commit f75f9c2b2958e6179415665865dec6466726a8ce
author Victor Boivie <boivie@webrtc.org> Fri Sep 24 09:50:29 2021
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Sep 27 10:52:46 2021
tree 4522ab098a11d9852d0f5da04403dc9d1e4730d2
parent 29b4049abc5928d995b51f8614dfb27dc7e3359e

dcsctp: Avoid integer overflow in HEARTBEAT-ACK

When a HEARTBEAT is sent out, the current timestamp is stored in the
parameter that will be returned by the HEARTBEAT-ACK. If the timestamp
from the HEARTBEAT-ACK would be from the future (either by jumping
clocks, bit errors, exploiting peer or a fuzzer), the measured RTT would
become really large, and when it was calculated, it would result in an
integer overflow; a wrapping subtraction.

This isn't a problem, as RetransmissionTimeout::ObserveRTT method would
discard measurements that were negative or too large, but it would
trigger an UBSAN violation.

Adding an additional check so that the subtraction doesn't ever wrap.

Bug: chromium:1252515
Change-Id: I1f97b1e773a4639b8193a528716ebd6a27fcb740
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/232904
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35095}