commit 6e2eb0afdb34955583ed231058adbe06c4625b0f
parent afef059795ccdb2157709667614a3741b583e9ba
Author: Nick Mathewson <nickm@torproject.org>
Date: Mon, 15 May 2017 18:05:32 -0400
Merge branch 'prop140_aftermath_url_v3'
Diffstat:
3 files changed, 171 insertions(+), 44 deletions(-)
diff --git a/src/or/directory.c b/src/or/directory.c
@@ -3288,8 +3288,9 @@ write_http_response_header_impl(dir_connection_t *conn, ssize_t length,
/** As write_http_response_header_impl, but sets encoding and content-typed
* based on whether the response will be <b>compressed</b> or not. */
static void
-write_http_response_header(dir_connection_t *conn, ssize_t length,
- compress_method_t method, long cache_lifetime)
+write_http_response_headers(dir_connection_t *conn, ssize_t length,
+ compress_method_t method,
+ const char *extra_headers, long cache_lifetime)
{
const char *methodname = compression_method_get_name(method);
const char *doctype;
@@ -3300,10 +3301,19 @@ write_http_response_header(dir_connection_t *conn, ssize_t length,
write_http_response_header_impl(conn, length,
doctype,
methodname,
- NULL,
+ extra_headers,
cache_lifetime);
}
+/** As write_http_response_headers, but assumes extra_headers is NULL */
+static void
+write_http_response_header(dir_connection_t *conn, ssize_t length,
+ compress_method_t method,
+ long cache_lifetime)
+{
+ write_http_response_headers(conn, length, method, NULL, cache_lifetime);
+}
+
/** Array of compression methods to use (if supported) for serving
* precompressed data, ordered from best to worst. */
static compress_method_t srv_meth_pref_precompressed[] = {
@@ -3661,6 +3671,27 @@ warn_consensus_is_too_old(const struct consensus_cache_entry_t *consensus,
}
}
+/**
+ * Parse a single hex-encoded sha3-256 digest from <b>hex</b> into
+ * <b>digest</b>. Return 0 on success. On failure, report that the hash came
+ * from <b>location</b>, report that we are taking <b>action</b> with it, and
+ * return -1.
+ */
+static int
+parse_one_diff_hash(uint8_t *digest, const char *hex, const char *location,
+ const char *action)
+{
+ if (base16_decode((char*)digest, DIGEST256_LEN, hex, strlen(hex)) ==
+ DIGEST256_LEN) {
+ return 0;
+ } else {
+ log_fn(LOG_PROTOCOL_WARN, LD_DIR,
+ "%s contained bogus digest %s; %s.",
+ location, escaped(hex), action);
+ return -1;
+ }
+}
+
/** If there is an X-Or-Diff-From-Consensus header included in <b>headers</b>,
* set <b>digest_out<b> to a new smartlist containing every 256-bit
* hex-encoded digest listed in that header and return 0. Otherwise return
@@ -3678,13 +3709,9 @@ parse_or_diff_from_header(smartlist_t **digests_out, const char *headers)
SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, -1);
SMARTLIST_FOREACH_BEGIN(hex_digests, const char *, hex) {
uint8_t digest[DIGEST256_LEN];
- if (base16_decode((char*)digest, sizeof(digest), hex, strlen(hex)) ==
- DIGEST256_LEN) {
+ if (!parse_one_diff_hash(digest, hex, "X-Or-Diff-From-Consensus header",
+ "ignoring")) {
smartlist_add(*digests_out, tor_memdup(digest, sizeof(digest)));
- } else {
- log_fn(LOG_PROTOCOL_WARN, LD_DIR,
- "X-Or-Diff-From-Consensus header contained bogus digest %s; "
- "ignoring.", escaped(hex));
}
} SMARTLIST_FOREACH_END(hex);
SMARTLIST_FOREACH(hex_digests, char *, cp, tor_free(cp));
@@ -3805,60 +3832,158 @@ find_best_compression_method(unsigned compression_methods, int stream)
return NO_METHOD;
}
-/** Helper function for GET /tor/status-vote/current/consensus
+/** Encodes the results of parsing a consensus request to figure out what
+ * consensus, and possibly what diffs, the user asked for. */
+typedef struct {
+ /** name of the flavor to retrieve. */
+ char *flavor;
+ /** flavor to retrive, as enum. */
+ consensus_flavor_t flav;
+ /** plus-separated list of authority fingerprints; see
+ * client_likes_consensus(). Aliases the URL in the request passed to
+ * parse_consensus_request(). */
+ const char *want_fps;
+ /** Optionally, a smartlist of sha3 digests-as-signed of the consensuses
+ * to return a diff from. */
+ smartlist_t *diff_from_digests;
+ /** If true, never send a full consensus. If there is no diff, send
+ * a 404 instead. */
+ int diff_only;
+} parsed_consensus_request_t;
+
+/** Remove all data held in <b>req</b>. Do not free <b>req</b> itself, since
+ * it is stack-allocated. */
+static void
+parsed_consensus_request_clear(parsed_consensus_request_t *req)
+{
+ if (!req)
+ return;
+ tor_free(req->flavor);
+ if (req->diff_from_digests) {
+ SMARTLIST_FOREACH(req->diff_from_digests, uint8_t *, d, tor_free(d));
+ smartlist_free(req->diff_from_digests);
+ }
+ memset(req, 0, sizeof(parsed_consensus_request_t));
+}
+
+/**
+ * Parse the URL and relevant headers of <b>args</b> for a current-consensus
+ * request to learn what flavor of consensus we want, what keys it must be
+ * signed with, and what diffs we would accept (or demand) instead. Return 0
+ * on success and -1 on failure.
*/
static int
-handle_get_current_consensus(dir_connection_t *conn,
- const get_handler_args_t *args)
+parse_consensus_request(parsed_consensus_request_t *out,
+ const get_handler_args_t *args)
{
const char *url = args->url;
- const compress_method_t compress_method =
- find_best_compression_method(args->compression_supported, 0);
- const time_t if_modified_since = args->if_modified_since;
- int clear_spool = 0;
+ memset(out, 0, sizeof(parsed_consensus_request_t));
+ out->flav = FLAV_NS;
- /* v3 network status fetch. */
- long lifetime = NETWORKSTATUS_CACHE_LIFETIME;
+ const char CONSENSUS_URL_PREFIX[] = "/tor/status-vote/current/consensus/";
+ const char CONSENSUS_FLAVORED_PREFIX[] =
+ "/tor/status-vote/current/consensus-";
- time_t now = time(NULL);
- const char *want_fps = NULL;
- char *flavor = NULL;
- int flav = FLAV_NS;
-#define CONSENSUS_URL_PREFIX "/tor/status-vote/current/consensus/"
-#define CONSENSUS_FLAVORED_PREFIX "/tor/status-vote/current/consensus-"
/* figure out the flavor if any, and who we wanted to sign the thing */
+ const char *after_flavor = NULL;
+
if (!strcmpstart(url, CONSENSUS_FLAVORED_PREFIX)) {
const char *f, *cp;
f = url + strlen(CONSENSUS_FLAVORED_PREFIX);
cp = strchr(f, '/');
if (cp) {
- want_fps = cp+1;
- flavor = tor_strndup(f, cp-f);
+ after_flavor = cp+1;
+ out->flavor = tor_strndup(f, cp-f);
} else {
- flavor = tor_strdup(f);
+ out->flavor = tor_strdup(f);
}
- flav = networkstatus_parse_flavor_name(flavor);
+ int flav = networkstatus_parse_flavor_name(out->flavor);
if (flav < 0)
flav = FLAV_NS;
+ out->flav = flav;
} else {
if (!strcmpstart(url, CONSENSUS_URL_PREFIX))
- want_fps = url+strlen(CONSENSUS_URL_PREFIX);
+ after_flavor = url+strlen(CONSENSUS_URL_PREFIX);
+ }
+
+ /* see whether we've been asked explicitly for a diff from an older
+ * consensus. (The user might also have said that a diff would be okay,
+ * via X-Or-Diff-From-Consensus */
+ const char DIFF_COMPONENT[] = "diff/";
+ char *diff_hash_in_url = NULL;
+ if (after_flavor && !strcmpstart(after_flavor, DIFF_COMPONENT)) {
+ after_flavor += strlen(DIFF_COMPONENT);
+ const char *cp = strchr(after_flavor, '/');
+ if (cp) {
+ diff_hash_in_url = tor_strndup(after_flavor, cp-after_flavor);
+ out->want_fps = cp+1;
+ } else {
+ diff_hash_in_url = tor_strdup(after_flavor);
+ out->want_fps = NULL;
+ }
+ } else {
+ out->want_fps = after_flavor;
+ }
+
+ if (diff_hash_in_url) {
+ uint8_t diff_from[DIGEST256_LEN];
+ out->diff_from_digests = smartlist_new();
+ out->diff_only = 1;
+ if (!parse_one_diff_hash(diff_from, diff_hash_in_url, "URL",
+ "rejecting")) {
+ smartlist_add(out->diff_from_digests,
+ tor_memdup(diff_from, DIGEST256_LEN));
+ } else {
+ return -1;
+ }
+ } else {
+ parse_or_diff_from_header(&out->diff_from_digests, args->headers);
+ }
+
+ return 0;
+}
+
+/** Helper function for GET /tor/status-vote/current/consensus
+ */
+static int
+handle_get_current_consensus(dir_connection_t *conn,
+ const get_handler_args_t *args)
+{
+ const compress_method_t compress_method =
+ find_best_compression_method(args->compression_supported, 0);
+ const time_t if_modified_since = args->if_modified_since;
+ int clear_spool = 0;
+
+ /* v3 network status fetch. */
+ long lifetime = NETWORKSTATUS_CACHE_LIFETIME;
+
+ time_t now = time(NULL);
+ const char *want_fps = NULL;
+ parsed_consensus_request_t req;
+
+ if (parse_consensus_request(&req, args) < 0) {
+ write_http_status_line(conn, 404, "Couldn't parse request");
+ goto done;
}
struct consensus_cache_entry_t *cached_consensus = NULL;
- smartlist_t *diff_from_digests = NULL;
+
compress_method_t compression_used = NO_METHOD;
- if (!parse_or_diff_from_header(&diff_from_digests, args->headers)) {
- tor_assert(diff_from_digests);
- cached_consensus = find_best_diff(diff_from_digests, flav,
+ if (req.diff_from_digests) {
+ cached_consensus = find_best_diff(req.diff_from_digests, req.flav,
args->compression_supported,
&compression_used);
- SMARTLIST_FOREACH(diff_from_digests, uint8_t *, d, tor_free(d));
- smartlist_free(diff_from_digests);
+ }
+
+ if (req.diff_only && !cached_consensus) {
+ write_http_status_line(conn, 404, "No such diff available");
+ // XXXX warn_consensus_is_too_old(v, req.flavor, now);
+ geoip_note_ns_response(GEOIP_REJECT_NOT_FOUND);
+ goto done;
}
if (! cached_consensus) {
- cached_consensus = find_best_consensus(flav,
+ cached_consensus = find_best_consensus(req.flav,
args->compression_supported,
&compression_used);
}
@@ -3875,9 +4000,8 @@ handle_get_current_consensus(dir_connection_t *conn,
if (cached_consensus && have_valid_until &&
!networkstatus_valid_until_is_reasonably_live(valid_until, now)) {
write_http_status_line(conn, 404, "Consensus is too old");
- warn_consensus_is_too_old(cached_consensus, flavor, now);
+ warn_consensus_is_too_old(cached_consensus, req.flavor, now);
geoip_note_ns_response(GEOIP_REJECT_NOT_FOUND);
- tor_free(flavor);
goto done;
}
@@ -3886,7 +4010,6 @@ handle_get_current_consensus(dir_connection_t *conn,
write_http_status_line(conn, 404, "Consensus not signed by sufficient "
"number of requested authorities");
geoip_note_ns_response(GEOIP_REJECT_NOT_ENOUGH_SIGS);
- tor_free(flavor);
goto done;
}
@@ -3898,7 +4021,6 @@ handle_get_current_consensus(dir_connection_t *conn,
spooled = spooled_resource_new_from_cache_entry(cached_consensus);
smartlist_add(conn->spool, spooled);
}
- tor_free(flavor);
}
lifetime = (have_fresh_until && fresh_until > now) ? fresh_until - now : 0;
@@ -3944,14 +4066,19 @@ handle_get_current_consensus(dir_connection_t *conn,
DIRREQ_DIRECT);
}
+ /* Use this header to tell caches that the response depends on the
+ * X-Or-Diff-From-Consensus header (or lack thereof). */
+ const char vary_header[] = "Vary: X-Or-Diff-From-Consensus\r\n";
+
clear_spool = 0;
// The compress_method might have been NO_METHOD, but we store the data
// compressed. Decompress them using `compression_used`. See fallback code in
// find_best_consensus() and find_best_diff().
- write_http_response_header(conn, -1,
+ write_http_response_headers(conn, -1,
compress_method == NO_METHOD ?
NO_METHOD : compression_used,
+ vary_header,
smartlist_len(conn->spool) == 1 ? lifetime : 0);
if (compress_method == NO_METHOD)
@@ -3964,6 +4091,7 @@ handle_get_current_consensus(dir_connection_t *conn,
goto done;
done:
+ parsed_consensus_request_clear(&req);
if (clear_spool) {
dir_conn_clear_spool(conn);
}
diff --git a/src/or/protover.c b/src/or/protover.c
@@ -288,7 +288,7 @@ protover_get_supported_protocols(void)
return
"Cons=1-2 "
"Desc=1-2 "
- "DirCache=1 "
+ "DirCache=1-2 "
"HSDir=1-2 "
"HSIntro=3-4 "
"HSRend=1-2 "
diff --git a/src/test/test_dir_handle_get.c b/src/test/test_dir_handle_get.c
@@ -64,6 +64,7 @@ new_dir_conn(void)
{
dir_connection_t *conn = dir_connection_new(AF_INET);
tor_addr_from_ipv4h(&conn->base_.addr, 0x7f000001);
+ TO_CONN(conn)->address = tor_strdup("127.0.0.1");
return conn;
}
@@ -1718,7 +1719,6 @@ test_dir_handle_get_status_vote_current_consensus_too_old(void *data)
MOCK(networkstatus_get_latest_consensus_by_flavor, mock_ns_get_by_flavor);
conn = new_dir_conn();
- TO_CONN(conn)->address = tor_strdup("127.0.0.1");
setup_capture_of_logs(LOG_WARN);
@@ -1815,7 +1815,6 @@ status_vote_current_consensus_ns_test(char **header, char **body,
tt_str_op("ab", OP_EQ, geoip_get_country_name(1));
conn = new_dir_conn();
- TO_CONN(conn)->address = tor_strdup("127.0.0.1");
tt_int_op(0, OP_EQ, directory_handle_command_get(conn,
GET("/tor/status-vote/current/consensus-ns"), NULL, 0));
