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=-15.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 823FEC4338F for ; Sat, 7 Aug 2021 07:58:12 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E5685610FF for ; Sat, 7 Aug 2021 07:58:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E5685610FF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mess.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WJhKtoatFgCpTa0cKN3r42INJBP8CXtA/cy147bIJks=; b=fnxq+SL+TV3A29 PDeD9YmQxY1iWfvdyr3mY1Hs2+1TEGf6g17jQW3gSjNK6SwDVHXuy9Aps55zE6mRTgM7yPe6jDMMt sO1HwOtTt/l27gsA0molUKMyZrk14M57JdbXlsQXkhYNQ+tfs81VcmDNNvzXMbTX/ZnvRQIUVLmp4 bg6KQnvlOaNkQ0la3TROjp0vX9ZR+lshlfuQIHzvMP9fojgp2tROriitejLrVgCJwSokQ4CIV2iKQ ff8oFBGE1nAZpddisA7PPrP6bcbaaN8x3g+fCoEjChtEQMS8DOoPiZvrqhULlE6os/GVew9Jn51LT DOtHvd81aMoO6pOJGabA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mCHDB-00EKow-7G; Sat, 07 Aug 2021 07:57:41 +0000 Received: from gofer.mess.org ([88.97.38.141]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mCHD7-00EKoH-9p for linux-mtd@lists.infradead.org; Sat, 07 Aug 2021 07:57:38 +0000 Received: by gofer.mess.org (Postfix, from userid 1000) id C6B4BC63FB; Sat, 7 Aug 2021 08:57:35 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mess.org; s=2020; t=1628323055; bh=7+YRLGbQ0OqK35xlQg1osSpZLKy+/hhBbICAg1J5RP4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HDKuu/BVA+dkpMHdtyCcDoNW1JhElbrDvfLvxKl8XpH3AYSZPK1jYQxINecbkVkMo 6/3VLABK/9cv5NkTXx5LkaIS4eqlt+nFUr1H4OSxPE77p45P7OVT1KtD+FtI8Nura3 wzb3PP0Mk1TkKbc4U5KvuyAKYn0pz0vHf3tnkYXp/gDSQ7G/XuLgIyN40liGHyglWw NM9OkzsSNlfOV3lQdXVqQ7lQIZdZUtH6PDWps2/c+5GYaZX0ggb7JnCBhwBWaCe4Ab 7I3rDcOHejIuWU0ttjS+y9Ji/mlY0B9AYMu0J+Va09xSe5agJG/r2VWZOLkwHXyKqw 6EFFnLOy7DBlg== Date: Sat, 7 Aug 2021 08:57:35 +0100 From: Sean Young To: Miquel Raynal Cc: linux-mtd@lists.infradead.org Subject: Re: [PATCH 4/4] mtd: rfd_ftl: fix use-after-free Message-ID: <20210807075735.GB2522@gofer.mess.org> References: <29e817be984471dc2438a9414a9a7e1768d62950.1626169090.git.sean@mess.org> <20210806202158.5aa6ee26@xps13> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210806202158.5aa6ee26@xps13> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210807_005737_527314_8397D565 X-CRM114-Status: GOOD ( 19.12 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Fri, Aug 06, 2021 at 08:21:58PM +0200, Miquel Raynal wrote: > Hi Sean, > = > Sean Young wrote on Tue, 13 Jul 2021 10:44:03 +0100: > = > > del_mtd_blktrans_dev() will kfree part, so this is a use-after-free. Use > > container_of() to make it clearer what the cast is doing. > > = > > Signed-off-by: Sean Young > > --- > > drivers/mtd/rfd_ftl.c | 14 +++++++------- > > 1 file changed, 7 insertions(+), 7 deletions(-) > > = > > diff --git a/drivers/mtd/rfd_ftl.c b/drivers/mtd/rfd_ftl.c > > index 7f5f6d247cae..af20a0a71108 100644 > > --- a/drivers/mtd/rfd_ftl.c > > +++ b/drivers/mtd/rfd_ftl.c > = > [...] > = > > @@ -800,10 +800,10 @@ static void rfd_ftl_remove_dev(struct > mtd_blktrans_dev *dev) > > part->mbd.mtd->name, i, part->blocks[i].erases); > > } > > = > > - del_mtd_blktrans_dev(dev); > > vfree(part->sector_map); > > kfree(part->header_cache); > > kfree(part->blocks); > > + del_mtd_blktrans_dev(&part->mbd); > = > I am not sure moving this call at the bottom of ftl_remove_dev makes > sense, can we keep it where it was and just do the s/dev/part->mbd/ ? The reason for this patch is that del_mtd_blktrans_dev() kfrees its argumen= t, so both part and dev point to freed memory. This means it's a use after fre= e. Thanks, Sean > = > > } > > = > > static struct mtd_blktrans_ops rfd_ftl_tr =3D { > = > Thanks, > Miqu=E8l > = > ______________________________________________________ > Linux MTD discussion mailing list > http://lists.infradead.org/mailman/listinfo/linux-mtd/ ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/