99 lines
2.7 KiB
Go
99 lines
2.7 KiB
Go
/*
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Copyright © 2024 Steven Polley <himself@stevenpolley.net>
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*/
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package cmd
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import (
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"encoding/base32"
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"fmt"
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"log"
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"net"
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"os"
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"time"
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"deadbeef.codes/steven/hyp/otphyp"
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"github.com/spf13/cobra"
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)
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// knockCmd represents the knock command
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var knockCmd = &cobra.Command{
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Use: "knock <hypServer>",
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Short: "Sends an authenticated knock sequence to the server specified",
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Long: `Runs the hyp client and performs an authentic knock sequence
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against the server provided.
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Example usage:
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hyp knock <hypServer>
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hyp knock hyp.deadbeef.codes
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hyp knock 10.69.4.20
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`,
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Args: cobra.ExactArgs(1),
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Run: func(cmd *cobra.Command, args []string) {
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// load secret and generate ports using secret and current time
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secretFilePath, err := cmd.Flags().GetString("secret")
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if err != nil {
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panic(fmt.Errorf("failed to parse command flag 'secret': %w", err))
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}
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maxJitter, err := cmd.Flags().GetInt("maxjitter")
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if err != nil {
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panic(fmt.Errorf("failed to parse command flag 'maxjitter': %w", err))
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}
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if maxJitter < 1 || maxJitter > 1500 {
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panic(fmt.Errorf("maxjitter must be value between 1 and 1500"))
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}
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refreshTime, err := cmd.Flags().GetInt("refreshtime")
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if err != nil {
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panic(fmt.Errorf("failed to parse command flag 'refreshtime': %w", err))
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}
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secretBytes, err := os.ReadFile(secretFilePath)
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if err != nil {
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log.Fatalf("failed to read file 'hyp.secret': %v", err)
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}
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decodedSecret, err := base32.StdEncoding.DecodeString(string(secretBytes))
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if err != nil {
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log.Fatalf("failed to base32 decode secret '%s': %v", secretFilePath, err)
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}
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for {
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ports, err := otphyp.GeneratePorts(decodedSecret, time.Now())
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if err != nil {
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log.Fatalf("failed to generate ports from shared secret: %v", err)
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}
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// Transmit
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for _, port := range ports {
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fmt.Printf("knock | %s:%d\n", args[0], port)
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conn, _ := net.Dial("udp", fmt.Sprintf("%s:%d", args[0], port))
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conn.Write([]byte{0})
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conn.Close()
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time.Sleep(time.Millisecond * time.Duration(maxJitter)) // TBD: Make this configurable with flag (maxJitter)
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}
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if refreshTime < 1 {
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break
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}
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sleepDuration := time.Minute * time.Duration(refreshTime)
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fmt.Printf("waiting until: %s...\n", time.Now().Add(sleepDuration).Format("15:04:05"))
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time.Sleep(sleepDuration)
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}
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},
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}
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func init() {
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rootCmd.AddCommand(knockCmd)
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knockCmd.PersistentFlags().String("secret", "hyp.secret", "Path to the file containing the hyp secret")
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knockCmd.PersistentFlags().Int("maxjitter", 200, "Specifies the time in milliseconds between transmissions while performing the knock sequence")
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knockCmd.PersistentFlags().Int("refreshtime", 0, "If specified, the hyp client will run persistently and send a full knock sequence at this interval in minutes")
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}
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