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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 5AC2EC282CA for ; Tue, 12 Feb 2019 15:39:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1498C2184E for ; Tue, 12 Feb 2019 15:39:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=synopsys.com header.i=@synopsys.com header.b="dQyMDdy3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730359AbfBLPjr (ORCPT ); Tue, 12 Feb 2019 10:39:47 -0500 Received: from us01smtprelay-2.synopsys.com ([198.182.47.9]:57134 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726238AbfBLPjq (ORCPT ); Tue, 12 Feb 2019 10:39:46 -0500 Received: from mailhost.synopsys.com (dc2-mailhost2.synopsys.com [10.12.135.162]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtprelay.synopsys.com (Postfix) with ESMTPS id 8A25124E15A4; Tue, 12 Feb 2019 07:39:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synopsys.com; s=mail; t=1549985985; bh=fNi2x0SlQbTYnWYSmxbfyWwIJE+Y97tU3KWZJfeUv0c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dQyMDdy3C5N5bD0ElT5wYazJupiIkYcLrbZDUKgrcACeqLTkg+wYOXjsWmki5aHYe QfoFNn7o3xkDw00g/ApF4VLPDOcyLpQVEs+J+y6irRNDshJtX58mNOOvm6W8iUl+LO eaX9VTks+8tPnwu1tgQWMsOkPhYnBZ3xffhiwzsxCR0Hn4i45tN1pXv/H1RaOyli8H gCXEEfepFvys6gctG2mlRxePA8ohRi3y5Yon8fuCwmkxQZKMBphJ7Net34RlVDh+8N GnU41nJoEc+xC/6GYvh0JC0f5ThfeTs0C8Q1RDBfUBpEBTT3SUrq4+Ac6D351XpJjW crndRMAW0aSNA== Received: from paltsev-e7480.internal.synopsys.com (unknown [10.121.8.62]) by mailhost.synopsys.com (Postfix) with ESMTP id CF2DFA0090; Tue, 12 Feb 2019 15:39:43 +0000 (UTC) From: Eugeniy Paltsev To: linux-snps-arc@lists.infradead.org, Vineet Gupta Cc: linux-kernel@vger.kernel.org, Alexey Brodkin , Corentin Labbe , khilman@baylibre.com, Eugeniy Paltsev Subject: [PATCH 1/2] ARC: U-boot: check arguments paranoidly Date: Tue, 12 Feb 2019 18:39:31 +0300 Message-Id: <20190212153932.28371-2-Eugeniy.Paltsev@synopsys.com> X-Mailer: git-send-email 2.14.5 In-Reply-To: <20190212153932.28371-1-Eugeniy.Paltsev@synopsys.com> References: <20190212153932.28371-1-Eugeniy.Paltsev@synopsys.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Handle U-boot arguments paranoidly: * don't allow to pass unknown tag. * try to use external device tree blob only if corresponding tag (TAG_DTB) is set. * check that magic number is correct. * don't check uboot_tag if kernel build with no ARC_UBOOT_SUPPORT. NOTE: If U-boot args are invalid we skip them and try to use embedded device tree blob. We can't panic on invalid U-boot args as we really pass invalid args due to bug in U-boot code. This happens if we don't provide external DTB to U-boot and don't set 'bootargs' U-boot environment variable (which is default case at least for HSDK board) In that case we will pass {r0 = 1 (bootargs in r2); r1 = 0; r2 = 0;} to linux which is invalid. NOTE: We can safely check U-boot magic value (0x0) in linux passed via r1 register as U-boot pass it from the beginning. While I'm at it refactor U-boot arguments handling code. Signed-off-by: Eugeniy Paltsev --- arch/arc/kernel/head.S | 5 +-- arch/arc/kernel/setup.c | 92 +++++++++++++++++++++++++++++++++++-------------- 2 files changed, 69 insertions(+), 28 deletions(-) diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S index 8b90d25a15cc..fccea361e896 100644 --- a/arch/arc/kernel/head.S +++ b/arch/arc/kernel/head.S @@ -93,10 +93,11 @@ ENTRY(stext) #ifdef CONFIG_ARC_UBOOT_SUPPORT ; Uboot - kernel ABI ; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2 - ; r1 = magic number (board identity, unused as of now + ; r1 = magic number (always zero as of now) ; r2 = pointer to uboot provided cmdline or external DTB in mem - ; These are handled later in setup_arch() + ; 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 feb90093e6b1..84d394a37e79 100644 --- a/arch/arc/kernel/setup.c +++ b/arch/arc/kernel/setup.c @@ -36,7 +36,8 @@ unsigned int intr_to_DE_cnt; /* Part of U-boot ABI: see head.S */ int __initdata uboot_tag; -char __initdata *uboot_arg; +int __initdata uboot_magic; +unsigned int __initdata uboot_arg; const struct machine_desc *machine_desc; @@ -462,43 +463,82 @@ void setup_processor(void) arc_chk_core_config(); } -static inline int is_kernel(unsigned long addr) +static inline bool uboot_arg_invalid(unsigned int addr) { - if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end) - return 1; - return 0; + /* + * Check that it is a untranslated address (although MMU is not enabled + * yet, it being a high address ensures this is not by fluke) + */ + if (addr < PAGE_OFFSET) + return true; + + /* Check that address doesn't clobber resident kernel image */ + return addr >= (unsigned int)_stext && addr <= (unsigned int)_end; } -void __init setup_arch(char **cmdline_p) +#define IGNORE_ARGS "Ignore U-boot args: " + +/* uboot_{tag, magic} values for U-boot - kernel ABI revision 0; see head.S */ +#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_VAL 0 + +void __init handle_uboot_args(void) { + bool use_embedded_dtb = true; + bool append_cmdline = false; + #ifdef CONFIG_ARC_UBOOT_SUPPORT - /* make sure that uboot passed pointer to cmdline/dtb is valid */ - if (uboot_tag && is_kernel((unsigned long)uboot_arg)) - panic("Invalid uboot arg\n"); + /* check that we know this tag */ + if (uboot_tag != UBOOT_TAG_NONE && + uboot_tag != UBOOT_TAG_CMDLINE && + uboot_tag != UBOOT_TAG_DTB) { + pr_warn(IGNORE_ARGS "invalid uboot tag: '%08x'\n", uboot_tag); + goto ignore_uboot_args; + } + + if (uboot_magic != UBOOT_MAGIC_VAL) { + pr_warn(IGNORE_ARGS "non zero uboot magic\n"); + goto ignore_uboot_args; + } + + if (uboot_tag != UBOOT_TAG_NONE && uboot_arg_invalid(uboot_arg)) { + pr_warn(IGNORE_ARGS "invalid uboot arg: '%08x'\n", uboot_arg); + goto ignore_uboot_args; + } + + /* see if U-boot passed an external Device Tree blob */ + if (uboot_tag == UBOOT_TAG_DTB) { + machine_desc = setup_machine_fdt((void *)uboot_arg); + + /* external Device Tree blob is invalid - use embedded one */ + use_embedded_dtb = !machine_desc; + } + + if (uboot_tag == UBOOT_TAG_CMDLINE) + append_cmdline = true; - /* See if u-boot passed an external Device Tree blob */ - machine_desc = setup_machine_fdt(uboot_arg); /* uboot_tag == 2 */ - if (!machine_desc) +ignore_uboot_args: #endif - { - /* No, so try the embedded one */ + + if (use_embedded_dtb) { machine_desc = setup_machine_fdt(__dtb_start); if (!machine_desc) panic("Embedded DT invalid\n"); + } - /* - * If we are here, it is established that @uboot_arg didn't - * point to DT blob. Instead if u-boot says it is cmdline, - * append to embedded DT cmdline. - * setup_machine_fdt() would have populated @boot_command_line - */ - if (uboot_tag == 1) { - /* Ensure a whitespace between the 2 cmdlines */ - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, uboot_arg, - COMMAND_LINE_SIZE); - } + if (append_cmdline) { + /* Ensure a whitespace between the 2 cmdlines */ + strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); + strlcat(boot_command_line, (char *)uboot_arg, COMMAND_LINE_SIZE); } +} + +void __init setup_arch(char **cmdline_p) +{ + handle_uboot_args(); /* Save unparsed command line copy for /proc/cmdline */ *cmdline_p = boot_command_line; -- 2.14.5