writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInvalidRequest), r.URL)
		return
	}

	// Empty DN list and not self, list access keys for all users
	if isAll {
		if !globalIAMSys.IsAllowed(policy.Args{
			AccountName:     cred.AccessKey,
			Groups:          cred.Groups,
			Action:          policy.ListUsersAdminAction,
			ConditionValues: getConditionValues(r, "", cred),
			IsOwner:         owner,

			//   error.
			// * if you don’t have the s3:ListBucket
			//   permission, Amazon S3 will return an HTTP
			//   status code 403 ("access denied") error.`
			if globalPolicySys.IsAllowed(policy.BucketPolicyArgs{
				Action:          policy.ListBucketAction,
				BucketName:      bucket,
				ConditionValues: getConditionValues(r, "", auth.AnonymousCredentials),
				IsOwner:         false,
			}) {