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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9462AC433EF for ; Wed, 22 Dec 2021 16:44:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344136AbhLVQoQ (ORCPT ); Wed, 22 Dec 2021 11:44:16 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:48110 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344135AbhLVQnW (ORCPT ); Wed, 22 Dec 2021 11:43:22 -0500 Received: from localhost (127.0.0.1) (HELO v370.home.net.pl) by /usr/run/smtp (/usr/run/postfix/private/idea_relay_lmtp) via UNIX with SMTP (IdeaSmtpServer 4.0.0) id b9f83e74db13ff34; Wed, 22 Dec 2021 17:43:21 +0100 Received: from kreacher.localnet (unknown [213.134.181.48]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by v370.home.net.pl (Postfix) with ESMTPSA id 6469766AF2B; Wed, 22 Dec 2021 17:43:20 +0100 (CET) From: "Rafael J. Wysocki" To: Linux ACPI Cc: LKML , Bob Moore Subject: [PATCH 05/19] ACPICA: Avoid subobject buffer overflow when validating RSDP signature Date: Wed, 22 Dec 2021 17:24:44 +0100 Message-ID: <8005250.T7Z3S40VBb@kreacher> In-Reply-To: <11889746.O9o76ZdvQC@kreacher> References: <11889746.O9o76ZdvQC@kreacher> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="UTF-8" X-CLIENT-IP: 213.134.181.48 X-CLIENT-HOSTNAME: 213.134.181.48 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedvuddruddtiedgkeeiucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecujffqoffgrffnpdggtffipffknecuuegrihhlohhuthemucduhedtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvffufffkjghfggfgtgesthfuredttddtjeenucfhrhhomhepfdftrghfrggvlhculfdrucghhihsohgtkhhifdcuoehrjhifsehrjhifhihsohgtkhhirdhnvghtqeenucggtffrrghtthgvrhhnpefgkedtheeuheetffeuleelhefhfffgjedthedvtdefteejffevteehhedvjefgudenucffohhmrghinhepghhithhhuhgsrdgtohhmnecukfhppedvudefrddufeegrddukedurdegkeenucevlhhushhtvghrufhiiigvpeefnecurfgrrhgrmhepihhnvghtpedvudefrddufeegrddukedurdegkedphhgvlhhopehkrhgvrggthhgvrhdrlhhotggrlhhnvghtpdhmrghilhhfrhhomhepfdftrghfrggvlhculfdrucghhihsohgtkhhifdcuoehrjhifsehrjhifhihsohgtkhhirdhnvghtqedprhgtphhtthhopehlihhnuhigqdgrtghpihesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdhkvghrnhgvlhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehrohgsvghrthdrmhhoohhrvgesihhnthgvlhdrtghomh X-DCC--Metrics: v370.home.net.pl 1024; Body=3 Fuz1=3 Fuz2=3 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org From: Jessica Clarke ACPICA commit 6bb72909c1e3d415aee214104a01bc9834b2d4ce Since the Signature member is accessed through an struct acpi_table_header, the pointer to it is only to a 4-char array, and so trying to read past the 4th character, as will be done when it is an RSDP, reads beyond the bounds of the accessed member. On CHERI, and thus Arm's experimental Morello prototype architecture, pointers are represented as capabilities, which are unforgeable bounded pointers, providing always-on fine-grained spatial memory safety. By default, subobject bounds enforcement is not enabled, only bounds on allocations, but it is enabled in the cheri_BSD (a port of free_BSD) kernel as intra-object overflow attacks are common on operating system kernels, and so this overflow is detected there and traps. Link: https://github.com/acpica/acpica/commit/6bb72909 Signed-off-by: Bob Moore Signed-off-by: Rafael J. Wysocki --- drivers/acpi/acpica/tbprint.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/acpica/tbprint.c b/drivers/acpi/acpica/tbprint.c index 254823d494a2..4dac16bd63d3 100644 --- a/drivers/acpi/acpica/tbprint.c +++ b/drivers/acpi/acpica/tbprint.c @@ -101,7 +101,8 @@ acpi_tb_print_table_header(acpi_physical_address address, ACPI_INFO(("%-4.4s 0x%8.8X%8.8X %06X", header->signature, ACPI_FORMAT_UINT64(address), header->length)); - } else if (ACPI_VALIDATE_RSDP_SIG(header->signature)) { + } else if (ACPI_VALIDATE_RSDP_SIG(ACPI_CAST_PTR(struct acpi_table_rsdp, + header)->signature)) { /* RSDP has no common fields */ -- 2.26.2