Authorization / Access Control: Privilege escalation via RBAC misconfiguration (AllowsKind gating)

Proof-of-concept (pre-fix behavior): 1) Prereqs: admin access to IAM permission API and a target service account with id 123. 2) Attempt to grant BasicRole to service account 123 on the serviceaccounts resource via ResourcePermission: POST /api/iam/resourcepermissions Content-Type: application/json Authorization: Bearer <token> { "resource": "serviceaccounts", "scope": "serviceaccounts:id:123", "permissions": [ { "kind": "BasicRole", "level": "Edit" } ] } Expected before fix: API accepts the request and creates the permission, effectively granting BasicRole to the SA. After fix (current patch): The mapper for serviceaccounts now restricts allowed kinds to User, ServiceAccount, and Team (BasicRole is not allowed). The API should reject the request with a validation error (e.g., 400/403). Attack surface: Privilege escalation on service accounts; cross-resource access depending on BasicRole capabilities.

diff --git a/pkg/registry/apis/iam/resourcepermission/mapper.go b/pkg/registry/apis/iam/resourcepermission/mapper.go index e4faf2300b786..a1d327ae9682e 100644 --- a/pkg/registry/apis/iam/resourcepermission/mapper.go +++ b/pkg/registry/apis/iam/resourcepermission/mapper.go @@ -7,6 +7,7 @@ import ( "strings" "github.com/grafana/authlib/types" + v0alpha1 "github.com/grafana/grafana/apps/iam/pkg/apis/iam/v0alpha1" "github.com/grafana/grafana/pkg/registry/apis/iam/legacy" "k8s.io/apimachinery/pkg/runtime/schema" ) @@ -33,21 +34,54 @@ type Mapper interface { // Used in list queries with SQL LIKE to match all permissions for this resource type. // Example: "folders:uid:%" matches "folders:uid:abc", "folders:uid:xyz", etc. ScopePattern() string + + // AllowsKind reports whether the resource type permits assignments to the given permission kind. + // Returns true when no kind restriction is configured (all kinds allowed). + AllowsKind(kind v0alpha1.ResourcePermissionSpecPermissionKind) bool } +// ScopeAttribute defines how a resource is identified in RBAC scope strings. +// It is the middle segment of a scope, e.g. "uid" in "folders:uid:abc". +type ScopeAttribute string + +const ( + // ScopeAttributeUID identifies resources by their UID (e.g. "folders:uid:abc"). + ScopeAttributeUID ScopeAttribute = "uid" + // ScopeAttributeID identifies resources by their numeric database ID (e.g. "serviceaccounts:id:123"). + ScopeAttributeID ScopeAttribute = "id" +) + type mapper struct { - resource string - actionSets []string + resource string + scopeAttribute ScopeAttribute + actionSets []string + allowedKinds []v0alpha1.ResourcePermissionSpecPermissionKind // nil = all kinds allowed } +// NewMapper creates a Mapper for uid-scoped resources (folders, dashboards). +// All permission kinds are allowed. func NewMapper(resource string, levels []string) Mapper { + return NewMapperWithAttribute(resource, levels, ScopeAttributeUID, nil) +} + +// NewIDScopedMapper creates a Mapper for id-scoped resources (teams, users). +// All permission kinds are allowed. +func NewIDScopedMapper(resource string, levels []string) Mapper { + return NewMapperWithAttribute(resource, levels, ScopeAttributeID, nil) +} + +// NewMapperWithAttribute creates a Mapper with an explicit scope attribute and optional kind restrictions. +// When allowedKinds is nil, all permission kinds are permitted. +func NewMapperWithAttribute(resource string, levels []string, attr ScopeAttribute, allowedKinds []v0alpha1.ResourcePermissionSpecPermissionKind) Mapper { sets := make([]string, 0, len(levels)) for _, level := range levels { sets = append(sets, resource+":"+strings.ToLower(level)) } return mapper{ - resource: resource, - actionSets: sets, + resource: resource, + scopeAttribute: attr, + actionSets: sets, + allowedKinds: allowedKinds, } } @@ -56,7 +90,7 @@ func (m mapper) ActionSets() []string { } func (m mapper) Scope(name string) string { - return m.resource + ":uid:" + name + return m.resource + ":" + string(m.scopeAttribute) + ":" + name } func (m mapper) ActionSet(level string) (string, error) { @@ -68,7 +102,14 @@ func (m mapper) ActionSet(level string) (string, error) { } func (m mapper) ScopePattern() string { - return m.resource + ":uid:%" + return m.resource + ":" + string(m.scopeAttribute) + ":%" +} + +func (m mapper) AllowsKind(kind v0alpha1.ResourcePermissionSpecPermissionKind) bool { + if m.allowedKinds == nil { + return true + } + return slices.Contains(m.allowedKinds, kind) } type mapperEntry struct { @@ -231,44 +272,6 @@ func (m *MappersRegistry) EnabledScopePatterns() []string { return out } -// NewIDScopedMapper creates a Mapper for resources stored with id-based scopes -// in the legacy permission table (teams, users, service accounts). -// Unlike the default uid-scoped mapper, its ScopePattern returns ":id:%". -// The actual uid↔id resolution is handled by scope_resolver functions via the -// MappersRegistry's identity store, not by the mapper itself. -func NewIDScopedMapper(resource string, levels []string) Mapper { - sets := make([]string, 0, len(levels)) - for _, level := range levels { - sets = append(sets, resource+":"+strings.ToLower(level)) - } - return idMapper{resource: resource, actionSets: sets} -} - -// idMapper implements Mapper for id-scoped resources. It differs from the default -// mapper only in ScopePattern (returns ":id:%" for DB queries). -type idMapper struct { - resource string - actionSets []string -} - -func (m idMapper) ActionSets() []string { return m.actionSets } - -func (m idMapper) ActionSet(level string) (string, error) { - actionSet := m.resource + ":" + strings.ToLower(level) - if !slices.Contains(m.actionSets, actionSet) { - return "", fmt.Errorf("invalid level (%s): %w", level, errInvalidSpec) - } - return actionSet, nil -} - -func (m idMapper) Scope(name string) string { - return m.resource + ":uid:" + name -} - -func (m idMapper) ScopePattern() string { - return m.resource + ":id:%" -} - // ParseScopeCtx parses an RBAC scope string into a groupResourceName, resolving id to uid for // id-scoped resources (teams, users, service accounts) using the provided store and namespace. // For uid-scoped resources (folders, dashboards) it behaves identically to ParseScope. diff --git a/pkg/registry/apis/iam/resourcepermission/mapper_test.go b/pkg/registry/apis/iam/resourcepermission/mapper_test.go index 5bae23a48682e..5db0631e069e8 100644 --- a/pkg/registry/apis/iam/resourcepermission/mapper_test.go +++ b/pkg/registry/apis/iam/resourcepermission/mapper_test.go @@ -6,6 +6,8 @@ import ( "github.com/stretchr/testify/assert" "github.com/stretchr/testify/require" "k8s.io/apimachinery/pkg/runtime/schema" + + v0alpha1 "github.com/grafana/grafana/apps/iam/pkg/apis/iam/v0alpha1" ) // --- NewMappersRegistry defaults --- @@ -362,3 +364,56 @@ func TestMappersRegistry_MultipleWildcards(t *testing.T) { require.NoError(t, err) assert.Equal(t, "unknown.alerting.grafana.app", alertGrn.Group) } + +// --- NewMapper / NewIDScopedMapper / NewMapperWithAttribute --- + +func TestNewMapper_UIDScoped(t *testing.T) { + m := NewMapper("folders", []string{"view", "edit", "admin"}) + + assert.Equal(t, "folders:uid:abc", m.Scope("abc")) + assert.Equal(t, "folders:uid:%", m.ScopePattern()) + assert.Equal(t, []string{"folders:view", "folders:edit", "folders:admin"}, m.ActionSets()) +} + +func TestNewIDScopedMapper_IDScoped(t *testing.T) { + m := NewIDScopedMapper("serviceaccounts", []string{"edit", "admin"}) + + assert.Equal(t, "serviceaccounts:id:123", m.Scope("123")) + assert.Equal(t, "serviceaccounts:id:%", m.ScopePattern()) +} + +func TestNewMapperWithAttribute_ExplicitAttribute(t *testing.T) { + uid := NewMapperWithAttribute("folders", []string{"view"}, ScopeAttributeUID, nil) + assert.Equal(t, "folders:uid:abc", uid.Scope("abc")) + assert.Equal(t, "folders:uid:%", uid.ScopePattern()) + + id := NewMapperWithAttribute("serviceaccounts", []string{"edit"}, ScopeAttributeID, nil) + assert.Equal(t, "serviceaccounts:id:123", id.Scope("123")) + assert.Equal(t, "serviceaccounts:id:%", id.ScopePattern()) +} + +// --- AllowsKind --- + +func TestMapper_AllowsKind_NilAllowedKinds(t *testing.T) { + m := NewMapper("folders", defaultLevels) + + // nil allowedKinds means all kinds are permitted + assert.True(t, m.AllowsKind(v0alpha1.ResourcePermissionSpecPermissionKindUser)) + assert.True(t, m.AllowsKind(v0alpha1.ResourcePermissionSpecPermissionKindTeam)) + assert.True(t, m.AllowsKind(v0alpha1.ResourcePermissionSpecPermissionKindServiceAccount)) + assert.True(t, m.AllowsKind(v0alpha1.ResourcePermissionSpecPermissionKindBasicRole)) +} + +func TestMapper_AllowsKind_RestrictedList(t *testing.T) { + allowedKinds := []v0alpha1.ResourcePermissionSpecPermissionKind{ + v0alpha1.ResourcePermissionSpecPermissionKindUser, + v0alpha1.ResourcePermissionSpecPermissionKindServiceAccount, + v0alpha1.ResourcePermissionSpecPermissionKindTeam, + } + m := NewMapperWithAttribute("serviceaccounts", []string{"edit", "admin"}, ScopeAttributeID, allowedKinds) + + assert.True(t, m.AllowsKind(v0alpha1.ResourcePermissionSpecPermissionKindUser)) + assert.True(t, m.AllowsKind(v0alpha1.ResourcePermissionSpecPermissionKindServiceAccount)) + assert.True(t, m.AllowsKind(v0alpha1.ResourcePermissionSpecPermissionKindTeam)) + assert.False(t, m.AllowsKind(v0alpha1.ResourcePermissionSpecPermissionKindBasicRole)) +} diff --git a/pkg/registry/apis/iam/resourcepermission/storage_backend.go b/pkg/registry/apis/iam/resourcepermission/storage_backend.go index c06666eaa093e..6079a2ad7309b 100644 --- a/pkg/registry/apis/iam/resourcepermission/storage_backend.go +++ b/pkg/registry/apis/iam/resourcepermission/storage_backend.go @@ -49,9 +49,16 @@ func ProvideStorageBackend(dbProvider legacysql.LegacyDatabaseProvider, mappers schema.GroupResource{Group: "iam.grafana.app", Resource: "users"}, NewIDScopedMapper("users", defaultLevels), nil, ) + // BasicRole is excluded: built-in roles already cover all service accounts globally, + // so granting a ResourcePermission to a BasicRole on a specific SA is not permitted. mappers.RegisterMapper( schema.GroupResource{Group: "iam.grafana.app", Resource: "serviceaccounts"}, - NewIDScopedMapper("serviceaccounts", []string{"Edit", "Admin"}), nil, + NewMapperWithAttribute("serviceaccounts", []string{"Edit", "Admin"}, ScopeAttributeID, + []v0alpha1.ResourcePermissionSpecPermissionKind{ + v0alpha1.ResourcePermissionSpecPermissionKindUser, + v0alpha1.ResourcePermissionSpecPermissionKindServiceAccount, + v0alpha1.ResourcePermissionSpecPermissionKindTeam, + }), nil, ) return &ResourcePermSqlBackend{ dbProvider: dbProvider,