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=-9.0 required=3.0 tests=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 6AF53C282C8 for ; Mon, 28 Jan 2019 10:04:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 35BD62087F for ; Mon, 28 Jan 2019 10:04:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726828AbfA1KEj (ORCPT ); Mon, 28 Jan 2019 05:04:39 -0500 Received: from smtp03.citrix.com ([162.221.156.55]:28666 "EHLO SMTP03.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726719AbfA1KEf (ORCPT ); Mon, 28 Jan 2019 05:04:35 -0500 X-IronPort-AV: E=Sophos;i="5.56,533,1539648000"; d="scan'208";a="76590249" From: Ross Lagerwall To: CC: , , "Rafael J . Wysocki" , Len Brown , Tony Luck , Borislav Petkov , Huang Ying , Ross Lagerwall Subject: [PATCH v2 1/2] acpi/apei: Fix possible out-of-bounds access to BERT region Date: Mon, 28 Jan 2019 10:04:23 +0000 Message-ID: <20190128100424.30278-2-ross.lagerwall@citrix.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20190128100424.30278-1-ross.lagerwall@citrix.com> References: <20190128100424.30278-1-ross.lagerwall@citrix.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Check that the length recorded in the generic error status block is within the region before checking the contents of the region itself. Otherwise it may result in an out-of-bounds access if the system firmware has generated a status block with an invalid length (larger than the mapped region). Also move the block_status check so that it only happens after the block has been verified to be within the mapped region. Signed-off-by: Ross Lagerwall --- drivers/acpi/apei/bert.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/drivers/acpi/apei/bert.c b/drivers/acpi/apei/bert.c index 12771fcf0417..0d948d0a41af 100644 --- a/drivers/acpi/apei/bert.c +++ b/drivers/acpi/apei/bert.c @@ -42,15 +42,7 @@ static void __init bert_print_all(struct acpi_bert_region *region, int remain = region_len; u32 estatus_len; - if (!estatus->block_status) - return; - - while (remain > sizeof(struct acpi_bert_region)) { - if (cper_estatus_check(estatus)) { - pr_err(FW_BUG "Invalid error record.\n"); - return; - } - + while (remain >= sizeof(struct acpi_bert_region)) { estatus_len = cper_estatus_len(estatus); if (remain < estatus_len) { pr_err(FW_BUG "Truncated status block (length: %u).\n", @@ -58,6 +50,15 @@ static void __init bert_print_all(struct acpi_bert_region *region, return; } + /* No more error records. */ + if (!estatus->block_status) + return; + + if (cper_estatus_check(estatus)) { + pr_err(FW_BUG "Invalid error record.\n"); + return; + } + pr_info_once("Error records from previous boot:\n"); cper_estatus_print(KERN_INFO HW_ERR, estatus); @@ -70,10 +71,6 @@ static void __init bert_print_all(struct acpi_bert_region *region, estatus->block_status = 0; estatus = (void *)estatus + estatus_len; - /* No more error records. */ - if (!estatus->block_status) - return; - remain -= estatus_len; } } -- 2.17.2