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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 1584CC5518A for ; Wed, 22 Apr 2020 10:48:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DEEDC2073A for ; Wed, 22 Apr 2020 10:48:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587552481; bh=lzAr4ppCgdjZHX3lpnDUbHFj+hcvIzVExwUEm8K4/hI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sd4iPL7dcw2cFi5JAkYLcsRnVRliWeSV5KlFw19O6xjU2V/nfpdkWTmNy0Xv7tlxD mlkAgj0V0VPssS6/Aenb1fk6W6Id+OhYM69NKSO6MzpahKk/W/TaBzcN+xGk2m6iYi OvbA6TVIGbAW3NI2+RfKTGoloc3IZCgWn8iIMGmg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729617AbgDVKPA (ORCPT ); Wed, 22 Apr 2020 06:15:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:49704 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728876AbgDVKOu (ORCPT ); Wed, 22 Apr 2020 06:14:50 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 5925F2071E; Wed, 22 Apr 2020 10:14:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587550489; bh=lzAr4ppCgdjZHX3lpnDUbHFj+hcvIzVExwUEm8K4/hI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z1Ao0dv753hrRcKzu/otFrr3T6BRpjW5dyfbulS5vKWEegEE8gkWfk+E+AUqfuPan ok2PNJItVJUVF/nv3Ym5lLk/Xpcp1CXDFD0bZNwSdBdZlvJfK6ZDXfANOS3ujQGmC5 gIxP/LpjpqjU8i05BGZIDBpzU4JxLZEPtp68L5JM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martyn Welch , Gabriel Krisman Bertazi , Richard Weinberger , Sasha Levin Subject: [PATCH 4.19 37/64] um: ubd: Prevent buffer overrun on command completion Date: Wed, 22 Apr 2020 11:57:21 +0200 Message-Id: <20200422095019.630791494@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200422095008.799686511@linuxfoundation.org> References: <20200422095008.799686511@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: Gabriel Krisman Bertazi [ Upstream commit 6e682d53fc1ef73a169e2a5300326cb23abb32ee ] On the hypervisor side, when completing commands and the pipe is full, we retry writing only the entries that failed, by offsetting io_req_buffer, but we don't reduce the number of bytes written, which can cause a buffer overrun of io_req_buffer, and write garbage to the pipe. Cc: Martyn Welch Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/drivers/ubd_kern.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index 83c470364dfb3..748bd0921dfff 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -1574,7 +1574,9 @@ int io_thread(void *arg) written = 0; do { - res = os_write_file(kernel_fd, ((char *) io_req_buffer) + written, n); + res = os_write_file(kernel_fd, + ((char *) io_req_buffer) + written, + n - written); if (res >= 0) { written += res; } else { -- 2.20.1