snow/wireguard-go
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device: timers: seed unsafe rng before use for jitter

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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 <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2021-10-28 13:34:21 +02:00
parent e42c6c4bc2
commit 60683d7361
1 changed files with 11 additions and 3 deletions
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14
device/timers.go
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@ -8,12 +8,20 @@
package device package device
import ( import (
"math/rand" "crypto/rand"
unsafeRand "math/rand"
"sync" "sync"
"sync/atomic" "sync/atomic"
"time" "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. // A Timer manages time-based aspects of the WireGuard protocol.
// Timer roughly copies the interface of the Linux kernel's struct timer_list. // Timer roughly copies the interface of the Linux kernel's struct timer_list.
type Timer struct { type Timer struct {
@ -144,7 +152,7 @@ func expiredPersistentKeepalive(peer *Peer) {
/* Should be called after an authenticated data packet is sent. */ /* Should be called after an authenticated data packet is sent. */
func (peer *Peer) timersDataSent() { func (peer *Peer) timersDataSent() {
if peer.timersActive() && !peer.timers.newHandshake.IsPending() { 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. */ /* Should be called after a handshake initiation message is sent. */
func (peer *Peer) timersHandshakeInitiated() { func (peer *Peer) timersHandshakeInitiated() {
if peer.timersActive() { 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)))
} }
} }