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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 C3872C4646C for ; Mon, 10 May 2021 12:02:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1377613DE for ; Mon, 10 May 2021 12:02:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236776AbhEJMAj (ORCPT ); Mon, 10 May 2021 08:00:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:46208 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236056AbhEJLHY (ORCPT ); Mon, 10 May 2021 07:07:24 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id ED8DE616ED; Mon, 10 May 2021 10:57:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620644274; bh=xZJ482XOAPo4NHz/gYmgW/ROsIxqwtHKbtewnL8D5nY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ktzVX/b7YVu/KmQRvXpK8vtqqY6U+DWzIrpyBZ4N/sM24E1s1wmV3kG97S9/a6Wxj pC1AapgIqhShT7894hK6SLQ5pA+sbKSLvZNRE2OizTxN8SduskW6SRd2w2Ka0Q8kf3 tUYS0ZFX5NKGc5nQ+IfX41XVcxrQhB/VVPep5IyQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Langsdorf , "Rafael J. Wysocki" Subject: [PATCH 5.12 016/384] ACPI: custom_method: fix potential use-after-free issue Date: Mon, 10 May 2021 12:16:45 +0200 Message-Id: <20210510102015.406981762@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102014.849075526@linuxfoundation.org> References: <20210510102014.849075526@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mark Langsdorf commit e483bb9a991bdae29a0caa4b3a6d002c968f94aa upstream. In cm_write(), buf is always freed when reaching the end of the function. If the requested count is less than table.length, the allocated buffer will be freed but subsequent calls to cm_write() will still try to access it. Remove the unconditional kfree(buf) at the end of the function and set the buf to NULL in the -EINVAL error path to match the rest of function. Fixes: 03d1571d9513 ("ACPI: custom_method: fix memory leaks") Signed-off-by: Mark Langsdorf Cc: 5.4+ # 5.4+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/custom_method.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -55,6 +55,7 @@ static ssize_t cm_write(struct file *fil (*ppos + count < count) || (count > uncopied_bytes)) { kfree(buf); + buf = NULL; return -EINVAL; } @@ -76,7 +77,6 @@ static ssize_t cm_write(struct file *fil add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE); } - kfree(buf); return count; }