From patchwork Fri Jan 30 19:50:44 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Weinberger X-Patchwork-Id: 435010 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 67B671401D0 for ; Sat, 31 Jan 2015 06:51:15 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756744AbbA3Tu4 (ORCPT ); Fri, 30 Jan 2015 14:50:56 -0500 Received: from mail.sigma-star.at ([95.130.255.111]:14385 "EHLO mail.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751342AbbA3Tuz (ORCPT ); Fri, 30 Jan 2015 14:50:55 -0500 Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.sigma-star.at (Postfix) with ESMTP id 084E316B42A1; Fri, 30 Jan 2015 20:50:51 +0100 (CET) X-Virus-Scanned: amavisd-new at mail.sigma-star.at Received: from linux.site (richard.vpn.sigmapriv.at [10.3.0.5]) by mail.sigma-star.at (Postfix) with ESMTPSA id EDE2316B4018; Fri, 30 Jan 2015 20:50:49 +0100 (CET) From: Richard Weinberger To: davem@davemloft.net Cc: corbet@lwn.net, shemming@brocade.com, linux-doc@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Richard Weinberger Subject: [PATCH] Documentation: Update netlink_mmap.txt Date: Fri, 30 Jan 2015 20:50:44 +0100 Message-Id: <1422647444-4004-1-git-send-email-richard@nod.at> X-Mailer: git-send-email 2.2.2 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Update netlink_mmap.txt wrt. commit 4682a0358639b29cf ("netlink: Always copy on mmap TX."). Signed-off-by: Richard Weinberger --- Documentation/networking/netlink_mmap.txt | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/Documentation/networking/netlink_mmap.txt b/Documentation/networking/netlink_mmap.txt index c6af4ba..30a95fd 100644 --- a/Documentation/networking/netlink_mmap.txt +++ b/Documentation/networking/netlink_mmap.txt @@ -199,16 +199,9 @@ frame header. TX limitations -------------- -Kernel processing usually involves validation of the message received by -user-space, then processing its contents. The kernel must assure that -userspace is not able to modify the message contents after they have been -validated. In order to do so, the message is copied from the ring frame -to an allocated buffer if either of these conditions is false: - -- only a single mapping of the ring exists -- the file descriptor is not shared between processes - -This means that for threaded programs, the kernel will fall back to copying. +As of Jan 2015 the message is always copied from the ring frame to an +allocated buffer due to unresolved security concerns. +See commit 4682a0358639b29cf ("netlink: Always copy on mmap TX."). Example -------