open-vault/builtin/credential/aws-ec2/backend.go
2016-05-30 14:11:15 -04:00

177 lines
5.6 KiB
Go

package awsEc2
import (
"sync"
"time"
"github.com/aws/aws-sdk-go/service/ec2"
"github.com/hashicorp/vault/helper/salt"
"github.com/hashicorp/vault/logical"
"github.com/hashicorp/vault/logical/framework"
)
func Factory(conf *logical.BackendConfig) (logical.Backend, error) {
b, err := Backend(conf)
if err != nil {
return nil, err
}
return b.Setup(conf)
}
type backend struct {
*framework.Backend
Salt *salt.Salt
// 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 initiatite
// 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. 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.
EC2ClientsMap map[string]*ec2.EC2
}
func Backend(conf *logical.BackendConfig) (*framework.Backend, error) {
salt, err := salt.NewSalt(conf.StorageView, &salt.Config{
HashFunc: salt.SHA256Hash,
})
if err != nil {
return nil, err
}
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,
Salt: salt,
EC2ClientsMap: make(map[string]*ec2.EC2),
}
b.Backend = &framework.Backend{
PeriodicFunc: b.periodicFunc,
AuthRenew: b.pathLoginRenew,
Help: backendHelp,
PathsSpecial: &logical.Paths{
Unauthenticated: []string{
"login",
},
},
Paths: []*framework.Path{
pathLogin(b),
pathListRole(b),
pathListRoles(b),
pathRole(b),
pathRoleTag(b),
pathConfigClient(b),
pathConfigCertificate(b),
pathConfigTidyRoletagBlacklist(b),
pathConfigTidyIdentityWhitelist(b),
pathListCertificates(b),
pathListRoletagBlacklist(b),
pathRoletagBlacklist(b),
pathTidyRoletagBlacklist(b),
pathListIdentityWhitelist(b),
pathIdentityWhitelist(b),
pathTidyIdentityWhitelist(b),
},
}
return b.Backend, 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(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().UTC().Before(b.nextTidyTime) {
// safety_buffer defaults to 180 days for roletag blacklist
safety_buffer := 15552000
tidyBlacklistConfigEntry, err := b.lockedConfigTidyRoleTags(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(req.Storage, safety_buffer)
}
// reset the safety_buffer to 72h
safety_buffer = 259200
tidyWhitelistConfigEntry, err := b.lockedConfigTidyIdentities(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(req.Storage, safety_buffer)
}
// Update the time at which to run the tidy functions again.
b.nextTidyTime = time.Now().UTC().Add(b.tidyCooldownPeriod)
}
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.
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.
`