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Stop inadvertently upgrading client intro connections to ntor

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Also stop logging the intro point details on error by default.

Fixes #20012, introduced with ntor in tor 0.2.4.8-alpha.
This commit is contained in:
teor 2016-08-31 15:10:58 +10:00
parent e3bf8854c8
commit 0a3009bb85
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GPG Key ID: 450CBA7F968F094B
2 changed files with 20 additions and 33 deletions
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12
changes/bug20012 Normal file
View File

@ -0,0 +1,12 @@
o Major bugfixes (hidden services):
- Clients require hidden services to include the TAP keys
for their intro points in the hidden service descriptor.
This prevents an inadvertent upgrade to ntor, which a
malicious hidden service could use to discover which
consensus a client has.
Fixes bug 20012; bugfix on 0.2.4.8-alpha. Patch by teor.
o Minor bugfixes (hidden services):
- Stop logging intro point details to the client log on
certain error conditions.
Fixed as part of bug 20012; bugfix on 0.2.4.8-alpha.
Patch by teor.

37
src/or/rendclient.c
View File

@ -1373,41 +1373,16 @@ rend_client_get_random_intro_impl(const rend_cache_entry_t *entry,
smartlist_del(usable_nodes, i);
goto again;
}
/* Do we need to look up the router or is the extend info complete? */
/* All version 2 HS descriptors come with a TAP onion key.
* Clients used to try to get the TAP onion key from the consensus, but this
* meant that hidden services could discover which consensus clients have. */
if (!extend_info_supports_tap(intro->extend_info)) {
const node_t *node;
extend_info_t *new_extend_info;
if (tor_digest_is_zero(intro->extend_info->identity_digest))
node = node_get_by_hex_id(intro->extend_info->nickname);
else
node = node_get_by_id(intro->extend_info->identity_digest);
if (!node) {
log_info(LD_REND, "Unknown router with nickname '%s'; trying another.",
intro->extend_info->nickname);
log_info(LD_REND, "The HS descriptor is missing a TAP onion key for the "
"intro-point relay '%s'; trying another.",
safe_str_client(extend_info_describe(intro->extend_info)));
smartlist_del(usable_nodes, i);
goto again;
}
#ifdef ENABLE_TOR2WEB_MODE
new_extend_info = extend_info_from_node(node, options->Tor2webMode);
#else
new_extend_info = extend_info_from_node(node, 0);
#endif
if (!new_extend_info) {
const char *alternate_reason = "";
#ifdef ENABLE_TOR2WEB_MODE
alternate_reason = ", or we cannot connect directly to it";
#endif
log_info(LD_REND, "We don't have a descriptor for the intro-point relay "
"'%s'%s; trying another.",
extend_info_describe(intro->extend_info), alternate_reason);
smartlist_del(usable_nodes, i);
goto again;
} else {
extend_info_free(intro->extend_info);
intro->extend_info = new_extend_info;
}
tor_assert(intro->extend_info != NULL);
}
/* Check if we should refuse to talk to this router. */
if (strict &&
routerset_contains_extendinfo(options->ExcludeNodes,