commit 272dd90b5c9998130f65edd65df1c066dc4599aa Author: Robert Ransom rransom.8774@gmail.com Date: Sun Oct 30 02:13:46 2011 -0700

Ignore timestamps of INTRODUCE2 cells --- changes/bug3460 | 11 +++++++++++ src/or/or.h | 6 +++--- src/or/rendservice.c | 12 +----------- 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/changes/bug3460 b/changes/bug3460 new file mode 100644 index 0000000..4fbca01 --- /dev/null +++ b/changes/bug3460 @@ -0,0 +1,11 @@ + o Major bugfixes: + + - Ignore the timestamps of INTRODUCE2 cells received by a hidden + service. Previously, hidden services would check that the + timestamp was within 30 minutes of their system clock, so that + services could keep only INTRODUCE2 cells they had received in + the last hour in their replay-detection cache. Bugfix on + 0.2.1.6-alpha, when the v3 intro-point protocol (the first one + which sent a timestamp field in the INTRODUCE2 cell) was + introduced; fixes bug 3460. + diff --git a/src/or/or.h b/src/or/or.h index b53220f..8455dc8 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -756,9 +756,9 @@ typedef struct rend_data_t { char rend_cookie[REND_COOKIE_LEN]; } rend_data_t;

-/** Time interval for tracking possible replays of INTRODUCE2 cells. - * Incoming cells with timestamps half of this interval in the past or - * future are dropped immediately. */ +/** Time interval for tracking replays of DH public keys received in + * INTRODUCE2 cells. Used only to avoid launching multiple + * simultaneous attempts to connect to the same rendezvous point. */ #define REND_REPLAY_TIME_INTERVAL (60 * 60)

/** Used to indicate which way a cell is going on a circuit. */ diff --git a/src/or/rendservice.c b/src/or/rendservice.c index 413d4f6..4680617 100644 --- a/src/or/rendservice.c +++ b/src/or/rendservice.c @@ -1037,7 +1037,6 @@ rend_service_introduce(origin_circuit_t *circuit, const uint8_t *request, len = r; if (*buf == 3) { /* Version 3 INTRODUCE2 cell. */ - time_t ts = 0; v3_shift = 1; auth_type = buf[1]; switch (auth_type) { @@ -1059,17 +1058,8 @@ rend_service_introduce(origin_circuit_t *circuit, const uint8_t *request, log_info(LD_REND, "Unknown authorization type '%d'", auth_type); }

- /* Check timestamp. */ - ts = ntohl(get_uint32(buf+1+v3_shift)); + /* Skip the timestamp field. We no longer use it. */ v3_shift += 4; - if ((now - ts) < -1 * REND_REPLAY_TIME_INTERVAL / 2 || - (now - ts) > REND_REPLAY_TIME_INTERVAL / 2) { - /* This is far more likely to mean that a client's clock is - * skewed than that a replay attack is in progress. */ - log_info(LD_REND, "INTRODUCE2 cell is too %s. Discarding.", - (now - ts) < 0 ? "old" : "new"); - return -1; - } } if (*buf == 2 || *buf == 3) { /* Version 2 INTRODUCE2 cell. */