secrets/database: advanced TTL management for static roles

builtin/logical/database/backend.go

@@ -25,6 +25,7 @@ import (
 	"github.com/hashicorp/vault/sdk/helper/locksutil"
 	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/hashicorp/vault/sdk/queue"
+	"github.com/robfig/cron/v3"
 )
 
 const (
@@ -127,6 +128,13 @@ func Backend(conf *logical.BackendConfig) *databaseBackend {
 	b.connections = syncmap.NewSyncMap[string, *dbPluginInstance]()
 	b.queueCtx, b.cancelQueueCtx = context.WithCancel(context.Background())
 	b.roleLocks = locksutil.CreateLocks()
+
+	// TODO(JM): don't allow seconds in production, this is helpful for
+	// development/testing though
+	parser := cron.NewParser(
+		cron.Second | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.DowOptional,
+	)
+	b.scheduleParser = parser
 	return &b
 }
 
@@ -176,6 +184,8 @@ type databaseBackend struct {
 	// the running gauge collection process
 	gaugeCollectionProcess     *metricsutil.GaugeCollectionProcess
 	gaugeCollectionProcessStop sync.Once
+
+	scheduleParser cron.Parser
 }
 
 func (b *databaseBackend) DatabaseConfig(ctx context.Context, s logical.Storage, name string) (*DatabaseConfig, error) {

builtin/logical/database/path_creds_create.go

@@ -249,10 +249,18 @@ func (b *databaseBackend) pathStaticCredsRead() framework.OperationFunc {
 		respData := map[string]interface{}{
 			"username":            role.StaticAccount.Username,
 			"ttl":                 role.StaticAccount.CredentialTTL().Seconds(),
-			"rotation_period":     role.StaticAccount.RotationPeriod.Seconds(),
 			"last_vault_rotation": role.StaticAccount.LastVaultRotation,
 		}
 
+		if role.StaticAccount.UsesRotationPeriod() {
+			respData["rotation_period"] = role.StaticAccount.RotationPeriod.Seconds()
+		} else if role.StaticAccount.UsesRotationSchedule() {
+			respData["rotation_schedule"] = role.StaticAccount.RotationSchedule
+			if role.StaticAccount.RotationWindow.Seconds() != 0 {
+				respData["rotation_window"] = role.StaticAccount.RotationWindow.Seconds()
+			}
+		}
+
 		switch role.CredentialType {
 		case v5.CredentialTypePassword:
 			respData["password"] = role.StaticAccount.Password

builtin/logical/database/path_roles.go

@@ -17,6 +17,7 @@ import (
 	"github.com/hashicorp/vault/sdk/helper/locksutil"
 	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/hashicorp/vault/sdk/queue"
+	"github.com/robfig/cron/v3"
 )
 
 func pathListRoles(b *databaseBackend) []*framework.Path {
@@ -196,7 +197,18 @@ func staticFields() map[string]*framework.FieldSchema {
 			Type: framework.TypeDurationSecond,
 			Description: `Period for automatic
 	credential rotation of the given username. Not valid unless used with
-	"username".`,
+	"username". Mutually exclusive with "rotation_schedule."`,
+		},
+		"rotation_schedule": {
+			Type: framework.TypeString,
+			Description: `Schedule for automatic credential rotation of the
+	given username. Mutually exclusive with "rotation_period."`,
+		},
+		"rotation_window": {
+			Type: framework.TypeDurationSecond,
+			Description: `The window of time in which rotations are allowed to
+	occur starting from a given "rotation_schedule". Requires "rotation_schedule"
+	to be specified`,
 		},
 		"rotation_statements": {
 			Type: framework.TypeStringSlice,
@@ -293,10 +305,20 @@ func (b *databaseBackend) pathStaticRoleRead(ctx context.Context, req *logical.R
 	if role.StaticAccount != nil {
 		data["username"] = role.StaticAccount.Username
 		data["rotation_statements"] = role.Statements.Rotation
-		data["rotation_period"] = role.StaticAccount.RotationPeriod.Seconds()
 		if !role.StaticAccount.LastVaultRotation.IsZero() {
 			data["last_vault_rotation"] = role.StaticAccount.LastVaultRotation
 		}
+
+		// only return one of the mutually exclusive fields in the response
+		if role.StaticAccount.UsesRotationPeriod() {
+			data["rotation_period"] = role.StaticAccount.RotationPeriod.Seconds()
+		} else if role.StaticAccount.UsesRotationSchedule() {
+			data["rotation_schedule"] = role.StaticAccount.RotationSchedule
+			// rotation_window is only valid with rotation_schedule
+			if role.StaticAccount.RotationWindow != 0 {
+				data["rotation_window"] = role.StaticAccount.RotationWindow.Seconds()
+			}
+		}
 	}
 
 	if len(role.CredentialConfig) > 0 {
@@ -480,6 +502,7 @@ func (b *databaseBackend) pathRoleCreateUpdate(ctx context.Context, req *logical
 }
 
 func (b *databaseBackend) pathStaticRoleCreateUpdate(ctx context.Context, req *logical.Request, data *framework.FieldData) (*logical.Response, error) {
+	response := &logical.Response{}
 	name := data.Get("name").(string)
 	if name == "" {
 		return logical.ErrorResponse("empty role name attribute given"), nil
@@ -536,12 +559,18 @@ func (b *databaseBackend) pathStaticRoleCreateUpdate(ctx context.Context, req *l
 	}
 	role.StaticAccount.Username = username
 
-	// If it's a Create operation, both username and rotation_period must be included
-	rotationPeriodSecondsRaw, ok := data.GetOk("rotation_period")
-	if !ok && createRole {
-		return logical.ErrorResponse("rotation_period is required to create static accounts"), nil
+	rotationPeriodSecondsRaw, rotationPeriodOk := data.GetOk("rotation_period")
+	rotationSchedule := data.Get("rotation_schedule").(string)
+	rotationScheduleOk := rotationSchedule != ""
+	rotationWindowSecondsRaw, rotationWindowOk := data.GetOk("rotation_window")
+
+	if rotationScheduleOk && rotationPeriodOk {
+		return logical.ErrorResponse("mutually exclusive fields rotation_period and rotation_schedule were both specified; only one of them can be provided"), nil
+	} else if createRole && (!rotationScheduleOk && !rotationPeriodOk) {
+		return logical.ErrorResponse("one of rotation_schedule or rotation_period must be provided to create a static account"), nil
 	}
-	if ok {
+
+	if rotationPeriodOk {
 		rotationPeriodSeconds := rotationPeriodSecondsRaw.(int)
 		if rotationPeriodSeconds < defaultQueueTickSeconds {
 			// If rotation frequency is specified, and this is an update, the value
@@ -550,6 +579,40 @@ func (b *databaseBackend) pathStaticRoleCreateUpdate(ctx context.Context, req *l
 			return logical.ErrorResponse(fmt.Sprintf("rotation_period must be %d seconds or more", defaultQueueTickSeconds)), nil
 		}
 		role.StaticAccount.RotationPeriod = time.Duration(rotationPeriodSeconds) * time.Second
+
+		if rotationWindowOk {
+			return logical.ErrorResponse("rotation_window is invalid with use of rotation_period"), nil
+		}
+
+		// Unset rotation schedule and window if rotation period is set since
+		// these are mutually exclusive
+		role.StaticAccount.RotationSchedule = ""
+		role.StaticAccount.RotationWindow = 0
+	}
+
+	if rotationScheduleOk {
+		schedule, err := b.scheduleParser.Parse(rotationSchedule)
+		if err != nil {
+			return logical.ErrorResponse("could not parse rotation_schedule", "error", err), nil
+		}
+		role.StaticAccount.RotationSchedule = rotationSchedule
+		sched, ok := schedule.(*cron.SpecSchedule)
+		if !ok {
+			return logical.ErrorResponse("could not parse rotation_schedule"), nil
+		}
+		role.StaticAccount.Schedule = *sched
+
+		if rotationWindowOk {
+			rotationWindowSeconds := rotationWindowSecondsRaw.(int)
+			if rotationWindowSeconds < minRotationWindowSeconds {
+				return logical.ErrorResponse(fmt.Sprintf("rotation_window must be %d seconds or more", minRotationWindowSeconds)), nil
+			}
+			role.StaticAccount.RotationWindow = time.Duration(rotationWindowSeconds) * time.Second
+		}
+
+		// Unset rotation period if rotation schedule is set since these are
+		// mutually exclusive
+		role.StaticAccount.RotationPeriod = 0
 	}
 
 	if rotationStmtsRaw, ok := data.GetOk("rotation_statements"); ok {
@@ -623,14 +686,23 @@ func (b *databaseBackend) pathStaticRoleCreateUpdate(ctx context.Context, req *l
 		}
 	}
 
-	item.Priority = lvr.Add(role.StaticAccount.RotationPeriod).Unix()
+	_, rotationPeriodChanged := data.Raw["rotation_period"]
+	_, rotationScheduleChanged := data.Raw["rotation_schedule"]
+	if rotationPeriodChanged {
+		b.logger.Debug("init priority for RotationPeriod", "lvr", lvr, "next", lvr.Add(role.StaticAccount.RotationPeriod))
+		item.Priority = lvr.Add(role.StaticAccount.RotationPeriod).Unix()
+	} else if rotationScheduleChanged {
+		next := role.StaticAccount.Schedule.Next(lvr)
+		b.logger.Debug("init priority for Schedule", "lvr", lvr, "next", next)
+		item.Priority = role.StaticAccount.Schedule.Next(lvr).Unix()
+	}
 
 	// Add their rotation to the queue
 	if err := b.pushItem(item); err != nil {
 		return nil, err
 	}
 
-	return nil, nil
+	return response, nil
 }
 
 type roleEntry struct {
@@ -730,24 +802,103 @@ type staticAccount struct {
 	// LastVaultRotation represents the last time Vault rotated the password
 	LastVaultRotation time.Time `json:"last_vault_rotation"`
 
+	// NextVaultRotation represents the next time Vault is expected to rotate
+	// the password
+	NextVaultRotation time.Time `json:"next_vault_rotation"`
+
 	// RotationPeriod is number in seconds between each rotation, effectively a
 	// "time to live". This value is compared to the LastVaultRotation to
 	// determine if a password needs to be rotated
 	RotationPeriod time.Duration `json:"rotation_period"`
 
+	// RotationSchedule is a "chron style" string representing the allowed
+	// schedule for each rotation.
+	// e.g. "1 0 * * *" would rotate at one minute past midnight (00:01) every
+	// day.
+	RotationSchedule string `json:"rotation_schedule"`
+
+	// RotationWindow is number in seconds in which rotations are allowed to
+	// occur starting from a given rotation_schedule.
+	RotationWindow time.Duration `json:"rotation_window"`
+
+	// Schedule holds the parsed "chron style" string representing the allowed
+	// schedule for each rotation.
+	Schedule cron.SpecSchedule `json:"schedule"`
+
 	// RevokeUser is a boolean flag to indicate if Vault should revoke the
 	// database user when the role is deleted
 	RevokeUserOnDelete bool `json:"revoke_user_on_delete"`
 }
 
-// NextRotationTime calculates the next rotation by adding the Rotation Period
-// to the last known vault rotation
+// NextRotationTime calculates the next rotation for period and schedule-based
+// rotations.
+//
+// Period-based expiries are calculated by adding the Rotation Period to the
+// last known vault rotation. Schedule-based expiries are calculated by
+// querying for the next schedule expiry since the last known vault rotation.
 func (s *staticAccount) NextRotationTime() time.Time {
-	return s.LastVaultRotation.Add(s.RotationPeriod)
+	if s.UsesRotationPeriod() {
+		return s.LastVaultRotation.Add(s.RotationPeriod)
+	}
+	return s.Schedule.Next(s.LastVaultRotation)
+}
+
+// NextRotationTimeFromInput calculates the next rotation time for period and
+// schedule-based roles based on the input.
+func (s *staticAccount) NextRotationTimeFromInput(input time.Time) time.Time {
+	if s.UsesRotationPeriod() {
+		return input.Add(s.RotationPeriod)
+	}
+	return s.Schedule.Next(input)
+}
+
+// UsesRotationSchedule returns true if the given static account has been
+// configured to rotate credentials on a schedule (i.e. NOT on a rotation period).
+func (s *staticAccount) UsesRotationSchedule() bool {
+	return s.RotationSchedule != "" && s.RotationPeriod == 0
+}
+
+// UsesRotationPeriod returns true if the given static account has been
+// configured to rotate credentials on a period (i.e. NOT on a rotation schedule).
+func (s *staticAccount) UsesRotationPeriod() bool {
+	return s.RotationPeriod != 0 && s.RotationSchedule == ""
+}
+
+// IsInsideRotationWindow returns true if the current time t is within a given
+// static account's rotation window.
+//
+// Returns true if the rotation window is not set. In this case, the rotation
+// window is effectively the span of time between two consecutive rotation
+// schedules and we should not prevent rotation.
+func (s *staticAccount) IsInsideRotationWindow(t time.Time) bool {
+	if s.UsesRotationSchedule() && s.RotationWindow != 0 {
+		return t.Before(s.NextVaultRotation.Add(s.RotationWindow))
+	}
+	return true
+}
+
+// ShouldRotate returns true if a given static account should have its
+// credentials rotated.
+//
+// This will return true when the priority <= the current Unix time. If this
+// static account is schedule-based with a rotation window, this method will
+// return false if now is outside the rotation window.
+func (s *staticAccount) ShouldRotate(priority int64) bool {
+	now := time.Now()
+	return priority <= now.Unix() && s.IsInsideRotationWindow(now)
+}
+
+// SetNextVaultRotation
+func (s *staticAccount) SetNextVaultRotation(t time.Time) {
+	if s.UsesRotationPeriod() {
+		s.NextVaultRotation = t.Add(s.RotationPeriod)
+	} else {
+		s.NextVaultRotation = s.Schedule.Next(t)
+	}
 }
 
 // CredentialTTL calculates the approximate time remaining until the credential is
-// no longer valid. This is approximate because the periodic rotation is only
+// no longer valid. This is approximate because the rotation expiry is only
 // checked approximately every 5 seconds, and each rotation can take a small
 // amount of time to process. This can result in a negative TTL time while the
 // rotation function processes the Static Role and performs the rotation. If the