From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752291AbdI3G1n (ORCPT ); Sat, 30 Sep 2017 02:27:43 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:42266 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751089AbdI3G1m (ORCPT ); Sat, 30 Sep 2017 02:27:42 -0400 Date: Sat, 30 Sep 2017 07:27:37 +0100 (WEST) Message-Id: <20170930.072737.128573396497381459.davem@davemloft.net> To: Jason@zx2c4.com Cc: johannes.berg@intel.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, johannes@sipsolutions.net Subject: Re: [PATCH v2] netlink: do not proceed if dump's start() errs From: David Miller In-Reply-To: <20170927224144.1749-1-Jason@zx2c4.com> References: <20170927224144.1749-1-Jason@zx2c4.com> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Fri, 29 Sep 2017 23:27:41 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Jason A. Donenfeld" Date: Thu, 28 Sep 2017 00:41:44 +0200 > Drivers that use the start method for netlink dumping rely on dumpit not > being called if start fails. For example, ila_xlat.c allocates memory > and assigns it to cb->args[0] in its start() function. It might fail to > do that and return -ENOMEM instead. However, even when returning an > error, dumpit will be called, which, in the example above, quickly > dereferences the memory in cb->args[0], which will OOPS the kernel. This > is but one example of how this goes wrong. > > Since start() has always been a function with an int return type, it > therefore makes sense to use it properly, rather than ignoring it. This > patch thus returns early and does not call dumpit() when start() fails. > > Signed-off-by: Jason A. Donenfeld > Cc: Johannes Berg Johannes, this looks straightforward to me, but please would you give it a quick review? Thank you.