open-vault/builtin/logical/pki/path_config_crl.go
Alexander Scheel e03fb14be4
Support for generating Delta CRLs (#16773)
* Allow generation of up-to-date delta CRLs

While switching to periodic rebuilds of CRLs alleviates the constant
rebuild pressure on Vault during times of high revocation, the CRL
proper becomes stale. One response to this is to switch to OCSP, but not
every system has support for this. Additionally, OCSP usually requires
connectivity and isn't used to augment a pre-distributed CRL (and is
instead used independently).

By generating delta CRLs containing only new revocations, an existing
CRL can be supplemented with newer revocations without requiring Vault
to rebuild all complete CRLs. Admins can periodically fetch the delta
CRL and add it to the existing CRL and applications should be able to
support using serials from both.

Because delta CRLs are emptied when the next complete CRL is rebuilt, it
is important that applications fetch the delta CRL and correlate it to
their complete CRL; if their complete CRL is older than the delta CRL's
extension number, applications MUST fetch the newer complete CRL to
ensure they have a correct combination.

This modifies the revocation process and adds several new configuration
options, controlling whether Delta CRLs are enabled and when we'll
rebuild it.

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Add tests for delta CRLs

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Add changelog entry

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Add documentation on delta CRLs

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Address review feedback: fix several bugs

Thanks Steve!

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Correctly invoke periodic func on active nodes

We need to ensure we read the updated config (in case of OCSP request
handling on standby nodes), but otherwise want to avoid CRL/DeltaCRL
re-building.

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>
2022-08-29 11:37:09 -04:00

240 lines
7.9 KiB
Go

package pki
import (
"context"
"fmt"
"time"
"github.com/hashicorp/vault/sdk/framework"
"github.com/hashicorp/vault/sdk/helper/errutil"
"github.com/hashicorp/vault/sdk/logical"
)
const latestCrlConfigVersion = 1
// CRLConfig holds basic CRL configuration information
type crlConfig struct {
Version int `json:"version"`
Expiry string `json:"expiry"`
Disable bool `json:"disable"`
OcspDisable bool `json:"ocsp_disable"`
AutoRebuild bool `json:"auto_rebuild"`
AutoRebuildGracePeriod string `json:"auto_rebuild_grace_period"`
OcspExpiry string `json:"ocsp_expiry"`
EnableDelta bool `json:"enable_delta"`
DeltaRebuildInterval string `json:"delta_rebuild_interval"`
}
// Implicit default values for the config if it does not exist.
var defaultCrlConfig = crlConfig{
Version: latestCrlConfigVersion,
Expiry: "72h",
Disable: false,
OcspDisable: false,
OcspExpiry: "12h",
AutoRebuild: false,
AutoRebuildGracePeriod: "12h",
EnableDelta: false,
DeltaRebuildInterval: "15m",
}
func pathConfigCRL(b *backend) *framework.Path {
return &framework.Path{
Pattern: "config/crl",
Fields: map[string]*framework.FieldSchema{
"expiry": {
Type: framework.TypeString,
Description: `The amount of time the generated CRL should be
valid; defaults to 72 hours`,
Default: "72h",
},
"disable": {
Type: framework.TypeBool,
Description: `If set to true, disables generating the CRL entirely.`,
},
"ocsp_disable": {
Type: framework.TypeBool,
Description: `If set to true, ocsp unauthorized responses will be returned.`,
},
"ocsp_expiry": {
Type: framework.TypeString,
Description: `The amount of time an OCSP response will be valid (controls
the NextUpdate field); defaults to 12 hours`,
Default: "1h",
},
"auto_rebuild": {
Type: framework.TypeBool,
Description: `If set to true, enables automatic rebuilding of the CRL`,
},
"auto_rebuild_grace_period": {
Type: framework.TypeString,
Description: `The time before the CRL expires to automatically rebuild it, when enabled. Must be shorter than the CRL expiry. Defaults to 12h.`,
Default: "12h",
},
"enable_delta": {
Type: framework.TypeBool,
Description: `Whether to enable delta CRLs between authoritative CRL rebuilds`,
},
"delta_rebuild_interval": {
Type: framework.TypeString,
Description: `The time between delta CRL rebuilds if a new revocation has occurred. Must be shorter than the CRL expiry. Defaults to 15m.`,
Default: "15m",
},
},
Operations: map[logical.Operation]framework.OperationHandler{
logical.ReadOperation: &framework.PathOperation{
Callback: b.pathCRLRead,
},
logical.UpdateOperation: &framework.PathOperation{
Callback: b.pathCRLWrite,
// Read more about why these flags are set in backend.go.
ForwardPerformanceStandby: true,
ForwardPerformanceSecondary: true,
},
},
HelpSynopsis: pathConfigCRLHelpSyn,
HelpDescription: pathConfigCRLHelpDesc,
}
}
func (b *backend) pathCRLRead(ctx context.Context, req *logical.Request, _ *framework.FieldData) (*logical.Response, error) {
sc := b.makeStorageContext(ctx, req.Storage)
config, err := sc.getRevocationConfig()
if err != nil {
return nil, err
}
return &logical.Response{
Data: map[string]interface{}{
"expiry": config.Expiry,
"disable": config.Disable,
"ocsp_disable": config.OcspDisable,
"ocsp_expiry": config.OcspExpiry,
"auto_rebuild": config.AutoRebuild,
"auto_rebuild_grace_period": config.AutoRebuildGracePeriod,
"enable_delta": config.EnableDelta,
"delta_rebuild_interval": config.DeltaRebuildInterval,
},
}, nil
}
func (b *backend) pathCRLWrite(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
sc := b.makeStorageContext(ctx, req.Storage)
config, err := sc.getRevocationConfig()
if err != nil {
return nil, err
}
if expiryRaw, ok := d.GetOk("expiry"); ok {
expiry := expiryRaw.(string)
_, err := time.ParseDuration(expiry)
if err != nil {
return logical.ErrorResponse(fmt.Sprintf("given expiry could not be decoded: %s", err)), nil
}
config.Expiry = expiry
}
oldDisable := config.Disable
if disableRaw, ok := d.GetOk("disable"); ok {
config.Disable = disableRaw.(bool)
}
if ocspDisableRaw, ok := d.GetOk("ocsp_disable"); ok {
config.OcspDisable = ocspDisableRaw.(bool)
}
if expiryRaw, ok := d.GetOk("ocsp_expiry"); ok {
expiry := expiryRaw.(string)
duration, err := time.ParseDuration(expiry)
if err != nil {
return logical.ErrorResponse(fmt.Sprintf("given ocsp_expiry could not be decoded: %s", err)), nil
}
if duration < 0 {
return logical.ErrorResponse(fmt.Sprintf("ocsp_expiry must be greater than or equal to 0 got: %s", duration)), nil
}
config.OcspExpiry = expiry
}
oldAutoRebuild := config.AutoRebuild
if autoRebuildRaw, ok := d.GetOk("auto_rebuild"); ok {
config.AutoRebuild = autoRebuildRaw.(bool)
}
if autoRebuildGracePeriodRaw, ok := d.GetOk("auto_rebuild_grace_period"); ok {
autoRebuildGracePeriod := autoRebuildGracePeriodRaw.(string)
if _, err := time.ParseDuration(autoRebuildGracePeriod); err != nil {
return logical.ErrorResponse(fmt.Sprintf("given auto_rebuild_grace_period could not be decoded: %s", err)), nil
}
config.AutoRebuildGracePeriod = autoRebuildGracePeriod
}
if enableDeltaRaw, ok := d.GetOk("enable_delta"); ok {
config.EnableDelta = enableDeltaRaw.(bool)
}
if deltaRebuildIntervalRaw, ok := d.GetOk("delta_rebuild_interval"); ok {
deltaRebuildInterval := deltaRebuildIntervalRaw.(string)
if _, err := time.ParseDuration(deltaRebuildInterval); err != nil {
return logical.ErrorResponse(fmt.Sprintf("given delta_rebuild_interval could not be decoded: %s", err)), nil
}
config.DeltaRebuildInterval = deltaRebuildInterval
}
expiry, _ := time.ParseDuration(config.Expiry)
if config.AutoRebuild {
gracePeriod, _ := time.ParseDuration(config.AutoRebuildGracePeriod)
if gracePeriod >= expiry {
return logical.ErrorResponse(fmt.Sprintf("CRL auto-rebuilding grace period (%v) must be strictly shorter than CRL expiry (%v) value when auto-rebuilding of CRLs is enabled", config.AutoRebuildGracePeriod, config.Expiry)), nil
}
}
if config.EnableDelta {
deltaRebuildInterval, _ := time.ParseDuration(config.DeltaRebuildInterval)
if deltaRebuildInterval >= expiry {
return logical.ErrorResponse(fmt.Sprintf("CRL delta rebuild window (%v) must be strictly shorter than CRL expiry (%v) value when delta CRLs are enabled", config.DeltaRebuildInterval, config.Expiry)), nil
}
}
if config.EnableDelta && !config.AutoRebuild {
return logical.ErrorResponse(fmt.Sprintf("Delta CRLs cannot be enabled when auto rebuilding is disabled as the complete CRL is always regenerated!")), nil
}
entry, err := logical.StorageEntryJSON("config/crl", config)
if err != nil {
return nil, err
}
err = req.Storage.Put(ctx, entry)
if err != nil {
return nil, err
}
b.crlBuilder.markConfigDirty()
b.crlBuilder.reloadConfigIfRequired(sc)
if oldDisable != config.Disable || (oldAutoRebuild && !config.AutoRebuild) {
// It wasn't disabled but now it is (or equivalently, we were set to
// auto-rebuild and we aren't now), so rotate the CRL.
crlErr := b.crlBuilder.rebuild(ctx, b, req, true)
if crlErr != nil {
switch crlErr.(type) {
case errutil.UserError:
return logical.ErrorResponse(fmt.Sprintf("Error during CRL building: %s", crlErr)), nil
default:
return nil, fmt.Errorf("error encountered during CRL building: %w", crlErr)
}
}
}
return nil, nil
}
const pathConfigCRLHelpSyn = `
Configure the CRL expiration.
`
const pathConfigCRLHelpDesc = `
This endpoint allows configuration of the CRL lifetime.
`