snow/wireguard-go
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device: rework padding calculation and don't shadow paddedSize

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Reported-by: Jayakumar S <jayakumar82.s@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2020-05-18 14:32:31 -06:00
parent f60b3919be
commit 99eb7896be
1 changed files with 17 additions and 15 deletions
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32
device/send.go
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@ -448,6 +448,21 @@ func (peer *Peer) RoutineNonce() {
} }
} }
func calculatePaddingSize(packetSize, mtu int) int {
lastUnit := packetSize
if mtu == 0 {
return ((lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1)) - lastUnit
}
if lastUnit > mtu {
lastUnit %= mtu
}
paddedSize := ((lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1))
if paddedSize > mtu {
paddedSize = mtu
}
return paddedSize - lastUnit
}
/* Encrypts the elements in the queue /* Encrypts the elements in the queue
* and marks them for sequential consumption (by releasing the mutex) * and marks them for sequential consumption (by releasing the mutex)
* *
@ -514,21 +529,8 @@ func (device *Device) RoutineEncryption() {
// pad content to multiple of 16 // pad content to multiple of 16
mtu := int(atomic.LoadInt32(&device.tun.mtu)) paddingSize := calculatePaddingSize(len(elem.packet), int(atomic.LoadInt32(&device.tun.mtu)))
var paddedSize int for i := 0; i < paddingSize; i++ {
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)
if paddedSize > mtu {
paddedSize = mtu
}
}
for i := len(elem.packet); i < paddedSize; i++ {
elem.packet = append(elem.packet, 0) elem.packet = append(elem.packet, 0)
} }