[tor-commits] [tor/master] Use digest256map for computing microdescriptor downloads
nickm at torproject.org
nickm at torproject.org
Sat Nov 1 21:05:31 UTC 2014
commit dc05b8549a73064337020eb3f0d8d91c8149518a
Author: Nick Mathewson <nickm at torproject.org>
Date: Fri Oct 31 11:32:32 2014 -0400
Use digest256map for computing microdescriptor downloads
---
changes/bug13399 | 7 +++++++
src/or/microdesc.c | 36 ++++++++++++++++++------------------
src/or/microdesc.h | 2 +-
src/or/routerlist.c | 30 ++++++++++++++++++------------
src/or/routerlist.h | 2 +-
5 files changed, 45 insertions(+), 32 deletions(-)
diff --git a/changes/bug13399 b/changes/bug13399
new file mode 100644
index 0000000..bbd0b23
--- /dev/null
+++ b/changes/bug13399
@@ -0,0 +1,7 @@
+ o Minor bugfixes:
+ - Use a full 256 bits of the SHA256 digest of a microdescriptor when
+ computing which microdescriptors to download. This keeps us from
+ erroneous download behavior if two microdescriptor digests ever have
+ the same first 160 bits. Fixes part of bug 13399; bugfix on
+ 0.2.3.1-alpha.
+
diff --git a/src/or/microdesc.c b/src/or/microdesc.c
index e8c11a9..7b82600 100644
--- a/src/or/microdesc.c
+++ b/src/or/microdesc.c
@@ -163,19 +163,18 @@ microdescs_add_to_cache(microdesc_cache_t *cache,
md->last_listed = listed_at);
}
if (requested_digests256) {
- digestmap_t *requested; /* XXXX actually we should just use a
- digest256map */
- requested = digestmap_new();
+ digest256map_t *requested;
+ requested = digest256map_new();
/* Set requested[d] to DIGEST_REQUESTED for every md we requested. */
- SMARTLIST_FOREACH(requested_digests256, const char *, cp,
- digestmap_set(requested, cp, DIGEST_REQUESTED));
+ SMARTLIST_FOREACH(requested_digests256, const uint8_t *, cp,
+ digest256map_set(requested, cp, DIGEST_REQUESTED));
/* Set requested[d] to DIGEST_INVALID for every md we requested which we
* will never be able to parse. Remove the ones we didn't request from
* invalid_digests.
*/
- SMARTLIST_FOREACH_BEGIN(invalid_digests, char *, cp) {
- if (digestmap_get(requested, cp)) {
- digestmap_set(requested, cp, DIGEST_INVALID);
+ SMARTLIST_FOREACH_BEGIN(invalid_digests, uint8_t *, cp) {
+ if (digest256map_get(requested, cp)) {
+ digest256map_set(requested, cp, DIGEST_INVALID);
} else {
tor_free(cp);
SMARTLIST_DEL_CURRENT(invalid_digests, cp);
@@ -185,8 +184,9 @@ microdescs_add_to_cache(microdesc_cache_t *cache,
* ones we never requested from the 'descriptors' smartlist.
*/
SMARTLIST_FOREACH_BEGIN(descriptors, microdesc_t *, md) {
- if (digestmap_get(requested, md->digest)) {
- digestmap_set(requested, md->digest, DIGEST_RECEIVED);
+ if (digest256map_get(requested, (const uint8_t*)md->digest)) {
+ digest256map_set(requested, (const uint8_t*)md->digest,
+ DIGEST_RECEIVED);
} else {
log_fn(LOG_PROTOCOL_WARN, LD_DIR, "Received non-requested microdesc");
microdesc_free(md);
@@ -195,14 +195,14 @@ microdescs_add_to_cache(microdesc_cache_t *cache,
} SMARTLIST_FOREACH_END(md);
/* Remove the ones we got or the invalid ones from requested_digests256.
*/
- SMARTLIST_FOREACH_BEGIN(requested_digests256, char *, cp) {
- void *status = digestmap_get(requested, cp);
+ SMARTLIST_FOREACH_BEGIN(requested_digests256, uint8_t *, cp) {
+ void *status = digest256map_get(requested, cp);
if (status == DIGEST_RECEIVED || status == DIGEST_INVALID) {
tor_free(cp);
SMARTLIST_DEL_CURRENT(requested_digests256, cp);
}
} SMARTLIST_FOREACH_END(cp);
- digestmap_free(requested, NULL);
+ digest256map_free(requested, NULL);
}
/* For every requested microdescriptor that was unparseable, mark it
@@ -794,7 +794,7 @@ microdesc_average_size(microdesc_cache_t *cache)
* smartlist. Omit all microdescriptors whose digest appear in <b>skip</b>. */
smartlist_t *
microdesc_list_missing_digest256(networkstatus_t *ns, microdesc_cache_t *cache,
- int downloadable_only, digestmap_t *skip)
+ int downloadable_only, digest256map_t *skip)
{
smartlist_t *result = smartlist_new();
time_t now = time(NULL);
@@ -806,7 +806,7 @@ microdesc_list_missing_digest256(networkstatus_t *ns, microdesc_cache_t *cache,
!download_status_is_ready(&rs->dl_status, now,
get_options()->TestingMicrodescMaxDownloadTries))
continue;
- if (skip && digestmap_get(skip, rs->descriptor_digest))
+ if (skip && digest256map_get(skip, (const uint8_t*)rs->descriptor_digest))
continue;
if (tor_mem_is_zero(rs->descriptor_digest, DIGEST256_LEN))
continue;
@@ -831,7 +831,7 @@ update_microdesc_downloads(time_t now)
const or_options_t *options = get_options();
networkstatus_t *consensus;
smartlist_t *missing;
- digestmap_t *pending;
+ digest256map_t *pending;
if (should_delay_dir_fetches(options, NULL))
return;
@@ -845,14 +845,14 @@ update_microdesc_downloads(time_t now)
if (!we_fetch_microdescriptors(options))
return;
- pending = digestmap_new();
+ pending = digest256map_new();
list_pending_microdesc_downloads(pending);
missing = microdesc_list_missing_digest256(consensus,
get_microdesc_cache(),
1,
pending);
- digestmap_free(pending, NULL);
+ digest256map_free(pending, NULL);
launch_descriptor_downloads(DIR_PURPOSE_FETCH_MICRODESC,
missing, NULL, now);
diff --git a/src/or/microdesc.h b/src/or/microdesc.h
index f858d9f..fdfe892 100644
--- a/src/or/microdesc.h
+++ b/src/or/microdesc.h
@@ -37,7 +37,7 @@ size_t microdesc_average_size(microdesc_cache_t *cache);
smartlist_t *microdesc_list_missing_digest256(networkstatus_t *ns,
microdesc_cache_t *cache,
int downloadable_only,
- digestmap_t *skip);
+ digest256map_t *skip);
void microdesc_free_(microdesc_t *md, const char *fname, int line);
#define microdesc_free(md) \
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index 0099486..214b7c4 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -79,6 +79,7 @@ static const char *signed_descriptor_get_body_impl(
const signed_descriptor_t *desc,
int with_annotations);
static void list_pending_downloads(digestmap_t *result,
+ digest256map_t *result256,
int purpose, const char *prefix);
static void list_pending_fpsk_downloads(fp_pair_map_t *result);
static void launch_dummy_descriptor_download_as_needed(time_t now,
@@ -717,7 +718,8 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now)
* First, we get the lists of already pending downloads so we don't
* duplicate effort.
*/
- list_pending_downloads(pending_id, DIR_PURPOSE_FETCH_CERTIFICATE, "fp/");
+ list_pending_downloads(pending_id, NULL,
+ DIR_PURPOSE_FETCH_CERTIFICATE, "fp/");
list_pending_fpsk_downloads(pending_cert);
/*
@@ -4268,7 +4270,7 @@ clear_dir_servers(void)
* corresponding elements of <b>result</b> to a nonzero value.
*/
static void
-list_pending_downloads(digestmap_t *result,
+list_pending_downloads(digestmap_t *result, digest256map_t *result256,
int purpose, const char *prefix)
{
const size_t p_len = strlen(prefix);
@@ -4278,7 +4280,7 @@ list_pending_downloads(digestmap_t *result,
if (purpose == DIR_PURPOSE_FETCH_MICRODESC)
flags = DSR_DIGEST256|DSR_BASE64;
- tor_assert(result);
+ tor_assert(result || result256);
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
if (conn->type == CONN_TYPE_DIR &&
@@ -4291,11 +4293,19 @@ list_pending_downloads(digestmap_t *result,
}
} SMARTLIST_FOREACH_END(conn);
- SMARTLIST_FOREACH(tmp, char *, d,
+ if (result) {
+ SMARTLIST_FOREACH(tmp, char *, d,
{
digestmap_set(result, d, (void*)1);
tor_free(d);
});
+ } else if (result256) {
+ SMARTLIST_FOREACH(tmp, uint8_t *, d,
+ {
+ digest256map_set(result256, d, (void*)1);
+ tor_free(d);
+ });
+ }
smartlist_free(tmp);
}
@@ -4307,20 +4317,16 @@ list_pending_descriptor_downloads(digestmap_t *result, int extrainfo)
{
int purpose =
extrainfo ? DIR_PURPOSE_FETCH_EXTRAINFO : DIR_PURPOSE_FETCH_SERVERDESC;
- list_pending_downloads(result, purpose, "d/");
+ list_pending_downloads(result, NULL, purpose, "d/");
}
/** For every microdescriptor we are currently downloading by descriptor
- * digest, set result[d] to (void*)1. (Note that microdescriptor digests
- * are 256-bit, and digestmap_t only holds 160-bit digests, so we're only
- * getting the first 20 bytes of each digest here.)
- *
- * XXXX Let there be a digestmap256_t, and use that instead.
+ * digest, set result[d] to (void*)1.
*/
void
-list_pending_microdesc_downloads(digestmap_t *result)
+list_pending_microdesc_downloads(digest256map_t *result)
{
- list_pending_downloads(result, DIR_PURPOSE_FETCH_MICRODESC, "d/");
+ list_pending_downloads(NULL, result, DIR_PURPOSE_FETCH_MICRODESC, "d/");
}
/** For every certificate we are currently downloading by (identity digest,
diff --git a/src/or/routerlist.h b/src/or/routerlist.h
index ac6f95b..c6151de 100644
--- a/src/or/routerlist.h
+++ b/src/or/routerlist.h
@@ -196,7 +196,7 @@ int hid_serv_get_responsible_directories(smartlist_t *responsible_dirs,
int hid_serv_acting_as_directory(void);
int hid_serv_responsible_for_desc_id(const char *id);
-void list_pending_microdesc_downloads(digestmap_t *result);
+void list_pending_microdesc_downloads(digest256map_t *result);
void launch_descriptor_downloads(int purpose,
smartlist_t *downloadable,
const routerstatus_t *source,
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