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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 6D0DAC38A29 for ; Wed, 15 Apr 2020 12:26:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 444AC20936 for ; Wed, 15 Apr 2020 12:26:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586953591; bh=TXZIIcAEiQ/wpsaKSiN6BSXBSoCued4W7EnX5YJPXsc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XKQJvg2MbCFTrGEcw+3QUsf97fqk1LubGXpavRNAi2GjY360NIGxkPv9bHv5jsEou pJSlzf235f9mPCHv+gsRwcapbQ2mIQkpHjfWhdONnXm/zJhpdP8v3kVmc6aLyVpXsh hfZsJ3duj9ScUNPiaRtWWJYtQiWfJFooEdOzw7jM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S369263AbgDOM03 (ORCPT ); Wed, 15 Apr 2020 08:26:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:39006 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409169AbgDOLpY (ORCPT ); Wed, 15 Apr 2020 07:45:24 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 82FC1206A2; Wed, 15 Apr 2020 11:45:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586951124; bh=TXZIIcAEiQ/wpsaKSiN6BSXBSoCued4W7EnX5YJPXsc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gHBcJlSjsnJOD9VmEkzedYqQq+5F8jnvJ8/5pQ133tZ7SPyySvxQWdqYIDpzvKw7c DQyawIfhUbdubD0Rk5yrqmiuRriYh8wTV2hdDxMFqOWhkjyGwqihpn6yhDP6mvCIkX kepOQqsw+2wXUDhcA5nGu94oHky4PKV/QkOjTZ0g= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Gabriel Krisman Bertazi , Martyn Welch , Richard Weinberger , Sasha Levin , linux-um@lists.infradead.org Subject: [PATCH AUTOSEL 5.4 37/84] um: ubd: Prevent buffer overrun on command completion Date: Wed, 15 Apr 2020 07:43:54 -0400 Message-Id: <20200415114442.14166-37-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200415114442.14166-1-sashal@kernel.org> References: <20200415114442.14166-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 6627d7c30f370..0f5d0a699a49b 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -1606,7 +1606,9 @@ 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; } -- 2.20.1