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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 E8534C4360C for ; Fri, 4 Oct 2019 15:19:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5E00207FF for ; Fri, 4 Oct 2019 15:19:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389862AbfJDPTw (ORCPT ); Fri, 4 Oct 2019 11:19:52 -0400 Received: from mx2.suse.de ([195.135.220.15]:46946 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389461AbfJDPTw (ORCPT ); Fri, 4 Oct 2019 11:19:52 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 02FADAF35; Fri, 4 Oct 2019 15:19:50 +0000 (UTC) Date: Fri, 4 Oct 2019 17:20:03 +0200 From: Jean Delvare To: LKML Cc: Tony Luck , Borislav Petkov Subject: [PATCH] firmware: dmi: Fix unlikely out-of-bounds read in save_mem_devices Message-ID: <20191004172003.689f2c04@endymion> Organization: SUSE Linux X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Before reading the Extended Size field, we should ensure it fits in the DMI record. There is already a record length check but it does not cover that field. It would take a seriously corrupted DMI table to hit that bug, so no need to worry, but we should still fix it. Signed-off-by: Jean Delvare Fixes: 6deae96b42eb ("firmware, DMI: Add function to look up a handle and return DIMM size") Cc: Tony Luck Cc: Borislav Petkov --- drivers/firmware/dmi_scan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- linux-5.3.orig/drivers/firmware/dmi_scan.c 2019-10-04 16:14:24.575714482 +0200 +++ linux-5.3/drivers/firmware/dmi_scan.c 2019-10-04 16:18:18.878669652 +0200 @@ -408,7 +408,7 @@ static void __init save_mem_devices(cons bytes = ~0ull; else if (size & 0x8000) bytes = (u64)(size & 0x7fff) << 10; - else if (size != 0x7fff) + else if (size != 0x7fff || dm->length < 0x20) bytes = (u64)size << 20; else bytes = (u64)get_unaligned((u32 *)&d[0x1C]) << 20; -- Jean Delvare SUSE L3 Support