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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 66E5BC49ED7 for ; Fri, 13 Sep 2019 13:10:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3BC2520CC7 for ; Fri, 13 Sep 2019 13:10:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568380256; bh=p2OG/25OntIVnTzVIz2+SUyWxOBIql0bEaDlV5Vj7Nc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=y297Soz9USQ2HfrOzFHCVXYX1V6k7vJAyM51do9EbpcwyjyTYzbZG7zYHp5JyBZHq 5z4muOj35rt9+aqrzM198hzIqAI2JdWXtuywo+lmVjOd7kcPqcowAbrRnXL6bqs/cp gOhrTea4W+RPIk/jTZv6aQIqCJua/h3XwHNNUt+k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388825AbfIMNKv (ORCPT ); Fri, 13 Sep 2019 09:10:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:35648 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388817AbfIMNKr (ORCPT ); Fri, 13 Sep 2019 09:10:47 -0400 Received: from localhost (unknown [104.132.45.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 64902206BB; Fri, 13 Sep 2019 13:10:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568380247; bh=p2OG/25OntIVnTzVIz2+SUyWxOBIql0bEaDlV5Vj7Nc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yb3ti1xl1QQtrFStmVEwBZiK/07T43LeaiufwktavLA0ALXXMclbCV7D+mwbBb0ba NluT1Nx44EXDdfoj1NmaQfUusqxJlBM52t/r/Bcs52fo8rXLyu6tu3Y86HPcwZVQnZ jYZlfb6GX3eln6TP+HkApa8188elLkbHXKp0XCjk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Thomas Hellstrom Subject: [PATCH 4.14 05/21] drm/vmwgfx: Fix double free in vmw_recv_msg() Date: Fri, 13 Sep 2019 14:06:58 +0100 Message-Id: <20190913130503.441739156@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190913130501.285837292@linuxfoundation.org> References: <20190913130501.285837292@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Dan Carpenter commit 08b0c891605acf727e43e3e03a25857d3e789b61 upstream. We recently added a kfree() after the end of the loop: if (retries == RETRIES) { kfree(reply); return -EINVAL; } There are two problems. First the test is wrong and because retries equals RETRIES if we succeed on the last iteration through the loop. Second if we fail on the last iteration through the loop then the kfree is a double free. When you're reading this code, please note the break statement at the end of the while loop. This patch changes the loop so that if it's not successful then "reply" is NULL and we can test for that afterward. Cc: Fixes: 6b7c3b86f0b6 ("drm/vmwgfx: fix memory leak when too many retries have occurred") Signed-off-by: Dan Carpenter Reviewed-by: Thomas Hellstrom Signed-off-by: Thomas Hellstrom Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/vmwgfx/vmwgfx_msg.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c @@ -264,7 +264,7 @@ static int vmw_recv_msg(struct rpc_chann if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) == 0) { kfree(reply); - + reply = NULL; if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) { /* A checkpoint occurred. Retry. */ continue; @@ -288,7 +288,7 @@ static int vmw_recv_msg(struct rpc_chann if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) { kfree(reply); - + reply = NULL; if ((HIGH_WORD(ecx) & MESSAGE_STATUS_CPT) != 0) { /* A checkpoint occurred. Retry. */ continue; @@ -300,10 +300,8 @@ static int vmw_recv_msg(struct rpc_chann break; } - if (retries == RETRIES) { - kfree(reply); + if (!reply) return -EINVAL; - } *msg_len = reply_len; *msg = reply;