From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F03C9C04AB1 for ; Mon, 13 May 2019 07:36:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE3B2208C3 for ; Mon, 13 May 2019 07:36:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557732983; bh=wc9NZUreQghyl3dBxtE5NSp2+xKrNiH/bPdVGNTC6YY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=iLFtrEQJhrrFdsGc1C/lC3W/I7aV/Fr6rCxJ4rwAZyjxQLmxCeHHUBK6he+8ChMHf p6Yk3dEPWWiNT7abG4viYoR0vWbpHLewIW6W/8NIlPxUrIh0fuqlMc49dBAQHoWI2T 83MLNPh5xJBujVHFpeKJD74YNWg55JexZXyWCTPk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728066AbfEMHgW (ORCPT ); Mon, 13 May 2019 03:36:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:49168 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726270AbfEMHgW (ORCPT ); Mon, 13 May 2019 03:36:22 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D2EF3208C3; Mon, 13 May 2019 07:36:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557732981; bh=wc9NZUreQghyl3dBxtE5NSp2+xKrNiH/bPdVGNTC6YY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KW9nnrMDiQ9QRbJON9bnQe0/od4g6Masay1QNeqbLuGcN9nYUx/w8GA1JSaP3cffQ irdprW0rkdmVKuPL3q//vxAvJTiiQ/3fEQvCPfaTblCZuf0GbwieYnz7+WA8aw0EZU SxkRWgO2tcdQ1AogJNdbNv7pbKZVmkau2wSV6fh4= Date: Mon, 13 May 2019 09:36:19 +0200 From: Greg KH To: Gen Zhang Cc: linux-kernel Subject: Re: [PATCH] vt: Fix a missing-check bug in drivers/tty/vt/vt.c file of Linux 5.0.14 Message-ID: <20190513073619.GA5580@kroah.com> References: <20190510051415.GA6073@kroah.com> <20190510151206.GA31186@kroah.com> <20190511060741.GC18755@kroah.com> <20190512032719.GA16296@zhanggen-UX430UQ> <20190512062009.GA25153@kroah.com> <20190512084916.GA4615@zhanggen-UX430UQ> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190512084916.GA4615@zhanggen-UX430UQ> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 12, 2019 at 04:49:39PM +0800, Gen Zhang wrote: > On Sun, May 12, 2019 at 08:20:09AM +0200, Greg KH wrote: > > Yes, that worked! Now, can you resend it in a proper format that I can > > apply it in? (with changelog text, signed-off-by, etc.) as described in > > Documentation/SubmittingPatches, I will be glad to review it after the > > 5.2-rc1 release happens. > > > > thanks, > > > > greg k-h > From: Gen Zhang > Date: Sun, 11 May 2019 15:31:30 +0000 > Subject: [PATCH] vt: Fix a missing-check bug in drivers/tty/vt/vt.c file of Linux 5.0.14 Better, but no need for this to be in the body, just send it like any other patch on the mailing list. > > Hi, > I found this missing-check bug in drivers/tty/vt/vt.c when I was examining the source code. That doesn't need to be in the changelog text. > > In function con_init(), the pointer variable vc_cons[currcons].d, vc and vc->vc_screenbuf is allocated a memory space via kzalloc(). > And they are used in the following codes. Properly wrap your lines at 72 columns please. > > However, when there is a memory allocation error, kzalloc can be failed. > Thus null pointer (vc_cons[currcons].d, vc and vc->vc_screenbuf) dereference may happen. > And it will cause the kernel to crash. Therefore, we should check return value and handle an error. > > And this patch works in 5.1.1. No need to say that. > > Thank you! > > Kind regards > Gen Or that :) > > Signed-off-by: Gen Zhang > --- > --- drivers/tty/vt/vt.c > +++ drivers/tty/vt/vt.c > @@ -3349,10 +3349,14 @@ static int __init con_init(void) > > for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) { > vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT); > + if (!vc_cons[currcons].d || !vc) > + goto err_vc; What about the other memory that was allocated? You never free that. > INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK); > tty_port_init(&vc->port); > visual_init(vc, currcons, 1); > vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT); > + if (!vc->vc_screenbuf) > + goto err_vc_screenbuf; Same here, you are now leaking memory. Did you test this patch out with a kmalloc function that can fail? If not, please try to do so. thanks, greg k-h