A circuit is a path over the onion routing
* network. Applications can connect to one end of the circuit, and can
@ -2719,11 +2721,8 @@ typedef struct circuit_t {
* more. */
int deliver_window;
uint8_t n_chan_onionskin_len; /* XXXX MAKE THIS GET USED. */
/** For storage while n_chan is pending
* (state CIRCUIT_STATE_CHAN_WAIT). When defined, it is always
* length n_chan_onionskin_len */
char *n_chan_onionskin;
/** For storage while n_chan is pending (state CIRCUIT_STATE_CHAN_WAIT). */
struct create_cell_t *n_chan_create_cell;
/** When was this circuit created? We keep this timestamp with a higher
* resolution than most so that the circuit-build-time tracking code can