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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 061BDC43381 for ; Sat, 30 Mar 2019 00:54:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC188206DD for ; Sat, 30 Mar 2019 00:54:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553907287; bh=vemJgVnvUTgPaZf/beP1yOIgaEzuc5GHCyBce1gxYPI=; h=From:To:Cc:Subject:Date:List-ID:From; b=QvlREPX5Bg4mIQxZAjcpwWgoWh38qfKwUfvnPf6HT1ZgMcxszYwqYpDSlubU53Y7H Y0tYEoluDARHNLJtPfdw6IS030FkvIszvxnbcoRqRYBJPNi7hVn0Svcwn6DwiW2L9v f/yy1hSKB6LQX9V8j0jo/XdGdzRpLdBkc+4h1z50= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730706AbfC3Ayq (ORCPT ); Fri, 29 Mar 2019 20:54:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:33778 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731587AbfC3Ayn (ORCPT ); Fri, 29 Mar 2019 20:54:43 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 46D4B218CD; Sat, 30 Mar 2019 00:54:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553907283; bh=vemJgVnvUTgPaZf/beP1yOIgaEzuc5GHCyBce1gxYPI=; h=From:To:Cc:Subject:Date:From; b=Nn7hFODl5eweB1PFM2vxy1ybViXMOaaujC2uplsYFCjvh485pg7KYDrd4CAi+OPan PI3KWKCe+412j0pR608YUeSlOo/pN50jvp9AAiayGjEOXuWOxaUCtvyaheDEyhef9f FdhtPahkQuGIVxOpZLxJhS8d8E7VWfyjxgHNgn7U= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Eugeniy Paltsev , Vineet Gupta , Sasha Levin , linux-snps-arc@lists.infradead.org Subject: [PATCH AUTOSEL 4.14 01/37] ARC: u-boot args: check that magic number is correct Date: Fri, 29 Mar 2019 20:54:02 -0400 Message-Id: <20190330005441.27540-1-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eugeniy Paltsev [ Upstream commit edb64bca50cd736c6894cc6081d5263c007ce005 ] In case of devboards we really often disable bootloader and load Linux image in memory via JTAG. Even if kernel tries to verify uboot_tag and uboot_arg there is sill a chance that we treat some garbage in registers as valid u-boot arguments in JTAG case. E.g. it is enough to have '1' in r0 to treat any value in r2 as a boot command line. So check that magic number passed from u-boot is correct and drop u-boot arguments otherwise. That helps to reduce the possibility of using garbage as u-boot arguments in JTAG case. We can safely check U-boot magic value (0x0) in linux passed via r1 register as U-boot pass it from the beginning. So there is no backward-compatibility issues. Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin --- arch/arc/kernel/head.S | 1 + arch/arc/kernel/setup.c | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S index 1f945d0f40da..208bf2c9e7b0 100644 --- a/arch/arc/kernel/head.S +++ b/arch/arc/kernel/head.S @@ -107,6 +107,7 @@ ENTRY(stext) ; r2 = pointer to uboot provided cmdline or external DTB in mem ; These are handled later in handle_uboot_args() st r0, [@uboot_tag] + st r1, [@uboot_magic] st r2, [@uboot_arg] #endif diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c index 709649e5f9bc..6b8d106e0d53 100644 --- a/arch/arc/kernel/setup.c +++ b/arch/arc/kernel/setup.c @@ -35,6 +35,7 @@ unsigned int intr_to_DE_cnt; /* Part of U-boot ABI: see head.S */ int __initdata uboot_tag; +int __initdata uboot_magic; char __initdata *uboot_arg; const struct machine_desc *machine_desc; @@ -433,6 +434,8 @@ static inline bool uboot_arg_invalid(unsigned long addr) #define UBOOT_TAG_NONE 0 #define UBOOT_TAG_CMDLINE 1 #define UBOOT_TAG_DTB 2 +/* We always pass 0 as magic from U-boot */ +#define UBOOT_MAGIC_VALUE 0 void __init handle_uboot_args(void) { @@ -448,6 +451,11 @@ void __init handle_uboot_args(void) goto ignore_uboot_args; } + if (uboot_magic != UBOOT_MAGIC_VALUE) { + pr_warn(IGNORE_ARGS "non zero uboot magic\n"); + goto ignore_uboot_args; + } + if (uboot_tag != UBOOT_TAG_NONE && uboot_arg_invalid((unsigned long)uboot_arg)) { pr_warn(IGNORE_ARGS "invalid uboot arg: '%px'\n", uboot_arg); -- 2.19.1