pipes prototype

mitmproxy · Aug 21, 2023 · 2a05fc7 · 2a05fc7
1 parent 867b7e2
commit 2a05fc7
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Showing 3 changed files with 77 additions and 40 deletions.
diff --git a/macos-redirector/ipc/utils.swift b/macos-redirector/ipc/utils.swift
@@ -9,7 +9,7 @@ enum IpcError: Error {
 
 func readIpcMessage<T: SwiftProtobuf.Message>(ofType: T.Type, fh: FileHandle) throws -> T? {
     // read u32
-    guard let len_buf = try FileHandle.standardInput.read(upToCount: 4) else { throw IpcError.emptyRead }
+    guard let len_buf = try fh.read(upToCount: 4) else { throw IpcError.emptyRead }
     guard len_buf.count == 4 else { throw IpcError.incompleteRead }
     let len = len_buf[...].reduce(Int(0)) { $0 << 8 + Int($1) };
     // 4x \n (testing)
@@ -18,7 +18,15 @@ func readIpcMessage<T: SwiftProtobuf.Message>(ofType: T.Type, fh: FileHandle) th
     }
     guard len < 1024 * 1024 else { throw IpcError.tooLarge(len) }
     // read protobuf data
-    guard let data = try FileHandle.standardInput.read(upToCount: len) else { throw IpcError.incompleteRead }
+    guard let data = try fh.read(upToCount: len) else { throw IpcError.incompleteRead }
     // decode protobuf
     return try T(contiguousBytes: data)
 }
+
+
+func writeIpcMessage(message: SwiftProtobuf.Message, fh: FileHandle) throws {
+    let data = try message.serializedData()
+    let len = withUnsafeBytes(of: UInt32(data.count).bigEndian, Array.init)
+    try fh.write(contentsOf: len)
+    try fh.write(contentsOf: data)
+}
diff --git a/macos-redirector/macos-redirector/app.swift b/macos-redirector/macos-redirector/app.swift
@@ -22,7 +22,6 @@ struct App {
         while let spec = try readIpcMessage(ofType: Mitmproxy_Ipc_InterceptSpec.self, fh: FileHandle.standardInput) {
 
             log.debug("received intercept spec: \(spec.spec)")
-
             guard !spec.spec.starts(with: "!") else {
                 log.error("inverse specs are not implemented yet.")
                 continue
@@ -97,9 +96,8 @@ func startVPN() async throws -> NETunnelProviderManager {
 
     let providerProtocol = NETunnelProviderProtocol()
     providerProtocol.providerBundleIdentifier = networkExtensionIdentifier
-    // TODO: Use either of these to signal pipes.
-    //providerProtocol.providerConfiguration = ["server": "127.0.0.1", "port": 1234]
-    providerProtocol.serverAddress = "mitmproxy"
+    providerProtocol.serverAddress = "/tmp/mitmproxy-123"
+
     // XXX: it's unclear if these are actually necessary for per-app VPNs
     providerProtocol.enforceRoutes = true
     providerProtocol.includeAllNetworks = true

diff --git a/macos-redirector/network-extension/PacketTunnelProvider.swift b/macos-redirector/network-extension/PacketTunnelProvider.swift
@@ -1,52 +1,83 @@
 import NetworkExtension
 
 class PacketTunnelProvider: NEPacketTunnelProvider {
-
-    var t: Task<Void, Error>?
 
     override func startTunnel(options: [String : NSObject]?, completionHandler: @escaping (Error?) -> Void) {
-        log.debug("startTunnel options=\(String(describing:options), privacy: .public)")
+        log.debug("startTunnel")
+
+        let tunnelNetworkSettings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "10.0.0.42")
+        let ipv4Settings = NEIPv4Settings(addresses: ["10.0.0.1"], subnetMasks: ["255.255.255.0"])
+        ipv4Settings.includedRoutes = [
+            NEIPv4Route.default()
+        ]
+        tunnelNetworkSettings.ipv4Settings = ipv4Settings
+        tunnelNetworkSettings.dnsSettings = NEDNSSettings(servers: ["10.0.0.53"])
+
+        let addr = self.protocolConfiguration.serverAddress!
 
-        self.t = Task {
-
-            log.debug("setting network settings")
-
-            let tunnelNetworkSettings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "10.0.0.42")
-
-            let ipv4Settings = NEIPv4Settings(addresses: ["10.0.0.1"], subnetMasks: ["255.255.255.0"])
-            ipv4Settings.includedRoutes = [
-                NEIPv4Route.default()
-            ]
-            tunnelNetworkSettings.ipv4Settings = ipv4Settings
-
-            tunnelNetworkSettings.dnsSettings = NEDNSSettings(servers: ["10.0.0.53"])
-
-            do {
-                try await self.setTunnelNetworkSettings(tunnelNetworkSettings)
-            } catch let error {
-                completionHandler(error)
-                throw error
+        let proxy_file: FileHandle, redir_file: FileHandle
+        do {
+            proxy_file = try FileHandle(forReadingFrom: URL(fileURLWithPath: "\(addr).proxy"));
+            redir_file = try FileHandle(forWritingTo: URL(fileURLWithPath: "\(addr).redir"))
+        } catch {
+            return completionHandler(error)
+        }
+
+        self.setTunnelNetworkSettings(tunnelNetworkSettings) { err in
+            completionHandler(err)
+            log.debug("tunnel settings set (err=\(err))")
+            if err == nil {
+                self.redirectPackets(redir_file)
+                self.reinjectPackets(proxy_file)
             }
-
-            completionHandler(nil)
-
-            while !Task.isCancelled {
-                log.debug("reading packet objects...")
-                let packets = await self.packetFlow.readPacketObjects();
-                for packet in packets {
-                    log.debug("received packet: \(packet, privacy: .public)")
+        }
+
+        log.debug("startTunnel done")
+    }
+
+    func redirectPackets(_ wfile: FileHandle) {
+        log.debug("redirecting packets to \(wfile, privacy: .public)...")
+        self.packetFlow.readPacketObjects { packets in
+            for packet in packets {
+
+                var message = Mitmproxy_Ipc_FromRedirector()
+                message.packet.data = packet.data
+                message.packet.pid = 0 // TODO
+                message.packet.processName = packet.metadata!.sourceAppSigningIdentifier
+
+                do {
+                    try writeIpcMessage(message: message, fh: wfile)
+                } catch {
+                    log.error("redirectPackets errored: \(error)")
+                    exit(1)
                 }
+                self.redirectPackets(wfile)
             }
-            log.debug("packet task cancelled")
         }
-        log.debug("startTunnel done")
+    }
+
+    func reinjectPackets(_ rfile: FileHandle) {
+        log.debug("reading \(rfile, privacy: .public)...")
+        do {
+            while let packet = try readIpcMessage(ofType: Mitmproxy_Ipc_Packet.self, fh: rfile) {
+
+                log.debug("reinjecting packet...")
+                self.packetFlow.writePackets([packet.data], withProtocols: [AF_INET as NSNumber])
+
+            }
+        } catch {
+            log.error("redirectPackets errored: \(error)")
+            exit(1)
+        }
+
+        log.debug("exiting...")
+        exit(0)
     }
 
     override func stopTunnel(with reason: NEProviderStopReason, completionHandler: @escaping () -> Void) {
         log.debug("stopTunnel \(String(describing:reason))")
-        self.t?.cancel()
         completionHandler()
-        log.debug("stopTunnel done")
+        exit(0) // XXX: is that a reasonable approach to tear things down?
     }
 
     override func handleAppMessage(_ messageData: Data, completionHandler: ((Data?) -> Void)?) {