From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 12 Nov 2024 20:57:33 +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 1tAx13-0018Ec-1u for lore@lore.pengutronix.de; Tue, 12 Nov 2024 20:57:33 +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 1tAx13-00036H-01 for lore@pengutronix.de; Tue, 12 Nov 2024 20:57:33 +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:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ZigdfrCvFXMnA4eZTBeMU4xbPF6Px2UKwCevHPqrn2U=; b=DPcBDFaBHpZpOtGkmMzVG8dX98 cGIqS18zLHJzdVPe6X5XnckHyp/FxSy6g29fYCIB1Jh/Wdx3fn49r8LeywDAHU8UQSAwzmPj/Yjcw kXzyF6FoehgdPMwTnax3UdNxyj/RLQuDpwwwT1hQyfmS+1G1ovRBMRJtKirUTSPPgHJdxxg6+17x8 4StPY63FaTGsKSfZq6DcV5jOWGPG4BYYRM3/+EDWRMDaGyID8bb43ZM/w1cwsLDBhbj7ZqLDdKgfI 0SvsLbYMxHX5ihnFnHNkvG+aBEtQ9l9TXdw2FaL8vMTVLaWSi9pETzu6cQmrNRBUEWAvjHeWghzFq Bd3T/kOw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tAx0Z-00000004nGD-1QnT; Tue, 12 Nov 2024 19:57:03 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tAx0V-00000004nFW-3kSg for barebox@lists.infradead.org; Tue, 12 Nov 2024 19:57:01 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[IPV6:::1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1tAx0U-0002sv-LX; Tue, 12 Nov 2024 20:56:58 +0100 Message-ID: <383d6b94-1152-4257-b18c-9f31857944ca@pengutronix.de> Date: Tue, 12 Nov 2024 20:56:58 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Abdelrahman Youssef , s.hauer@pengutronix.de Cc: barebox@lists.infradead.org References: <20241112191058.397165-1-abdelrahmanyossef12@gmail.com> Content-Language: en-US From: Ahmad Fatoum In-Reply-To: <20241112191058.397165-1-abdelrahmanyossef12@gmail.com> 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-20241112_115659_966742_AC6C11F4 X-CRM114-Status: GOOD ( 22.40 ) 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=-5.3 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 autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH v2] of: fdt: fix possible overflow during parsing of fdt 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) Hello Abdelrahman, Thanks for your patch. On 12.11.24 20:10, Abdelrahman Youssef wrote: > While fuzzing, the name marked by FDT_BEGIN_NODE sometimes extends beyond > the struct block area, Causing a heap-overflow. > > Since `maxlen` is an unsigned integer representing the length of name, > It can be negative, So it overflows to large numbers, Causing strnlen() > to overflow. > > So we can just change the type of maxlen to signed and check if it's negative. > > Signed-off-by: Abdelrahman Youssef > --- Changelog would've been nice. This also should have been v3 not v2. > drivers/of/fdt.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > index 2c3ea31394..d8d8a4922c 100644 > --- a/drivers/of/fdt.c > +++ b/drivers/of/fdt.c > @@ -176,7 +176,7 @@ static struct device_node *__of_unflatten_dtb(const void *infdt, int size, > void *dt_strings; > struct fdt_header f; > int ret; > - unsigned int maxlen; > + int maxlen; > const struct fdt_header *fdt = infdt; > > ret = fdt_parse_header(infdt, size, &f); > @@ -210,6 +210,11 @@ static struct device_node *__of_unflatten_dtb(const void *infdt, int size, > maxlen = (unsigned long)fdt + f.off_dt_struct + > f.size_dt_struct - (unsigned long)name; > > + if (maxlen < 0) { > + ret = -ESPIPE; > + goto err; > + } > + > len = strnlen(name, maxlen + 1); Hmm is this + 1 correct? I am wondering if we should be dropping the + 1 here and make it maxlen <= 0 above. What do you think? Cheers, Ahmad > if (len > maxlen) {> ret = -ESPIPE; -- 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 |