// Not officially supported in POST requests.
		apiErr := errorCodes.ToAPIErr(ErrMalformedPOSTRequest)
		apiErr.Description = fmt.Sprintf("%s (%v)", apiErr.Description, errors.New("Trailing checksums not available for POST operations"))
		writeErrorResponse(ctx, w, apiErr, r.URL)
		return
	}

	formValues.Set("Bucket", bucket)
	if fileName != "" && strings.Contains(formValues.Get("Key"), "${filename}") {

		if len(policyBuf) > maxSVCSessionPolicySize {
			return auth.Credentials{}, time.Time{}, errSessionPolicyTooLarge
		}
	}

	// found newly requested service account, to be same as
	// parentUser, reject such operations.
	if parentUser == opts.accessKey {
		return auth.Credentials{}, time.Time{}, errIAMActionNotAllowed
	}
	if siteReplicatorSvcAcc == opts.accessKey && !opts.allowSiteReplicatorAccount {