Key: Constant time encoding
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld
@@ -0,0 +1,148 @@
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// SPDX-License-Identifier: MIT
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// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
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import Foundation
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extension Data {
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func isKey() -> Bool {
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return self.count == 32
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}
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func hexKey() -> String? {
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if self.count != 32 {
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return nil
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}
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var nibble1, nibble2: UInt
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var hex: [UInt8] = Array(repeating: 0, count: 64)
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for i in 0..<32 {
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let n = UInt(self[i])
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nibble1 = 87 + (n >> 4)
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nibble1 += (((UInt(bitPattern: Int(n >> 4) - 10)) >> 8) & 217)
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nibble2 = 87 + (n & 0xf)
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nibble2 += (((UInt(bitPattern: Int(n & 0xf) - 10)) >> 8) & 217)
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hex[i * 2] = UInt8(truncatingIfNeeded: nibble1)
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hex[i * 2 + 1] = UInt8(truncatingIfNeeded: nibble2)
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}
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return String(bytes: hex, encoding: .ascii)
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}
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private func decodeHex(c: UInt8) -> (UInt8, UInt8) {
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var alpha0, alpha, num0, num, val, ret: UInt8
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num = c ^ 48
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num0 = UInt8(truncatingIfNeeded: UInt(bitPattern: Int(num) - 10) >> 8)
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alpha = UInt8(truncatingIfNeeded: Int(c & 223) - 55)
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alpha0 = UInt8(truncatingIfNeeded: (UInt(bitPattern: Int(alpha) - 10) ^ UInt(bitPattern: Int(alpha) - 16)) >> 8)
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ret = UInt8(truncatingIfNeeded: UInt(bitPattern: Int(num0 | alpha0) - 1) >> 8)
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val = (num0 & num) | (alpha0 & alpha)
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return (val, ret)
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}
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init?(hexKey hexString: String) {
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let hex = [UInt8](hexString.utf8)
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if hex.count != 64 {
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return nil
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}
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self.init(repeating: 0, count: 32)
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var ret: UInt8 = 0
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for i in stride(from: 0, to: 64, by: 2) {
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var v1, v2, r: UInt8
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(v1, r) = decodeHex(c: hex[i])
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ret |= r
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(v2, r) = decodeHex(c: hex[i + 1])
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ret |= r
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self[i / 2] = (v1 << 4) | v2
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}
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if 1 & (UInt8(truncatingIfNeeded: Int(ret) - 1) >> 8) != 0 {
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return nil
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}
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}
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private func encodeBase64<T: RandomAccessCollection>(dest: inout ArraySlice<UInt8>, src: T) where T.Index == Int, T.Element == UInt8 {
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let a = Int((src[src.startIndex + 0] >> 2) & 63)
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let b = Int(((src[src.startIndex + 0] << 4) | (src[src.startIndex + 1] >> 4)) & 63)
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let c = Int(((src[src.startIndex + 1] << 2) | (src[src.startIndex + 2] >> 6)) & 63)
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let d = Int(src[src.startIndex + 2] & 63)
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for (i, x) in [a, b, c, d].enumerated() {
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var y: Int = x + 65
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y += ((25 - x) >> 8) & 6
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y -= ((51 - x) >> 8) & 75
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y -= ((61 - x) >> 8) & 15
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y += ((62 - x) >> 8) & 3
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dest[dest.startIndex + i] = UInt8(y)
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}
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}
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func base64Key() -> String? {
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if self.count != 32 {
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return nil
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}
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var base64: [UInt8] = Array(repeating: 0, count: 44)
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for i in 0..<(32 / 3) {
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encodeBase64(dest: &base64[(i * 4)..<(i * 4 + 4)], src: self[(i * 3)..<(i * 3 + 3)])
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}
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encodeBase64(dest: &base64[40..<44], src: [self[30], self[31], 0])
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base64[43] = 61
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return String(bytes: base64, encoding: .ascii)
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}
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private func decodeBase64<T: RandomAccessCollection>(src: T) -> Int where T.Index == Int, T.Element == UInt8 {
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var val: Int = 0
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for i in 0..<4 {
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let n = Int(src[src.startIndex + i])
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var a: Int = -1
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var b: Int
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b = ((((65 - 1) - n) & (n - (90 + 1))) >> 8)
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a += b & (n - 64)
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b = ((((97 - 1) - n) & (n - (122 + 1))) >> 8)
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a += b & (n - 70)
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b = ((((48 - 1) - n) & (n - (57 + 1))) >> 8)
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a += b & (n + 5)
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b = ((((43 - 1) - n) & (n - (43 + 1))) >> 8)
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a += b & 63
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b = ((((47 - 1) - n) & (n - (47 + 1))) >> 8)
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a += b & 64
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val |= a << (18 - 6 * i)
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}
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return val
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}
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init?(base64Key base64String: String) {
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let base64 = [UInt8](base64String.utf8)
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if base64.count != 44 || base64[43] != 61 {
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return nil
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}
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self.init(repeating: 0, count: 32)
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var ret: UInt8 = 0
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var val: Int
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for i in 0..<(32/3) {
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val = decodeBase64(src: base64[(i * 4)..<(i * 4 + 4)])
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ret |= UInt8(UInt32(val) >> UInt32(31))
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self[i * 3 + 0] = UInt8((val >> 16) & 0xff)
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self[i * 3 + 1] = UInt8((val >> 8) & 0xff)
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self[i * 3 + 2] = UInt8(val & 0xff)
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}
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val = decodeBase64(src: [base64[40], base64[41], base64[42], 65])
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ret |= UInt8((UInt32(val) >> 31) | UInt32(val & 0xff))
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self[30] = UInt8((val >> 16) & 0xff)
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self[31] = UInt8((val >> 8) & 0xff)
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if 1 & (UInt8(truncatingIfNeeded: Int(ret) - 1) >> 8) != 0 {
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return nil
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}
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}
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}
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@@ -126,7 +126,9 @@ extension TunnelConfiguration {
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func asWgQuickConfig() -> String {
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var output = "[Interface]\n"
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output.append("PrivateKey = \(interface.privateKey.base64EncodedString())\n")
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if let privateKey = interface.privateKey.base64Key() {
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output.append("PrivateKey = \(privateKey)\n")
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}
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if let listenPort = interface.listenPort {
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output.append("ListenPort = \(listenPort)\n")
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}
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@@ -144,9 +146,11 @@ extension TunnelConfiguration {
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for peer in peers {
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output.append("\n[Peer]\n")
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output.append("PublicKey = \(peer.publicKey.base64EncodedString())\n")
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if let preSharedKey = peer.preSharedKey {
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output.append("PresharedKey = \(preSharedKey.base64EncodedString())\n")
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if let publicKey = peer.publicKey.base64Key() {
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output.append("PublicKey = \(publicKey)\n")
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}
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if let preSharedKey = peer.preSharedKey?.base64Key {
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output.append("PresharedKey = \(preSharedKey)\n")
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}
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if !peer.allowedIPs.isEmpty {
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let allowedIPsString = peer.allowedIPs.map { $0.stringRepresentation }.joined(separator: ", ")
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@@ -168,7 +172,7 @@ extension TunnelConfiguration {
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guard let privateKeyString = attributes["privatekey"] else {
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throw ParseError.interfaceHasNoPrivateKey
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}
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guard let privateKey = Data(base64Encoded: privateKeyString), privateKey.count == TunnelConfiguration.keyLength else {
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guard let privateKey = Data(base64Key: privateKeyString), privateKey.count == TunnelConfiguration.keyLength else {
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throw ParseError.interfaceHasInvalidPrivateKey(privateKeyString)
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}
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var interface = InterfaceConfiguration(privateKey: privateKey)
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@@ -212,12 +216,12 @@ extension TunnelConfiguration {
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guard let publicKeyString = attributes["publickey"] else {
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throw ParseError.peerHasNoPublicKey
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}
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guard let publicKey = Data(base64Encoded: publicKeyString), publicKey.count == TunnelConfiguration.keyLength else {
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guard let publicKey = Data(base64Key: publicKeyString), publicKey.count == TunnelConfiguration.keyLength else {
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throw ParseError.peerHasInvalidPublicKey(publicKeyString)
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}
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var peer = PeerConfiguration(publicKey: publicKey)
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if let preSharedKeyString = attributes["presharedkey"] {
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guard let preSharedKey = Data(base64Encoded: preSharedKeyString), preSharedKey.count == TunnelConfiguration.keyLength else {
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guard let preSharedKey = Data(base64Key: preSharedKeyString), preSharedKey.count == TunnelConfiguration.keyLength else {
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throw ParseError.peerHasInvalidPreSharedKey(preSharedKeyString)
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}
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peer.preSharedKey = preSharedKey
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