Merge branch 'maint-0.4.7'

This commit is contained in:
David Goulet 2022-08-02 15:31:00 -04:00
commit f51c68729f
2 changed files with 18 additions and 1 deletions

8
changes/bug40644 Normal file
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@ -0,0 +1,8 @@
o Minor bugfixes (congestion control):
- Add a check for an integer underflow condition that might
happen in cases where the system clock is stopped, the
ORconn is blocked, and the endpoint sends more than a
congestion window worth of non-data control cells at once.
This would cause a large congestion window to be calculated
instead of a small one. No security impact. Fixes bug 40644;
bugfix on 0.4.7.5-alpha.

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@ -882,10 +882,19 @@ congestion_control_update_circuit_bdp(congestion_control_t *cc,
if (!cc->ewma_rtt_usec) {
uint64_t cwnd = cc->cwnd;
tor_assert_nonfatal(cc->cwnd <= cwnd_max);
/* If the channel is blocked, keep subtracting off the chan_q
* until we hit the min cwnd. */
if (blocked_on_chan) {
cwnd = MAX(cwnd - chan_q, cc->cwnd_min);
/* Cast is fine because we're less than int32 */
if (chan_q >= (int64_t)cwnd) {
log_notice(LD_CIRC,
"Clock stall with large chanq: %d %"PRIu64, chan_q, cwnd);
cwnd = cc->cwnd_min;
} else {
cwnd = MAX(cwnd - chan_q, cc->cwnd_min);
}
cc->blocked_chan = 1;
} else {
cc->blocked_chan = 0;