From 60683d73614862ba93895bf8a5aebc1e97a4ec52 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Thu, 28 Oct 2021 13:34:21 +0200 Subject: [PATCH] device: timers: seed unsafe rng before use for jitter Forgetting to seed the unsafe rng, the jitter before followed a fixed pattern, which didn't help when a fleet of computers all boot at once. Signed-off-by: Jason A. Donenfeld --- device/timers.go | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/device/timers.go b/device/timers.go index ee191e5..aa6f28a 100644 --- a/device/timers.go +++ b/device/timers.go @@ -8,12 +8,20 @@ package device import ( - "math/rand" + "crypto/rand" + unsafeRand "math/rand" "sync" "sync/atomic" "time" + "unsafe" ) +func init() { + var seed int64 + rand.Read(unsafe.Slice((*byte)(unsafe.Pointer(&seed)), unsafe.Sizeof(seed))) + unsafeRand.Seed(seed) +} + // A Timer manages time-based aspects of the WireGuard protocol. // Timer roughly copies the interface of the Linux kernel's struct timer_list. type Timer struct { @@ -144,7 +152,7 @@ func expiredPersistentKeepalive(peer *Peer) { /* Should be called after an authenticated data packet is sent. */ func (peer *Peer) timersDataSent() { if peer.timersActive() && !peer.timers.newHandshake.IsPending() { - peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout + time.Millisecond*time.Duration(rand.Int31n(RekeyTimeoutJitterMaxMs))) + peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout + time.Millisecond*time.Duration(unsafeRand.Int63n(RekeyTimeoutJitterMaxMs))) } } @@ -176,7 +184,7 @@ func (peer *Peer) timersAnyAuthenticatedPacketReceived() { /* Should be called after a handshake initiation message is sent. */ func (peer *Peer) timersHandshakeInitiated() { if peer.timersActive() { - peer.timers.retransmitHandshake.Mod(RekeyTimeout + time.Millisecond*time.Duration(rand.Int31n(RekeyTimeoutJitterMaxMs))) + peer.timers.retransmitHandshake.Mod(RekeyTimeout + time.Millisecond*time.Duration(unsafeRand.Int63n(RekeyTimeoutJitterMaxMs))) } }