mirror of https://github.com/coder/coder.git
136 lines
4.2 KiB
Go
136 lines
4.2 KiB
Go
package rbac
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import (
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"context"
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_ "embed"
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"golang.org/x/xerrors"
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"github.com/open-policy-agent/opa/rego"
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)
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type Authorizer interface {
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ByRoleName(ctx context.Context, subjectID string, roleNames []string, action Action, object Object) error
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PrepareByRoleName(ctx context.Context, subjectID string, roleNames []string, action Action, objectType string) (PreparedAuthorized, error)
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}
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type PreparedAuthorized interface {
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Authorize(ctx context.Context, object Object) error
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}
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// Filter takes in a list of objects, and will filter the list removing all
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// the elements the subject does not have permission for. All objects must be
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// of the same type.
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func Filter[O Objecter](ctx context.Context, auth Authorizer, subjID string, subjRoles []string, action Action, objects []O) ([]O, error) {
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if len(objects) == 0 {
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// Nothing to filter
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return objects, nil
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}
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objectType := objects[0].RBACObject().Type
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filtered := make([]O, 0)
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prepared, err := auth.PrepareByRoleName(ctx, subjID, subjRoles, action, objectType)
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if err != nil {
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return nil, xerrors.Errorf("prepare: %w", err)
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}
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for i := range objects {
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object := objects[i]
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rbacObj := object.RBACObject()
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if rbacObj.Type != objectType {
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return nil, xerrors.Errorf("object types must be uniform across the set (%s), found %s", objectType, object.RBACObject().Type)
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}
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err := prepared.Authorize(ctx, rbacObj)
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if err == nil {
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filtered = append(filtered, object)
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}
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}
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return filtered, nil
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}
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// RegoAuthorizer will use a prepared rego query for performing authorize()
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type RegoAuthorizer struct {
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query rego.PreparedEvalQuery
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}
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// Load the policy from policy.rego in this directory.
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//
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//go:embed policy.rego
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var policy string
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func NewAuthorizer() (*RegoAuthorizer, error) {
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ctx := context.Background()
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query, err := rego.New(
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// allowed is the `allow` field from the prepared query. This is the field to check if authorization is
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// granted.
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rego.Query("data.authz.allow"),
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rego.Module("policy.rego", policy),
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).PrepareForEval(ctx)
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if err != nil {
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return nil, xerrors.Errorf("prepare query: %w", err)
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}
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return &RegoAuthorizer{query: query}, nil
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}
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type authSubject struct {
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ID string `json:"id"`
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Roles []Role `json:"roles"`
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}
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// ByRoleName will expand all roleNames into roles before calling Authorize().
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// This is the function intended to be used outside this package.
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// The role is fetched from the builtin map located in memory.
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func (a RegoAuthorizer) ByRoleName(ctx context.Context, subjectID string, roleNames []string, action Action, object Object) error {
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roles, err := RolesByNames(roleNames)
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if err != nil {
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return err
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}
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return a.Authorize(ctx, subjectID, roles, action, object)
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}
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// Authorize allows passing in custom Roles.
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// This is really helpful for unit testing, as we can create custom roles to exercise edge cases.
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func (a RegoAuthorizer) Authorize(ctx context.Context, subjectID string, roles []Role, action Action, object Object) error {
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input := map[string]interface{}{
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"subject": authSubject{
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ID: subjectID,
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Roles: roles,
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},
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"object": object,
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"action": action,
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}
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results, err := a.query.Eval(ctx, rego.EvalInput(input))
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if err != nil {
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return ForbiddenWithInternal(xerrors.Errorf("eval rego: %w", err), input, results)
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}
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if !results.Allowed() {
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return ForbiddenWithInternal(xerrors.Errorf("policy disallows request"), input, results)
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}
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return nil
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}
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// Prepare will partially execute the rego policy leaving the object fields unknown (except for the type).
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// This will vastly speed up performance if batch authorization on the same type of objects is needed.
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func (RegoAuthorizer) Prepare(ctx context.Context, subjectID string, roles []Role, action Action, objectType string) (*PartialAuthorizer, error) {
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auth, err := newPartialAuthorizer(ctx, subjectID, roles, action, objectType)
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if err != nil {
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return nil, xerrors.Errorf("new partial authorizer: %w", err)
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}
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return auth, nil
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}
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func (a RegoAuthorizer) PrepareByRoleName(ctx context.Context, subjectID string, roleNames []string, action Action, objectType string) (PreparedAuthorized, error) {
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roles, err := RolesByNames(roleNames)
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if err != nil {
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return nil, err
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}
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return a.Prepare(ctx, subjectID, roles, action, objectType)
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}
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