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 F08C3C43381 for ; Sat, 30 Mar 2019 00:17:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC24521773 for ; Sat, 30 Mar 2019 00:17:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730361AbfC3ARQ (ORCPT ); Fri, 29 Mar 2019 20:17:16 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:44082 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729771AbfC3ARP (ORCPT ); Fri, 29 Mar 2019 20:17:15 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1hA1gP-00026s-82; Sat, 30 Mar 2019 00:17:13 +0000 From: Colin King To: Darren Hart , Andy Shevchenko , platform-driver-x86@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] platform/x86: alienware-wmi: fix kfree on potentially uninitialized pointer Date: Sat, 30 Mar 2019 00:17:12 +0000 Message-Id: <20190330001712.8923-1-colin.king@canonical.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King 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 --- drivers/platform/x86/alienware-wmi.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/drivers/platform/x86/alienware-wmi.c b/drivers/platform/x86/alienware-wmi.c index f10af5c383c5..c0d1555735cd 100644 --- a/drivers/platform/x86/alienware-wmi.c +++ b/drivers/platform/x86/alienware-wmi.c @@ -522,23 +522,22 @@ static acpi_status alienware_wmax_command(struct wmax_basic_args *in_args, 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, 0, 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, 0, 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; - } /* -- 2.20.1