Add --config-file to serve (#7)

* Add --config-file to `serve`

* use viper to support env var and config file

* properly integrate viper with cobra

* add viper

* slightly better error message

* set default option for --server-config-output

* show config file option in configure output

* add powershell command to the output

* Tidy go.mod

* Update docs and demo for new env arguments

---------

Co-authored-by: Luke Rindels <lrindels@pm.me>

Author: DennyDai

README.md

@@ -17,7 +17,7 @@ In this diagram, the client has generated and installed a WireGuard configuratio
 1. Download binaries from the [releases](https://github.com/sandialabs/wiretap/releases) page, one for your client machine and one for your server (if different os/arch)
 2. Run `./wiretap configure --port <port> --endpoint <socket> --routes <routes>` with the appropriate arguments
 3. Import the resulting `wiretap.conf` file into WireGuard on the client machine
-4. Copy and paste the arguments output from the configure command into Wiretap on the server machine
+4. Copy and paste the server command output that best suits your target system into Wiretap on the server machine
 
 ## Requirements
 
@@ -62,20 +62,25 @@ Following the example in the diagram:
 Configuration successfully generated.
 Import the config into WireGuard locally and pass the arguments below to Wiretap on the remote machine.
 
-config: wiretap.conf
+client config: wiretap.conf
 ────────────────────────────────
 [Interface]
-PrivateKey = qCvx4DBXqemoO8B7eRI2H9Em8zJn++rIBKO+F+ufQWE=
+PrivateKey = 0PjJSe+uFvCGolet/WJN7EBXauB9jjUfNhdwk9i4Q2Q=
 Address = 192.168.0.2/32
 Address = fd::2/128
 ListenPort = 1337
 
 [Peer]
-PublicKey = 6NxBlwJHujEFr5n9qvFAUyinj0l7Wadd/ZDQMCqTJAA=
+PublicKey = +xi5lM2V7nPwJ/02mF7CpK4pzgrtof2h1ykClkQqgnQ=
 AllowedIPs = 10.0.0.0/24,a::/128
 ────────────────────────────────
 
-args: serve --private qGrU0juci5PLJ1ydSufE/UwlErL/bqfcz6uWil705UU= --public ZhRIAcGVwT7l9dhEXv7cvYKwLxOZJR4bgU4zePZaT04= --endpoint 1.3.3.7:1337
+server config: wiretap_server.conf
+
+server command:
+POSIX Shell:  WIRETAP_INTERFACE_PRIVATEKEY=8O7ul6vWcdlcy515RD2kNwU2TRvEoe0UwCl1XjnFQ2Q= WIRETAP_PEER_PUBLICKEY=7QorkqrYFfSUpg+kw6ipFMee9d8r5BGmJprceluUzX8= WIRETAP_PEER_ENDPOINT=1.3.3.7:1337 ./wiretap serve
+ PowerShell:  $env:WIRETAP_INTERFACE_PRIVATEKEY="8O7ul6vWcdlcy515RD2kNwU2TRvEoe0UwCl1XjnFQ2Q="; $env:WIRETAP_PEER_PUBLICKEY="7QorkqrYFfSUpg+kw6ipFMee9d8r5BGmJprceluUzX8="; $env:WIRETAP_PEER_ENDPOINT="1.3.3.7:1337"; .\wiretap.exe serve
+Config File:  ./wiretap serve -f wiretap_server.conf
 
 ```
 
@@ -89,9 +94,13 @@ Don't forget to disable or remove the tunnel when you're done (e.g., `sudo wg-qu
 ### Deploy
 
 On the remote machine, upload the binary and then copy the command with the private and public keys to start Wiretap in server mode:
+```powershell
+$env:WIRETAP_INTERFACE_PRIVATEKEY="8O7ul6vWcdlcy515RD2kNwU2TRvEoe0UwCl1XjnFQ2Q="; $env:WIRETAP_PEER_PUBLICKEY="7QorkqrYFfSUpg+kw6ipFMee9d8r5BGmJprceluUzX8="; $env:WIRETAP_PEER_ENDPOINT="1.3.3.7:1337"; .\wiretap.exe serve
 ```
-.\wiretap.exe serve --private qGrU0juci5PLJ1ydSufE/UwlErL/bqfcz6uWil705UU= --public ZhRIAcGVwT7l9dhEXv7cvYKwLxOZJR4bgU4zePZaT04= --endpoint 1.3.3.7:1337
-```
+
+There are two other ways to pass arguments to the server:
+1. With a config file: `-f wiretap_server.conf`
+2. The legacy method of passing command line arguments (`--endpoint 1.3.3.7:1337 ...`). Be aware that this method exposes arguments to other users on the system. Compromising the private key could allow someone to connect to the client as a peer and/or decrypt traffic
 
 Confirm that the client and server have successfully completed the handshake. The client should see a successful handshake in whatever WireGuard interface is running. If using the command-line tools, check with `wg show`.
 
@@ -274,7 +283,7 @@ Configure Wiretap from the client machine. Remember, `--endpoint` is how the ser
 * `--routes` needs to be the subnet of the target network: `10.2.0.0/16`. But there is also an IPv6 subnet, so we should also put `fd:2::/64`. If you just wanted to route traffic to the target host, you could put `10.2.0.4/32` here instead
 
 ```bash
-./wiretap_linux_amd64 configure --endpoint 10.1.0.2:51820 --routes 10.2.0.0/16,fd:2::/64
+./wiretap configure --endpoint 10.1.0.2:51820 --routes 10.2.0.0/16,fd:2::/64
 ```
 
 Install the newly created WireGuard config with:
@@ -286,7 +295,7 @@ wg-quick up ./wiretap.conf
 Copy and paste the Wiretap arguments printed by the configure command into the server machine prompt. It should look like this:
 
 ```bash
-./wiretap_linux_amd64 serve --private <key> --public <key> --endpoint 10.1.0.2:51820
+WIRETAP_INTERFACE_PRIVATEKEY=<key> WIRETAP_PEER_PUBLICKEY=<key> WIRETAP_PEER_ENDPOINT=10.1.0.2:51820 ./wiretap serve
 ```
 
 #### Test
@@ -360,7 +369,7 @@ In this example, we're forwarding 51821/udp on the server to 51820 on the client
 
 Finally, run Wiretap with the forwarded local port as your endpoint on the server system:
 ```bash
-./wiretap serve --private <key> --public <key> --endpoint localhost:51821
+WIRETAP_INTERFACE_PRIVATEKEY=<key> WIRETAP_PEER_PUBLICKEY=<key> WIRETAP_PEER_ENDPOINT=localhost:51821 ./wiretap serve
 ```
 
 ### Nested Tunnels

demo.tape

@@ -42,6 +42,7 @@
 #   Show                            Show the subsequent commands in the output
 #
 # Run `socat TCP-LISTEN:6000,reuseaddr,fork UNIX-CLIENT:\"$DISPLAY\"` before recording to enable clipboard operations
+# If using XQuartz, also run `xhost + localhost`
 
 Output media/wiretap_demo.mp4
 
@@ -100,7 +101,7 @@ Sleep 2s
 
 # show curl doesn't work, then configure wiretap
 Type "curl http://10.2.0.4 --connect-timeout 3" Sleep 1s Enter Sleep 6s
-Type "./wiretap_linux_arm64 configure --endpoint 10.1.0.2:51820 --routes 10.2.0.0/16,fd:2::/64 -c" Sleep 1s Enter Sleep 4s
+Type "./wiretap configure --endpoint 10.1.0.2:51820 --routes 10.2.0.0/16,fd:2::/64 -c" Sleep 1s Enter Sleep 4s
 Type "wg-quick up ./wiretap.conf" Sleep 1s Enter Sleep 2s
 
 Ctrl+b
@@ -109,9 +110,8 @@ Sleep 2s
 
 # args are in clipboard now
 # this is bash magic, ESC+Ctrl+E will expand the current line
-# type ./wiretap_linux_arm64 $(xsel)
+# type $(xsel)
 # run expansion to make command line look like it was pasted
-Type "./wiretap_linux_arm64 " Sleep 1s
 Hide
 Type "$(xsel)"
 Escape

media/wiretap_demo.mp4

@@ -28,6 +28,8 @@ else
     EXT=
 endif
 
+OUTPUT=$(BIN)/$@_$(OS)_$(ARCH)$(EXT)## Output location
+
 # ld flags
 LDFLAGS=-s -w
 LDFLAGS+=-X wiretap/cmd.Version=$(VERSION)
@@ -37,7 +39,7 @@ LDFLAGS+=-X wiretap/cmd.Version=$(VERSION)
 
 ## wiretap: Build binary for the specified OS and architecture 
 wiretap:
-	$(ENV) $(GOBUILD) $(NOARGFLAGS) -o $(BIN)/$@_$(OS)_$(ARCH)$(EXT) -ldflags "$(LDFLAGS)" *.go
+	$(ENV) $(GOBUILD) $(NOARGFLAGS) -o $(OUTPUT) -ldflags "$(LDFLAGS)" *.go
 
 ## all: Build binaries for every OS/ARCH pair listed in the Makefile
 all: 

src/Makefile

@@ -17,6 +17,7 @@ type configureCmdConfig struct {
 	endpoint         string
 	port             int
 	configFile       string
+	serverConfigFile string
 	writeToClipboard bool
 	addr4            string
 	addr6            string
@@ -31,13 +32,31 @@ var configureCmd = configureCmdConfig{
 	endpoint:         Endpoint,
 	port:             Port,
 	configFile:       Config,
+	serverConfigFile: ServerConfig,
 	writeToClipboard: false,
 	addr4:            Subnet4.Addr().Next().Next().String() + "/32",
 	addr6:            Subnet6.Addr().Next().Next().String() + "/128",
 	apiAddr:          ApiAddr.String(),
 	disableApi:       false,
 }
 
+// Check if file exists, add number suffix if it does.
+func getUniqueFilename(filename string) string {
+	var err error
+	count := 1
+	ext := filepath.Ext(filename)
+	basename := strings.TrimSuffix(filename, ext)
+	for {
+		_, err = os.Stat(filename)
+		if os.IsNotExist(err) {
+			break
+		}
+		filename = fmt.Sprintf("%s_%d%s", basename, count, ext)
+		count += 1
+	}
+	return filename
+}
+
 // Add command and set flags.
 func init() {
 	// Usage info.
@@ -56,6 +75,7 @@ func init() {
 	cmd.Flags().StringVarP(&configureCmd.endpoint, "endpoint", "e", configureCmd.endpoint, "socket address of wireguard listener that server will connect to (example \"1.2.3.4:51820\")")
 	cmd.Flags().IntVarP(&configureCmd.port, "port", "p", configureCmd.port, "port of local wireguard listener")
 	cmd.Flags().StringVarP(&configureCmd.configFile, "output", "o", configureCmd.configFile, "wireguard config output filename")
+	cmd.Flags().StringVarP(&configureCmd.serverConfigFile, "server-config-output", "s", configureCmd.serverConfigFile, "wiretap server config output filename")
 	cmd.Flags().BoolVarP(&configureCmd.writeToClipboard, "clipboard", "c", configureCmd.writeToClipboard, "copy configuration args to clipboard")
 
 	cmd.Flags().StringVarP(&configureCmd.addr4, "ipv4", "4", configureCmd.addr4, "virtual wireguard interface ipv4 address")
@@ -104,41 +124,29 @@ func (c configureCmdConfig) Run() {
 	config, err := peer.GetConfig(configArgs)
 	check("failed to generate config", err)
 
-	// Add number to filename if it already exists.
-	count := 1
-	ext := filepath.Ext(c.configFile)
-	basename := strings.TrimSuffix(c.configFile, ext)
-	for {
-		_, err = os.Stat(c.configFile)
-		if os.IsNotExist(err) {
-			break
-		}
-		c.configFile = fmt.Sprintf("%s_%d%s", basename, count, ext)
-		count += 1
-	}
-
 	// Write config file and get status string.
+	c.configFile = getUniqueFilename(c.configFile)
 	var fileStatus string
 	err = os.WriteFile(c.configFile, []byte(config.AsFile()), 0600)
 	if err != nil {
-		fileStatus = fmt.Sprintf("%s %s", RedBold("config:"), Red(fmt.Sprintf("error writing config file: %v", err)))
+		fileStatus = fmt.Sprintf("%s %s", RedBold("client config:"), Red(fmt.Sprintf("error writing config file: %v", err)))
 	} else {
-		fileStatus = fmt.Sprintf("%s %s", GreenBold("config:"), Green(c.configFile))
+		fileStatus = fmt.Sprintf("%s %s", GreenBold("client config:"), Green(c.configFile))
 	}
 
-	// Generate argument string.
-	argString := fmt.Sprintf("serve --private %s --public %s",
-		config.GetPeerPrivateKey(0),
-		config.GetPublicKey(),
-	)
-
-	if len(config.GetPeerEndpoint(0)) > 0 {
-		argString = fmt.Sprintf("%s --endpoint %s", argString, config.GetPeerEndpoint(0))
+	// Write server config file and get status string.
+	c.serverConfigFile = getUniqueFilename(c.serverConfigFile)
+	var serverFileStatus string
+	err = os.WriteFile(c.serverConfigFile, []byte(config.AsServerFile()), 0600)
+	if err != nil {
+		serverFileStatus = fmt.Sprintf("%s %s", RedBold("server config:"), Red(fmt.Sprintf("error writing config file: %v", err)))
+	} else {
+		serverFileStatus = fmt.Sprintf("%s %s", GreenBold("server config:"), Green(c.serverConfigFile))
 	}
 
 	var clipboardStatus string
 	if c.writeToClipboard {
-		err = clipboard.WriteAll(argString)
+		err = clipboard.WriteAll(config.AsServerCommand("POSIX"))
 		if err != nil {
 			clipboardStatus = fmt.Sprintf("%s %s", RedBold("clipboard:"), Red(fmt.Sprintf("error copying to clipboard: %v", err)))
 		} else {
@@ -156,7 +164,12 @@ func (c configureCmdConfig) Run() {
 	fmt.Fprint(color.Output, WhiteBold(config.AsFile()))
 	fmt.Fprintln(color.Output, Green(strings.Repeat("─", 32)))
 	fmt.Fprintln(color.Output)
-	fmt.Fprintln(color.Output, GreenBold("args:"), Green(argString))
+	fmt.Fprintln(color.Output, serverFileStatus)
+	fmt.Fprintln(color.Output)
+	fmt.Fprintln(color.Output, GreenBold("server command:"))
+	fmt.Fprintln(color.Output, Cyan("POSIX Shell: "), Green(config.AsServerCommand("POSIX")))
+	fmt.Fprintln(color.Output, Cyan(" PowerShell: "), Green(config.AsServerCommand("POWERSHELL")))
+	fmt.Fprintln(color.Output, Cyan("Config File: "), Green("./wiretap serve -f " + c.serverConfigFile))
 	fmt.Fprintln(color.Output)
 	if c.writeToClipboard {
 		fmt.Fprintln(color.Output, clipboardStatus)

src/cmd/configure.go

@@ -13,16 +13,17 @@ import (
 
 // Defaults shared by multiple commands.
 var (
-	Version    = "v0.0.0"
-	Endpoint   = ""
-	Port       = 51820
-	Config     = "wiretap.conf"
-	Keepalive  = 25
-	ShowHidden = false
-	ApiAddr    = netip.MustParsePrefix("a::/128")
-	ApiPort    = 80
-	Subnet4    = netip.MustParsePrefix("192.168.0.0/24")
-	Subnet6    = netip.MustParsePrefix("fd::/64")
+	Version      = "v0.0.0"
+	Endpoint     = ""
+	Port         = 51820
+	Config       = "wiretap.conf"
+	ServerConfig = "wiretap_server.conf"
+	Keepalive    = 25
+	ShowHidden   = false
+	ApiAddr      = netip.MustParsePrefix("a::/128")
+	ApiPort      = 80
+	Subnet4      = netip.MustParsePrefix("192.168.0.0/24")
+	Subnet6      = netip.MustParsePrefix("fd::/64")
 )
 
 // Define colors.