From: Tobias Brunner <tobias@strongswan.org>
Date: Tue, 8 Jun 2021 13:33:36 +0000 (+0200)
Subject: receiver: Avoid division by 0 after system start if CLOCK_MONOTONIC is used
X-Git-Tag: 5.9.3dr4~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a90716cd4d5bd6e580ef3a671ac37378c6c3acca;p=thirdparty%2Fstrongswan.git

receiver: Avoid division by 0 after system start if CLOCK_MONOTONIC is used

Depending on how CLOCK_MONOTONIC is implemented, time_monotonic() might
return 0 within 1 second after the system is started.  If that's the
case, we just default to 0 for now to avoid a crash (doesn't "hide" the
system time, but it's only the uptime anyway in this case).

Closes strongswan/strongswan#435.
---

diff --git a/src/libcharon/network/receiver.c b/src/libcharon/network/receiver.c
index b191ed8d6a..ab520fea61 100644
--- a/src/libcharon/network/receiver.c
+++ b/src/libcharon/network/receiver.c
@@ -629,7 +629,7 @@ receiver_t *receiver_create()
 		},
 		.esp_cb_mutex = mutex_create(MUTEX_TYPE_DEFAULT),
 		.secret_switch = now,
-		.secret_offset = random() % now,
+		.secret_offset = now ? random() % now : 0,
 	);
 
 	if (lib->settings->get_bool(lib->settings,