change how nonce is tracked, so we allow packets if we've recently received a highest nonce ever, but don't bother tracking all received nonce values, this means duplicate packets are possible but only for a small window of time (and significantly reduces memory usage per session)

This commit is contained in:
Arceliar 2019-08-31 17:39:05 -05:00
parent 0806f3e6ea
commit cabdc27a54

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@ -6,7 +6,6 @@ package yggdrasil
import ( import (
"bytes" "bytes"
"container/heap"
"sync" "sync"
"time" "time"
@ -20,57 +19,40 @@ import (
// Duration that we keep track of old nonces per session, to allow some out-of-order packet delivery // Duration that we keep track of old nonces per session, to allow some out-of-order packet delivery
const nonceWindow = time.Second const nonceWindow = time.Second
// A heap of nonces, used with a map[nonce]time to allow out-of-order packets a little time to arrive without rejecting them
type nonceHeap []crypto.BoxNonce
func (h nonceHeap) Len() int { return len(h) }
func (h nonceHeap) Less(i, j int) bool { return h[i].Minus(&h[j]) < 0 }
func (h nonceHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
func (h *nonceHeap) Push(x interface{}) { *h = append(*h, x.(crypto.BoxNonce)) }
func (h *nonceHeap) Pop() interface{} {
l := len(*h)
var n crypto.BoxNonce
n, *h = (*h)[l-1], (*h)[:l-1]
return n
}
func (h nonceHeap) peek() *crypto.BoxNonce { return &h[0] }
// All the information we know about an active session. // All the information we know about an active session.
// This includes coords, permanent and ephemeral keys, handles and nonces, various sorts of timing information for timeout and maintenance, and some metadata for the admin API. // This includes coords, permanent and ephemeral keys, handles and nonces, various sorts of timing information for timeout and maintenance, and some metadata for the admin API.
type sessionInfo struct { type sessionInfo struct {
phony.Inbox // Protects all of the below, use it any time you read/change the contents of a session phony.Inbox // Protects all of the below, use it any time you read/change the contents of a session
sessions *sessions // sessions *sessions //
theirAddr address.Address // theirAddr address.Address //
theirSubnet address.Subnet // theirSubnet address.Subnet //
theirPermPub crypto.BoxPubKey // theirPermPub crypto.BoxPubKey //
theirSesPub crypto.BoxPubKey // theirSesPub crypto.BoxPubKey //
mySesPub crypto.BoxPubKey // mySesPub crypto.BoxPubKey //
mySesPriv crypto.BoxPrivKey // mySesPriv crypto.BoxPrivKey //
sharedPermKey crypto.BoxSharedKey // used for session pings sharedPermKey crypto.BoxSharedKey // used for session pings
sharedSesKey crypto.BoxSharedKey // derived from session keys sharedSesKey crypto.BoxSharedKey // derived from session keys
theirHandle crypto.Handle // theirHandle crypto.Handle //
myHandle crypto.Handle // myHandle crypto.Handle //
theirNonce crypto.BoxNonce // theirNonce crypto.BoxNonce //
theirNonceHeap nonceHeap // priority queue to keep track of the lowest nonce we recently accepted myNonce crypto.BoxNonce //
theirNonceMap map[crypto.BoxNonce]time.Time // time we added each nonce to the heap theirMTU uint16 //
myNonce crypto.BoxNonce // myMTU uint16 //
theirMTU uint16 // wasMTUFixed bool // Was the MTU fixed by a receive error?
myMTU uint16 // timeOpened time.Time // Time the sessino was opened
wasMTUFixed bool // Was the MTU fixed by a receive error? time time.Time // Time we last received a packet
timeOpened time.Time // Time the sessino was opened mtuTime time.Time // time myMTU was last changed
time time.Time // Time we last received a packet pingTime time.Time // time the first ping was sent since the last received packet
mtuTime time.Time // time myMTU was last changed pingSend time.Time // time the last ping was sent
pingTime time.Time // time the first ping was sent since the last received packet coords []byte // coords of destination
pingSend time.Time // time the last ping was sent reset bool // reset if coords change
coords []byte // coords of destination tstamp int64 // ATOMIC - tstamp from their last session ping, replay attack mitigation
reset bool // reset if coords change bytesSent uint64 // Bytes of real traffic sent in this session
tstamp int64 // ATOMIC - tstamp from their last session ping, replay attack mitigation bytesRecvd uint64 // Bytes of real traffic received in this session
bytesSent uint64 // Bytes of real traffic sent in this session init chan struct{} // Closed when the first session pong arrives, used to signal that the session is ready for initial use
bytesRecvd uint64 // Bytes of real traffic received in this session cancel util.Cancellation // Used to terminate workers
init chan struct{} // Closed when the first session pong arrives, used to signal that the session is ready for initial use conn *Conn // The associated Conn object
cancel util.Cancellation // Used to terminate workers callbacks []chan func() // Finished work from crypto workers
conn *Conn // The associated Conn object
callbacks []chan func() // Finished work from crypto workers
} }
func (sinfo *sessionInfo) reconfigure() { func (sinfo *sessionInfo) reconfigure() {
@ -105,8 +87,6 @@ func (s *sessionInfo) _update(p *sessionPing) bool {
s.theirHandle = p.Handle s.theirHandle = p.Handle
s.sharedSesKey = *crypto.GetSharedKey(&s.mySesPriv, &s.theirSesPub) s.sharedSesKey = *crypto.GetSharedKey(&s.mySesPriv, &s.theirSesPub)
s.theirNonce = crypto.BoxNonce{} s.theirNonce = crypto.BoxNonce{}
s.theirNonceHeap = nil
s.theirNonceMap = make(map[crypto.BoxNonce]time.Time)
} }
if p.MTU >= 1280 || p.MTU == 0 { if p.MTU >= 1280 || p.MTU == 0 {
s.theirMTU = p.MTU s.theirMTU = p.MTU
@ -420,36 +400,16 @@ func (sinfo *sessionInfo) _nonceIsOK(theirNonce *crypto.BoxNonce) bool {
// This is newer than the newest nonce we've seen // This is newer than the newest nonce we've seen
return true return true
} }
if len(sinfo.theirNonceHeap) > 0 { return time.Since(sinfo.time) < nonceWindow
if theirNonce.Minus(sinfo.theirNonceHeap.peek()) > 0 {
if _, isIn := sinfo.theirNonceMap[*theirNonce]; !isIn {
// This nonce is recent enough that we keep track of older nonces, but it's not one we've seen yet
return true
}
}
}
return false
} }
// Updates the nonce mask by (possibly) shifting the bitmask and setting the bit corresponding to this nonce to 1, and then updating the most recent nonce // Updates the nonce mask by (possibly) shifting the bitmask and setting the bit corresponding to this nonce to 1, and then updating the most recent nonce
func (sinfo *sessionInfo) _updateNonce(theirNonce *crypto.BoxNonce) { func (sinfo *sessionInfo) _updateNonce(theirNonce *crypto.BoxNonce) {
// Start with some cleanup
for len(sinfo.theirNonceHeap) > 64 {
if time.Since(sinfo.theirNonceMap[*sinfo.theirNonceHeap.peek()]) < nonceWindow {
// This nonce is still fairly new, so keep it around
break
}
// TODO? reallocate the map in some cases, to free unused map space?
delete(sinfo.theirNonceMap, *sinfo.theirNonceHeap.peek())
heap.Pop(&sinfo.theirNonceHeap)
}
if theirNonce.Minus(&sinfo.theirNonce) > 0 { if theirNonce.Minus(&sinfo.theirNonce) > 0 {
// This nonce is the newest we've seen, so make a note of that // This nonce is the newest we've seen, so make a note of that
sinfo.theirNonce = *theirNonce sinfo.theirNonce = *theirNonce
sinfo.time = time.Now()
} }
// Add it to the heap/map so we know not to allow it again
heap.Push(&sinfo.theirNonceHeap, *theirNonce)
sinfo.theirNonceMap[*theirNonce] = time.Now()
} }
// Resets all sessions to an uninitialized state. // Resets all sessions to an uninitialized state.
@ -515,7 +475,6 @@ func (sinfo *sessionInfo) _recvPacket(p *wire_trafficPacket) {
return return
} }
sinfo._updateNonce(&p.Nonce) sinfo._updateNonce(&p.Nonce)
sinfo.time = time.Now()
sinfo.bytesRecvd += uint64(len(bs)) sinfo.bytesRecvd += uint64(len(bs))
sinfo.conn.recvMsg(sinfo, bs) sinfo.conn.recvMsg(sinfo, bs)
} }