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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 B55F7C28CBC for ; Sun, 3 May 2020 07:44:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8520E2078E for ; Sun, 3 May 2020 07:44:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kroah.com header.i=@kroah.com header.b="SBKzxKKV"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="eE0KlyWu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727067AbgECHo3 (ORCPT ); Sun, 3 May 2020 03:44:29 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:47827 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726950AbgECHo2 (ORCPT ); Sun, 3 May 2020 03:44:28 -0400 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id 4FB805C02D5; Sun, 3 May 2020 03:44:25 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Sun, 03 May 2020 03:44:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kroah.com; h= date:from:to:cc:subject:message-id:references:mime-version :content-type:content-transfer-encoding:in-reply-to; s=fm3; bh=N 8Cx2/KCwTZPc2wHmE1jAvckSENViw1r2VmOZsfUcHU=; b=SBKzxKKV4sCWKYcCN LVT7VdEFGxsw/3J0Nuoj/ydxG/+xzG6V0a6qcccGnBoR1liRZ/QbxN/HP+1jFso1 P2Wz6ej36q9FhfsmZRTdSvkxtgWvYZkAte+IYoLR3dq+u9uAzStZYUbvQ14Tpcmv vQXTPEfJ3Ky4+TxilTQCAD/sQAhZSsiUy7CS5EnjaMsJOyRadV9iYlriV0O8hQcx KwJtixXFyKvMWuPSfVO/xbONXNxxR1dRWr+tYo2IMRIdTk0Tad5OmTW1R7Q/WbY9 uZpToOQ9Btw7VHj2vi8khH3sONdftl1HDivBuElxb8P1qt0FqfrMTLRvwd/ny2ND /4Iag== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm2; bh=N8Cx2/KCwTZPc2wHmE1jAvckSENViw1r2VmOZsfUc HU=; b=eE0KlyWu+1lRvJ9mOk78jOBCGLM3BUIpXo3gVQgSwB9tWg8jR4MoG6O9N 1UqkYXpxTHieG5GP/rDIETTIEIUods8sqX1S5yyMmY65gl1XAvmoElcmzrPuq3/m KMIi99N8R7vS2vARtN2zj3Z5DDMaGfd8pnXAsg8jlkAKlgV1V14sh6hwNkQKlSQk VGKvhX5ouDl8DAsBw7M7RObdIUApncFYccAdAX8dU5EQZTr06NsyQj7U+UVRyF2x Wo7dOQAQI89uhyMLM+e/IBKMGBLX++FkkXQB6fyy8pW6ZpxfgRBLCeNJJtPmFcL2 733ZLH9SXIkYhxIPhh5r2uoQNKrlw== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduhedrjedugddvgecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepfffhvffukfhfgggtugfgjgesthekre dttddtjeenucfhrhhomhepifhrvghgucfmjfcuoehgrhgvgheskhhrohgrhhdrtghomheq necuggftrfgrthhtvghrnhepueehkeehlefffeeiudetfeekjeffvdeuheejjeffheelud fgteekvdelkeduuddvnecukfhppeekfedrkeeirdekledruddtjeenucevlhhushhtvghr ufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtg homh X-ME-Proxy: Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id D2B313065FC6; Sun, 3 May 2020 03:44:24 -0400 (EDT) Date: Sun, 3 May 2020 09:44:20 +0200 From: Greg KH To: Dongyang Zhan Cc: linux-serial@vger.kernel.org Subject: Re: Fwd: Possible null pointer dereference in con_init() Message-ID: <20200503074420.GA536697@kroah.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Sun, May 03, 2020 at 03:20:50PM +0800, Dongyang Zhan wrote: > Hi, > > I am a security researcher, my name is Dongyang Zhan. I found a potential bug. > > I hope you can help me to confirm it. > > Thank you. > > In Linux 4.10.17, function con_init() in /drivers/tty/vt/vt.c forgets > to handle the failure of the memory allocation operation (e.g., > vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), > GFP_NOWAIT)). > > Source code and comments； > vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT); > 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); > vc_init(vc, vc->vc_rows, vc->vc_cols, > currcons || !vc->vc_sw->con_save_screen); > > If the allocation fails, dereferencing vc will cause a null pointer dereference. But that allocation can not fail, so all is fine. thanks, greg k-h