Resolve AWS IAM unique IDs (#2814)

builtin/credential/aws/backend.go

@@ -1,9 +1,11 @@
 package awsauth
 
 import (
+	"fmt"
 	"sync"
 	"time"
 
+	"github.com/aws/aws-sdk-go/aws/endpoints"
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/aws/aws-sdk-go/service/iam"
 	"github.com/hashicorp/vault/logical"
@@ -54,6 +56,15 @@ type backend struct {
 	// When the credentials are modified or deleted, all the cached client objects
 	// will be flushed. The empty STS role signifies the master account
 	IAMClientsMap map[string]map[string]*iam.IAM
+
+	// AWS Account ID of the "default" AWS credentials
+	// This cache avoids the need to call GetCallerIdentity repeatedly to learn it
+	// We can't store this because, in certain pathological cases, it could change
+	// out from under us, such as a standby and active Vault server in different AWS
+	// accounts using their IAM instance profile to get their credentials.
+	defaultAWSAccountID string
+
+	resolveArnToUniqueIDFunc func(logical.Storage, string) (string, error)
 }
 
 func Backend(conf *logical.BackendConfig) (*backend, error) {
@@ -65,6 +76,8 @@ func Backend(conf *logical.BackendConfig) (*backend, error) {
 		IAMClientsMap:      make(map[string]map[string]*iam.IAM),
 	}
 
+	b.resolveArnToUniqueIDFunc = b.resolveArnToRealUniqueId
+
 	b.Backend = &framework.Backend{
 		PeriodicFunc: b.periodicFunc,
 		AuthRenew:    b.pathLoginRenew,
@@ -171,9 +184,86 @@ func (b *backend) invalidate(key string) {
 		defer b.configMutex.Unlock()
 		b.flushCachedEC2Clients()
 		b.flushCachedIAMClients()
+		b.defaultAWSAccountID = ""
 	}
 }
 
+// Putting this here so we can inject a fake resolver into the backend for unit testing
+// purposes
+func (b *backend) resolveArnToRealUniqueId(s logical.Storage, arn string) (string, error) {
+	entity, err := parseIamArn(arn)
+	if err != nil {
+		return "", err
+	}
+	// This odd-looking code is here because IAM is an inherently global service. IAM and STS ARNs
+	// don't have regions in them, and there is only a single global endpoint for IAM; see
+	// http://docs.aws.amazon.com/general/latest/gr/rande.html#iam_region
+	// However, the ARNs do have a partition in them, because the GovCloud and China partitions DO
+	// have their own separate endpoints, and the partition is encoded in the ARN. If Amazon's Go SDK
+	// would allow us to pass a partition back to the IAM client, it would be much simpler. But it
+	// doesn't appear that's possible, so in order to properly support GovCloud and China, we do a
+	// circular dance of extracting the partition from the ARN, finding any arbitrary region in the
+	// partition, and passing that region back back to the SDK, so that the SDK can figure out the
+	// proper partition from the arbitrary region we passed in to look up the endpoint.
+	// Sigh
+	region := getAnyRegionForAwsPartition(entity.Partition)
+	if region == nil {
+		return "", fmt.Errorf("Unable to resolve partition %q to a region", entity.Partition)
+	}
+	iamClient, err := b.clientIAM(s, region.ID(), entity.AccountNumber)
+	if err != nil {
+		return "", err
+	}
+
+	switch entity.Type {
+	case "user":
+		userInfo, err := iamClient.GetUser(&iam.GetUserInput{UserName: &entity.FriendlyName})
+		if err != nil {
+			return "", err
+		}
+		if userInfo == nil {
+			return "", fmt.Errorf("got nil result from GetUser")
+		}
+		return *userInfo.User.UserId, nil
+	case "role":
+		roleInfo, err := iamClient.GetRole(&iam.GetRoleInput{RoleName: &entity.FriendlyName})
+		if err != nil {
+			return "", err
+		}
+		if roleInfo == nil {
+			return "", fmt.Errorf("got nil result from GetRole")
+		}
+		return *roleInfo.Role.RoleId, nil
+	case "instance-profile":
+		profileInfo, err := iamClient.GetInstanceProfile(&iam.GetInstanceProfileInput{InstanceProfileName: &entity.FriendlyName})
+		if err != nil {
+			return "", err
+		}
+		if profileInfo == nil {
+			return "", fmt.Errorf("got nil result from GetInstanceProfile")
+		}
+		return *profileInfo.InstanceProfile.InstanceProfileId, nil
+	default:
+		return "", fmt.Errorf("unrecognized error type %#v", entity.Type)
+	}
+}
+
+// Adapted from https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/
+// the "Enumerating Regions and Endpoint Metadata" section
+func getAnyRegionForAwsPartition(partitionId string) *endpoints.Region {
+	resolver := endpoints.DefaultResolver()
+	partitions := resolver.(endpoints.EnumPartitions).Partitions()
+
+	for _, p := range partitions {
+		if p.ID() == partitionId {
+			for _, r := range p.Regions() {
+				return &r
+			}
+		}
+	}
+	return nil
+}
+
 const backendHelp = `
 aws-ec2 auth backend takes in PKCS#7 signature of an AWS EC2 instance and a client
 created nonce to authenticates the EC2 instance with Vault.

builtin/credential/aws/backend_test.go

@@ -9,11 +9,13 @@ import (
 	"os"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/sts"
 	"github.com/hashicorp/vault/helper/policyutil"
 	"github.com/hashicorp/vault/logical"
+	"github.com/hashicorp/vault/logical/framework"
 	logicaltest "github.com/hashicorp/vault/logical/testing"
 )
 
@@ -1346,7 +1348,7 @@ func TestBackendAcc_LoginWithCallerIdentity(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Received error retrieving identity: %s", err)
 	}
-	testIdentityArn, _, _, err := parseIamArn(*testIdentity.Arn)
+	entity, err := parseIamArn(*testIdentity.Arn)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1385,7 +1387,7 @@ func TestBackendAcc_LoginWithCallerIdentity(t *testing.T) {
 
 	// configuring the valid role we'll be able to login to
 	roleData := map[string]interface{}{
-		"bound_iam_principal_arn": testIdentityArn,
+		"bound_iam_principal_arn": entity.canonicalArn(),
 		"policies":                "root",
 		"auth_type":               iamAuthType,
 	}
@@ -1417,8 +1419,17 @@ func TestBackendAcc_LoginWithCallerIdentity(t *testing.T) {
 		t.Fatalf("bad: failed to create role; resp:%#v\nerr:%v", resp, err)
 	}
 
+	fakeArn := "arn:aws:iam::123456789012:role/FakeRole"
+	fakeArnResolver := func(s logical.Storage, arn string) (string, error) {
+		if arn == fakeArn {
+			return fmt.Sprintf("FakeUniqueIdFor%s", fakeArn), nil
+		}
+		return b.resolveArnToRealUniqueId(s, arn)
+	}
+	b.resolveArnToUniqueIDFunc = fakeArnResolver
+
 	// now we're creating the invalid role we won't be able to login to
-	roleData["bound_iam_principal_arn"] = "arn:aws:iam::123456789012:role/FakeRole"
+	roleData["bound_iam_principal_arn"] = fakeArn
 	roleRequest.Path = "role/" + testInvalidRoleName
 	resp, err = b.HandleRequest(roleRequest)
 	if err != nil || (resp != nil && resp.IsError()) {
@@ -1491,7 +1502,7 @@ func TestBackendAcc_LoginWithCallerIdentity(t *testing.T) {
 		t.Errorf("bad: expected failed login due to bad auth type: resp:%#v\nerr:%v", resp, err)
 	}
 
-	// finally, the happy path tests :)
+	// finally, the happy path test :)
 
 	loginData["role"] = testValidRoleName
 	resp, err = b.HandleRequest(loginRequest)
@@ -1501,4 +1512,52 @@ func TestBackendAcc_LoginWithCallerIdentity(t *testing.T) {
 	if resp == nil || resp.Auth == nil || resp.IsError() {
 		t.Errorf("bad: expected valid login: resp:%#v", resp)
 	}
+
+	renewReq := &logical.Request{
+		Storage: storage,
+		Auth:    &logical.Auth{},
+	}
+	empty_login_fd := &framework.FieldData{
+		Raw:    map[string]interface{}{},
+		Schema: pathLogin(b).Fields,
+	}
+	renewReq.Auth.InternalData = resp.Auth.InternalData
+	renewReq.Auth.Metadata = resp.Auth.Metadata
+	renewReq.Auth.LeaseOptions = resp.Auth.LeaseOptions
+	renewReq.Auth.Policies = resp.Auth.Policies
+	renewReq.Auth.IssueTime = time.Now()
+	// ensure we can renew
+	resp, err = b.pathLoginRenew(renewReq, empty_login_fd)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp == nil {
+		t.Fatal("got nil response from renew")
+	}
+	if resp.IsError() {
+		t.Fatalf("got error when renewing: %#v", *resp)
+	}
+
+	// Now, fake out the unique ID resolver to ensure we fail login if the unique ID
+	// changes from under us
+	b.resolveArnToUniqueIDFunc = resolveArnToFakeUniqueId
+	// First, we need to update the role to force Vault to use our fake resolver to
+	// pick up the fake user ID
+	roleData["bound_iam_principal_arn"] = entity.canonicalArn()
+	roleRequest.Path = "role/" + testValidRoleName
+	resp, err = b.HandleRequest(roleRequest)
+	if err != nil || (resp != nil && resp.IsError()) {
+		t.Fatalf("bad: failed to recreate role: resp:%#v\nerr:%v", resp, err)
+	}
+	resp, err = b.HandleRequest(loginRequest)
+	if err != nil || resp == nil || !resp.IsError() {
+		t.Errorf("bad: expected failed login due to changed AWS role ID: resp: %#v\nerr:%v", resp, err)
+	}
+
+	// and ensure a renew no longer works
+	resp, err = b.pathLoginRenew(renewReq, empty_login_fd)
+	if err == nil || (resp != nil && !resp.IsError()) {
+		t.Errorf("bad: expected failed renew due to changed AWS role ID: resp: %#v", resp, err)
+	}
+
 }

builtin/credential/aws/client.go

@@ -8,6 +8,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/aws/aws-sdk-go/service/iam"
+	"github.com/aws/aws-sdk-go/service/sts"
 	"github.com/hashicorp/go-cleanhttp"
 	"github.com/hashicorp/vault/helper/awsutil"
 	"github.com/hashicorp/vault/logical"
@@ -70,7 +71,7 @@ func (b *backend) getRawClientConfig(s logical.Storage, region, clientType strin
 // It uses getRawClientConfig to obtain config for the runtime environemnt, and if
 // stsRole is a non-empty string, it will use AssumeRole to obtain a set of assumed
 // credentials. The credentials will expire after 15 minutes but will auto-refresh.
-func (b *backend) getClientConfig(s logical.Storage, region, stsRole, clientType string) (*aws.Config, error) {
+func (b *backend) getClientConfig(s logical.Storage, region, stsRole, accountID, clientType string) (*aws.Config, error) {
 
 	config, err := b.getRawClientConfig(s, region, clientType)
 	if err != nil {
@@ -80,20 +81,39 @@ func (b *backend) getClientConfig(s logical.Storage, region, stsRole, clientType
 		return nil, fmt.Errorf("could not compile valid credentials through the default provider chain")
 	}
 
+	stsConfig, err := b.getRawClientConfig(s, region, "sts")
+	if stsConfig == nil {
+		return nil, fmt.Errorf("could not configure STS client")
+	}
+	if err != nil {
+		return nil, err
+	}
 	if stsRole != "" {
-		assumeRoleConfig, err := b.getRawClientConfig(s, region, "sts")
-		if err != nil {
-			return nil, err
-		}
-		if assumeRoleConfig == nil {
-			return nil, fmt.Errorf("could not configure STS client")
-		}
-		assumedCredentials := stscreds.NewCredentials(session.New(assumeRoleConfig), stsRole)
+		assumedCredentials := stscreds.NewCredentials(session.New(stsConfig), stsRole)
 		// Test that we actually have permissions to assume the role
 		if _, err = assumedCredentials.Get(); err != nil {
 			return nil, err
 		}
 		config.Credentials = assumedCredentials
+	} else {
+		if b.defaultAWSAccountID == "" {
+			client := sts.New(session.New(stsConfig))
+			if client == nil {
+				return nil, fmt.Errorf("could not obtain sts client: %v", err)
+			}
+			inputParams := &sts.GetCallerIdentityInput{}
+			identity, err := client.GetCallerIdentity(inputParams)
+			if err != nil {
+				return nil, fmt.Errorf("unable to fetch current caller: %v", err)
+			}
+			if identity == nil {
+				return nil, fmt.Errorf("got nil result from GetCallerIdentity")
+			}
+			b.defaultAWSAccountID = *identity.Account
+		}
+		if b.defaultAWSAccountID != accountID {
+			return nil, fmt.Errorf("unable to fetch client for account ID %s -- default client is for account %s", accountID, b.defaultAWSAccountID)
+		}
 	}
 
 	return config, nil
@@ -121,8 +141,25 @@ func (b *backend) flushCachedIAMClients() {
 	}
 }
 
+func (b *backend) stsRoleForAccount(s logical.Storage, accountID string) (string, error) {
+	// Check if an STS configuration exists for the AWS account
+	sts, err := b.lockedAwsStsEntry(s, accountID)
+	if err != nil {
+		return "", fmt.Errorf("error fetching STS config for account ID %q: %q\n", accountID, err)
+	}
+	// An empty STS role signifies the master account
+	if sts != nil {
+		return sts.StsRole, nil
+	}
+	return "", nil
+}
+
 // clientEC2 creates a client to interact with AWS EC2 API
-func (b *backend) clientEC2(s logical.Storage, region string, stsRole string) (*ec2.EC2, error) {
+func (b *backend) clientEC2(s logical.Storage, region, accountID string) (*ec2.EC2, error) {
+	stsRole, err := b.stsRoleForAccount(s, accountID)
+	if err != nil {
+		return nil, err
+	}
 	b.configMutex.RLock()
 	if b.EC2ClientsMap[region] != nil && b.EC2ClientsMap[region][stsRole] != nil {
 		defer b.configMutex.RUnlock()
@@ -142,8 +179,7 @@ func (b *backend) clientEC2(s logical.Storage, region string, stsRole string) (*
 
 	// Create an AWS config object using a chain of providers
 	var awsConfig *aws.Config
-	var err error
-	awsConfig, err = b.getClientConfig(s, region, stsRole, "ec2")
+	awsConfig, err = b.getClientConfig(s, region, stsRole, accountID, "ec2")
 
 	if err != nil {
 		return nil, err
@@ -168,7 +204,11 @@ func (b *backend) clientEC2(s logical.Storage, region string, stsRole string) (*
 }
 
 // clientIAM creates a client to interact with AWS IAM API
-func (b *backend) clientIAM(s logical.Storage, region string, stsRole string) (*iam.IAM, error) {
+func (b *backend) clientIAM(s logical.Storage, region, accountID string) (*iam.IAM, error) {
+	stsRole, err := b.stsRoleForAccount(s, accountID)
+	if err != nil {
+		return nil, err
+	}
 	b.configMutex.RLock()
 	if b.IAMClientsMap[region] != nil && b.IAMClientsMap[region][stsRole] != nil {
 		defer b.configMutex.RUnlock()
@@ -188,8 +228,7 @@ func (b *backend) clientIAM(s logical.Storage, region string, stsRole string) (*
 
 	// Create an AWS config object using a chain of providers
 	var awsConfig *aws.Config
-	var err error
-	awsConfig, err = b.getClientConfig(s, region, stsRole, "iam")
+	awsConfig, err = b.getClientConfig(s, region, stsRole, accountID, "iam")
 
 	if err != nil {
 		return nil, err

builtin/credential/aws/path_config_client.go

@@ -129,6 +129,9 @@ func (b *backend) pathConfigClientDelete(
 	// Remove all the cached EC2 client objects in the backend.
 	b.flushCachedIAMClients()
 
+	// unset the cached default AWS account ID
+	b.defaultAWSAccountID = ""
+
 	return nil, nil
 }
 
@@ -234,6 +237,7 @@ func (b *backend) pathConfigClientCreateUpdate(
 	if changedCreds {
 		b.flushCachedEC2Clients()
 		b.flushCachedIAMClients()
+		b.defaultAWSAccountID = ""
 	}
 
 	return nil, nil

builtin/credential/aws/path_login.go

@@ -151,20 +151,8 @@ func (b *backend) instanceIamRoleARN(iamClient *iam.IAM, instanceProfileName str
 // validateInstance queries the status of the EC2 instance using AWS EC2 API
 // and checks if the instance is running and is healthy
 func (b *backend) validateInstance(s logical.Storage, instanceID, region, accountID string) (*ec2.Instance, error) {
-
-	// Check if an STS configuration exists for the AWS account
-	sts, err := b.lockedAwsStsEntry(s, accountID)
-	if err != nil {
-		return nil, fmt.Errorf("error fetching STS config for account ID %q: %q\n", accountID, err)
-	}
-	// An empty STS role signifies the master account
-	stsRole := ""
-	if sts != nil {
-		stsRole = sts.StsRole
-	}
-
 	// Create an EC2 client to pull the instance information
-	ec2Client, err := b.clientEC2(s, region, stsRole)
+	ec2Client, err := b.clientEC2(s, region, accountID)
 	if err != nil {
 		return nil, err
 	}
@@ -472,32 +460,20 @@ func (b *backend) verifyInstanceMeetsRoleRequirements(
 
 		// Extract out the instance profile name from the instance
 		// profile ARN
-		iamInstanceProfileARNSlice := strings.SplitAfter(iamInstanceProfileARN, "/")
-		iamInstanceProfileName := iamInstanceProfileARNSlice[len(iamInstanceProfileARNSlice)-1]
+		iamInstanceProfileEntity, err := parseIamArn(iamInstanceProfileARN)
 
-		if iamInstanceProfileName == "" {
-			return nil, fmt.Errorf("failed to extract out IAM instance profile name from IAM instance profile ARN")
-		}
-
-		// Check if an STS configuration exists for the AWS account
-		sts, err := b.lockedAwsStsEntry(s, identityDoc.AccountID)
 		if err != nil {
-			return fmt.Errorf("error fetching STS config for account ID %q: %q\n", identityDoc.AccountID, err), nil
-		}
-		// An empty STS role signifies the master account
-		stsRole := ""
-		if sts != nil {
-			stsRole = sts.StsRole
+			return nil, fmt.Errorf("failed to parse IAM instance profile ARN %q; error: %v", iamInstanceProfileARN, err)
 		}
 
 		// Use instance profile ARN to fetch the associated role ARN
-		iamClient, err := b.clientIAM(s, identityDoc.Region, stsRole)
+		iamClient, err := b.clientIAM(s, identityDoc.Region, identityDoc.AccountID)
 		if err != nil {
 			return nil, fmt.Errorf("could not fetch IAM client: %v", err)
 		} else if iamClient == nil {
 			return nil, fmt.Errorf("received a nil iamClient")
 		}
-		iamRoleARN, err := b.instanceIamRoleARN(iamClient, iamInstanceProfileName)
+		iamRoleARN, err := b.instanceIamRoleARN(iamClient, iamInstanceProfileEntity.FriendlyName)
 		if err != nil {
 			return nil, fmt.Errorf("IAM role ARN could not be fetched: %v", err)
 		}
@@ -959,6 +935,19 @@ func (b *backend) pathLoginRenewIam(
 	if roleEntry.BoundIamPrincipalARN != "" && roleEntry.BoundIamPrincipalARN != canonicalArn {
 		return nil, fmt.Errorf("role no longer bound to arn %q", canonicalArn)
 	}
+	// Need to hanndle the case where an auth token was generated before we put client_user_id in the metadata
+	// Basic goal here is:
+	//  1. If no client_user_id metadata exists, then skip the check (it might be nice to fill it in later, but
+	//     could be complicated)
+	//  2. If role is not bound to an ID, that means that checking the unique ID has been disabled, so skip the
+	//     check
+	//  3. Otherwise, ensure that the stored client_user_id matches the bound IAM principal ID. If an IAM user
+	//     or role is deleted and recreated, then existing clients will NOT be able to renew and they'll need
+	//     to reauthenticate to Vault with updated IAM credentials
+	originalUserId, ok := req.Auth.Metadata["client_user_id"]
+	if ok && roleEntry.BoundIamPrincipalID != "" && roleEntry.BoundIamPrincipalID != req.Auth.Metadata["client_user_id"] {
+		return nil, fmt.Errorf("role no longer bound to ID %q", originalUserId)
+	}
 
 	return framework.LeaseExtend(roleEntry.TTL, roleEntry.MaxTTL, b.System())(req, data)
 
@@ -1134,18 +1123,21 @@ func (b *backend) pathLoginUpdateIam(
 		}
 	}
 
-	clientArn, accountID, err := submitCallerIdentityRequest(method, endpoint, parsedUrl, body, headers)
+	callerID, err := submitCallerIdentityRequest(method, endpoint, parsedUrl, body, headers)
 	if err != nil {
 		return logical.ErrorResponse(fmt.Sprintf("error making upstream request: %v", err)), nil
 	}
-	canonicalArn, principalName, sessionName, err := parseIamArn(clientArn)
+	// This could either be a "userID:SessionID" (in the case of an assumed role) or just a "userID"
+	// (in the case of an IAM user).
+	callerUniqueId := strings.Split(callerID.UserId, ":")[0]
+	entity, err := parseIamArn(callerID.Arn)
 	if err != nil {
 		return logical.ErrorResponse(fmt.Sprintf("Error parsing arn: %v", err)), nil
 	}
 
 	roleName := data.Get("role").(string)
 	if roleName == "" {
-		roleName = principalName
+		roleName = entity.FriendlyName
 	}
 
 	roleEntry, err := b.lockedAWSRole(req.Storage, roleName)
@@ -1162,8 +1154,15 @@ func (b *backend) pathLoginUpdateIam(
 
 	// The role creation should ensure that either we're inferring this is an EC2 instance
 	// or that we're binding an ARN
-	if roleEntry.BoundIamPrincipalARN != "" && roleEntry.BoundIamPrincipalARN != canonicalArn {
-		return logical.ErrorResponse(fmt.Sprintf("IAM Principal %q does not belong to the role %q", clientArn, roleName)), nil
+	// The only way BoundIamPrincipalID could get set is if BoundIamPrincipalARN was also set and
+	// resolving to internal IDs was turned on, which can't be turned off. So, there should be no
+	// way for this to be set and not match BoundIamPrincipalARN
+	if roleEntry.BoundIamPrincipalID != "" {
+		if callerUniqueId != roleEntry.BoundIamPrincipalID {
+			return logical.ErrorResponse(fmt.Sprintf("expected IAM %s %s to resolve to unique AWS ID %q but got %q instead", entity.Type, entity.FriendlyName, roleEntry.BoundIamPrincipalID, callerUniqueId)), nil
+		}
+	} else if roleEntry.BoundIamPrincipalARN != "" && roleEntry.BoundIamPrincipalARN != entity.canonicalArn() {
+		return logical.ErrorResponse(fmt.Sprintf("IAM Principal %q does not belong to the role %q", callerID.Arn, roleName)), nil
 	}
 
 	policies := roleEntry.Policies
@@ -1171,9 +1170,9 @@ func (b *backend) pathLoginUpdateIam(
 	inferredEntityType := ""
 	inferredEntityId := ""
 	if roleEntry.InferredEntityType == ec2EntityType {
-		instance, err := b.validateInstance(req.Storage, sessionName, roleEntry.InferredAWSRegion, accountID)
+		instance, err := b.validateInstance(req.Storage, entity.SessionInfo, roleEntry.InferredAWSRegion, callerID.Account)
 		if err != nil {
-			return logical.ErrorResponse(fmt.Sprintf("failed to verify %s as a valid EC2 instance in region %s", sessionName, roleEntry.InferredAWSRegion)), nil
+			return logical.ErrorResponse(fmt.Sprintf("failed to verify %s as a valid EC2 instance in region %s", entity.SessionInfo, roleEntry.InferredAWSRegion)), nil
 		}
 
 		// build a fake identity doc to pass on metadata about the instance to verifyInstanceMeetsRoleRequirements
@@ -1181,7 +1180,7 @@ func (b *backend) pathLoginUpdateIam(
 			Tags:        nil, // Don't really need the tags, so not doing the work of converting them from Instance.Tags to identityDocument.Tags
 			InstanceID:  *instance.InstanceId,
 			AmiID:       *instance.ImageId,
-			AccountID:   accountID,
+			AccountID:   callerID.Account,
 			Region:      roleEntry.InferredAWSRegion,
 			PendingTime: instance.LaunchTime.Format(time.RFC3339),
 		}
@@ -1191,11 +1190,11 @@ func (b *backend) pathLoginUpdateIam(
 			return nil, err
 		}
 		if validationError != nil {
-			return logical.ErrorResponse(fmt.Sprintf("Error validating instance: %s", validationError)), nil
+			return logical.ErrorResponse(fmt.Sprintf("error validating instance: %s", validationError)), nil
 		}
 
 		inferredEntityType = ec2EntityType
-		inferredEntityId = sessionName
+		inferredEntityId = entity.SessionInfo
 	}
 
 	resp := &logical.Response{
@@ -1203,18 +1202,19 @@ func (b *backend) pathLoginUpdateIam(
 			Period:   roleEntry.Period,
 			Policies: policies,
 			Metadata: map[string]string{
-				"client_arn":           clientArn,
-				"canonical_arn":        canonicalArn,
+				"client_arn":           callerID.Arn,
+				"canonical_arn":        entity.canonicalArn(),
+				"client_user_id":       callerUniqueId,
 				"auth_type":            iamAuthType,
 				"inferred_entity_type": inferredEntityType,
 				"inferred_entity_id":   inferredEntityId,
 				"inferred_aws_region":  roleEntry.InferredAWSRegion,
-				"account_id":           accountID,
+				"account_id":           entity.AccountNumber,
 			},
 			InternalData: map[string]interface{}{
 				"role_name": roleName,
 			},
-			DisplayName: principalName,
+			DisplayName: entity.FriendlyName,
 			LeaseOptions: logical.LeaseOptions{
 				Renewable: true,
 				TTL:       roleEntry.TTL,
@@ -1267,29 +1267,44 @@ func hasValuesForIamAuth(data *framework.FieldData) (bool, bool) {
 		(hasRequestMethod || hasRequestUrl || hasRequestBody || hasRequestHeaders)
 }
 
-func parseIamArn(iamArn string) (string, string, string, error) {
+func parseIamArn(iamArn string) (*iamEntity, error) {
 	// iamArn should look like one of the following:
-	// 1. arn:aws:iam::<account_id>:user/<UserName>
+	// 1. arn:aws:iam::<account_id>:<entity_type>/<UserName>
 	// 2. arn:aws:sts::<account_id>:assumed-role/<RoleName>/<RoleSessionName>
 	// if we get something like 2, then we want to transform that back to what
 	// most people would expect, which is arn:aws:iam::<account_id>:role/<RoleName>
+	var entity iamEntity
 	fullParts := strings.Split(iamArn, ":")
-	principalFullName := fullParts[5]
-	// principalFullName would now be something like user/<UserName> or assumed-role/<RoleName>/<RoleSessionName>
-	parts := strings.Split(principalFullName, "/")
-	principalName := parts[1]
-	// now, principalName should either be <UserName> or <RoleName>
-	transformedArn := iamArn
-	sessionName := ""
-	if parts[0] == "assumed-role" {
-		transformedArn = fmt.Sprintf("arn:aws:iam::%s:role/%s", fullParts[4], principalName)
-		// fullParts[4] is the <account_id>
-		sessionName = parts[2]
-		// sessionName is <RoleSessionName>
-	} else if parts[0] != "user" {
-		return "", "", "", fmt.Errorf("unrecognized principal type: %q", parts[0])
+	if fullParts[0] != "arn" {
+		return nil, fmt.Errorf("unrecognized arn: does not begin with arn:")
 	}
-	return transformedArn, principalName, sessionName, nil
+	// normally aws, but could be aws-cn or aws-us-gov
+	entity.Partition = fullParts[1]
+	if fullParts[2] != "iam" && fullParts[2] != "sts" {
+		return nil, fmt.Errorf("unrecognized service: %v, not one of iam or sts", fullParts[2])
+	}
+	// fullParts[3] is the region, which doesn't matter for AWS IAM entities
+	entity.AccountNumber = fullParts[4]
+	// fullParts[5] would now be something like user/<UserName> or assumed-role/<RoleName>/<RoleSessionName>
+	parts := strings.Split(fullParts[5], "/")
+	entity.Type = parts[0]
+	entity.Path = strings.Join(parts[1:len(parts)-1], "/")
+	entity.FriendlyName = parts[len(parts)-1]
+	// now, entity.FriendlyName should either be <UserName> or <RoleName>
+	switch entity.Type {
+	case "assumed-role":
+		// Assumed roles don't have paths and have a slightly different format
+		// parts[2] is <RoleSessionName>
+		entity.Path = ""
+		entity.FriendlyName = parts[1]
+		entity.SessionInfo = parts[2]
+	case "user":
+	case "role":
+	case "instance-profile":
+	default:
+		return &iamEntity{}, fmt.Errorf("unrecognized principal type: %q", entity.Type)
+	}
+	return &entity, nil
 }
 
 func validateVaultHeaderValue(headers http.Header, requestUrl *url.URL, requiredHeaderValue string) error {
@@ -1392,7 +1407,7 @@ func parseGetCallerIdentityResponse(response string) (GetCallerIdentityResponse,
 	return result, err
 }
 
-func submitCallerIdentityRequest(method, endpoint string, parsedUrl *url.URL, body string, headers http.Header) (string, string, error) {
+func submitCallerIdentityRequest(method, endpoint string, parsedUrl *url.URL, body string, headers http.Header) (*GetCallerIdentityResult, error) {
 	// NOTE: We need to ensure we're calling STS, instead of acting as an unintended network proxy
 	// The protection against this is that this method will only call the endpoint specified in the
 	// client config (defaulting to sts.amazonaws.com), so it would require a Vault admin to override
@@ -1401,7 +1416,7 @@ func submitCallerIdentityRequest(method, endpoint string, parsedUrl *url.URL, bo
 	client := cleanhttp.DefaultClient()
 	response, err := client.Do(request)
 	if err != nil {
-		return "", "", fmt.Errorf("error making request: %v", err)
+		return nil, fmt.Errorf("error making request: %v", err)
 	}
 	if response != nil {
 		defer response.Body.Close()
@@ -1409,17 +1424,13 @@ func submitCallerIdentityRequest(method, endpoint string, parsedUrl *url.URL, bo
 	// we check for status code afterwards to also print out response body
 	responseBody, err := ioutil.ReadAll(response.Body)
 	if response.StatusCode != 200 {
-		return "", "", fmt.Errorf("received error code %s from STS: %s", response.StatusCode, string(responseBody))
+		return nil, fmt.Errorf("received error code %s from STS: %s", response.StatusCode, string(responseBody))
 	}
 	callerIdentityResponse, err := parseGetCallerIdentityResponse(string(responseBody))
 	if err != nil {
-		return "", "", fmt.Errorf("error parsing STS response")
+		return nil, fmt.Errorf("error parsing STS response")
 	}
-	clientArn := callerIdentityResponse.GetCallerIdentityResult[0].Arn
-	if clientArn == "" {
-		return "", "", fmt.Errorf("no ARN validated")
-	}
-	return clientArn, callerIdentityResponse.GetCallerIdentityResult[0].Account, nil
+	return &callerIdentityResponse.GetCallerIdentityResult[0], nil
 }
 
 type GetCallerIdentityResponse struct {
@@ -1457,6 +1468,29 @@ type roleTagLoginResponse struct {
 	DisallowReauthentication bool          `json:"disallow_reauthentication" structs:"disallow_reauthentication" mapstructure:"disallow_reauthentication"`
 }
 
+type iamEntity struct {
+	Partition     string
+	AccountNumber string
+	Type          string
+	Path          string
+	FriendlyName  string
+	SessionInfo   string
+}
+
+func (e *iamEntity) canonicalArn() string {
+	entityType := e.Type
+	// canonicalize "assumed-role" into "role"
+	if entityType == "assumed-role" {
+		entityType = "role"
+	}
+	// Annoyingly, the assumed-role entity type doesn't have the Path of the role which was assumed
+	// So, we "canonicalize" it by just completely dropping the path. The other option would be to
+	// make an AWS API call to look up the role by FriendlyName, which introduces more complexity to
+	// code and test, and it also breaks backwards compatibility in an area where we would really want
+	// it
+	return fmt.Sprintf("arn:%s:iam::%s:%s/%s", e.Partition, e.AccountNumber, entityType, e.FriendlyName)
+}
+
 const iamServerIdHeader = "X-Vault-AWS-IAM-Server-ID"
 
 const pathLoginSyn = `

builtin/credential/aws/path_login_test.go

@@ -48,37 +48,36 @@ func TestBackend_pathLogin_getCallerIdentityResponse(t *testing.T) {
 }
 
 func TestBackend_pathLogin_parseIamArn(t *testing.T) {
-	userArn := "arn:aws:iam::123456789012:user/MyUserName"
-	assumedRoleArn := "arn:aws:sts::123456789012:assumed-role/RoleName/RoleSessionName"
-	baseRoleArn := "arn:aws:iam::123456789012:role/RoleName"
-
-	xformedUser, principalFriendlyName, sessionName, err := parseIamArn(userArn)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if xformedUser != userArn {
-		t.Fatalf("expected to transform ARN %#v into %#v but got %#v instead", userArn, userArn, xformedUser)
-	}
-	if principalFriendlyName != "MyUserName" {
-		t.Fatalf("expected to extract MyUserName from ARN %#v but got %#v instead", userArn, principalFriendlyName)
-	}
-	if sessionName != "" {
-		t.Fatalf("expected to extract no session name from ARN %#v but got %#v instead", userArn, sessionName)
+	testParser := func(inputArn, expectedCanonicalArn string, expectedEntity iamEntity) {
+		entity, err := parseIamArn(inputArn)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if expectedCanonicalArn != "" && entity.canonicalArn() != expectedCanonicalArn {
+			t.Fatalf("expected to canonicalize ARN %q into %q but got %q instead", inputArn, expectedCanonicalArn, entity.canonicalArn())
+		}
+		if *entity != expectedEntity {
+			t.Fatalf("expected to get iamEntity %#v from input ARN %q but instead got %#v", expectedEntity, inputArn, *entity)
+		}
 	}
 
-	xformedRole, principalFriendlyName, sessionName, err := parseIamArn(assumedRoleArn)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if xformedRole != baseRoleArn {
-		t.Fatalf("expected to transform ARN %#v into %#v but got %#v instead", assumedRoleArn, baseRoleArn, xformedRole)
-	}
-	if principalFriendlyName != "RoleName" {
-		t.Fatalf("expected to extract principal name of RoleName from ARN %#v but got %#v instead", assumedRoleArn, sessionName)
-	}
-	if sessionName != "RoleSessionName" {
-		t.Fatalf("expected to extract role session name of RoleSessionName from ARN %#v but got %#v instead", assumedRoleArn, sessionName)
-	}
+	testParser("arn:aws:iam::123456789012:user/UserPath/MyUserName",
+		"arn:aws:iam::123456789012:user/MyUserName",
+		iamEntity{Partition: "aws", AccountNumber: "123456789012", Type: "user", Path: "UserPath", FriendlyName: "MyUserName"},
+	)
+	canonicalRoleArn := "arn:aws:iam::123456789012:role/RoleName"
+	testParser("arn:aws:sts::123456789012:assumed-role/RoleName/RoleSessionName",
+		canonicalRoleArn,
+		iamEntity{Partition: "aws", AccountNumber: "123456789012", Type: "assumed-role", FriendlyName: "RoleName", SessionInfo: "RoleSessionName"},
+	)
+	testParser("arn:aws:iam::123456789012:role/RolePath/RoleName",
+		canonicalRoleArn,
+		iamEntity{Partition: "aws", AccountNumber: "123456789012", Type: "role", Path: "RolePath", FriendlyName: "RoleName"},
+	)
+	testParser("arn:aws:iam::123456789012:instance-profile/profilePath/InstanceProfileName",
+		"",
+		iamEntity{Partition: "aws", AccountNumber: "123456789012", Type: "instance-profile", Path: "profilePath", FriendlyName: "InstanceProfileName"},
+	)
 }
 
 func TestBackend_validateVaultHeaderValue(t *testing.T) {

builtin/credential/aws/path_role.go

@@ -63,6 +63,14 @@ with an IAM instance profile ARN which has a prefix that matches
 the value specified by this parameter. The value is prefix-matched
 (as though it were a glob ending in '*'). This is only checked when
 auth_type is ec2.`,
+			},
+			"resolve_aws_unique_ids": {
+				Type:    framework.TypeBool,
+				Default: true,
+				Description: `If set, resolve all AWS IAM ARNs into AWS's internal unique IDs.
+When an IAM entity (e.g., user, role, or instance profile) is deleted, then all references
+to it within the role will be invalidated, which prevents a new IAM entity from being created
+with the same name and matching the role's IAM binds. Once set, this cannot be unset.`,
 			},
 			"inferred_entity_type": {
 				Type: framework.TypeString,
@@ -210,7 +218,7 @@ func (b *backend) lockedAWSRole(s logical.Storage, roleName string) (*awsRoleEnt
 	if roleEntry == nil {
 		return nil, nil
 	}
-	needUpgrade, err := upgradeRoleEntry(roleEntry)
+	needUpgrade, err := b.upgradeRoleEntry(s, roleEntry)
 	if err != nil {
 		return nil, fmt.Errorf("error upgrading roleEntry: %v", err)
 	}
@@ -228,7 +236,7 @@ func (b *backend) lockedAWSRole(s logical.Storage, roleName string) (*awsRoleEnt
 			return nil, nil
 		}
 		// now re-check to see if we need to upgrade
-		if needUpgrade, err = upgradeRoleEntry(roleEntry); err != nil {
+		if needUpgrade, err = b.upgradeRoleEntry(s, roleEntry); err != nil {
 			return nil, fmt.Errorf("error upgrading roleEntry: %v", err)
 		}
 		if needUpgrade {
@@ -284,7 +292,7 @@ func (b *backend) nonLockedSetAWSRole(s logical.Storage, roleName string,
 
 // If needed, updates the role entry and returns a bool indicating if it was updated
 // (and thus needs to be persisted)
-func upgradeRoleEntry(roleEntry *awsRoleEntry) (bool, error) {
+func (b *backend) upgradeRoleEntry(s logical.Storage, roleEntry *awsRoleEntry) (bool, error) {
 	if roleEntry == nil {
 		return false, fmt.Errorf("received nil roleEntry")
 	}
@@ -307,6 +315,18 @@ func upgradeRoleEntry(roleEntry *awsRoleEntry) (bool, error) {
 		upgraded = true
 	}
 
+	if roleEntry.AuthType == iamAuthType &&
+		roleEntry.ResolveAWSUniqueIDs &&
+		roleEntry.BoundIamPrincipalARN != "" &&
+		roleEntry.BoundIamPrincipalID == "" {
+		principalId, err := b.resolveArnToUniqueIDFunc(s, roleEntry.BoundIamPrincipalARN)
+		if err != nil {
+			return false, err
+		}
+		roleEntry.BoundIamPrincipalID = principalId
+		upgraded = true
+	}
+
 	return upgraded, nil
 
 }
@@ -411,7 +431,7 @@ func (b *backend) pathRoleCreateUpdate(
 	if roleEntry == nil {
 		roleEntry = &awsRoleEntry{}
 	} else {
-		needUpdate, err := upgradeRoleEntry(roleEntry)
+		needUpdate, err := b.upgradeRoleEntry(req.Storage, roleEntry)
 		if err != nil {
 			return logical.ErrorResponse(fmt.Sprintf("failed to update roleEntry: %v", err)), nil
 		}
@@ -445,6 +465,19 @@ func (b *backend) pathRoleCreateUpdate(
 		roleEntry.BoundSubnetID = boundSubnetIDRaw.(string)
 	}
 
+	if resolveAWSUniqueIDsRaw, ok := data.GetOk("resolve_aws_unique_ids"); ok {
+		switch {
+		case req.Operation == logical.CreateOperation:
+			roleEntry.ResolveAWSUniqueIDs = resolveAWSUniqueIDsRaw.(bool)
+		case roleEntry.ResolveAWSUniqueIDs && !resolveAWSUniqueIDsRaw.(bool):
+			return logical.ErrorResponse("changing resolve_aws_unique_ids from true to false is not allowed"), nil
+		default:
+			roleEntry.ResolveAWSUniqueIDs = resolveAWSUniqueIDsRaw.(bool)
+		}
+	} else if req.Operation == logical.CreateOperation {
+		roleEntry.ResolveAWSUniqueIDs = data.Get("resolve_aws_unique_ids").(bool)
+	}
+
 	if boundIamRoleARNRaw, ok := data.GetOk("bound_iam_role_arn"); ok {
 		roleEntry.BoundIamRoleARN = boundIamRoleARNRaw.(string)
 	}
@@ -454,7 +487,26 @@ func (b *backend) pathRoleCreateUpdate(
 	}
 
 	if boundIamPrincipalARNRaw, ok := data.GetOk("bound_iam_principal_arn"); ok {
-		roleEntry.BoundIamPrincipalARN = boundIamPrincipalARNRaw.(string)
+		principalARN := boundIamPrincipalARNRaw.(string)
+		roleEntry.BoundIamPrincipalARN = principalARN
+		// Explicitly not checking to see if the user has changed the ARN under us
+		// This allows the user to sumbit an update with the same ARN to force Vault
+		// to re-resolve the ARN to the unique ID, in case an entity was deleted and
+		// recreated
+		if roleEntry.ResolveAWSUniqueIDs {
+			principalID, err := b.resolveArnToUniqueIDFunc(req.Storage, principalARN)
+			if err != nil {
+				return logical.ErrorResponse(fmt.Sprintf("failed updating the unique ID of ARN %#v: %#v", principalARN, err)), nil
+			}
+			roleEntry.BoundIamPrincipalID = principalID
+		}
+	} else if roleEntry.ResolveAWSUniqueIDs && roleEntry.BoundIamPrincipalARN != "" {
+		// we're turning on resolution on this role, so ensure we update it
+		principalID, err := b.resolveArnToUniqueIDFunc(req.Storage, roleEntry.BoundIamPrincipalARN)
+		if err != nil {
+			return logical.ErrorResponse(fmt.Sprintf("unable to resolve ARN %#v to internal ID: %#v", roleEntry.BoundIamPrincipalARN, err)), nil
+		}
+		roleEntry.BoundIamPrincipalID = principalID
 	}
 
 	if inferRoleTypeRaw, ok := data.GetOk("inferred_entity_type"); ok {
@@ -682,6 +734,7 @@ type awsRoleEntry struct {
 	BoundAmiID                 string        `json:"bound_ami_id" structs:"bound_ami_id" mapstructure:"bound_ami_id"`
 	BoundAccountID             string        `json:"bound_account_id" structs:"bound_account_id" mapstructure:"bound_account_id"`
 	BoundIamPrincipalARN       string        `json:"bound_iam_principal_arn" structs:"bound_iam_principal_arn" mapstructure:"bound_iam_principal_arn"`
+	BoundIamPrincipalID        string        `json:"bound_iam_principal_id" structs:"bound_iam_principal_id" mapstructure:"bound_iam_principal_id"`
 	BoundIamRoleARN            string        `json:"bound_iam_role_arn" structs:"bound_iam_role_arn" mapstructure:"bound_iam_role_arn"`
 	BoundIamInstanceProfileARN string        `json:"bound_iam_instance_profile_arn" structs:"bound_iam_instance_profile_arn" mapstructure:"bound_iam_instance_profile_arn"`
 	BoundRegion                string        `json:"bound_region" structs:"bound_region" mapstructure:"bound_region"`
@@ -689,6 +742,7 @@ type awsRoleEntry struct {
 	BoundVpcID                 string        `json:"bound_vpc_id" structs:"bound_vpc_id" mapstructure:"bound_vpc_id"`
 	InferredEntityType         string        `json:"inferred_entity_type" structs:"inferred_entity_type" mapstructure:"inferred_entity_type"`
 	InferredAWSRegion          string        `json:"inferred_aws_region" structs:"inferred_aws_region" mapstructure:"inferred_aws_region"`
+	ResolveAWSUniqueIDs        bool          `json:"resolve_aws_unique_ids" structs:"resolve_aws_unique_ids" mapstructure:"resolve_aws_unique_ids"`
 	RoleTag                    string        `json:"role_tag" structs:"role_tag" mapstructure:"role_tag"`
 	AllowInstanceMigration     bool          `json:"allow_instance_migration" structs:"allow_instance_migration" mapstructure:"allow_instance_migration"`
 	TTL                        time.Duration `json:"ttl" structs:"ttl" mapstructure:"ttl"`

builtin/credential/aws/path_role_test.go

@@ -135,7 +135,81 @@ func TestBackend_pathRoleEc2(t *testing.T) {
 	if resp != nil {
 		t.Fatalf("bad: response: expected:nil actual:%#v\n", resp)
 	}
+}
 
+func Test_enableIamIDResolution(t *testing.T) {
+	config := logical.TestBackendConfig()
+	storage := &logical.InmemStorage{}
+	config.StorageView = storage
+
+	b, err := Backend(config)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = b.Setup(config)
+	if err != nil {
+		t.Fatal(err)
+	}
+	roleName := "upgradable_role"
+
+	b.resolveArnToUniqueIDFunc = resolveArnToFakeUniqueId
+
+	data := map[string]interface{}{
+		"auth_type":               iamAuthType,
+		"policies":                "p,q",
+		"bound_iam_principal_arn": "arn:aws:iam::123456789012:role/MyRole",
+		"resolve_aws_unique_ids":  false,
+	}
+
+	submitRequest := func(roleName string, op logical.Operation) (*logical.Response, error) {
+		return b.HandleRequest(&logical.Request{
+			Operation: op,
+			Path:      "role/" + roleName,
+			Data:      data,
+			Storage:   storage,
+		})
+	}
+
+	resp, err := submitRequest(roleName, logical.CreateOperation)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp != nil && resp.IsError() {
+		t.Fatalf("failed to create role: %#v", resp)
+	}
+
+	resp, err = submitRequest(roleName, logical.ReadOperation)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp == nil || resp.IsError() {
+		t.Fatalf("failed to read role: resp:%#v,\nerr:%#v", resp, err)
+	}
+	if resp.Data["bound_iam_principal_id"] != "" {
+		t.Fatalf("expected to get no unique ID in role, but got %q", resp.Data["bound_iam_principal_id"])
+	}
+
+	data = map[string]interface{}{
+		"resolve_aws_unique_ids": true,
+	}
+	resp, err = submitRequest(roleName, logical.UpdateOperation)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp != nil && resp.IsError() {
+		t.Fatalf("unable to upgrade role to resolve internal IDs: resp:%#v", resp)
+	}
+
+	resp, err = submitRequest(roleName, logical.ReadOperation)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp == nil || resp.IsError() {
+		t.Fatalf("failed to read role: resp:%#v,\nerr:%#v", resp, err)
+	}
+	if resp.Data["bound_iam_principal_id"] != "FakeUniqueId1" {
+		t.Fatalf("bad: expected upgrade of role resolve principal ID to %q, but got %q instead", "FakeUniqueId1", resp.Data["bound_iam_principal_id"])
+	}
 }
 
 func TestBackend_pathIam(t *testing.T) {
@@ -174,6 +248,7 @@ func TestBackend_pathIam(t *testing.T) {
 		"policies":                "p,q,r,s",
 		"max_ttl":                 "2h",
 		"bound_iam_principal_arn": "n:aws:iam::123456789012:user/MyUserName",
+		"resolve_aws_unique_ids":  false,
 	}
 	resp, err = b.HandleRequest(&logical.Request{
 		Operation: logical.CreateOperation,
@@ -369,6 +444,7 @@ func TestBackend_pathRoleMixedTypes(t *testing.T) {
 
 	data["inferred_entity_type"] = ec2EntityType
 	data["inferred_aws_region"] = "us-east-1"
+	data["resolve_aws_unique_ids"] = false
 	resp, err = submitRequest("multipleTypesInferred", logical.CreateOperation)
 	if err != nil {
 		t.Fatal(err)
@@ -376,6 +452,29 @@ func TestBackend_pathRoleMixedTypes(t *testing.T) {
 	if resp.IsError() {
 		t.Fatalf("didn't allow creation of roles with only inferred bindings")
 	}
+
+	b.resolveArnToUniqueIDFunc = resolveArnToFakeUniqueId
+	data["resolve_aws_unique_ids"] = true
+	resp, err = submitRequest("withInternalIdResolution", logical.CreateOperation)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp.IsError() {
+		t.Fatalf("didn't allow creation of role resolving unique IDs")
+	}
+	resp, err = submitRequest("withInternalIdResolution", logical.ReadOperation)
+	if resp.Data["bound_iam_principal_id"] != "FakeUniqueId1" {
+		t.Fatalf("expected fake unique ID of FakeUniqueId1, got %q", resp.Data["bound_iam_principal_id"])
+	}
+	data["resolve_aws_unique_ids"] = false
+	resp, err = submitRequest("withInternalIdResolution", logical.UpdateOperation)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !resp.IsError() {
+		t.Fatalf("allowed changing resolve_aws_unique_ids from true to false")
+	}
+
 }
 
 func TestAwsEc2_RoleCrud(t *testing.T) {
@@ -417,11 +516,12 @@ func TestAwsEc2_RoleCrud(t *testing.T) {
 		"bound_ami_id":                   "testamiid",
 		"bound_account_id":               "testaccountid",
 		"bound_region":                   "testregion",
-		"bound_iam_role_arn":             "testiamrolearn",
-		"bound_iam_instance_profile_arn": "testiaminstanceprofilearn",
+		"bound_iam_role_arn":             "arn:aws:iam::123456789012:role/MyRole",
+		"bound_iam_instance_profile_arn": "arn:aws:iam::123456789012:instance-profile/MyInstanceProfile",
 		"bound_subnet_id":                "testsubnetid",
 		"bound_vpc_id":                   "testvpcid",
 		"role_tag":                       "testtag",
+		"resolve_aws_unique_ids":         false,
 		"allow_instance_migration":       true,
 		"ttl":                       "10m",
 		"max_ttl":                   "20m",
@@ -451,12 +551,14 @@ func TestAwsEc2_RoleCrud(t *testing.T) {
 		"bound_account_id":               "testaccountid",
 		"bound_region":                   "testregion",
 		"bound_iam_principal_arn":        "",
-		"bound_iam_role_arn":             "testiamrolearn",
-		"bound_iam_instance_profile_arn": "testiaminstanceprofilearn",
+		"bound_iam_principal_id":         "",
+		"bound_iam_role_arn":             "arn:aws:iam::123456789012:role/MyRole",
+		"bound_iam_instance_profile_arn": "arn:aws:iam::123456789012:instance-profile/MyInstanceProfile",
 		"bound_subnet_id":                "testsubnetid",
 		"bound_vpc_id":                   "testvpcid",
 		"inferred_entity_type":           "",
 		"inferred_aws_region":            "",
+		"resolve_aws_unique_ids":         false,
 		"role_tag":                       "testtag",
 		"allow_instance_migration":       true,
 		"ttl":                       time.Duration(600),
@@ -519,7 +621,8 @@ func TestAwsEc2_RoleDurationSeconds(t *testing.T) {
 
 	roleData := map[string]interface{}{
 		"auth_type":                      "ec2",
-		"bound_iam_instance_profile_arn": "testarn",
+		"bound_iam_instance_profile_arn": "arn:aws:iam::123456789012:instance-profile/test-profile-name",
+		"resolve_aws_unique_ids":         false,
 		"ttl":     "10s",
 		"max_ttl": "20s",
 		"period":  "30s",
@@ -554,3 +657,7 @@ func TestAwsEc2_RoleDurationSeconds(t *testing.T) {
 		t.Fatalf("bad: period; expected: 30, actual: %d", resp.Data["period"])
 	}
 }
+
+func resolveArnToFakeUniqueId(s logical.Storage, arn string) (string, error) {
+	return "FakeUniqueId1", nil
+}

website/source/docs/auth/aws.html.md

@@ -1427,6 +1427,48 @@ The response will be in JSON. For example:
         activated. This only applies to the iam auth method.
       </li>
     </ul>
+    <ul>
+    <li>
+        <span class="param">resolve_aws_unique_ids</span>
+        <span class="param-flags">optional</span>
+        When set, resolves the `bound_iam_principal_arn` to the [AWS Unique
+        ID](http://docs.aws.amazon.com/IAM/latest/UserGuide/reference_identifiers.html#identifiers-unique-ids).
+        This requires Vault to be able to call `iam:GetUser` or `iam:GetRole` on
+        the `bound_iam_principal_arn` that is being bound. Resolving to
+        internal AWS IDs more closely mimics the behavior of AWS services in
+        that if an IAM user or role is deleted and a new one is recreated with
+        the same name, those new users or roles won't get access to roles in
+        Vault that were permissioned to the prior principals of the same name.
+        The default value for new roles is true, while the default value for
+        roles that existed prior to this option existing is false (you can
+        check the value for a given role using the GET method on the role). Any
+        authentication tokens created prior to this being supported won't
+        verify the unique ID upon token renewal.  When this is changed from
+        false to true on an existing role, Vault will attempt to resolve the
+        role's bound IAM ARN to the unique ID and, if unable to do so, will
+        fail to enable this option.  Changing this from `true` to `false` is
+        not supported; if absolutely necessary, you would need to delete the
+        role and recreate it explicitly setting it to `false`. However; the
+        instances in which you would want to do this should be rare. If the
+        role creation (or upgrading to use this) succeed, then Vault has
+        already been able to resolve internal IDs, and it doesn't need any
+        further IAM permissions to authenticate users. If a role has been
+        deleted and recreated, and Vault has cached the old unique ID, you
+        should just call this endpoint specifying the same
+        `bound_iam_principal_arn` and, as long as Vault still has the necessary
+        IAM permissions to resolve the unique ID, Vault will update the unique
+        ID. (If it does not have the necessary permissions to resolve the
+        unique ID, then it will fail to update.) If this option is set to
+        false, then you MUST leave out the path component in
+        bound_iam_principal_arn for **roles** only, but not IAM users. That is,
+        if your IAM role ARN is of the form
+        `arn:aws:iam::123456789012:role/some/path/to/MyRoleName`, you **must**
+        specify a bound_iam_principal_arn of
+        `arn:aws:iam::123456789012:role/MyRoleName` for authentication to
+        work.
+      </li>
+    </ul>
+
     <ul>
       <li>
         <span class="param">ttl</span>