nim-libp2p/libp2p/protocols/secure/secio.nim

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## Nim-LibP2P
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## Copyright (c) 2019 Status Research & Development GmbH
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## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
{.push raises: [Defect].}
import std/[oids, strformat]
import chronos, chronicles, stew/endians2, bearssl
import nimcrypto/[hmac, sha2, sha, hash, rijndael, twofish, bcmode]
import secure,
../../stream/connection,
../../peerinfo,
../../crypto/crypto,
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../../crypto/ecnist,
../../peerid,
../../utility,
../../errors
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export hmac, sha2, sha, hash, rijndael, bcmode
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logScope:
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topics = "libp2p secio"
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const
SecioCodec* = "/secio/1.0.0"
SecioMaxMessageSize = 8 * 1024 * 1024 ## 8mb
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SecioMaxMacSize = sha512.sizeDigest
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SecioNonceSize = 16
SecioExchanges = "P-256,P-384,P-521"
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SecioCiphers = "TwofishCTR,AES-256,AES-128"
SecioHashes = "SHA256,SHA512"
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type
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Secio = ref object of Secure
rng: ref BrHmacDrbgContext
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localPrivateKey: PrivateKey
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localPublicKey: PublicKey
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remotePublicKey: PublicKey
SecureCipherType {.pure.} = enum
Aes128, Aes256, Twofish
SecureMacType {.pure.} = enum
Sha1, Sha256, Sha512
SecureCipher = object
case kind: SecureCipherType
of SecureCipherType.Aes128:
ctxaes128: CTR[aes128]
of SecureCipherType.Aes256:
ctxaes256: CTR[aes256]
of SecureCipherType.Twofish:
ctxtwofish256: CTR[twofish256]
SecureMac = object
case kind: SecureMacType
of SecureMacType.Sha256:
ctxsha256: HMAC[sha256]
of SecureMacType.Sha512:
ctxsha512: HMAC[sha512]
of SecureMacType.Sha1:
ctxsha1: HMAC[sha1]
SecioConn = ref object of SecureConn
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writerMac: SecureMac
readerMac: SecureMac
writerCoder: SecureCipher
readerCoder: SecureCipher
SecioError* = object of LPError
func shortLog*(conn: SecioConn): auto =
try:
if conn.isNil: "SecioConn(nil)"
elif conn.peerInfo.isNil: $conn.oid
else: &"{shortLog(conn.peerInfo.peerId)}:{conn.oid}"
except ValueError as exc:
raise newException(Defect, exc.msg)
chronicles.formatIt(SecioConn): shortLog(it)
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proc init(mac: var SecureMac, hash: string, key: openarray[byte]) =
if hash == "SHA256":
mac = SecureMac(kind: SecureMacType.Sha256)
mac.ctxsha256.init(key)
elif hash == "SHA512":
mac = SecureMac(kind: SecureMacType.Sha512)
mac.ctxsha512.init(key)
elif hash == "SHA1":
mac = SecureMac(kind: SecureMacType.Sha1)
mac.ctxsha1.init(key)
proc update(mac: var SecureMac, data: openarray[byte]) =
case mac.kind
of SecureMacType.Sha256:
update(mac.ctxsha256, data)
of SecureMacType.Sha512:
update(mac.ctxsha512, data)
of SecureMacType.Sha1:
update(mac.ctxsha1, data)
proc sizeDigest(mac: SecureMac): int {.inline.} =
case mac.kind
of SecureMacType.Sha256:
result = int(mac.ctxsha256.sizeDigest())
of SecureMacType.Sha512:
result = int(mac.ctxsha512.sizeDigest())
of SecureMacType.Sha1:
result = int(mac.ctxsha1.sizeDigest())
proc finish(mac: var SecureMac, data: var openarray[byte]) =
case mac.kind
of SecureMacType.Sha256:
discard finish(mac.ctxsha256, data)
of SecureMacType.Sha512:
discard finish(mac.ctxsha512, data)
of SecureMacType.Sha1:
discard finish(mac.ctxsha1, data)
proc reset(mac: var SecureMac) =
case mac.kind
of SecureMacType.Sha256:
reset(mac.ctxsha256)
of SecureMacType.Sha512:
reset(mac.ctxsha512)
of SecureMacType.Sha1:
reset(mac.ctxsha1)
proc init(sc: var SecureCipher, cipher: string, key: openarray[byte],
iv: openarray[byte]) {.inline.} =
if cipher == "AES-128":
sc = SecureCipher(kind: SecureCipherType.Aes128)
sc.ctxaes128.init(key, iv)
elif cipher == "AES-256":
sc = SecureCipher(kind: SecureCipherType.Aes256)
sc.ctxaes256.init(key, iv)
elif cipher == "TwofishCTR":
sc = SecureCipher(kind: SecureCipherType.Twofish)
sc.ctxtwofish256.init(key, iv)
proc encrypt(cipher: var SecureCipher, input: openarray[byte],
output: var openarray[byte]) {.inline.} =
case cipher.kind
of SecureCipherType.Aes128:
cipher.ctxaes128.encrypt(input, output)
of SecureCipherType.Aes256:
cipher.ctxaes256.encrypt(input, output)
of SecureCipherType.Twofish:
cipher.ctxtwofish256.encrypt(input, output)
proc decrypt(cipher: var SecureCipher, input: openarray[byte],
output: var openarray[byte]) {.inline.} =
case cipher.kind
of SecureCipherType.Aes128:
cipher.ctxaes128.decrypt(input, output)
of SecureCipherType.Aes256:
cipher.ctxaes256.decrypt(input, output)
of SecureCipherType.Twofish:
cipher.ctxtwofish256.decrypt(input, output)
proc macCheckAndDecode(sconn: SecioConn, data: var seq[byte]): bool =
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## This procedure checks MAC of recieved message ``data`` and if message is
## authenticated, then decrypt message.
##
## Procedure returns ``false`` if message is too short or MAC verification
## failed.
var macData: array[SecioMaxMacSize, byte]
let macsize = sconn.readerMac.sizeDigest()
if len(data) < macsize:
trace "Message is shorter then MAC size", message_length = len(data),
mac_size = macsize
return false
let mark = len(data) - macsize
sconn.readerMac.update(data.toOpenArray(0, mark - 1))
sconn.readerMac.finish(macData)
sconn.readerMac.reset()
if not equalMem(addr data[mark], addr macData[0], macsize):
trace "Invalid MAC",
calculated = toHex(macData.toOpenArray(0, macsize - 1)),
stored = toHex(data.toOpenArray(mark, data.high))
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return false
sconn.readerCoder.decrypt(data.toOpenArray(0, mark - 1),
data.toOpenArray(0, mark - 1))
data.setLen(mark)
result = true
proc readRawMessage(conn: Connection): Future[seq[byte]] {.async.} =
while true: # Discard 0-length payloads
var lengthBuf: array[4, byte]
await conn.readExactly(addr lengthBuf[0], lengthBuf.len)
let length = uint32.fromBytesBE(lengthBuf)
trace "Recieved message header", header = lengthBuf.shortLog, length = length
if length > SecioMaxMessageSize: # Verify length before casting!
trace "Received size of message exceed limits", conn, length = length
raise (ref SecioError)(msg: "Message exceeds maximum length")
if length > 0:
var buf = newSeq[byte](int(length))
await conn.readExactly(addr buf[0], buf.len)
trace "Received message body",
conn, length = buf.len, buff = buf.shortLog
return buf
trace "Discarding 0-length payload", conn
method readMessage*(sconn: SecioConn): Future[seq[byte]] {.async.} =
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## Read message from channel secure connection ``sconn``.
when chronicles.enabledLogLevel == LogLevel.TRACE:
logScope:
stream_oid = $sconn.stream.oid
var buf = await sconn.stream.readRawMessage()
if sconn.macCheckAndDecode(buf):
result = buf
else:
trace "Message MAC verification failed", buf = buf.shortLog
raise (ref SecioError)(msg: "message failed MAC verification")
method write*(sconn: SecioConn, message: seq[byte]) {.async.} =
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## Write message ``message`` to secure connection ``sconn``.
if message.len == 0:
return
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var
left = message.len
offset = 0
while left > 0:
let
chunkSize = if left > SecioMaxMessageSize - 64: SecioMaxMessageSize - 64 else: left
macsize = sconn.writerMac.sizeDigest()
length = chunkSize + macsize
var msg = newSeq[byte](chunkSize + 4 + macsize)
msg[0..<4] = uint32(length).toBytesBE()
sconn.writerCoder.encrypt(message.toOpenArray(offset, offset + chunkSize - 1),
msg.toOpenArray(4, 4 + chunkSize - 1))
left = left - chunkSize
offset = offset + chunkSize
let mo = 4 + chunkSize
sconn.writerMac.update(msg.toOpenArray(4, 4 + chunkSize - 1))
sconn.writerMac.finish(msg.toOpenArray(mo, mo + macsize - 1))
sconn.writerMac.reset()
trace "Writing message", message = msg.shortLog, left, offset
await sconn.stream.write(msg)
sconn.activity = true
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proc newSecioConn(conn: Connection,
hash: string,
cipher: string,
secrets: Secret,
order: int,
remotePubKey: PublicKey): SecioConn
{.raises: [Defect, SecioError].} =
## Create new secure stream/lpstream, using specified hash algorithm ``hash``,
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## cipher algorithm ``cipher``, stretched keys ``secrets`` and order
## ``order``.
conn.peerInfo =
if conn.peerInfo != nil:
conn.peerInfo
else:
PeerInfo.init(remotePubKey)
result = SecioConn.init(conn, conn.peerInfo, conn.observedAddr)
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let i0 = if order < 0: 1 else: 0
let i1 = if order < 0: 0 else: 1
trace "Writer credentials", mackey = secrets.macOpenArray(i0).shortLog,
enckey = secrets.keyOpenArray(i0).shortLog,
iv = secrets.ivOpenArray(i0).shortLog
trace "Reader credentials", mackey = secrets.macOpenArray(i1).shortLog,
enckey = secrets.keyOpenArray(i1).shortLog,
iv = secrets.ivOpenArray(i1).shortLog
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result.writerMac.init(hash, secrets.macOpenArray(i0))
result.readerMac.init(hash, secrets.macOpenArray(i1))
result.writerCoder.init(cipher, secrets.keyOpenArray(i0),
secrets.ivOpenArray(i0))
result.readerCoder.init(cipher, secrets.keyOpenArray(i1),
secrets.ivOpenArray(i1))
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proc transactMessage(conn: Connection,
msg: seq[byte]): Future[seq[byte]] {.async.} =
trace "Sending message", message = msg.shortLog, length = len(msg)
await conn.write(msg)
return await conn.readRawMessage()
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method handshake*(s: Secio, conn: Connection, initiator: bool = false): Future[SecureConn] {.async.} =
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var
localNonce: array[SecioNonceSize, byte]
remoteNonce: seq[byte]
remoteBytesPubkey: seq[byte]
remoteEBytesPubkey: seq[byte]
remoteEBytesSig: seq[byte]
remotePubkey: PublicKey
remoteEPubkey: ecnist.EcPublicKey
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remoteESignature: Signature
remoteExchanges: string
remoteCiphers: string
remoteHashes: string
remotePeerId: PeerID
localPeerId: PeerID
localBytesPubkey = s.localPublicKey.getBytes().tryGet()
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brHmacDrbgGenerate(s.rng[], localNonce)
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var request = createProposal(localNonce,
localBytesPubkey,
SecioExchanges,
SecioCiphers,
SecioHashes)
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localPeerId = PeerID.init(s.localPublicKey).tryGet()
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trace "Local proposal", schemes = SecioExchanges,
ciphers = SecioCiphers,
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hashes = SecioHashes,
pubkey = localBytesPubkey.shortLog,
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peer = localPeerId
var answer = await transactMessage(conn, request)
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if len(answer) == 0:
trace "Proposal exchange failed", conn
raise (ref SecioError)(msg: "Proposal exchange failed")
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if not decodeProposal(answer, remoteNonce, remoteBytesPubkey, remoteExchanges,
remoteCiphers, remoteHashes):
trace "Remote proposal decoding failed", conn
raise (ref SecioError)(msg: "Remote proposal decoding failed")
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if not remotePubkey.init(remoteBytesPubkey):
trace "Remote public key incorrect or corrupted",
pubkey = remoteBytesPubkey.shortLog
raise (ref SecioError)(msg: "Remote public key incorrect or corrupted")
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remotePeerId = PeerID.init(remotePubkey).tryGet()
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# TODO: PeerID check against supplied PeerID
let order = getOrder(remoteBytesPubkey, localNonce, localBytesPubkey,
remoteNonce).tryGet()
trace "Remote proposal", schemes = remoteExchanges, ciphers = remoteCiphers,
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hashes = remoteHashes,
pubkey = remoteBytesPubkey.shortLog, order = order,
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peer = remotePeerId
let scheme = selectBest(order, SecioExchanges, remoteExchanges)
let cipher = selectBest(order, SecioCiphers, remoteCiphers)
let hash = selectBest(order, SecioHashes, remoteHashes)
if len(scheme) == 0 or len(cipher) == 0 or len(hash) == 0:
trace "No algorithms in common", peer = remotePeerId
raise (ref SecioError)(msg: "No algorithms in common")
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trace "Encryption scheme selected", scheme = scheme, cipher = cipher,
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hash = hash
var ekeypair = ephemeral(scheme, s.rng[]).tryGet()
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# We need EC public key in raw binary form
var epubkey = ekeypair.pubkey.getRawBytes().tryGet()
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var localCorpus = request[4..^1] & answer & epubkey
var signature = s.localPrivateKey.sign(localCorpus).tryGet()
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var localExchange = createExchange(epubkey, signature.getBytes())
var remoteExchange = await transactMessage(conn, localExchange)
if len(remoteExchange) == 0:
trace "Corpus exchange failed", conn
raise (ref SecioError)(msg: "Corpus exchange failed")
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if not decodeExchange(remoteExchange, remoteEBytesPubkey, remoteEBytesSig):
trace "Remote exchange decoding failed", conn
raise (ref SecioError)(msg: "Remote exchange decoding failed")
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if not remoteESignature.init(remoteEBytesSig):
trace "Remote signature incorrect or corrupted", signature = remoteEBytesSig.shortLog
raise (ref SecioError)(msg: "Remote signature incorrect or corrupted")
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var remoteCorpus = answer & request[4..^1] & remoteEBytesPubkey
if not remoteESignature.verify(remoteCorpus, remotePubkey):
trace "Signature verification failed", scheme = $remotePubkey.scheme,
signature = $remoteESignature,
pubkey = $remotePubkey,
corpus = $remoteCorpus
raise (ref SecioError)(msg: "Signature verification failed")
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trace "Signature verified", scheme = remotePubkey.scheme
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if not remoteEPubkey.initRaw(remoteEBytesPubkey):
trace "Remote ephemeral public key incorrect or corrupted",
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pubkey = toHex(remoteEBytesPubkey)
raise (ref SecioError)(msg: "Remote ephemeral public key incorrect or corrupted")
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var secret = getSecret(remoteEPubkey, ekeypair.seckey)
if len(secret) == 0:
trace "Shared secret could not be created"
raise (ref SecioError)(msg: "Shared secret could not be created")
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trace "Shared secret calculated", secret = secret.shortLog
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var keys = stretchKeys(cipher, hash, secret)
trace "Authenticated encryption parameters",
iv0 = toHex(keys.ivOpenArray(0)), key0 = keys.keyOpenArray(0).shortLog,
mac0 = keys.macOpenArray(0).shortLog,
iv1 = keys.ivOpenArray(1).shortLog, key1 = keys.keyOpenArray(1).shortLog,
mac1 = keys.macOpenArray(1).shortLog
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# Perform Nonce exchange over encrypted channel.
var secioConn = newSecioConn(conn, hash, cipher, keys, order, remotePubkey)
result = secioConn
await secioConn.write(remoteNonce)
var res = await secioConn.readMessage()
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if res != @localNonce:
trace "Nonce verification failed", receivedNonce = res.shortLog,
localNonce = localNonce.shortLog
raise (ref SecioError)(msg: "Nonce verification failed")
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else:
trace "Secure handshake succeeded"
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method init(s: Secio) {.gcsafe.} =
procCall Secure(s).init()
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s.codec = SecioCodec
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proc newSecio*(rng: ref BrHmacDrbgContext, localPrivateKey: PrivateKey): Secio =
let pkRes = localPrivateKey.getKey()
if pkRes.isErr:
raise newException(Defect, "Can't fetch local private key")
result = Secio(
rng: rng,
localPrivateKey: localPrivateKey,
localPublicKey: localPrivateKey.getKey().get(),
)
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result.init()