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Merge remote-tracking branch 'teor/bug20472-029-v2' into maint-0.2.9

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This commit is contained in:
Nick Mathewson 2016-11-01 13:05:33 -04:00
commit 733b245283
5 changed files with 40 additions and 53 deletions
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4
changes/bug20472 Normal file
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@ -0,0 +1,4 @@
o Minor bugfixes (circuits):
- Remove a BUG warning in circuit_pick_extend_handshake. Instead, assume
all nodes support EXTEND2. Use ntor whenever a key is available.
Bugfix on commit 10aa913 from 19163 in 0.2.9.3-alpha. Fixes bug 20472.

65
src/or/circuitbuild.c
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@ -814,7 +814,8 @@ circuit_timeout_want_to_count_circ(origin_circuit_t *circ)
/** Decide whether to use a TAP or ntor handshake for connecting to <b>ei</b>
* directly, and set *<b>cell_type_out</b> and *<b>handshake_type_out</b>
* accordingly.
* Note that TAP handshakes are only used for direct connections:
* Note that TAP handshakes in CREATE cells are only used for direct
* connections:
* - from Tor2web to intro points not in the client's consensus, and
* - from Single Onions to rend points not in the service's consensus.
* This is checked in onion_populate_cpath. */
@ -823,58 +824,43 @@ circuit_pick_create_handshake(uint8_t *cell_type_out,
uint16_t *handshake_type_out,
const extend_info_t *ei)
{
/* XXXX030 Remove support for deciding to use TAP. */
/* torspec says: In general, clients SHOULD use CREATE whenever they are
* using the TAP handshake, and CREATE2 otherwise. */
if (extend_info_supports_ntor(ei)) {
*cell_type_out = CELL_CREATE2;
*handshake_type_out = ONION_HANDSHAKE_TYPE_NTOR;
return;
} else {
/* XXXX030 Remove support for deciding to use TAP and EXTEND. */
*cell_type_out = CELL_CREATE;
*handshake_type_out = ONION_HANDSHAKE_TYPE_TAP;
}
*cell_type_out = CELL_CREATE;
*handshake_type_out = ONION_HANDSHAKE_TYPE_TAP;
}
/** Decide whether to use a TAP or ntor handshake for connecting to <b>ei</b>
* directly, and set *<b>handshake_type_out</b> accordingly. Decide whether,
* in extending through <b>node</b> to do so, we should use an EXTEND2 or an
* EXTEND cell to do so, and set *<b>cell_type_out</b> and
* *<b>create_cell_type_out</b> accordingly.
* Note that TAP handshakes are only used for extend handshakes:
/** Decide whether to use a TAP or ntor handshake for extending to <b>ei</b>
* and set *<b>handshake_type_out</b> accordingly. Decide whether we should
* use an EXTEND2 or an EXTEND cell to do so, and set *<b>cell_type_out</b>
* and *<b>create_cell_type_out</b> accordingly.
* Note that TAP handshakes in EXTEND cells are only used:
* - from clients to intro points, and
* - from hidden services to rend points.
* This is checked in onion_populate_cpath. */
* This is checked in onion_populate_cpath.
*/
static void
circuit_pick_extend_handshake(uint8_t *cell_type_out,
uint8_t *create_cell_type_out,
uint16_t *handshake_type_out,
const node_t *node_prev,
const extend_info_t *ei)
{
uint8_t t;
circuit_pick_create_handshake(&t, handshake_type_out, ei);
/* XXXX030 Remove support for deciding to use TAP. */
/* It is an error to extend if there is no previous node. */
if (BUG(node_prev == NULL)) {
*cell_type_out = RELAY_COMMAND_EXTEND;
*create_cell_type_out = CELL_CREATE;
return;
}
/* It is an error for a node with a known version to be so old it does not
* support ntor. */
tor_assert_nonfatal(routerstatus_version_supports_ntor(node_prev->rs, 1));
/* Assume relays without tor versions or routerstatuses support ntor.
* The authorities enforce ntor support, and assuming and failing is better
* than allowing a malicious node to perform a protocol downgrade to TAP. */
if (*handshake_type_out != ONION_HANDSHAKE_TYPE_TAP &&
(node_has_curve25519_onion_key(node_prev) ||
(routerstatus_version_supports_ntor(node_prev->rs, 1)))) {
/* torspec says: Clients SHOULD use the EXTEND format whenever sending a TAP
* handshake... In other cases, clients SHOULD use EXTEND2. */
if (*handshake_type_out != ONION_HANDSHAKE_TYPE_TAP) {
*cell_type_out = RELAY_COMMAND_EXTEND2;
*create_cell_type_out = CELL_CREATE2;
} else {
/* XXXX030 Remove support for deciding to use TAP and EXTEND. */
*cell_type_out = RELAY_COMMAND_EXTEND;
*create_cell_type_out = CELL_CREATE;
}
@ -1030,15 +1016,10 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
return - END_CIRC_REASON_INTERNAL;
}
{
const node_t *prev_node;
prev_node = node_get_by_id(hop->prev->extend_info->identity_digest);
circuit_pick_extend_handshake(&ec.cell_type,
&ec.create_cell.cell_type,
&ec.create_cell.handshake_type,
prev_node,
hop->extend_info);
}
circuit_pick_extend_handshake(&ec.cell_type,
&ec.create_cell.cell_type,
&ec.create_cell.handshake_type,
hop->extend_info);
tor_addr_copy(&ec.orport_ipv4.addr, &hop->extend_info->addr);
ec.orport_ipv4.port = hop->extend_info->port;

6
src/or/networkstatus.c
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@ -2360,10 +2360,10 @@ client_would_use_router(const routerstatus_t *rs, time_t now,
/* We'd drop it immediately for being too old. */
return 0;
}
if (!routerstatus_version_supports_ntor(rs, 1)) {
/* We'd ignore it because it doesn't support ntor.
if (!routerstatus_version_supports_extend2_cells(rs, 1)) {
/* We'd ignore it because it doesn't support EXTEND2 cells.
* If we don't know the version, download the descriptor so we can
* check if it supports ntor. */
* check if it supports EXTEND2 cells and ntor. */
return 0;
}
return 1;

14
src/or/routerlist.c
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@ -2344,9 +2344,10 @@ router_add_running_nodes_to_smartlist(smartlist_t *sl, int allow_invalid,
continue;
if (node_is_unreliable(node, need_uptime, need_capacity, need_guard))
continue;
/* Don't choose nodes if we are certain they can't do ntor */
if (node->rs && !routerstatus_version_supports_ntor(node->rs, 1))
/* Don't choose nodes if we are certain they can't do EXTEND2 cells */
if (node->rs && !routerstatus_version_supports_extend2_cells(node->rs, 1))
continue;
/* Don't choose nodes if we are certain they can't do ntor. */
if ((node->ri || node->md) && !node_has_curve25519_onion_key(node))
continue;
/* Choose a node with an OR address that matches the firewall rules */
@ -5609,13 +5610,14 @@ routerinfo_has_curve25519_onion_key(const routerinfo_t *ri)
return 1;
}
/* Is rs running a tor version known to support ntor?
/* Is rs running a tor version known to support EXTEND2 cells?
* If allow_unknown_versions is true, return true if we can't tell
* (from a versions line or a protocols line) whether it supports ntor.
* (from a versions line or a protocols line) whether it supports extend2
* cells.
* Otherwise, return false if the version is unknown. */
int
routerstatus_version_supports_ntor(const routerstatus_t *rs,
int allow_unknown_versions)
routerstatus_version_supports_extend2_cells(const routerstatus_t *rs,
int allow_unknown_versions)
{
if (!rs) {
return allow_unknown_versions;

4
src/or/routerlist.h
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@ -207,8 +207,8 @@ int routerinfo_incompatible_with_extrainfo(const crypto_pk_t *ri,
signed_descriptor_t *sd,
const char **msg);
int routerinfo_has_curve25519_onion_key(const routerinfo_t *ri);
int routerstatus_version_supports_ntor(const routerstatus_t *rs,
int allow_unknown_versions);
int routerstatus_version_supports_extend2_cells(const routerstatus_t *rs,
int allow_unknown_versions);
void routerlist_assert_ok(const routerlist_t *rl);
const char *esc_router_info(const routerinfo_t *router);