snow/wireguard-go
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send: account for zero mtu

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Don't divide by zero.
This commit is contained in:
Jason A. Donenfeld 2020-02-13 16:20:56 +01:00
parent 6ed56ff2df
commit 9cbcff10dd
1 changed files with 12 additions and 4 deletions
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10
device/send.go
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@ -515,11 +515,19 @@ func (device *Device) RoutineEncryption() {
// pad content to multiple of 16 // pad content to multiple of 16
mtu := int(atomic.LoadInt32(&device.tun.mtu)) mtu := int(atomic.LoadInt32(&device.tun.mtu))
lastUnit := len(elem.packet) % mtu var paddedSize int
if mtu == 0 {
paddedSize = (len(elem.packet) + PaddingMultiple - 1) & ^(PaddingMultiple - 1)
} else {
lastUnit := len(elem.packet)
if lastUnit > mtu {
lastUnit %= mtu
}
paddedSize := (lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1) paddedSize := (lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1)
if paddedSize > mtu { if paddedSize > mtu {
paddedSize = mtu paddedSize = mtu
} }
}
for i := len(elem.packet); i < paddedSize; i++ { for i := len(elem.packet); i < paddedSize; i++ {
elem.packet = append(elem.packet, 0) elem.packet = append(elem.packet, 0)
} }