From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59414 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755970AbeDKSrm (ORCPT ); Wed, 11 Apr 2018 14:47:42 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrey Konovalov , Firo Yang , "David S. Miller" , Sasha Levin Subject: [PATCH 4.4 095/190] hdlcdrv: Fix divide by zero in hdlcdrv_ioctl Date: Wed, 11 Apr 2018 20:35:41 +0200 Message-Id: <20180411183556.135523359@linuxfoundation.org> In-Reply-To: <20180411183550.114495991@linuxfoundation.org> References: <20180411183550.114495991@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Firo Yang [ Upstream commit fb3ce90b7d7761b6f7f28f0ff5c456ef6b5229a1 ] syszkaller fuzzer triggered a divide by zero, when set calibration through ioctl(). To fix it, test 'bitrate' if it is negative or 0, just return -EINVAL. Reported-by: Andrey Konovalov Signed-off-by: Firo Yang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/hamradio/hdlcdrv.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/net/hamradio/hdlcdrv.c +++ b/drivers/net/hamradio/hdlcdrv.c @@ -574,6 +574,8 @@ static int hdlcdrv_ioctl(struct net_devi case HDLCDRVCTL_CALIBRATE: if(!capable(CAP_SYS_RAWIO)) return -EPERM; + if (s->par.bitrate <= 0) + return -EINVAL; if (bi.data.calibrate > INT_MAX / s->par.bitrate) return -EINVAL; s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;