From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 31 Jan 2024 18:21:46 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rVEHR-00E5WU-01 for lore@lore.pengutronix.de; Wed, 31 Jan 2024 18:21:46 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rVEHR-0000Mo-JD for lore@pengutronix.de; Wed, 31 Jan 2024 18:21:46 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=p+FczEolr1bVEGLdKzg/mgn9UYnZDASE7r0vRCI6IE4=; b=KS9+aO45JjUoZyUPEjGo8i7jbC EU/ROKcvTPADziF+x1WfhgVvbjaLe2mEpwIDeFGvL+iw0BIdyubZCtuTeHt+L7dt0X/ctAx9aaTAp HuYB2hvPoCCbAWt3rWXk/fjYnMk6PtlCRI7esYKXGRulm1MvnN7/F6KujN+E9/3mav5OvBBP5Lay5 qLa++ixQGiZ9mEFpyMla1VSBPib0tlc+/Vr0jChPUsRy+QljlQY+j4jXCqFNZZPyJr7/MgOm8CsGM TlhFohzUtgXUzuYrvI1j3bIW8VeO2TvAgVwLZRfE2wO/HIVFXZnflCLFPL6G6Y4A+5rkvZ8JQgTgV rI81+PAg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rVEH1-00000004o8N-3mGb; Wed, 31 Jan 2024 17:21:19 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rVEGz-00000004o7n-0aAs for barebox@lists.infradead.org; Wed, 31 Jan 2024 17:21:18 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1rVEGx-0000HK-PW; Wed, 31 Jan 2024 18:21:15 +0100 Message-ID: Date: Wed, 31 Jan 2024 18:21:14 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: Stefan Kerkmann , Sascha Hauer , BAREBOX References: <20240131-fix-fdt-memory-safety-v1-0-3d3a2c797eec@pengutronix.de> <20240131-fix-fdt-memory-safety-v1-2-3d3a2c797eec@pengutronix.de> From: Ahmad Fatoum In-Reply-To: <20240131-fix-fdt-memory-safety-v1-2-3d3a2c797eec@pengutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240131_092117_209839_28072D0D X-CRM114-Status: GOOD ( 22.23 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.7 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 2/2] of: fdt: fix oob writes with large ftd properties X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) On 31.01.24 17:57, Stefan Kerkmann wrote: > OOB writes can be triggered when fdt->dt_size * 2 is still smaller than > the property for which memory should be allocated. This can happen under > rare circumstances when editing a fdt with the of_property command and a > property is larger than 128k in size. > > This happend when editing a FIT image (which is a ftd) with the > of_property command and the Kernel image was around 8M in size. > > The simplified call chain is the following: > > of_property -> of_flatten_dtb -> create new fdt with 64k in size (this is > fixed) -> __of_flatten_dtb -> attempt to copy kernel image (8M) -> > fdt_ensure_space -> allocate only 128k for fdt->dt -> memcopy 8M into fdt->dt > buffer -> crash > > The fix is to grow fdt->dt to hold at least the new property. The power > of 2 increment is untouched to keep the same behaviour otherwise. > > Signed-off-by: Stefan Kerkmann > --- > drivers/of/fdt.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > index 4f79a6120f..1f24ed0bbc 100644 > --- a/drivers/of/fdt.c > +++ b/drivers/of/fdt.c > @@ -399,6 +399,10 @@ static int fdt_ensure_space(struct fdt *fdt, int dtsize) > previous = fdt->dt; > new_size = fdt->dt_size * 2; > > + while (new_size <= dtsize) { > + new_size *= 2; > + } A nitpick that I solely note because I already had feedback on the first patch: Kernel coding style is to omit { braces } for single statement blocks. In your case you could just do: if (new_size <= dtsize) new_size = roundup_pow_of_two(new_size + dtsize); I think to skip the loop. Cheers, Ahmad > + > if ((fdt->dt = memalign_realloc(previous, fdt->dt_size, > new_size)) == NULL) { > free(previous); > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |