aboutsummaryrefslogtreecommitdiff
path: root/src
diff options
context:
space:
mode:
authorNick Mathewson <nickm@torproject.org>2013-06-16 20:23:33 -0400
committerNick Mathewson <nickm@torproject.org>2013-06-16 20:24:48 -0400
commitdc516a543604e081583cbe725bc4b0a89768fc78 (patch)
treec13365c9b5b74abd7d10cf697c5428d962d9b5dd /src
parent2a95f3171681ee53c97ccba9d80f4454b462aaa7 (diff)
downloadtor-dc516a543604e081583cbe725bc4b0a89768fc78.tar
tor-dc516a543604e081583cbe725bc4b0a89768fc78.tar.gz
Limit hidden service descriptors to at most 10 guard nodes.
Fixes bug 9002; bugfix on 0.1.1.11-alpha (which introduced guard nodes), or on 0.0.6pre1 (which introduced hidden services).
Diffstat (limited to 'src')
-rw-r--r--src/or/rendcommon.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/src/or/rendcommon.c b/src/or/rendcommon.c
index 4722690c1..812fce973 100644
--- a/src/or/rendcommon.c
+++ b/src/or/rendcommon.c
@@ -1002,6 +1002,10 @@ rend_cache_lookup_v2_desc_as_dir(const char *desc_id, const char **desc)
return 0;
}
+/* Do not allow more than this many introduction points in a hidden service
+ * descriptor */
+#define MAX_INTRO_POINTS 10
+
/** Parse *desc, calculate its service id, and store it in the cache.
* If we have a newer v0 descriptor with the same ID, ignore this one.
* If we have an older descriptor with the same ID, replace it.
@@ -1070,6 +1074,15 @@ rend_cache_store(const char *desc, size_t desc_len, int published,
rend_service_descriptor_free(parsed);
return -1;
}
+ if (parsed->intro_nodes &&
+ smartlist_len(parsed->intro_nodes) > MAX_INTRO_POINTS) {
+ log_warn(LD_REND, "Found too many introduction points on a hidden "
+ "service descriptor for %s. This is probably a (misguided) "
+ "attempt to improve reliability, but it could also be an "
+ "attempt to do a guard enumeration attack. Rejecting.",
+ safe_str_client(query));
+ return -2;
+ }
tor_snprintf(key, sizeof(key), "0%s", query);
e = (rend_cache_entry_t*) strmap_get_lc(rend_cache, key);
if (e && e->parsed->timestamp > parsed->timestamp) {
@@ -1288,6 +1301,7 @@ rend_cache_store_v2_desc_as_client(const char *desc,
}
/* Decode/decrypt introduction points. */
if (intro_content) {
+ int n_intro_points;
if (rend_query->auth_type != REND_NO_AUTH &&
!tor_mem_is_zero(rend_query->descriptor_cookie,
sizeof(rend_query->descriptor_cookie))) {
@@ -1308,13 +1322,20 @@ rend_cache_store_v2_desc_as_client(const char *desc,
intro_size = ipos_decrypted_size;
}
}
- if (rend_parse_introduction_points(parsed, intro_content,
- intro_size) <= 0) {
+ n_intro_points = rend_parse_introduction_points(parsed, intro_content,
+ intro_size);
+ if (n_intro_points <= 0) {
log_warn(LD_REND, "Failed to parse introduction points. Either the "
"service has published a corrupt descriptor or you have "
"provided invalid authorization data.");
retval = -2;
goto err;
+ } else if (n_intro_points > MAX_INTRO_POINTS) {
+ log_warn(LD_REND, "Found too many introduction points on a hidden "
+ "service descriptor for %s. This is probably a (misguided) "
+ "attempt to improve reliability, but it could also be an "
+ "attempt to do a guard enumeration attack. Rejecting.",
+ safe_str_client(rend_query->onion_address));
}
} else {
log_info(LD_REND, "Descriptor does not contain any introduction points.");