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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 D8CA9C0650F for ; Thu, 8 Aug 2019 13:22:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6F682171F for ; Thu, 8 Aug 2019 13:22:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565270573; bh=gRtTbqNQGMilfVLZgzVIN2dGKouuTcp6PKE2RGisMZ8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=JYkrNZHJQGqgn9TNLTMyI5axqm7gRV4MMXQKzqd5MZ1mTCaauW+m4q1zNHAt6RgAj mgAQRFNU42TpArFLzRS78t+4ipfX47hoXdQvqSQqOZZktw4uOQqw1ubOYBvrBztu35 RzZyGI4AyI6FP3IyoTVikyzowh80w+1YwIjrlOCE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732986AbfHHNWx (ORCPT ); Thu, 8 Aug 2019 09:22:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:59748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728327AbfHHNWw (ORCPT ); Thu, 8 Aug 2019 09:22:52 -0400 Received: from localhost (unknown [122.178.245.201]) (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 980D12171F; Thu, 8 Aug 2019 13:22:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565270572; bh=gRtTbqNQGMilfVLZgzVIN2dGKouuTcp6PKE2RGisMZ8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CfuZkLufkWM94Ez0D0cbwNQHrIlzQRthIovDrrS22TQNSXx90SmYMQPaougEPvAZs FBNvUm6i4QzjYxkbxH8VZM483i4Treskd4OiNBrPWnXu/yLeESS+GlXy2Izt4fe2GY q5m4EPWA38HRMBXNmcdoZDHknDQ74mRKzF4qRegk= Date: Thu, 8 Aug 2019 18:51:40 +0530 From: Vinod Koul To: Jia-Ju Bai Cc: dan.j.williams@intel.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dma: mv_xor: Fix a possible null-pointer dereference in mv_xor_prep_dma_xor() Message-ID: <20190808132140.GZ12733@vkoul-mobl.Dlink> References: <20190727093027.11781-1-baijiaju1990@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190727093027.11781-1-baijiaju1990@gmail.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27-07-19, 17:30, Jia-Ju Bai wrote: > In mv_xor_prep_dma_xor(), there is an if statement on line 577 to check > whether sw_desc is NULL: > if (sw_desc) > > When sw_desc is NULL, it is used on line 594: > dev_dbg(..., sw_desc, &sw_desc->async_tx); > > Thus, a possible null-pointer dereference may occur. > > To fix this bug, sw_desc is checked before being used. > > This bug is found by a static analysis tool STCheck written by us. > > Signed-off-by: Jia-Ju Bai > --- > drivers/dma/mv_xor.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c > index 0ac8e7b34e12..08c0b2a9eb32 100644 > --- a/drivers/dma/mv_xor.c > +++ b/drivers/dma/mv_xor.c > @@ -589,9 +589,11 @@ mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src, > } > } > > - dev_dbg(mv_chan_to_devp(mv_chan), > - "%s sw_desc %p async_tx %p \n", > - __func__, sw_desc, &sw_desc->async_tx); > + if (sw_desc) { > + dev_dbg(mv_chan_to_devp(mv_chan), > + "%s sw_desc %p async_tx %p \n", > + __func__, sw_desc, &sw_desc->async_tx); > + } why not move this into the preceeding if condition? > return sw_desc ? &sw_desc->async_tx : NULL; > } > > -- > 2.17.0 -- ~Vinod