From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Thu, 22 Jul 2021 16:23:37 +0000 (+0200)
Subject: daemon/session: fix an issue with timers
X-Git-Tag: v5.4.0~3^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=91ce241ac548574014e68d2e036afa83137448e2;p=thirdparty%2Fknot-resolver.git

daemon/session: fix an issue with timers

The practical problem was also mitigated by libuv >= 1.32.0 (2ee2d46)
---

diff --git a/NEWS b/NEWS
index 0c27d6c5a..6c4d2b061 100644
--- a/NEWS
+++ b/NEWS
@@ -10,6 +10,7 @@ Bugfixes
 - trust_anchors.set_insecure: improve precision (#673, !1177)
 - plug memory leaks related to TCP (!1182)
 - policy.FLAGS: fix not applying properly in edge cases (!1179)
+- fix a crash with older libuv inside timer processing (!1195)
 
 Incompatible changes
 --------------------
diff --git a/daemon/session.c b/daemon/session.c
index a0bf23f3f..668295ca0 100644
--- a/daemon/session.c
+++ b/daemon/session.c
@@ -503,18 +503,24 @@ int session_timer_start(struct session *session, uv_timer_cb cb,
 			uint64_t timeout, uint64_t repeat)
 {
 	uv_timer_t *timer = &session->timeout;
+	// Session might be closing and get here e.g. through a late on_send callback.
+	const bool is_closing = uv_is_closing((uv_handle_t *)timer);
+	if (is_closing || kr_fails_assert(is_closing == session->sflags.closing))
+		return kr_error(EINVAL);
+
 	if (kr_fails_assert(timer->data == session))
 		return kr_error(EINVAL);
 	int ret = uv_timer_start(timer, cb, timeout, repeat);
 	if (ret != 0) {
 		uv_timer_stop(timer);
-		return kr_error(ENOMEM);
+		return kr_error(ret);
 	}
-	return 0;
+	return kr_ok();
 }
 
 int session_timer_restart(struct session *session)
 {
+	kr_require(!uv_is_closing((uv_handle_t *)&session->timeout));
 	return uv_timer_again(&session->timeout);
 }