Merge pull request #13 from swift-libp2p/fix-unaligned-pointer

Fix unaligned pointer

Author: btoms20

Sources/Multiaddr/Address.swift

@@ -95,7 +95,8 @@ extension Address {
         switch addrProtocol {
         case .tcp, .udp, .dccp, .sctp:
             guard addressData.count == 2 else { throw MultiaddrError.parseAddressFail }
-            return String(addressData.uint16.bigEndian)
+            guard let uint16 = addressData.uint16 else { throw MultiaddrError.parseAddressFail }
+            return String(uint16.bigEndian)
         case .ip4:
             return try IPv4.string(for: addressData)
         case .ip6:

Sources/Multiaddr/Extensions/Data+Multiaddr.swift

@@ -19,9 +19,25 @@
 import Foundation
 
 extension Data {
-    var uint16: UInt16 {
-        withUnsafeBytes {
-            $0.load(as: UInt16.self)
+
+    var uint16: UInt16? {
+        self.value(ofType: UInt16.self, at: 0, convertEndian: true)
+    }
+
+    var uint32: UInt32? {
+        self.value(ofType: UInt32.self, at: 0, convertEndian: true)
+    }
+
+    fileprivate func value<T: BinaryInteger>(ofType: T.Type, at offset: Int, convertEndian: Bool = false) -> T? {
+        let byteCount = MemoryLayout<T>.size
+        let startIndex = self.index(self.startIndex, offsetBy: offset)
+        let endIndex = self.index(startIndex, offsetBy: byteCount)
+        guard self.endIndex >= endIndex else { return nil }
+        let bytes = self[startIndex..<endIndex]
+        if convertEndian {
+            return bytes.reversed().reduce(0) { T($0) << 8 + T($1) }
+        } else {
+            return bytes.reduce(0) { T($0) << 8 + T($1) }
         }
     }
 }

Sources/Multiaddr/Protocol Helpers/IPV4.swift

@@ -41,8 +41,11 @@ struct IPv4 {
         guard data.count == MemoryLayout<UInt32>.size else {
             throw MultiaddrError.parseIPv4AddressFail
         }
+        guard let uint32 = data.uint32 else {
+            throw MultiaddrError.parseIPv4AddressFail
+        }
         var output = Data(count: Int(INET_ADDRSTRLEN))
-        var address = in_addr(s_addr: data.uint32)
+        var address = in_addr(s_addr: uint32)
 
         guard
             let presentationBytes = output.withUnsafeMutableBytes({
@@ -59,14 +62,6 @@ struct IPv4 {
     }
 }
 
-extension Data {
-    var uint32: UInt32 {
-        withUnsafeBytes {
-            $0.load(as: UInt32.self)
-        }
-    }
-}
-
 extension BinaryInteger {
     // returns little endian; use .bigEndian.bytes for BE.
     var bytes: Data {

Sources/Multiaddr/Protocol Helpers/Onion.swift

@@ -34,7 +34,6 @@ struct Onion {
         guard let portValue = UInt16(port) else { throw MultiaddrError.invalidPortValue }
         guard portValue != 0 else { throw MultiaddrError.invalidPortValue }
 
-        //base32DecodeToData(host)
         guard var onionData = try? BaseEncoding.decode(host, as: .base32).data else {
             throw MultiaddrError.invalidOnionHostAddress
         }
@@ -48,12 +47,14 @@ struct Onion {
 
     static func string(for data: Data) throws -> String {
         guard data.count == 12 else { throw MultiaddrError.invalidOnionHostAddress }
+
         let addressBytes = data.prefix(10)
+        let addressEncodedString = addressBytes.asString(base: .base32).lowercased()
+
         let portBytes = data.suffix(2)
+        guard let port = portBytes.uint16 else { throw MultiaddrError.invalidPortValue }
+        let portString = String(port.bigEndian)
 
-        //base32Encode(addressBytes).lowercased()
-        let addressEncodedString = addressBytes.asString(base: .base32).lowercased()
-        let portString = String(portBytes.uint16.bigEndian)
         return "\(addressEncodedString):\(portString)"
     }
 }
@@ -73,7 +74,6 @@ struct Onion3 {
         guard let portValue = UInt16(port) else { throw MultiaddrError.invalidPortValue }
         guard portValue != 0 else { throw MultiaddrError.invalidPortValue }
 
-        //base32DecodeToData(host)
         guard var onionData = try? BaseEncoding.decode(host, as: .base32).data else {
             throw MultiaddrError.invalidOnionHostAddress
         }
@@ -88,11 +88,12 @@ struct Onion3 {
     static func string(for data: Data) throws -> String {
         //guard data.count == 52 else { throw MultiaddrError.invalidOnionHostAddress }
         let portBytes = Data(data.suffix(2))
-        let addressBytes = Data(data.dropLast(2))
+        guard let port = portBytes.uint16 else { throw MultiaddrError.invalidPortValue }
+        let portString = String(port.bigEndian)
 
-        //base32Encode(addressBytes).lowercased()
+        let addressBytes = Data(data.dropLast(2))
         let addressEncodedString = addressBytes.asString(base: .base32).lowercased()
-        let portString = String(portBytes.uint16.bigEndian)
+
         return "\(addressEncodedString):\(portString)"
     }
 }