From afb5d8b2db432b8433ba80a1206ae41ef4f4ea8b Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Tue, 29 Sep 2020 14:19:17 +0200 Subject: ntpd: fix the case where two replies received at once and first one causes a step function old new delta recv_and_process_peer_pkt 2476 2486 +10 Signed-off-by: Denys Vlasenko --- networking/ntpd.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/networking/ntpd.c b/networking/ntpd.c index d721fe80c..44e711232 100644 --- a/networking/ntpd.c +++ b/networking/ntpd.c @@ -2025,6 +2025,15 @@ recv_and_process_peer_pkt(peer_t *p) offset = 0; + /* The below can happen as follows: + * = we receive two peer rsponses at once. + * = recv_and_process_peer_pkt(PEER1) -> update_local_clock() + * -> step_time() and it closes all other fds, sets all ->fd to -1. + * = recv_and_process_peer_pkt(PEER2) sees PEER2->fd == -1 + */ + if (p->p_fd < 0) + return; + /* We can recvfrom here and check from.IP, but some multihomed * ntp servers reply from their *other IP*. * TODO: maybe we should check at least what we can: from.port == 123? -- cgit v1.2.3