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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 BCF9FC49ED7 for ; Fri, 20 Sep 2019 14:37:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AE8520B7C for ; Fri, 20 Sep 2019 14:37:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392782AbfITOh0 (ORCPT ); Fri, 20 Sep 2019 10:37:26 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35872 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388067AbfITOZB (ORCPT ); Fri, 20 Sep 2019 10:25:01 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iBJqE-0004xE-1T; Fri, 20 Sep 2019 15:24:58 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iBJqD-0007rN-42; Fri, 20 Sep 2019 15:24:57 +0100 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, Denis Kirjanov , "Darren Hart (VMware)" , "Colin Ian King" Date: Fri, 20 Sep 2019 15:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 035/132] platform/x86: alienware-wmi: fix kfree on potentially uninitialized pointer In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.74-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Colin Ian King commit 98e2630284ab741804bd0713e932e725466f2f84 upstream. Currently the kfree of output.pointer can be potentially freeing an uninitalized pointer in the case where out_data is NULL. Fix this by reworking the case where out_data is not-null to perform the ACPI status check and also the kfree of outpoint.pointer in one block and hence ensuring the pointer is only freed when it has been used. Also replace the if (ptr != NULL) idiom with just if (ptr). Fixes: ff0e9f26288d ("platform/x86: alienware-wmi: Correct a memory leak") Signed-off-by: Colin Ian King Signed-off-by: Darren Hart (VMware) [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/platform/x86/alienware-wmi.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) --- a/drivers/platform/x86/alienware-wmi.c +++ b/drivers/platform/x86/alienware-wmi.c @@ -433,23 +433,22 @@ static acpi_status alienware_hdmi_comman input.length = (acpi_size) sizeof(*in_args); input.pointer = in_args; - if (out_data != NULL) { + if (out_data) { output.length = ACPI_ALLOCATE_BUFFER; output.pointer = NULL; status = wmi_evaluate_method(WMAX_CONTROL_GUID, 1, command, &input, &output); - } else + if (ACPI_SUCCESS(status)) { + obj = (union acpi_object *)output.pointer; + if (obj && obj->type == ACPI_TYPE_INTEGER) + *out_data = (u32)obj->integer.value; + } + kfree(output.pointer); + } else { status = wmi_evaluate_method(WMAX_CONTROL_GUID, 1, command, &input, NULL); - - if (ACPI_SUCCESS(status) && out_data != NULL) { - obj = (union acpi_object *)output.pointer; - if (obj && obj->type == ACPI_TYPE_INTEGER) - *out_data = (u32) obj->integer.value; } - kfree(output.pointer); return status; - } static ssize_t show_hdmi_cable(struct device *dev,