diff --git a/src/or/onion.c b/src/or/onion.c
index ce5eb93b1a..753ddcff77 100644
--- a/src/or/onion.c
+++ b/src/or/onion.c
@@ -337,7 +337,7 @@ onion_skin_server_handshake(int type,
break;
case ONION_HANDSHAKE_TYPE_NTOR:
#ifdef CURVE25519_ENABLED
- if (onionskin_len != NTOR_ONIONSKIN_LEN)
+ if (onionskin_len < NTOR_ONIONSKIN_LEN)
return -1;
{
size_t keys_tmp_len = keys_out_len + DIGEST_LEN;
@@ -409,7 +409,7 @@ onion_skin_client_handshake(int type,
return 0;
#ifdef CURVE25519_ENABLED
case ONION_HANDSHAKE_TYPE_NTOR:
- if (reply_len != NTOR_REPLY_LEN)
+ if (reply_len < NTOR_REPLY_LEN)
return -1;
{
size_t keys_tmp_len = keys_out_len + DIGEST_LEN;
@@ -442,7 +442,8 @@ check_create_cell(const create_cell_t *cell, int unknown_ok)
{
switch (cell->cell_type) {
case CELL_CREATE:
- if (cell->handshake_type != ONION_HANDSHAKE_TYPE_TAP)
+ if (cell->handshake_type != ONION_HANDSHAKE_TYPE_TAP &&
+ cell->handshake_type != ONION_HANDSHAKE_TYPE_NTOR)
return -1;
break;
case CELL_CREATE_FAST:
@@ -502,6 +503,14 @@ parse_create2_payload(create_cell_t *cell_out, const uint8_t *p, size_t p_len)
return 0;
}
+/** Magic string which, in a CREATE or EXTEND cell, indicates that a seeming
+ * TAP payload is really an ntor payload. We'd do away with this if every
+ * relay supported EXTEND2, but we want to be able to extend from A to B with
+ * ntor even when A doesn't understand EXTEND2 and so can't generate a
+ * CREATE2 cell.
+ **/
+#define NTOR_CREATE_MAGIC "ntorNTORntorNTOR"
+
/** Parse a CREATE, CREATE_FAST, or CREATE2 cell from cell_in into
* cell_out. Return 0 on success, -1 on failure. (We reject some
* syntactically valid CREATE2 cells that we can't generate or react to.) */
@@ -513,9 +522,16 @@ create_cell_parse(create_cell_t *cell_out, const cell_t *cell_in)
switch (cell_in->command) {
case CELL_CREATE:
cell_out->cell_type = CELL_CREATE;
- cell_out->handshake_type = ONION_HANDSHAKE_TYPE_TAP;
- cell_out->handshake_len = TAP_ONIONSKIN_CHALLENGE_LEN;
- memcpy(cell_out->onionskin, cell_in->payload, TAP_ONIONSKIN_CHALLENGE_LEN);
+ if (tor_memeq(cell_in->payload, NTOR_CREATE_MAGIC, 16)) {
+ cell_out->handshake_type = ONION_HANDSHAKE_TYPE_NTOR;
+ cell_out->handshake_len = NTOR_ONIONSKIN_LEN;
+ memcpy(cell_out->onionskin, cell_in->payload+16, NTOR_ONIONSKIN_LEN);
+ } else {
+ cell_out->handshake_type = ONION_HANDSHAKE_TYPE_TAP;
+ cell_out->handshake_len = TAP_ONIONSKIN_CHALLENGE_LEN;
+ memcpy(cell_out->onionskin, cell_in->payload,
+ TAP_ONIONSKIN_CHALLENGE_LEN);
+ }
break;
case CELL_CREATE_FAST:
cell_out->cell_type = CELL_CREATE_FAST;
@@ -603,7 +619,8 @@ check_extend_cell(const extend_cell_t *cell)
if (cell->cell_type != RELAY_COMMAND_EXTEND)
return -1;
} else if (cell->create_cell.cell_type == CELL_CREATE2) {
- if (cell->cell_type != RELAY_COMMAND_EXTEND2)
+ if (cell->cell_type != RELAY_COMMAND_EXTEND2 &&
+ cell->cell_type != RELAY_COMMAND_EXTEND)
return -1;
} else {
/* In particular, no CREATE_FAST cells are allowed */
@@ -647,11 +664,19 @@ extend_cell_parse(extend_cell_t *cell_out, const uint8_t command,
tor_addr_from_ipv4n(&cell_out->orport_ipv4.addr, get_uint32(payload));
cell_out->orport_ipv4.port = ntohs(get_uint16(payload+4));
tor_addr_make_unspec(&cell_out->orport_ipv6.addr);
- cell_out->create_cell.cell_type = CELL_CREATE;
- cell_out->create_cell.handshake_type = ONION_HANDSHAKE_TYPE_TAP;
- cell_out->create_cell.handshake_len = TAP_ONIONSKIN_CHALLENGE_LEN;
- memcpy(cell_out->create_cell.onionskin, payload + 6,
- TAP_ONIONSKIN_CHALLENGE_LEN);
+ if (tor_memeq(payload + 6, NTOR_CREATE_MAGIC, 16)) {
+ cell_out->create_cell.cell_type = CELL_CREATE2;
+ cell_out->create_cell.handshake_type = ONION_HANDSHAKE_TYPE_NTOR;
+ cell_out->create_cell.handshake_len = NTOR_ONIONSKIN_LEN;
+ memcpy(cell_out->create_cell.onionskin, payload + 22,
+ NTOR_ONIONSKIN_LEN);
+ } else {
+ cell_out->create_cell.cell_type = CELL_CREATE;
+ cell_out->create_cell.handshake_type = ONION_HANDSHAKE_TYPE_TAP;
+ cell_out->create_cell.handshake_len = TAP_ONIONSKIN_CHALLENGE_LEN;
+ memcpy(cell_out->create_cell.onionskin, payload + 6,
+ TAP_ONIONSKIN_CHALLENGE_LEN);
+ }
memcpy(cell_out->node_id, payload + 6 + TAP_ONIONSKIN_CHALLENGE_LEN,
DIGEST_LEN);
break;
@@ -787,17 +812,28 @@ extended_cell_parse(extended_cell_t *cell_out,
int
create_cell_format(cell_t *cell_out, const create_cell_t *cell_in)
{
+ uint8_t *p;
+ size_t space;
if (check_create_cell(cell_in, 0) < 0)
return -1;
memset(cell_out->payload, 0, sizeof(cell_out->payload));
cell_out->command = cell_in->cell_type;
+ p = cell_out->payload;
+ space = sizeof(cell_out->payload);
+
switch (cell_in->cell_type) {
case CELL_CREATE:
+ if (cell_in->handshake_type == ONION_HANDSHAKE_TYPE_NTOR) {
+ memcpy(p, NTOR_CREATE_MAGIC, 16);
+ p += 16;
+ space -= 16;
+ }
+ /* Fall through */
case CELL_CREATE_FAST:
- tor_assert(cell_in->handshake_len <= sizeof(cell_out->payload));
- memcpy(cell_out->payload, cell_in->onionskin, cell_in->handshake_len);
+ tor_assert(cell_in->handshake_len <= space);
+ memcpy(p, cell_in->onionskin, cell_in->handshake_len);
break;
case CELL_CREATE2:
tor_assert(cell_in->handshake_len <= sizeof(cell_out->payload)-4);
@@ -865,8 +901,13 @@ extend_cell_format(uint8_t *command_out, uint16_t *len_out,
*len_out = 6 + TAP_ONIONSKIN_CHALLENGE_LEN + DIGEST_LEN;
set_uint32(p, tor_addr_to_ipv4n(&cell_in->orport_ipv4.addr));
set_uint16(p+4, ntohs(cell_in->orport_ipv4.port));
- memcpy(p+6, cell_in->create_cell.onionskin,
- TAP_ONIONSKIN_CHALLENGE_LEN);
+ if (cell_in->create_cell.handshake_type == ONION_HANDSHAKE_TYPE_NTOR) {
+ memcpy(p+6, NTOR_CREATE_MAGIC, 16);
+ memcpy(p+22, cell_in->create_cell.onionskin, NTOR_ONIONSKIN_LEN);
+ } else {
+ memcpy(p+6, cell_in->create_cell.onionskin,
+ TAP_ONIONSKIN_CHALLENGE_LEN);
+ }
memcpy(p+6+TAP_ONIONSKIN_CHALLENGE_LEN, cell_in->node_id, DIGEST_LEN);
}
break;
diff --git a/src/test/test_cell_formats.c b/src/test/test_cell_formats.c
index 2af87af727..bdbc555eb1 100644
--- a/src/test/test_cell_formats.c
+++ b/src/test/test_cell_formats.c
@@ -456,6 +456,26 @@ test_cfmt_create_cells(void *arg)
tt_int_op(-1, ==, create_cell_parse(&cc, &cell));
#endif
+ /* A valid create cell with an ntor payload, in legacy format. */
+ memset(&cell, 0, sizeof(cell));
+ memset(b, 0, sizeof(b));
+ crypto_rand((char*)b, NTOR_ONIONSKIN_LEN);
+ cell.command = CELL_CREATE;
+ memcpy(cell.payload, "ntorNTORntorNTOR", 16);
+ memcpy(cell.payload+16, b, NTOR_ONIONSKIN_LEN);
+#ifdef CURVE25519_ENABLED
+ tt_int_op(0, ==, create_cell_parse(&cc, &cell));
+ tt_int_op(CELL_CREATE, ==, cc.cell_type);
+ tt_int_op(ONION_HANDSHAKE_TYPE_NTOR, ==, cc.handshake_type);
+ tt_int_op(NTOR_ONIONSKIN_LEN, ==, cc.handshake_len);
+ test_memeq(cc.onionskin, b, NTOR_ONIONSKIN_LEN + 10);
+ tt_int_op(0, ==, create_cell_format(&cell2, &cc));
+ tt_int_op(cell.command, ==, cell2.command);
+ test_memeq(cell.payload, cell2.payload, CELL_PAYLOAD_SIZE);
+#else
+ tt_int_op(-1, ==, create_cell_parse(&cc, &cell));
+#endif
+
/* == Okay, now let's try to parse some impossible stuff. */
/* It has to be some kind of a create cell! */
@@ -573,6 +593,7 @@ test_cfmt_created_cells(void *arg)
static void
test_cfmt_extend_cells(void *arg)
{
+ cell_t cell;
uint8_t b[512];
extend_cell_t ec;
create_cell_t *cc = &ec.create_cell;
@@ -607,6 +628,31 @@ test_cfmt_extend_cells(void *arg)
tt_int_op(p2_len, ==, 26+TAP_ONIONSKIN_CHALLENGE_LEN);
test_memeq(p2, p, RELAY_PAYLOAD_SIZE);
+ /* Let's do an ntor stuffed in a legacy EXTEND cell */
+ memset(p, 0, sizeof(p));
+ memset(b, 0, sizeof(b));
+ crypto_rand((char*)b, NTOR_ONIONSKIN_LEN);
+ memcpy(p, "\x12\xf4\x00\x01\x01\x02", 6); /* 18 244 0 1 : 258 */
+ memcpy(p+6,"ntorNTORntorNTOR", 16);
+ memcpy(p+22, b, NTOR_ONIONSKIN_LEN);
+ memcpy(p+6+TAP_ONIONSKIN_CHALLENGE_LEN, "electroencephalogram", 20);
+ tt_int_op(0, ==, extend_cell_parse(&ec, RELAY_COMMAND_EXTEND,
+ p, 26+TAP_ONIONSKIN_CHALLENGE_LEN));
+ tt_int_op(RELAY_COMMAND_EXTEND, ==, ec.cell_type);
+ tt_str_op("18.244.0.1", ==, fmt_addr(&ec.orport_ipv4.addr));
+ tt_int_op(258, ==, ec.orport_ipv4.port);
+ tt_int_op(AF_UNSPEC, ==, tor_addr_family(&ec.orport_ipv6.addr));
+ test_memeq(ec.node_id, "electroencephalogram", 20);
+ tt_int_op(cc->cell_type, ==, CELL_CREATE2);
+ tt_int_op(cc->handshake_type, ==, ONION_HANDSHAKE_TYPE_NTOR);
+ tt_int_op(cc->handshake_len, ==, NTOR_ONIONSKIN_LEN);
+ test_memeq(cc->onionskin, b, NTOR_ONIONSKIN_LEN+20);
+ tt_int_op(0, ==, extend_cell_format(&p2_cmd, &p2_len, p2, &ec));
+ tt_int_op(p2_cmd, ==, RELAY_COMMAND_EXTEND);
+ tt_int_op(p2_len, ==, 26+TAP_ONIONSKIN_CHALLENGE_LEN);
+ test_memeq(p2, p, RELAY_PAYLOAD_SIZE);
+ tt_int_op(0, ==, create_cell_format(&cell, cc));
+
/* Now let's do a minimal ntor EXTEND2 cell. */
memset(&ec, 0xff, sizeof(ec));
memset(p, 0, sizeof(p));