From patchwork Mon Jan 18 11:33:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 366023 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 36C13C433E0 for ; Mon, 18 Jan 2021 18:25:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0871222CA1 for ; Mon, 18 Jan 2021 18:25:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405563AbhARPHE (ORCPT ); Mon, 18 Jan 2021 10:07:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:37470 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390785AbhARLmp (ORCPT ); Mon, 18 Jan 2021 06:42:45 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 328C522D6E; Mon, 18 Jan 2021 11:42:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610970136; bh=829m9skplpEvLOASKY/h3GNXJNG+KmW0IxGw1D4EQXI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jRm2Lm+1MxJnm15OHWjoj5ndqbpUnEqr/2wz7lYs5UiGP/RHyPJgEM9MnxHcdSTQx rB+6rhmtCpot7ZXl06YREI2AdXvFCzIfDMEeS3x2itMdiyK3sTnwrXlcFMRV3Zybqq aFfFv4xE3xOOOMwjVQ+lYozyTWIv/w0oK5yCdkHY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dexuan Cui , Jethro Beekman , "Rafael J. Wysocki" Subject: [PATCH 5.10 035/152] ACPI: scan: Harden acpi_device_add() against device ID overflows Date: Mon, 18 Jan 2021 12:33:30 +0100 Message-Id: <20210118113354.463000985@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210118113352.764293297@linuxfoundation.org> References: <20210118113352.764293297@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Dexuan Cui commit a58015d638cd4e4555297b04bec9b49028369075 upstream. Linux VM on Hyper-V crashes with the latest mainline: [ 4.069624] detected buffer overflow in strcpy [ 4.077733] kernel BUG at lib/string.c:1149! .. [ 4.085819] RIP: 0010:fortify_panic+0xf/0x11 ... [ 4.085819] Call Trace: [ 4.085819] acpi_device_add.cold.15+0xf2/0xfb [ 4.085819] acpi_add_single_object+0x2a6/0x690 [ 4.085819] acpi_bus_check_add+0xc6/0x280 [ 4.085819] acpi_ns_walk_namespace+0xda/0x1aa [ 4.085819] acpi_walk_namespace+0x9a/0xc2 [ 4.085819] acpi_bus_scan+0x78/0x90 [ 4.085819] acpi_scan_init+0xfa/0x248 [ 4.085819] acpi_init+0x2c1/0x321 [ 4.085819] do_one_initcall+0x44/0x1d0 [ 4.085819] kernel_init_freeable+0x1ab/0x1f4 This is because of the recent buffer overflow detection in the commit 6a39e62abbaf ("lib: string.h: detect intra-object overflow in fortified string functions") Here acpi_device_bus_id->bus_id can only hold 14 characters, while the the acpi_device_hid(device) returns a 22-char string "HYPER_V_GEN_COUNTER_V1". Per ACPI Spec v6.2, Section 6.1.5 _HID (Hardware ID), if the ID is a string, it must be of the form AAA#### or NNNN####, i.e. 7 chars or 8 chars. The field bus_id in struct acpi_device_bus_id was originally defined as char bus_id[9], and later was enlarged to char bus_id[15] in 2007 in the commit bb0958544f3c ("ACPI: use more understandable bus_id for ACPI devices") Fix the issue by changing the field bus_id to const char *, and use kstrdup_const() to initialize it. Signed-off-by: Dexuan Cui Tested-By: Jethro Beekman [ rjw: Subject change, whitespace adjustment ] Cc: All applicable Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/internal.h | 2 +- drivers/acpi/scan.c | 15 ++++++++++++++- 2 files changed, 15 insertions(+), 2 deletions(-) --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -97,7 +97,7 @@ void acpi_scan_table_handler(u32 event, extern struct list_head acpi_bus_id_list; struct acpi_device_bus_id { - char bus_id[15]; + const char *bus_id; unsigned int instance_no; struct list_head node; }; --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -486,6 +486,7 @@ static void acpi_device_del(struct acpi_ acpi_device_bus_id->instance_no--; else { list_del(&acpi_device_bus_id->node); + kfree_const(acpi_device_bus_id->bus_id); kfree(acpi_device_bus_id); } break; @@ -674,7 +675,14 @@ int acpi_device_add(struct acpi_device * } if (!found) { acpi_device_bus_id = new_bus_id; - strcpy(acpi_device_bus_id->bus_id, acpi_device_hid(device)); + acpi_device_bus_id->bus_id = + kstrdup_const(acpi_device_hid(device), GFP_KERNEL); + if (!acpi_device_bus_id->bus_id) { + pr_err(PREFIX "Memory allocation error for bus id\n"); + result = -ENOMEM; + goto err_free_new_bus_id; + } + acpi_device_bus_id->instance_no = 0; list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list); } @@ -709,6 +717,11 @@ int acpi_device_add(struct acpi_device * if (device->parent) list_del(&device->node); list_del(&device->wakeup_list); + + err_free_new_bus_id: + if (!found) + kfree(new_bus_id); + mutex_unlock(&acpi_device_lock); err_detach: