From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752341AbdH1IJB (ORCPT ); Mon, 28 Aug 2017 04:09:01 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33214 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751755AbdH1II6 (ORCPT ); Mon, 28 Aug 2017 04:08:58 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai Subject: [PATCH 4.12 38/99] ALSA: core: Fix unexpected error at replacing user TLV Date: Mon, 28 Aug 2017 10:04:36 +0200 Message-Id: <20170828080457.476669083@linuxfoundation.org> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170828080455.968552605@linuxfoundation.org> References: <20170828080455.968552605@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 88c54cdf61f508ebcf8da2d819f5dfc03e954d1d upstream. When user tries to replace the user-defined control TLV, the kernel checks the change of its content via memcmp(). The problem is that the kernel passes the return value from memcmp() as is. memcmp() gives a non-zero negative value depending on the comparison result, and this shall be recognized as an error code. The patch covers that corner-case, return 1 properly for the changed TLV. Fixes: 8aa9b586e420 ("[ALSA] Control API - more robust TLV implementation") Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/control.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/sound/core/control.c +++ b/sound/core/control.c @@ -1157,7 +1157,7 @@ static int snd_ctl_elem_user_tlv(struct mutex_lock(&ue->card->user_ctl_lock); change = ue->tlv_data_size != size; if (!change) - change = memcmp(ue->tlv_data, new_data, size); + change = memcmp(ue->tlv_data, new_data, size) != 0; kfree(ue->tlv_data); ue->tlv_data = new_data; ue->tlv_data_size = size;