From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sun, 6 Feb 2022 14:25:07 +0000 (+0900)
Subject: sd-dhcp6-client: fix overflow in calculating timeout value
X-Git-Tag: v251-rc1~291^2~42
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=cc5184823fde84768d10ae42f20f843b65d52adc;p=thirdparty%2Fsystemd.git

sd-dhcp6-client: fix overflow in calculating timeout value
---

diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
index ff7e04bbdc6..a830b44f76d 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -808,6 +808,10 @@ static int client_send_message(sd_dhcp6_client *client, usec_t time_now) {
         return 0;
 }
 
+static usec_t client_timeout_compute_random(usec_t val) {
+        return usec_sub_unsigned(val, random_u64_range(val / 10));
+}
+
 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
         sd_dhcp6_client *client = userdata;
 
@@ -861,10 +865,6 @@ static int client_timeout_resend_expire(sd_event_source *s, uint64_t usec, void
         return 0;
 }
 
-static usec_t client_timeout_compute_random(usec_t val) {
-        return val - (random_u32() % USEC_PER_SEC) * val / 10 / USEC_PER_SEC;
-}
-
 static int client_timeout_resend(sd_event_source *s, uint64_t usec, void *userdata) {
         int r = 0;
         sd_dhcp6_client *client = userdata;