Files
threshold/internal/perms/grants.go
T
Jeff Mitchell fc664eb35f Improve grant validation (#3081)
This adds several relationships into the resource package that are then
made use of to improve the grant validation that runs during Parse. By
understanding mappings between ID and resource type the validation
checks can far better align with actual allowed grant formats so we can
find several common misunderstandings before they simply result in an
authorization failure.

In the future some of these functions could be used in the logic in the
actual ACL checks but it's not currently necessary and I don't want to
lump that change in with this.

Note that the tests have not meaningfully changed, but they _have_ had
to be updated because the stricter validation is actually catching
issues.
2023-03-16 10:11:55 -04:00

546 lines
19 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package perms
import (
"encoding/json"
"fmt"
"sort"
"strings"
"unicode"
"github.com/hashicorp/boundary/globals"
"github.com/hashicorp/boundary/internal/errors"
"github.com/hashicorp/boundary/internal/types/action"
"github.com/hashicorp/boundary/internal/types/resource"
"github.com/hashicorp/boundary/internal/types/scope"
)
// GrantTuple is simply a struct that can be reference from other code to return
// a set of scopes and grants to parse
type GrantTuple struct {
RoleId string
ScopeId string
Grant string
}
// Scope provides an in-memory representation of iam.Scope without the
// underlying storage references or capabilities.
type Scope struct {
// Id is the public id of the iam.Scope
Id string
// Type is the scope's type (org or project)
Type scope.Type
}
// Grant is a Go representation of a parsed grant
type Grant struct {
// The scope ID, which will be a project ID or an org ID
scope Scope
// The ID in the grant, if provided.
id string
// The type, if provided
typ resource.Type
// The set of actions being granted
actions map[action.Type]bool
// The set of output fields granted
OutputFields *OutputFields
// This is used as a temporary staging area before validating permissions to
// allow the same validation code across grant string formats
actionsBeingParsed []string
}
func (g Grant) Id() string {
return g.id
}
func (g Grant) Type() resource.Type {
return g.typ
}
func (g Grant) Actions() (typs []action.Type, strs []string) {
typs = make([]action.Type, 0, len(g.actions))
strs = make([]string, 0, len(g.actions))
for k, v := range g.actions {
// Nothing should be in there if not true, but doesn't hurt to validate
if !v {
continue
}
typs = append(typs, k)
strs = append(strs, k.String())
}
return
}
// hasActionOrSubaction checks whether a grant's action set contains the given
// action or contains an action that is a subaction of the passed-in parameter.
// This is used for validation checking of parsed grants. N.B.: this is the
// opposite check of action.Type.IsActionOrParent, which is why the ordering is
// reversed going into that call.
func (g Grant) hasActionOrSubaction(act action.Type) bool {
for k := range g.actions {
if act.IsActionOrParent(k) {
return true
}
}
return false
}
func (g Grant) clone() *Grant {
ret := &Grant{
scope: g.scope,
id: g.id,
typ: g.typ,
}
if g.actionsBeingParsed != nil {
ret.actionsBeingParsed = append(ret.actionsBeingParsed, g.actionsBeingParsed...)
}
if g.actions != nil {
ret.actions = make(map[action.Type]bool, len(g.actions))
for action := range g.actions {
ret.actions[action] = true
}
}
if outFields, hasSetFields := g.OutputFields.Fields(); hasSetFields {
fieldsToAdd := make([]string, 0, len(outFields))
for _, v := range outFields {
fieldsToAdd = append(fieldsToAdd, v)
}
ret.OutputFields = ret.OutputFields.AddFields(fieldsToAdd)
}
return ret
}
// CanonicalString returns the canonical representation of the grant
func (g Grant) CanonicalString() string {
var builder []string
if g.id != "" {
builder = append(builder, fmt.Sprintf("id=%s", g.id))
}
if g.typ != resource.Unknown {
builder = append(builder, fmt.Sprintf("type=%s", g.typ.String()))
}
if len(g.actions) > 0 {
actions := make([]string, 0, len(g.actions))
for action := range g.actions {
actions = append(actions, action.String())
}
sort.Strings(actions)
builder = append(builder, fmt.Sprintf("actions=%s", strings.Join(actions, ",")))
}
if outFields, hasSetFields := g.OutputFields.Fields(); hasSetFields {
builder = append(builder, fmt.Sprintf("output_fields=%s", strings.Join(outFields, ",")))
}
return strings.Join(builder, ";")
}
// MarshalJSON provides a custom marshaller for grants
func (g Grant) MarshalJSON() ([]byte, error) {
const op = "perms.(Grant).MarshalJSON"
res := make(map[string]any, 4)
if g.id != "" {
res["id"] = g.id
}
if g.typ != resource.Unknown {
res["type"] = g.typ.String()
}
if len(g.actions) > 0 {
actions := make([]string, 0, len(g.actions))
for action := range g.actions {
actions = append(actions, action.String())
}
sort.Strings(actions)
res["actions"] = actions
}
if outFields, hasSetFields := g.OutputFields.Fields(); hasSetFields {
res["output_fields"] = outFields
}
b, err := json.Marshal(res)
if err != nil {
return nil, errors.WrapDeprecated(err, op, errors.WithCode(errors.Encode))
}
return b, nil
}
// This is purposefully unexported since the values being set here are not being
// checked for validity. This should only be called by the main parsing function
// when JSON is detected.
func (g *Grant) unmarshalJSON(data []byte) error {
const op = "perms.(Grant).unmarshalJSON"
raw := make(map[string]any, 4)
if err := json.Unmarshal(data, &raw); err != nil {
return errors.WrapDeprecated(err, op, errors.WithCode(errors.Decode))
}
if rawId, ok := raw["id"]; ok {
id, ok := rawId.(string)
if !ok {
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unable to interpret %q as string", "id"))
}
g.id = id
}
if rawType, ok := raw["type"]; ok {
typ, ok := rawType.(string)
if !ok {
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unable to interpret %q as string", "type"))
}
g.typ = resource.Map[typ]
if g.typ == resource.Unknown {
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unknown type specifier %q", typ))
}
}
if rawActions, ok := raw["actions"]; ok {
interfaceActions, ok := rawActions.([]any)
if !ok {
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unable to interpret %q as array", "actions"))
}
if len(interfaceActions) > 0 {
g.actionsBeingParsed = make([]string, 0, len(interfaceActions))
for _, v := range interfaceActions {
actionStr, ok := v.(string)
switch {
case !ok:
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unable to interpret %v in actions array as string", v))
case actionStr == "":
return errors.NewDeprecated(errors.InvalidParameter, op, "empty action found")
default:
g.actionsBeingParsed = append(g.actionsBeingParsed, strings.ToLower(actionStr))
}
}
}
}
if rawOutputFields, ok := raw["output_fields"]; ok {
interfaceOutputFields, ok := rawOutputFields.([]any)
if !ok {
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unable to interpret %q as array", "output_fields"))
}
// We do the make here because we detect later if the field was set but
// no values given
switch len(interfaceOutputFields) {
case 0:
// JSON was set but no fields defined, add an empty array
g.OutputFields = g.OutputFields.AddFields([]string{})
default:
fields := make([]string, 0, len(interfaceOutputFields))
for _, v := range interfaceOutputFields {
field, ok := v.(string)
switch {
case !ok:
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unable to interpret %v in output_fields array as string", v))
default:
fields = append(fields, field)
}
}
g.OutputFields = g.OutputFields.AddFields(fields)
}
}
return nil
}
func (g *Grant) unmarshalText(grantString string) error {
const op = "perms.(Grant).unmarshalText"
segments := strings.Split(grantString, ";")
for _, segment := range segments {
kv := strings.Split(segment, "=")
// Ensure we don't accept "foo=bar=baz", "=foo", or "foo="
switch {
case len(kv) != 2:
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("segment %q not formatted correctly, wrong number of equal signs", segment))
case len(kv[0]) == 0:
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("segment %q not formatted correctly, missing key", segment))
case len(kv[1]) == 0 && kv[0] != "output_fields":
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("segment %q not formatted correctly, missing value", segment))
}
switch kv[0] {
case "id":
g.id = kv[1]
case "type":
typeString := strings.ToLower(kv[1])
g.typ = resource.Map[typeString]
if g.typ == resource.Unknown {
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unknown type specifier %q", typeString))
}
case "actions":
actions := strings.Split(kv[1], ",")
if len(actions) > 0 {
g.actionsBeingParsed = make([]string, 0, len(actions))
for _, action := range actions {
if action == "" {
return errors.NewDeprecated(errors.InvalidParameter, op, "empty action found")
}
g.actionsBeingParsed = append(g.actionsBeingParsed, strings.ToLower(action))
}
}
case "output_fields":
switch len(kv[1]) {
case 0:
g.OutputFields = g.OutputFields.AddFields([]string{})
default:
g.OutputFields = g.OutputFields.AddFields(strings.Split(kv[1], ","))
}
}
}
return nil
}
// Parse parses a grant string. Note that this does not do checking
// of the validity of IDs and such; that's left for other parts of the system.
// We may not check at all (e.g. let it be an authz-time failure) or could check
// after submission to catch errors.
//
// The scope must be the org and project where this grant originated, not the
// request.
func Parse(scopeId, grantString string, opt ...Option) (Grant, error) {
const op = "perms.Parse"
if len(grantString) == 0 {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, "missing grant string")
}
if scopeId == "" {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, "missing scope id")
}
grantString = strings.ToValidUTF8(grantString, string(unicode.ReplacementChar))
grant := Grant{
scope: Scope{Id: strings.ToValidUTF8(scopeId, string(unicode.ReplacementChar))},
}
switch {
case scopeId == scope.Global.String():
grant.scope.Type = scope.Global
case strings.HasPrefix(scopeId, scope.Org.Prefix()):
grant.scope.Type = scope.Org
case strings.HasPrefix(scopeId, scope.Project.Prefix()):
grant.scope.Type = scope.Project
default:
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, "invalid scope type")
}
switch {
case grantString[0] == '{':
if err := grant.unmarshalJSON([]byte(grantString)); err != nil {
return Grant{}, errors.WrapDeprecated(err, op, errors.WithMsg("unable to parse JSON grant string"))
}
default:
if err := grant.unmarshalText(grantString); err != nil {
return Grant{}, errors.WrapDeprecated(err, op, errors.WithMsg("unable to parse grant string"))
}
}
opts := getOpts(opt...)
// Check for templated values ID, and substitute in with the authenticated
// values if so. If we are using a dummy user or account ID, store the
// original ID and return it at the end; this is usually the case when
// validating grant formats.
var origId string
if grant.id != "" && strings.HasPrefix(grant.id, "{{") {
id := strings.TrimSuffix(strings.TrimPrefix(grant.id, "{{"), "}}")
id = strings.TrimSpace(id)
switch id {
case "user.id", ".User.Id":
if opts.withUserId != "" {
grant.id = strings.ToValidUTF8(opts.withUserId, string(unicode.ReplacementChar))
}
// Otherwise, substitute in a dummy value
origId = grant.id
grant.id = "u_dummy"
case "account.id", ".Account.Id":
if opts.withAccountId != "" {
grant.id = strings.ToValidUTF8(opts.withAccountId, string(unicode.ReplacementChar))
}
origId = grant.id
grant.id = "acctoidc_dummy"
default:
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unknown template %q in grant %q value", grant.id, "id"))
}
}
if err := grant.validateType(); err != nil {
return Grant{}, errors.WrapDeprecated(err, op)
}
if err := grant.parseAndValidateActions(); err != nil {
return Grant{}, errors.WrapDeprecated(err, op)
}
if !opts.withSkipFinalValidation {
switch {
case grant.id == "*":
// Matches
// id=*;type=sometype;actions=foo,bar
// or
// id=*;type=*;actions=foo,bar
// This can be a non-unknown type or wildcard
if grant.typ == resource.Unknown {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains wildcard id and no specified type", grant.CanonicalString()))
}
case grant.id != "":
// Non-wildcard but specified ID. This can match
// id=foo_bar;actions=foo,bar
// or
// id=foo_bar;type=sometype;actions=foo,bar
// or
// id=foo_bar;type=*;actions=foo,bar
// but notably the specified types have to actually make sense: in
// the second example the type corresponding to the ID must have the
// specified type as a child type; in the third the ID must be a
// type that has child types.
idType := globals.ResourceTypeFromPrefix(grant.id)
if idType == resource.Unknown {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains an id %q of an unknown resource type", grant.CanonicalString(), grant.id))
}
switch grant.typ {
case resource.Unknown:
// This is fine as-is but we do not support collection actions
// without a type (either directly specified or wildcard) so
// check that
if grant.actions[action.Create] ||
grant.actions[action.List] {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains create or list action in a format that does not allow these", grant.CanonicalString()))
}
case resource.All:
// Verify that the ID is a type that has child types
if !resource.HasChildTypes(idType) {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains an id that does not support child types", grant.CanonicalString()))
}
default:
// Specified resource type, verify it's a child
if resource.Parent(grant.typ) != idType {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains type %s that is not a child type of the type (%s) of the specified id", grant.CanonicalString(), grant.typ.String(), idType.String()))
}
}
default: // no specified id
switch grant.typ {
case resource.Unknown:
// Error -- no ID or type isn't valid (although we should never
// get to this point because original parsing should error)
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains no id or type", grant.CanonicalString()))
case resource.All:
// "type=*;actions=..." is not supported -- we require you to
// explicitly set a pin or set the ID to *
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains wildcard type with no id value", grant.CanonicalString()))
default:
// Here we have type=something,actions=<something else>. This
// means we're operating on collections and support only create
// or list. Note that wildcard actions are not okay here; that
// uses the format id=*;type=<something>;actions=*
switch len(grant.actions) {
case 0:
// It's okay to have no actions if only output fields are being defined
if _, hasSetFields := grant.OutputFields.Fields(); !hasSetFields {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains no actions or output fields", grant.CanonicalString()))
}
case 1:
if !grant.hasActionOrSubaction(action.Create) &&
!grant.hasActionOrSubaction(action.List) {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains non-create or non-list action in a format that only allows these", grant.CanonicalString()))
}
case 2:
if !grant.hasActionOrSubaction(action.Create) || !grant.hasActionOrSubaction(action.List) {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains non-create or non-list action in a format that only allows these", grant.CanonicalString()))
}
default:
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("parsed grant string %q contains non-create or non-list action in a format that only allows these", grant.CanonicalString()))
}
}
}
// This might be zero if output fields is populated
if len(grant.actions) > 0 {
// Create a dummy resource and pass it through Allowed and ensure that
// we get allowed.
acl := NewACL(grant)
r := Resource{
ScopeId: scopeId,
Id: grant.id,
Type: grant.typ,
}
if !resource.TopLevelType(grant.typ) {
r.Pin = grant.id
}
var allowed bool
for k := range grant.actions {
results := acl.Allowed(r, k, globals.AnonymousUserId, WithSkipAnonymousUserRestrictions(true))
if results.Authorized {
allowed = true
break
}
}
if !allowed {
return Grant{}, errors.NewDeprecated(errors.InvalidParameter, op, "parsed grant string would not result in any action being authorized")
}
}
}
// If we substituted in a dummy value, replace with the original now
if origId != "" {
grant.id = origId
}
return grant, nil
}
// validateType ensures that we are not allowing access to disallowed resource
// types. It does not explicitly check the resource string itself; that's the
// job of the parsing functions to look up the string from the Map and ensure
// it's not unknown.
func (g Grant) validateType() error {
const op = "perms.(Grant).validateType"
switch g.typ {
case resource.Controller:
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unknown type specifier %q", g.typ))
}
return nil
}
func (g *Grant) parseAndValidateActions() error {
const op = "perms.(Grant).parseAndValidateActions"
if len(g.actionsBeingParsed) == 0 {
g.actionsBeingParsed = nil
// If there are no actions it's fine if the grant is just used to
// specify output fields
if _, hasSetFields := g.OutputFields.Fields(); hasSetFields {
return nil
}
return errors.NewDeprecated(errors.InvalidParameter, op, "missing actions")
}
for _, a := range g.actionsBeingParsed {
if a == "" {
return errors.NewDeprecated(errors.InvalidParameter, op, "empty action found")
}
if g.actions == nil {
g.actions = make(map[action.Type]bool, len(g.actionsBeingParsed))
}
if am := action.Map[a]; am == action.Unknown {
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("unknown action %q", a))
} else {
g.actions[am] = true
}
}
if len(g.actions) > 1 && g.actions[action.All] {
return errors.NewDeprecated(errors.InvalidParameter, op, fmt.Sprintf("%q cannot be specified with other actions", action.All.String()))
}
g.actionsBeingParsed = nil
return nil
}