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 9AFB9C49ED7 for ; Fri, 13 Sep 2019 13:11:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7427420CC7 for ; Fri, 13 Sep 2019 13:11:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568380312; bh=VD0f0+ab+C+4GW+EAuXTuKN+g/TJz9sfwB1E3e6vQIs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=NuoDspw2YTiU6JUkdSZwhyChFv8lreIxMAat5PMhDWU1TagYLbHDU013LkWNgsa6p v5QR+DRQ4WcBKYxtPcjz5V5oo7l1qhiUdYw9QGFrkEttflw5x5JEwBQLDE5CL9dHLF OC9jYMySkO8GzIYznCv69m4fIZ70NhyK/42o3XTc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389046AbfIMNLv (ORCPT ); Fri, 13 Sep 2019 09:11:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:37026 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388096AbfIMNLr (ORCPT ); Fri, 13 Sep 2019 09:11:47 -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 66645214AE; Fri, 13 Sep 2019 13:11:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568380307; bh=VD0f0+ab+C+4GW+EAuXTuKN+g/TJz9sfwB1E3e6vQIs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PZD4ykgWbKxsDBbfTJReFXrXrAAd9KaNmrpUWO0BJH/+44o75AupMsA+p6HVCAXlh P2pXXodCvpsDJo9lPPaXrtCQVo0CM91t4NGlOXvZkmJxn4Dsz16asbMKxCFDOIKG8a 2PC8W1/5xPzpZV7hAKjGrpyFZUGYU7CetK7DuZNM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Thomas Hellstrom Subject: [PATCH 4.19 007/190] drm/vmwgfx: Fix double free in vmw_recv_msg() Date: Fri, 13 Sep 2019 14:04:22 +0100 Message-Id: <20190913130600.230044997@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190913130559.669563815@linuxfoundation.org> References: <20190913130559.669563815@linuxfoundation.org> User-Agent: quilt/0.66 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: 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 @@ -353,7 +353,7 @@ static int vmw_recv_msg(struct rpc_chann !!(HIGH_WORD(ecx) & MESSAGE_STATUS_HB)); 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; @@ -377,7 +377,7 @@ 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; @@ -389,10 +389,8 @@ static int vmw_recv_msg(struct rpc_chann break; } - if (retries == RETRIES) { - kfree(reply); + if (!reply) return -EINVAL; - } *msg_len = reply_len; *msg = reply;