Allow assume role for AWS_MSK_IAM

Author: everesio

Diff for: README.md

@@ -191,8 +191,10 @@ You can launch a kafka-proxy container with auth-ldap plugin for trying it out w
             --proxy-listener-write-buffer-size int                 Sets the size of the operating system's transmit buffer associated with the connection. If zero, system default is used
             --proxy-request-buffer-size int                        Request buffer size pro tcp connection (default 4096)
             --proxy-response-buffer-size int                       Response buffer size pro tcp connection (default 4096)
+            --sasl-aws-identity-lookup                             Verify AWS authentication identity
             --sasl-aws-profile string                              AWS profile
             --sasl-aws-region string                               Region for AWS IAM Auth
+            --sasl-aws-role-arn string                             AWS Role ARN to assume
             --sasl-enable                                          Connect using SASL
             --sasl-jaas-config-file string                         Location of JAAS config file with SASL username and password
             --sasl-method string                                   SASL method to use (PLAIN, SCRAM-SHA-256, SCRAM-SHA-512, GSSAPI, AWS_MSK_IAM (default "PLAIN")

Diff for: cmd/kafka-proxy/server.go

@@ -187,6 +187,8 @@ func initFlags() {
 	// SASL AWS_MSK_IAM
 	Server.Flags().StringVar(&c.Kafka.SASL.AWSConfig.Region, "sasl-aws-region", "", "Region for AWS IAM Auth")
 	Server.Flags().StringVar(&c.Kafka.SASL.AWSConfig.Profile, "sasl-aws-profile", "", "AWS profile")
+	Server.Flags().StringVar(&c.Kafka.SASL.AWSConfig.RoleArn, "sasl-aws-role-arn", "", "AWS Role ARN to assume")
+	Server.Flags().BoolVar(&c.Kafka.SASL.AWSConfig.IdentityLookup, "sasl-aws-identity-lookup", false, "Verify AWS authentication identity")
 
 	// SASL by Proxy plugin
 	Server.Flags().BoolVar(&c.Kafka.SASL.Plugin.Enable, "sasl-plugin-enable", false, "Use plugin for SASL authentication")

Diff for: config/config.go

@@ -48,8 +48,10 @@ type GSSAPIConfig struct {
 }
 
 type AWSConfig struct {
-	Region  string
-	Profile string
+	Region         string
+	Profile        string
+	RoleArn        string
+	IdentityLookup bool
 }
 
 type Config struct {

Diff for: proxy/sasl_aws_msk_iam.go

@@ -4,15 +4,18 @@ import (
 	"bytes"
 	"context"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"net"
 	"time"
 
+	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/aws/aws-sdk-go-v2/config"
+	"github.com/aws/aws-sdk-go-v2/credentials/stscreds"
+	"github.com/aws/aws-sdk-go-v2/service/sts"
 	proxyconfig "github.com/grepplabs/kafka-proxy/config"
 	"github.com/grepplabs/kafka-proxy/proxy/protocol"
-	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
@@ -44,6 +47,21 @@ func NewAwsMSKIamAuth(
 	if err != nil {
 		return nil, fmt.Errorf("loading aws config: %v", err)
 	}
+	if awsConfig.RoleArn != "" {
+		stsClient := sts.NewFromConfig(cfg)
+		assumeRoleProvider := stscreds.NewAssumeRoleProvider(stsClient, awsConfig.RoleArn)
+		cfg.Credentials = aws.NewCredentialsCache(assumeRoleProvider)
+	}
+	if awsConfig.IdentityLookup {
+		ctx := context.Background()
+		ctx, cancel := context.WithTimeout(ctx, 15*time.Second)
+		defer cancel()
+		output, err := sts.NewFromConfig(cfg).GetCallerIdentity(ctx, &sts.GetCallerIdentityInput{})
+		if err != nil {
+			return nil, fmt.Errorf("failed to get caller identity: %v", err)
+		}
+		logrus.Infof("AWS_MSK_IAM caller identity %s", aws.ToString(output.Arn))
+	}
 	return &AwsMSKIamAuth{
 		clientID:     clientId,
 		signer:       newMechanism(cfg),
@@ -56,11 +74,11 @@ func NewAwsMSKIamAuth(
 // sendAndReceiveSASLAuth handles the entire SASL authentication process
 func (a *AwsMSKIamAuth) sendAndReceiveSASLAuth(conn DeadlineReaderWriter, brokerString string) error {
 	if err := a.saslHandshake(conn); err != nil {
-		return errors.Wrap(err, "handshake failed")
+		return fmt.Errorf("handshake failed: %w", err)
 	}
 
 	if err := a.saslAuthenticate(conn, brokerString); err != nil {
-		return errors.Wrap(err, "authenticate failed")
+		return fmt.Errorf("authenticate failed: %w", err)
 	}
 
 	return nil
@@ -76,21 +94,21 @@ func (a *AwsMSKIamAuth) saslHandshake(conn DeadlineReaderWriter) error {
 		Body:     rb,
 	}
 	if err := a.write(conn, req); err != nil {
-		return errors.Wrap(err, "writing SASL handshake")
+		return fmt.Errorf("writing SASL handshake: %w", err)
 	}
 
 	payload, err := a.read(conn)
 	if err != nil {
-		return errors.Wrap(err, "reading SASL handshake")
+		return fmt.Errorf("reading SASL handshake: %w", err)
 	}
 
 	res := &protocol.SaslHandshakeResponseV0orV1{}
 	if err := protocol.Decode(payload, res); err != nil {
-		return errors.Wrap(err, "parsing SASL handshake response")
+		return fmt.Errorf("parsing SASL handshake response: %w", err)
 	}
 
-	if res.Err != protocol.ErrNoError {
-		return errors.Wrap(res.Err, "sasl handshake protocol error")
+	if !errors.Is(res.Err, protocol.ErrNoError) {
+		return fmt.Errorf("sasl handshake protocol error: %w", res.Err)
 	}
 	logrus.Debugf("Successful IAM SASL handshake. Available mechanisms: %v", res.EnabledMechanisms)
 	return nil
@@ -114,59 +132,59 @@ func (a *AwsMSKIamAuth) saslAuthenticate(conn DeadlineReaderWriter, brokerString
 		Body:     saslAuthReqV0,
 	}
 	if err := a.write(conn, req); err != nil {
-		return errors.Wrap(err, "writing SASL authentication request")
+		return fmt.Errorf("writing SASL authentication request: %w", err)
 	}
 
 	payload, err := a.read(conn)
 	if err != nil {
-		return errors.Wrap(err, "reading SASL authentication response")
+		return fmt.Errorf("reading SASL authentication response: %w", err)
 	}
 
 	res := &protocol.SaslAuthenticateResponseV0{}
 	err = protocol.Decode(payload, res)
 	if err != nil {
-		return errors.Wrap(err, "parsing SASL authentication response")
+		return fmt.Errorf("parsing SASL authentication response: %w", err)
 	}
-	if res.Err != protocol.ErrNoError {
-		return errors.Wrap(res.Err, "sasl authentication protocol error")
+	if !errors.Is(res.Err, protocol.ErrNoError) {
+		return fmt.Errorf("sasl authentication protocol error: %w", res.Err)
 	}
 	return nil
 }
 
 func (a *AwsMSKIamAuth) write(conn DeadlineReaderWriter, req *protocol.Request) error {
 	reqBuf, err := protocol.Encode(req)
 	if err != nil {
-		return errors.Wrap(err, "serializing request")
+		return fmt.Errorf("serializing request: %w", err)
 	}
 
 	sizeBuf := make([]byte, 4)
 	binary.BigEndian.PutUint32(sizeBuf, uint32(len(reqBuf)))
 
 	if err := conn.SetWriteDeadline(time.Now().Add(a.writeTimeout)); err != nil {
-		return errors.Wrap(err, "setting write deadline")
+		return fmt.Errorf("setting write deadline: %w", err)
 	}
 
 	if _, err := conn.Write(bytes.Join([][]byte{sizeBuf, reqBuf}, nil)); err != nil {
-		return errors.Wrap(err, "writing bytes")
+		return fmt.Errorf("writing bytes: %w", err)
 	}
 	return nil
 }
 
 func (a *AwsMSKIamAuth) read(conn DeadlineReaderWriter) ([]byte, error) {
 	if err := conn.SetReadDeadline(time.Now().Add(a.readTimeout)); err != nil {
-		return nil, errors.Wrap(err, "setting read deadline")
+		return nil, fmt.Errorf("setting read deadline: %w", err)
 	}
 
 	//wait for the handshake response
 	header := make([]byte, 8) // response header
 	if _, err := io.ReadFull(conn, header); err != nil {
-		return nil, errors.Wrap(err, "reading header")
+		return nil, fmt.Errorf("reading header: %w", err)
 	}
 
 	length := binary.BigEndian.Uint32(header[:4])
 	payload := make([]byte, length-4)
 	if _, err := io.ReadFull(conn, payload); err != nil {
-		return nil, errors.Wrap(err, "reading payload")
+		return nil, fmt.Errorf("reading payload: %w", err)
 	}
 
 	return payload, nil