From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Thu, 01 Feb 2024 12:29:48 +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 1rVVGM-00FYFw-2K for lore@lore.pengutronix.de; Thu, 01 Feb 2024 12:29:47 +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 1rVVGN-0005eY-DH for lore@pengutronix.de; Thu, 01 Feb 2024 12:29:47 +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:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=lnkqDUQ0lxO7PiFpHaQFFRiY6A6pmP+Gi5SP4/kYBRI=; b=eTaSdF0whOug5mdCWTL/5XPQjB M/0rrvnvwtSE823p34X442pIlJ9Jn4HQufIEy76SU8RydsjnVlVO37R69g++hzBMpW/6/S1YkRxa6 Zifhw3WjxQF/ViK1LGzvDYOb+NZO0ipOLHrQc/RSQdrsn7NahF5CXsdV4ACCx/EfDf4/YBhT4CuLG KlwYmqnvxEHocqlXcqlLjUGPU+VpYxY+wxWtm8WAmh+TETMxGFjR1lSMno4XQK3rCfCrrzrQPlUPf i+/xtRys5HwbuwVhroeEE8lQcP+0FiV1Urh7w+z7zdSCKaSi0UufU7BJbNBuze5ROi2X3uFrHNwyw ZS22eyFQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rVVFx-00000007aPM-3FxA; Thu, 01 Feb 2024 11:29:21 +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 1rVVFu-00000007aOW-33aw for barebox@lists.infradead.org; Thu, 01 Feb 2024 11:29:19 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rVVFd-0005WZ-G2; Thu, 01 Feb 2024 12:29:01 +0100 Received: from [2a0a:edc0:0:1101:1d::54] (helo=dude05.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rVVFd-003qKs-2c; Thu, 01 Feb 2024 12:29:01 +0100 Received: from localhost ([::1] helo=dude05.red.stw.pengutronix.de) by dude05.red.stw.pengutronix.de with esmtp (Exim 4.96) (envelope-from ) id 1rVVFc-000aHm-3D; Thu, 01 Feb 2024 12:29:00 +0100 From: Stefan Kerkmann Date: Thu, 01 Feb 2024 12:28:50 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20240201-fix-fdt-memory-safety-v2-2-267b7b8813fd@pengutronix.de> References: <20240201-fix-fdt-memory-safety-v2-0-267b7b8813fd@pengutronix.de> In-Reply-To: <20240201-fix-fdt-memory-safety-v2-0-267b7b8813fd@pengutronix.de> To: Sascha Hauer , BAREBOX Cc: Stefan Kerkmann X-Mailer: b4 0.12.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240201_032918_806109_C3FC72CF X-CRM114-Status: GOOD ( 13.35 ) 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=-6.2 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: [PATCH v2 2/2] of: fdt: fix oob writes with large fdt 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) 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 544294a9ac..cf08fa1cfd 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -400,6 +401,9 @@ static int fdt_ensure_space(struct fdt *fdt, int dtsize) previous = fdt->dt; new_size = fdt->dt_size * 2; + if (new_size <= dtsize) + new_size = roundup_pow_of_two(fdt->dt_size + dtsize); + fdt->dt = memalign_realloc(previous, fdt->dt_size, new_size); if (!fdt->dt) { free(previous); -- 2.39.2