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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 77947C28CC5 for ; Sat, 8 Jun 2019 16:01:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C5D520833 for ; Sat, 8 Jun 2019 16:01:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="i2qCQIZn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727206AbfFHQBv (ORCPT ); Sat, 8 Jun 2019 12:01:51 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:33731 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727035AbfFHQBu (ORCPT ); Sat, 8 Jun 2019 12:01:50 -0400 Received: by mail-wr1-f66.google.com with SMTP id n9so5065468wru.0 for ; Sat, 08 Jun 2019 09:01:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=RQ2AJUcN8c4n4MbBpUGKpOy63cEfl59xAjHxyDDdc/s=; b=i2qCQIZnWSiv70yjcwzzyOiY/1zT2ZySOtxBbwz4bcf+8Hrfx3n6+Zav2YK5AgeGbT wXgSrjMYB8PxOuqBlzkQdYrulAj6a+2JJtBXYoyutXQEnurvtWxnwB0l3367rTC+arU+ W5XuVfJaqrvoJhCSAQW4kdFOs423bNEjr7H1FFUWaltgTcD2xFv8JzYIPHjkpydYV5Gd PYrQCWpJk64SQnrsE/XfhNtdhM8skSAo1pX8w3XW0tz3womzSTBnyeDGxAvfy6C9XpEC aT+iIXRU2ws/UIvEGBMGrU0UdSD+dGhiH1ONq3AKqITV2mXj18yca+PeXbGOlL5HlT0d 8AbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=RQ2AJUcN8c4n4MbBpUGKpOy63cEfl59xAjHxyDDdc/s=; b=fgd9v0z0xMeCC62mNADP9uyhx2d38BnaLGg+HGRClSz3UY2rr45KnVnzZamX0KlSiA IzlGF03njCErNqYNP3vIDtofsBeQDqNbuY3RAIjp8F2ydYhmLP/DNxQL/rA1rB0LVglC p20dKpotwL8ZvFlttRolreiDbHlmZ7S1BIGCWtyqAqgRN+lOROJRUyoOXCMHvM7YkeY1 0VWmzHP+6x5t6HKwhbV1syl88Q61JO5Yaevrf9gzDMgz7wxdHjt4BPgzx8VF/sKFxC+C giXz61eVy13RpFg20p4EcZjcdotbZgDGsl4u6DecrvQIgWXWudmRz6IGhNkrFpaAfMbb U4SA== X-Gm-Message-State: APjAAAVMLicG69zyvBCmHP0R+La45s6tyRyfrncNcG7kX6xmNEFmhJTL WqIcgjmwcugkR5jLn7CSVRO+oDA1 X-Google-Smtp-Source: APXvYqyNMYXW9w090K1Ty8j3y29UDGHNxzH+ovk14byW8TVxufJ6OwL5/qk1h4hWqMfA+0UiweBIZA== X-Received: by 2002:adf:e691:: with SMTP id r17mr21378607wrm.67.1560009709107; Sat, 08 Jun 2019 09:01:49 -0700 (PDT) Received: from zhanggen-UX430UQ ([108.61.173.19]) by smtp.gmail.com with ESMTPSA id x16sm3935606wmj.4.2019.06.08.09.01.44 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 08 Jun 2019 09:01:48 -0700 (PDT) Date: Sun, 9 Jun 2019 00:01:38 +0800 From: Gen Zhang To: gregkh@linuxfoundation.org, jslaby@suse.com, nico@fluxnic.net, kilobyte@angband.pl, textshell@uchuujin.de, mpatocka@redhat.com, daniel.vetter@ffwll.ch Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] vt: Fix a missing-check bug in con_init() Message-ID: <20190608160138.GA3840@zhanggen-UX430UQ> References: <20190528004529.GA12388@zhanggen-UX430UQ> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190528004529.GA12388@zhanggen-UX430UQ> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 28, 2019 at 08:45:29AM +0800, Gen Zhang wrote: > In function con_init(), the pointer variable vc_cons[currcons].d, vc and > vc->vc_screenbuf is allocated by kzalloc(). And they are used in the > following codes. However, kzalloc() returns NULL when fails, and null > pointer dereference may happen. And it will cause the kernel to crash. > Therefore, we should check the return value and handle the error. > > Further, since the allcoation is in a loop, we should free all the > allocated memory in a loop. > > Signed-off-by: Gen Zhang > Reviewed-by: Nicolas Pitre > --- > diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c > index fdd12f8..d50f68f 100644 > --- a/drivers/tty/vt/vt.c > +++ b/drivers/tty/vt/vt.c > @@ -3350,10 +3350,14 @@ 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) > + goto fail1; > 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 fail2; > vc_init(vc, vc->vc_rows, vc->vc_cols, > currcons || !vc->vc_sw->con_save_screen); > } > @@ -3375,6 +3379,16 @@ static int __init con_init(void) > register_console(&vt_console_driver); > #endif > return 0; > +fail1: > + while (currcons > 0) { > + currcons--; > + kfree(vc_cons[currcons].d->vc_screenbuf); > +fail2: > + kfree(vc_cons[currcons].d); > + vc_cons[currcons].d = NULL; > + } > + console_unlock(); > + return -ENOMEM; > } > console_initcall(con_init); > > --- Can anyone look into this patch? It's already reviewed by Nicolas Pitre . Thanks Gen