-i to use public key instead of private key

README.md

@@ -186,3 +186,34 @@ component of our commercial offering for deploying and remotely [operating SaaS
 3rd party enterprise infrastructure](https://gravitational.com/product). 
 
 For more info, drop us an email: [info@gravitational.com](mailto:info@gravitational.com)
+
+## Building from source
+
+Instructions below are for Ubuntu 17.04
+
+Pre-requisites
+
+1. Install golang >= 1.7: `sudo apt install golang-1.9`
+- required for `context` (https://stackoverflow.com/a/42802790/4126114)
+2. Verify version: `go version` (e.g. `go version go1.9.2 linux/amd64`)
+3. Set `GOPATH`: `export GOPATH=$HOME/go`
+
+
+To build the binaries
+
+1. Clone this repository: `go get github.com/gravitational/teleconsole`
+2. `cd $GOPATH/src/github.com/gravitational/teleconsole`
+3. Install dependencies: `go get ./...` (add `-v` for higher verbosity)
+4. Build binaries: `make`
+
+
+To run tests
+
+1. Install test dependencies: `get -t ./...`
+2. Run tests: `make test`
+
+
+To make a release
+
+- `make release`
+- check `Makefile` for more details

lib/identity.go

@@ -1,9 +1,6 @@
 package lib
 
 import (
-	"crypto/dsa"
-	"crypto/ecdsa"
-	"crypto/rsa"
 	"encoding/csv"
 	"encoding/json"
 	"fmt"
@@ -35,7 +32,7 @@ import (
 //    and logs in using it.
 //
 // 2. A named identity uses a user-supplied SSH key, either via github handle
-//    or as a file (like ~/.ssh/id_rsa). Named identities private key never
+//    or as a file (like ~/.ssh/id_rsa.pub). Named identities private key never
 //    leaves the machine, but the joining party is supposed to have a private
 //    key on their machine to be able to join.
 //
@@ -173,26 +170,20 @@ func loginFromFile(fp string) (*sshLogin, error) {
 	if err != nil {
 		return nil, trace.Wrap(err)
 	}
-	// parse the private key:
-	p, err := ssh.ParseRawPrivateKey(bytes)
-	if err != nil {
-		return nil, trace.Wrap(err)
-	}
-	// derive the public key from the private one:
-	var pubKey ssh.PublicKey = nil
-	switch pk := p.(type) {
-	case *rsa.PrivateKey:
-		pubKey, err = ssh.NewPublicKey(&pk.PublicKey)
-	case *dsa.PrivateKey:
-		pubKey, err = ssh.NewPublicKey(&pk.PublicKey)
-	case *ecdsa.PrivateKey:
-		pubKey, err = ssh.NewPublicKey(&pk.PublicKey)
-	default:
-		return nil, trace.Errorf("Unsupported SSH key format")
-	}
+	// parse the public key:
+  // https://godoc.org/golang.org/x/crypto/ssh#ParsePublicKey
+	pubKey, err := ssh.ParsePublicKey(bytes)
 	if err != nil {
+
+		// check if this was a private key and alert accordingly:
+		_, err := ssh.ParseRawPrivateKey(bytes)
+		if err == nil {
+			return nil, trace.Wrap(err, "Private keys are no longer supported. Check https://github.com/gravitational/teleconsole/issues/19 for more details")
+		}
+
 		return nil, trace.Wrap(err)
 	}
+
 	return &sshLogin{
 		Username: filepath.Base(fp),
 		Key: &client.Key{