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=unavailable 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 6B35FC4360F for ; Sat, 30 Mar 2019 00:50:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E169206DD for ; Sat, 30 Mar 2019 00:50:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553907052; bh=fpdcRjayh6oL3S9Dpm1LRC1Q8PZ9WXwm+cSMuiSVaew=; h=From:To:Cc:Subject:Date:List-ID:From; b=xBZqh+Bys+zm5gMdmB5dmjT0RDW04jMLnc8FllBAjYYg1pkEzSX7Nh1pzl5Vy/qBJ /1FnU3NH+gi3GBXqkCh7ZcWRb2+sC60hHxxhzKVG6BmjrRkvzeHk7LHHIT7BRz8k8h qFK4DdNBNvj2Sbg5YKC0csodW4BqNdfzHLLA7sPM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730416AbfC3Auu (ORCPT ); Fri, 29 Mar 2019 20:50:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:57400 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730162AbfC3Auu (ORCPT ); Fri, 29 Mar 2019 20:50:50 -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 119C8206DD; Sat, 30 Mar 2019 00:50:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553907049; bh=fpdcRjayh6oL3S9Dpm1LRC1Q8PZ9WXwm+cSMuiSVaew=; h=From:To:Cc:Subject:Date:From; b=GmYy6iKdSbtLFXMv1cxo1+CkZDGyIa2usOsli3OlRBuwK/bY5MB7U1UiMfMRfKLHZ +b9k2R4Ne56UsurGDq4GJmpZvHiTCqBDMguHVxABlgvoftrG8HnztL7Yo0Yxynq0av Z8BI2YSbpF9mBYofecgk2ueWuQ9YCYpt5RhAthPI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Eugeniy Paltsev , Vineet Gupta , Sasha Levin Subject: [PATCH AUTOSEL 5.0 01/67] ARC: u-boot args: check that magic number is correct Date: Fri, 29 Mar 2019 20:49:41 -0400 Message-Id: <20190330005047.25998-1-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 30e090625916..a72bbda2f7aa 100644 --- a/arch/arc/kernel/head.S +++ b/arch/arc/kernel/head.S @@ -106,6 +106,7 @@ 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] ; setup "current" tsk and optionally cache it in dedicated r25 diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c index 7b2340996cf8..7b3a7b3b380c 100644 --- a/arch/arc/kernel/setup.c +++ b/arch/arc/kernel/setup.c @@ -36,6 +36,7 @@ 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; @@ -497,6 +498,8 @@ 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) { @@ -511,6 +514,11 @@ 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