From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933856AbdKGAor (ORCPT ); Mon, 6 Nov 2017 19:44:47 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:53799 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933265AbdKGAVm (ORCPT ); Mon, 6 Nov 2017 19:21:42 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Ingo Molnar" , security@kernel.org, "Thomas Gleixner" , "Seunghun Han" , "Rafael J. Wysocki" Date: Mon, 06 Nov 2017 23:03:02 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 036/294] x86/acpi: Prevent out of bound access caused by broken ACPI tables In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.50-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Seunghun Han commit dad5ab0db8deac535d03e3fe3d8f2892173fa6a4 upstream. The bus_irq argument of mp_override_legacy_irq() is used as the index into the isa_irq_to_gsi[] array. The bus_irq argument originates from ACPI_MADT_TYPE_IO_APIC and ACPI_MADT_TYPE_INTERRUPT items in the ACPI tables, but is nowhere sanity checked. That allows broken or malicious ACPI tables to overwrite memory, which might cause malfunction, panic or arbitrary code execution. Add a sanity check and emit a warning when that triggers. [ tglx: Added warning and rewrote changelog ] Signed-off-by: Seunghun Han Signed-off-by: Thomas Gleixner Cc: security@kernel.org Cc: "Rafael J. Wysocki" Signed-off-by: Ingo Molnar Signed-off-by: Ben Hutchings --- arch/x86/kernel/acpi/boot.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -910,6 +910,14 @@ void __init mp_override_legacy_irq(u8 bu struct mpc_intsrc mp_irq; /* + * Check bus_irq boundary. + */ + if (bus_irq >= NR_IRQS_LEGACY) { + pr_warn("Invalid bus_irq %u for legacy override\n", bus_irq); + return; + } + + /* * Convert 'gsi' to 'ioapic.pin'. */ ioapic = mp_find_ioapic(gsi);