Adjust README section titel heights

The connection information can now be displayed in JSON format. To
activate it use the '--json' flag. It will only format the connection
information in JSON everything else will be still in plain text.

README.md

@@ -4,7 +4,7 @@ A small tool to log IPs, usernames and passwords from incoming ssh-auth requests
 It opens a minimal SSH-Server and listens on IPv4 and IPv6 for auth requests.
 The goal of this little tool is to log the requests coming from bots living inside the wild internet.
 
-# Install
+## Install
 Make sure you have Golang installed and configured.
 ```shell
 git clone https://git.sr.ht/~hamburghammer/sshlog
@@ -13,7 +13,7 @@ go build
 ```
 Now you should be able to execute the newly generated executable with `./sshlog`.
 
-# Usage
+## Usage
 Start with:
 ```shell
 sshlog -p 2222
@@ -27,7 +27,15 @@ Output:
 2021/06/02 23:08:54 SRC=127.0.0.1 USERNAME=test PASSWORD=fooof
 ```
 
-## Options
+Output with `--json`:
+```text
+2021/09/02 12:43:42 Starting ssh logger on port 2222...
+{"date": "2021-09-02T12:44:15+02:00", "src": "127.0.0.1", "username": "test", "password": "foo"}
+{"date": "2021-09-02T12:44:18+02:00", "src": "127.0.0.1", "username": "test", "password": "foof"}
+{"date": "2021-09-02T12:44:21+02:00", "src": "127.0.0.1", "username": "test", "password": "fooof"}
+```
+
+### Options
 ```text
 A small tool to log IPs, usernames and passwords from incoming ssh-auth requests.
 
@@ -36,12 +44,13 @@ USAGE:
 
 FLAGS:
   -h, --help          Prints this help message and exits.
+      --json          Log in JSON instead of plain text.
   -k, --key string    Path to the host key for the ssh server.
                       If absent it will automatically generate a new one for each run.
   -4, --onlyIPv4      Only listens on IPv4.
   -p, --port string   Port to listen for incoming connections. (default "22"))
 ```
 
-# Utils
+## Utils
 Inside the `util` directory you might find some additional information like how to create Systemd service for sshlog.
 

go.mod

@@ -4,5 +4,5 @@ go 1.16
 
 require (
 	github.com/spf13/pflag v1.0.5
-	golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a
+	golang.org/x/crypto v0.0.0-20210817164053-32db794688a5
 )

go.sum

@@ -1,10 +1,11 @@
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
-golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a h1:kr2P4QFmQr29mSLA43kwrOcgcReGTfbE9N577tCTuBc=
-golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a/go.mod h1:P+XmwS30IXTQdn5tA2iutPOUgjI07+tq3H3K9MVA1s8=
+golang.org/x/crypto v0.0.0-20210817164053-32db794688a5 h1:HWj/xjIHfjYU5nVXpTM0s39J9CbLn7Cc5a7IC5rwsMQ=
+golang.org/x/crypto v0.0.0-20210817164053-32db794688a5/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68 h1:nxC68pudNYkKU6jWhgrqdreuFiOQWj1Fs7T3VrH4Pjw=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1 h1:SrN+KX8Art/Sf4HNj6Zcz06G7VEz+7w9tdXTPOZ7+l4=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1 h1:v+OssWQX+hTHEmOBgwxdZxK4zHq3yOs8F9J7mk0PY8E=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=

main.go

@@ -12,6 +12,7 @@ import (
 	"os"
 	"strings"
 	"sync"
+	"time"
 
 	flags "github.com/spf13/pflag"
 
@@ -23,6 +24,7 @@ var (
 	isHelp   bool
 	keyPath  string
 	onlyIPv4 bool
+	isJson   bool
 )
 
 func init() {
@@ -30,6 +32,7 @@ func init() {
 	flags.StringVarP(&keyPath, "key", "k", "", "Path to the host key for the ssh server.\nIf absent it will automatically generate a new one for each run.")
 	flags.BoolVarP(&isHelp, "help", "h", false, "Prints this help message and exits.")
 	flags.BoolVarP(&onlyIPv4, "onlyIPv4", "4", false, "Only listens on IPv4.")
+	flags.BoolVar(&isJson, "json", false, "Log in JSON instead of plain text.")
 	flags.Parse()
 }
 
@@ -82,12 +85,13 @@ func startAccepting(listener net.Listener, hostKey ssh.Signer) {
 
 func getKey(path string) []byte {
 	if path != "" {
-		privateBytes, err := ioutil.ReadFile("private-key.pem")
+		privateBytes, err := ioutil.ReadFile(path)
 		if err != nil {
-			log.Fatalf("Failed to load private key (%s)", path)
+			log.Fatalf("Failed to load private key: %s", path)
 		}
 		return privateBytes
 	}
+
 	privatekey, err := rsa.GenerateKey(rand.Reader, 2048)
 	if err != nil {
 		log.Fatalf("Cannot generate RSA key\n")
@@ -105,9 +109,21 @@ func getKey(path string) []byte {
 
 func PrintData(con net.Conn, hostKey ssh.Signer) {
 	serverConfig := ssh.ServerConfig{PasswordCallback: func(conn ssh.ConnMetadata, password []byte) (*ssh.Permissions, error) {
-		log.Printf("SRC=%s USERNAME=%s PASSWORD=%s\n", getIPWithoutPort(conn.RemoteAddr().String()), conn.User(), string(password))
+		ip := getIPWithoutPort(conn.RemoteAddr().String())
 
-		return nil, fmt.Errorf("password rejected for %q", conn.User())
+		if isJson {
+			fmt.Printf(
+				"{\"date\": \"%s\", \"src\": \"%s\", \"username\": \"%s\", \"password\": \"%s\"}\n",
+				time.Now().Format(time.RFC3339),
+				ip,
+				conn.User(),
+				string(password),
+			)
+		} else {
+			log.Printf("SRC=%s USERNAME=%s PASSWORD=%s\n", ip, conn.User(), string(password))
+		}
+
+		return nil, fmt.Errorf("password rejected for %s", conn.User())
 	}}
 
 	serverConfig.AddHostKey(hostKey)