From 2d00f6a6db653afcdac9aad392ab45643a3413d5 Mon Sep 17 00:00:00 2001 From: cheatfate Date: Fri, 13 Sep 2019 11:20:37 -0600 Subject: [PATCH] wip: integrating secio --- libp2p/protocols/secure/secio.nim | 385 +++++++++++++++++++++++++++--- 1 file changed, 354 insertions(+), 31 deletions(-) diff --git a/libp2p/protocols/secure/secio.nim b/libp2p/protocols/secure/secio.nim index 1cb8ea151..862bc5cce 100644 --- a/libp2p/protocols/secure/secio.nim +++ b/libp2p/protocols/secure/secio.nim @@ -6,9 +6,16 @@ ## at your option. ## This file may not be copied, modified, or distributed except according to ## those terms. +import chronos, chronicles +import nimcrypto/[sysrand, hmac, sha2, sha, hash, rijndael, twofish, bcmode] +import secure, + ../../connection, + ../../crypto/crypto, + ../../crypto/ecnist, + ../../protobuf/minprotobuf, + ../../peer -import chronos, chronicles, nimcrypto/sysrand -import secure, ../../connection, ../../crypto/crypto +export hmac, sha2, sha, hash, rijndael, bcmode logScope: topic = "secio" @@ -16,76 +23,392 @@ logScope: const SecioCodec* = "/secio/1.0.0" SecioMaxMessageSize = 8 * 1024 * 1024 ## 8mb + SecioMaxMacSize = sha512.sizeDigest SecioNonceSize = 16 SecioExchanges = "P-256,P-384,P-521" - SecioCiphers = "AES-256,AES-128" - SecioHashes = "SHA-256,SHA-512" + SecioCiphers = "TwofishCTR,AES-256,AES-128" + SecioHashes = "SHA256,SHA512" type Secio = ref object of Secure + localPrivateKey: PrivateKey localPublicKey: PublicKey + 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] + + SecureConnection* = ref object of BufferStream + writerMac: SecureMac + readerMac: SecureMac + writerCoder: SecureCipher + readerCoder: SecureCipher + +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: SecureConnection, data: var seq[byte]): bool = + ## 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, len(data) - 1)) + return false + + sconn.readerCoder.decrypt(data.toOpenArray(0, mark - 1), + data.toOpenArray(0, mark - 1)) + data.setLen(mark) + result = true + +proc readMessage*(sconn: SecureConnection): Future[seq[byte]] {.async.} = + ## Read message from channel secure connection ``sconn``. + try: + var buf = newSeq[byte](4) + await sconn.conn.readExactly(addr buf[0], 4) + let length = (int(buf[0]) shl 24) or (int(buf[1]) shl 16) or + (int(buf[2]) shl 8) or (int(buf[3])) + trace "Recieved message header", header = toHex(buf), length = length + if length <= SecioMaxMessageSize: + buf.setLen(length) + await sconn.conn.readExactly(addr buf[0], length) + trace "Received message body", length = length, + buffer = toHex(buf) + if sconn.macCheckAndDecode(buf): + result = buf + else: + debug "Message MAC verification failed" + else: + debug "Received message header size is more then allowed", + length = length, allowed_length = SecioMaxMessageSize + except AsyncStreamIncompleteError: + debug "Connection dropped while reading" + except AsyncStreamReadError: + debug "Error reading from connection" + +proc writeMessage*(sconn: SecureConnection, message: seq[byte]) {.async.} = + ## Write message ``message`` to secure connection ``sconn``. + let macsize = sconn.writerMac.sizeDigest() + var msg = newSeq[byte](len(message) + 4 + macsize) + sconn.writerCoder.encrypt(message, msg.toOpenArray(4, 4 + len(message) - 1)) + let mo = 4 + len(message) + sconn.writerMac.update(msg.toOpenArray(4, 4 + len(message) - 1)) + sconn.writerMac.finish(msg.toOpenArray(mo, mo + macsize - 1)) + sconn.writerMac.reset() + let length = len(message) + macsize + msg[0] = byte(length shr 24) + msg[1] = byte(length shr 16) + msg[2] = byte(length shr 8) + msg[3] = byte(length and 0xFF) + trace "Writing message", message = toHex(msg) + try: + await sconn.pushTo(msg) + except AsyncStreamWriteError: + debug "Could not write to connection" + +proc newSecureConnection*(conn: Connection, hash: string, cipher: string, + secrets: Secret, + order: int): SecureConnection = + ## Create new secure connection, using specified hash algorithm ``hash``, + ## cipher algorithm ``cipher``, stretched keys ``secrets`` and order + ## ``order``. + new result + let i0 = if order < 0: 1 else: 0 + let i1 = if order < 0: 0 else: 1 + + result.conn = conn + trace "Writer credentials", mackey = toHex(secrets.macOpenArray(i0)), + enckey = toHex(secrets.keyOpenArray(i0)), + iv = toHex(secrets.ivOpenArray(i0)) + trace "Reader credentials", mackey = toHex(secrets.macOpenArray(i1)), + enckey = toHex(secrets.keyOpenArray(i1)), + iv = toHex(secrets.ivOpenArray(i1)) + 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)) proc transactMessage(conn: Connection, msg: seq[byte]): Future[seq[byte]] {.async.} = var buf = newSeq[byte](4) try: - debug "Sending proposal", message = toHex(msg) + trace "Sending message", message = toHex(msg), length = len(msg) await conn.write(msg) await conn.readExactly(addr buf[0], 4) let length = (int(buf[0]) shl 24) or (int(buf[1]) shl 16) or (int(buf[2]) shl 8) or (int(buf[3])) - debug "Recieved message header", header = toHex(buf), length = length + trace "Recieved message header", header = toHex(buf), length = length if length <= SecioMaxMessageSize: buf.setLen(length) await conn.readExactly(addr buf[0], length) - debug "Received message body", conn = conn, length = length + trace "Received message body", conn = conn, length = length result = buf else: - debug "Received size of message exceed limits", conn = conn, + trace "Received size of message exceed limits", conn = conn, length = length except AsyncStreamIncompleteError: - debug "Connection dropped while reading", conn = conn + trace "Connection dropped while reading", conn = conn except AsyncStreamReadError: - debug "Error reading from connection", conn = conn + trace "Error reading from connection", conn = conn except AsyncStreamWriteError: - debug "Could not write to connection", conn = conn + trace "Could not write to connection", conn = conn proc handshake*(p: Secio, conn: Connection) {.async.} = - var nonce: array[SecioNonceSize, byte] - var pk = p.localPublicKey.getBytes() - echo toHex(pk) - if randomBytes(nonce) != SecioNonceSize: + var + localNonce: array[SecioNonceSize, byte] + remoteNonce: seq[byte] + remoteBytesPubkey: seq[byte] + remoteEBytesPubkey: seq[byte] + remoteEBytesSig: seq[byte] + remotePubkey: PublicKey + remoteEPubkey: PublicKey = PublicKey(scheme: ECDSA) + remoteESignature: Signature + remoteExchanges: string + remoteCiphers: string + remoteHashes: string + remotePeerId: PeerID + localPeerId: PeerID + ekey: PrivateKey + localBytesPubkey = p.localPublicKey.getBytes() + + if randomBytes(localNonce) != SecioNonceSize: raise newException(CatchableError, "Could not generate random data") - + + var request = createProposal(localNonce, localBytesPubkey, SecioExchanges, + SecioCiphers, SecioHashes) + + localPeerId = PeerID.init(p.localPublicKey) + debug "Local proposal", schemes = SecioExchanges, ciphers = SecioCiphers, - hashes = SecioHashes, nonce = toHex(nonce), - pubkey = toHex(pk) - - echo "local proposal" + hashes = SecioHashes, + pubkey = toHex(localBytesPubkey), + peer = localPeerId - var answer = await transactMessage(conn, - createProposal(nonce, pk, SecioExchanges, SecioCiphers, SecioHashes) - ) - - echo toHex(answer) + var answer = await transactMessage(conn, request) if len(answer) == 0: - debug "Proposal exchange failed", conn = conn + trace "Proposal exchange failed", conn = conn return + if not decodeProposal(answer, remoteNonce, remoteBytesPubkey, remoteExchanges, + remoteCiphers, remoteHashes): + trace "Remote proposal decoding failed", conn = conn + return + + if not remotePubkey.init(remoteBytesPubkey): + trace "Remote public key incorrect or corrupted", pubkey = remoteBytesPubkey + return + + remotePeerId = PeerID.init(remotePubkey) + + # TODO: PeerID check against supplied PeerID + + let order = getOrder(remoteBytesPubkey, localNonce, localBytesPubkey, + remoteNonce) + debug "Remote proposal", schemes = remoteExchanges, ciphers = remoteCiphers, + hashes = remoteHashes, + pubkey = toHex(remoteBytesPubkey), order = order, + 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: + debug "No algorithms in common", peer = remotePeerId + return + + debug "Encryption scheme selected", scheme = scheme, cipher = cipher, + hash = hash + + var ekeypair = ephemeral(scheme) + # We need EC public key in raw binary form + var epubkey = ekeypair.pubkey.eckey.getRawBytes() + var localCorpus = request[4..^1] & answer & epubkey + var signature = p.localPrivateKey.sign(localCorpus) + + var localExchange = createExchange(epubkey, signature.getBytes()) + + var remoteExchange = await transactMessage(conn, localExchange) + if len(remoteExchange) == 0: + trace "Corpus exchange failed", conn = conn + return + + if not decodeExchange(remoteExchange, remoteEBytesPubkey, remoteEBytesSig): + trace "Remote exchange decoding failed", conn = conn + return + + if not remoteESignature.init(remoteEBytesSig): + trace "Remote signature incorrect or corrupted", + signature = toHex(remoteEBytesSig) + return + + var remoteCorpus = answer & request[4..^1] & remoteEBytesPubkey + if not remoteESignature.verify(remoteCorpus, remotePubkey): + debug "Signature verification failed", scheme = remotePubkey.scheme, + signature = remoteESignature, pubkey = remotePubkey, + corpus = remoteCorpus + return + + debug "Signature verified", scheme = remotePubkey.scheme + + if not remoteEPubkey.eckey.initRaw(remoteEBytesPubkey): + debug "Remote ephemeral public key incorrect or corrupted", + pubkey = toHex(remoteEBytesPubkey) + return + + var secret = getSecret(remoteEPubkey, ekeypair.seckey) + if len(secret) == 0: + trace "Shared secret could not be created", + pubkeyScheme = remoteEPubkey.scheme, + seckeyScheme = ekeypair.seckey.scheme + return + + trace "Shared secret calculated", secret = toHex(secret) + + var keys = stretchKeys(cipher, hash, secret) + + trace "Authenticated encryption parameters", + iv0 = toHex(keys.ivOpenArray(0)), key0 = toHex(keys.keyOpenArray(0)), + mac0 = toHex(keys.macOpenArray(0)), + iv1 = toHex(keys.ivOpenArray(1)), key1 = toHex(keys.keyOpenArray(1)), + mac1 = toHex(keys.macOpenArray(1)) + + # Perform Nonce exchange over encrypted channel. + + var sconn = newSecureConnection(conn, hash, cipher, keys, order) + await sconn.writeMessage(remoteNonce) + var res = await sconn.readMessage() + + if res != @localNonce: + debug "Nonce verification failed", receivedNonce = toHex(res), + localNonce = toHex(localNonce) + else: + debug "Secure handshake succeeded" + method init(p: Secio) {.gcsafe.} = - proc handle(conn: Connection, proto: string) {.async, gcsafe.} = + proc handle(conn: Connection, proto: string) {.async, gcsafe.} = echo "HERE" p.codec = SecioCodec p.handler = handle method secure*(p: Secio, conn: Connection): Future[Connection] {.async, gcsafe.} = - echo "handshaking" await p.handshake(conn) -proc newSecio*(localPublicKey: PublicKey): Secio = +proc newSecio*(localPrivateKey: PrivateKey): Secio = new result - result.localPublicKey = localPublicKey + result.localPrivateKey = localPrivateKey + result.localPublicKey = localPrivateKey.getKey() result.init() -