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,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 648B1C072B5 for ; Wed, 22 May 2019 01:40:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3863A21479 for ; Wed, 22 May 2019 01:40:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lV5LVIby" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728127AbfEVBkU (ORCPT ); Tue, 21 May 2019 21:40:20 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:42331 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726466AbfEVBkU (ORCPT ); Tue, 21 May 2019 21:40:20 -0400 Received: by mail-pf1-f193.google.com with SMTP id 13so396909pfw.9 for ; Tue, 21 May 2019 18:40:19 -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:mime-version:content-disposition :user-agent; bh=5CBN5GRDwJJmiW4ujQ4j8MkE9ryYC+5kRL/X54PqKsM=; b=lV5LVIbyNnZqNs7lWVt3EsuiM1CcKliXdywv9AQ2JP1Ooeo7y6Ch+a4SKUQi3ScZO2 gVUiHVvPmE8qo1KCzwZ+HGYLD49l/D6LRsJxWXTV6LO8Xi7O+v69ycAM/rC26vSQB9zl GzmUiX70pAaaMyv6DfZFOH8KY+sosNAkt9VoVZ0UU2pp89xfc3YA+HwQiO9Ccfs6RUYH msUpV1ZcsHElT5ps25TSwbm3hzYkjTyEcrazrxGWRfT+StS1pyCN+BvJ+Shm/AdVCvch n3/adOj7kg2nmgAkdGaQxgH0zogSrTE3kv0dck3MwmW8kUgGD6RAAn2aYBsXFpC1fQp4 ndgQ== 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:mime-version :content-disposition:user-agent; bh=5CBN5GRDwJJmiW4ujQ4j8MkE9ryYC+5kRL/X54PqKsM=; b=cFH442UPe1o3pvubzhXCV52ddCGC5TjOe8HPYb2giVhJD8bY98ChXP693ckqQShTAF CwuewaqMaH4X9359ktQdiC/9DVO4Ci2uDkjL//a1c6Rlrt/DKtmFPnCZ87KcPtvAo3nw ZFPW0v1G/Jc8VYNuRXJm+ncgsIhfVnlYZU/q3EEiCOLsqGPhbIkrviXQ6dppEp9WugUX sg15aef36L/iGkSvM+yrv4far4RKuEhOzKnrbuPfmtXEBqyZ5VTg3CwyPXt/IDdB5aXd yMsnMlpfQDTzorQS3F31OzzLDXpcbkmReeTffGPUJ9onzyVI5K+ItGlztfNpjPoAIP37 Jwsg== X-Gm-Message-State: APjAAAXDZebNf2ZbkTI6JvnpdhMfYKvwF61Y/+PWuqTHzp+hE/PgdNoK BoC2EhlyVn4w/peCWiKQ0cW2Rohzgkw= X-Google-Smtp-Source: APXvYqz9ixSRIE/gHn86++ZNZ+N8dqc0ilrj19blcxSExgRKNnaGL8090v85Ragbt14x5gwPT8YIDw== X-Received: by 2002:a63:8bc9:: with SMTP id j192mr86339409pge.212.1558489219565; Tue, 21 May 2019 18:40:19 -0700 (PDT) Received: from zhanggen-UX430UQ ([66.42.35.75]) by smtp.gmail.com with ESMTPSA id f186sm31952144pfb.5.2019.05.21.18.40.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 21 May 2019 18:40:19 -0700 (PDT) Date: Wed, 22 May 2019 09:40:06 +0800 From: Gen Zhang To: jslaby@suse.com Cc: linux-kernel@vger.kernel.org Subject: [PATCH] tty_io: Fix a missing-check bug in drivers/tty/tty_io.c Message-ID: <20190522014006.GB4093@zhanggen-UX430UQ> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 In alloc_tty_struct(), tty->dev is assigned by tty_get_device(). And it calls class_find_device(). And class_find_device() may return NULL. And tty->dev is dereferenced in the following codes. When tty_get_device() returns NULL, dereferencing this tty->dev null pointer may cause the kernel go wrong. Thus we should check tty->dev. Further, if tty_get_device() returns NULL, we should free tty and return NULL. Signed-off-by: Gen Zhang --- diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 033ac7e..1444b59 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -3008,6 +3008,10 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) tty->index = idx; tty_line_name(driver, idx, tty->name); tty->dev = tty_get_device(tty); + if (!tty->dev) { + kfree(tty); + return NULL; + } return tty; }