open-vault/builtin/credential/aws/backend.go
Jeff Mitchell 98bf463a65 Make single-lease revocation behave like expiration (#4883)
This change makes it so that if a lease is revoked through user action,
we set the expiration time to now and update pending, just as we do with
tokens. This allows the normal retry logic to apply in these cases as
well, instead of just erroring out immediately. The idea being that once
you tell Vault to revoke something it should keep doing its darndest to
actually make that happen.
2018-07-11 15:45:35 -04:00

303 lines
11 KiB
Go

package awsauth
import (
"context"
"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/helper/consts"
"github.com/hashicorp/vault/logical"
"github.com/hashicorp/vault/logical/framework"
"github.com/patrickmn/go-cache"
)
func Factory(ctx context.Context, conf *logical.BackendConfig) (logical.Backend, error) {
b, err := Backend(conf)
if err != nil {
return nil, err
}
if err := b.Setup(ctx, conf); err != nil {
return nil, err
}
return b, nil
}
type backend struct {
*framework.Backend
// Lock to make changes to any of the backend's configuration endpoints.
configMutex sync.RWMutex
// Lock to make changes to role entries
roleMutex sync.RWMutex
// Lock to make changes to the blacklist entries
blacklistMutex sync.RWMutex
// Guards the blacklist/whitelist tidy functions
tidyBlacklistCASGuard *uint32
tidyWhitelistCASGuard *uint32
// Duration after which the periodic function of the backend needs to
// tidy the blacklist and whitelist entries.
tidyCooldownPeriod time.Duration
// nextTidyTime holds the time at which the periodic func should initiate
// the tidy operations. This is set by the periodicFunc based on the value
// of tidyCooldownPeriod.
nextTidyTime time.Time
// Map to hold the EC2 client objects indexed by region and STS role.
// This avoids the overhead of creating a client object for every login request.
// When the credentials are modified or deleted, all the cached client objects
// will be flushed. The empty STS role signifies the master account
EC2ClientsMap map[string]map[string]*ec2.EC2
// Map to hold the IAM client objects indexed by region and STS role.
// This avoids the overhead of creating a client object for every login request.
// 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
// Map of AWS unique IDs to the full ARN corresponding to that unique ID
// This avoids the overhead of an AWS API hit for every login request
// using the IAM auth method when bound_iam_principal_arn contains a wildcard
iamUserIdToArnCache *cache.Cache
// 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(context.Context, logical.Storage, string) (string, error)
}
func Backend(conf *logical.BackendConfig) (*backend, error) {
b := &backend{
// Setting the periodic func to be run once in an hour.
// If there is a real need, this can be made configurable.
tidyCooldownPeriod: time.Hour,
EC2ClientsMap: make(map[string]map[string]*ec2.EC2),
IAMClientsMap: make(map[string]map[string]*iam.IAM),
iamUserIdToArnCache: cache.New(7*24*time.Hour, 24*time.Hour),
tidyBlacklistCASGuard: new(uint32),
tidyWhitelistCASGuard: new(uint32),
}
b.resolveArnToUniqueIDFunc = b.resolveArnToRealUniqueId
b.Backend = &framework.Backend{
PeriodicFunc: b.periodicFunc,
AuthRenew: b.pathLoginRenew,
Help: backendHelp,
PathsSpecial: &logical.Paths{
Unauthenticated: []string{
"login",
},
LocalStorage: []string{
"whitelist/identity/",
},
SealWrapStorage: []string{
"config/client",
},
},
Paths: []*framework.Path{
pathLogin(b),
pathListRole(b),
pathListRoles(b),
pathRole(b),
pathRoleTag(b),
pathConfigClient(b),
pathConfigCertificate(b),
pathConfigSts(b),
pathListSts(b),
pathConfigTidyRoletagBlacklist(b),
pathConfigTidyIdentityWhitelist(b),
pathListCertificates(b),
pathListRoletagBlacklist(b),
pathRoletagBlacklist(b),
pathTidyRoletagBlacklist(b),
pathListIdentityWhitelist(b),
pathIdentityWhitelist(b),
pathTidyIdentityWhitelist(b),
},
Invalidate: b.invalidate,
BackendType: logical.TypeCredential,
}
return b, nil
}
// periodicFunc performs the tasks that the backend wishes to do periodically.
// Currently this will be triggered once in a minute by the RollbackManager.
//
// The tasks being done currently by this function are to cleanup the expired
// entries of both blacklist role tags and whitelist identities. Tidying is done
// not once in a minute, but once in an hour, controlled by 'tidyCooldownPeriod'.
// Tidying of blacklist and whitelist are by default enabled. This can be
// changed using `config/tidy/roletags` and `config/tidy/identities` endpoints.
func (b *backend) periodicFunc(ctx context.Context, req *logical.Request) error {
// Run the tidy operations for the first time. Then run it when current
// time matches the nextTidyTime.
if b.nextTidyTime.IsZero() || !time.Now().Before(b.nextTidyTime) {
if b.System().LocalMount() || !b.System().ReplicationState().HasState(consts.ReplicationPerformanceSecondary) {
// safety_buffer defaults to 180 days for roletag blacklist
safety_buffer := 15552000
tidyBlacklistConfigEntry, err := b.lockedConfigTidyRoleTags(ctx, req.Storage)
if err != nil {
return err
}
skipBlacklistTidy := false
// check if tidying of role tags was configured
if tidyBlacklistConfigEntry != nil {
// check if periodic tidying of role tags was disabled
if tidyBlacklistConfigEntry.DisablePeriodicTidy {
skipBlacklistTidy = true
}
// overwrite the default safety_buffer with the configured value
safety_buffer = tidyBlacklistConfigEntry.SafetyBuffer
}
// tidy role tags if explicitly not disabled
if !skipBlacklistTidy {
b.tidyBlacklistRoleTag(ctx, req, safety_buffer)
}
}
// We don't check for replication state for whitelist identities as
// these are locally stored
safety_buffer := 259200
tidyWhitelistConfigEntry, err := b.lockedConfigTidyIdentities(ctx, req.Storage)
if err != nil {
return err
}
skipWhitelistTidy := false
// check if tidying of identities was configured
if tidyWhitelistConfigEntry != nil {
// check if periodic tidying of identities was disabled
if tidyWhitelistConfigEntry.DisablePeriodicTidy {
skipWhitelistTidy = true
}
// overwrite the default safety_buffer with the configured value
safety_buffer = tidyWhitelistConfigEntry.SafetyBuffer
}
// tidy identities if explicitly not disabled
if !skipWhitelistTidy {
b.tidyWhitelistIdentity(ctx, req, safety_buffer)
}
// Update the time at which to run the tidy functions again.
b.nextTidyTime = time.Now().Add(b.tidyCooldownPeriod)
}
return nil
}
func (b *backend) invalidate(ctx context.Context, key string) {
switch key {
case "config/client":
b.configMutex.Lock()
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(ctx context.Context, 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(ctx, 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 method takes in PKCS#7 signature of an AWS EC2 instance and a client
created nonce to authenticates the EC2 instance with Vault.
Authentication is backed by a preconfigured role in the backend. The role
represents the authorization of resources by containing Vault's policies.
Role can be created using 'role/<role>' endpoint.
If there is need to further restrict the capabilities of the role on the instance
that is using the role, 'role_tag' option can be enabled on the role, and a tag
can be generated using 'role/<role>/tag' endpoint. This tag represents the
subset of capabilities set on the role. When the 'role_tag' option is enabled on
the role, the login operation requires that a respective role tag is attached to
the EC2 instance which performs the login.
`