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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D0F29C2D0DB for ; Fri, 24 Jan 2020 16:48:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B22002071A for ; Fri, 24 Jan 2020 16:48:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388812AbgAXQsR (ORCPT ); Fri, 24 Jan 2020 11:48:17 -0500 Received: from ivanoab7.miniserver.com ([37.128.132.42]:58060 "EHLO www.kot-begemot.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387674AbgAXQsR (ORCPT ); Fri, 24 Jan 2020 11:48:17 -0500 Received: from tun252.jain.kot-begemot.co.uk ([192.168.18.6] helo=jain.kot-begemot.co.uk) by www.kot-begemot.co.uk with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1iv27r-0006Gu-PM; Fri, 24 Jan 2020 16:48:08 +0000 Received: from jain.kot-begemot.co.uk ([192.168.3.3]) by jain.kot-begemot.co.uk with esmtp (Exim 4.92) (envelope-from ) id 1iv27n-0005K8-Ga; Fri, 24 Jan 2020 16:48:06 +0000 Subject: Re: [PATCH] um: Fix some error handling in uml_vector_user_bpf() To: Dan Carpenter Cc: kernel-janitors@vger.kernel.org, Daniel Borkmann , Richard Weinberger , Jeff Dike , linux-um@lists.infradead.org, Song Liu , Alexei Starovoitov , Yonghong Song , Alex Dewar , bpf@vger.kernel.org, Andrii Nakryiko , Martin KaFai Lau References: <20200124101450.jxfzsh6sz7v324hv@kili.mountain> <36070c96-8e75-7d06-d945-87a9d366d0b9@cambridgegreys.com> <20200124164427.GF1870@kadam> From: Anton Ivanov Message-ID: Date: Fri, 24 Jan 2020 16:48:03 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200124164427.GF1870@kadam> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Clacks-Overhead: GNU Terry Pratchett Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 24/01/2020 16:44, Dan Carpenter wrote: > On Fri, Jan 24, 2020 at 12:52:18PM +0000, Anton Ivanov wrote: >> >> >> On 24/01/2020 10:14, Dan Carpenter wrote: >>> 1) The uml_vector_user_bpf() returns pointers so it should return NULL >>> instead of false. >>> 2) If the "bpf_prog" allocation failed, it would have eventually lead to >>> a crash. We can't succeed after the error happens so it should just >>> return. >>> >>> Fixes: 9807019a62dc ("um: Loadable BPF "Firmware" for vector drivers") >>> Signed-off-by: Dan Carpenter >>> --- >>> arch/um/drivers/vector_user.c | 10 +++++----- >>> 1 file changed, 5 insertions(+), 5 deletions(-) >>> >>> diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c >>> index ddcd917be0af..88483f5b034c 100644 >>> --- a/arch/um/drivers/vector_user.c >>> +++ b/arch/um/drivers/vector_user.c >>> @@ -732,13 +732,13 @@ void *uml_vector_user_bpf(char *filename) >>> if (stat(filename, &statbuf) < 0) { >>> printk(KERN_ERR "Error %d reading bpf file", -errno); >>> - return false; >>> + return NULL; >> >> I will sort this one out, thanks for noticing. >> >>> } >>> bpf_prog = uml_kmalloc(sizeof(struct sock_fprog), UM_GFP_KERNEL); >>> - if (bpf_prog != NULL) { >>> - bpf_prog->len = statbuf.st_size / sizeof(struct sock_filter); >>> - bpf_prog->filter = NULL; >>> - } >>> + if (!pfg_prog) >> >> ^^^^^ ? > > If we don't return here it leads to a NULL dereference. It says pfg_prog I cannot find this identifier :) > > regards, > dan carpenter > > > _______________________________________________ > linux-um mailing list > linux-um@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-um > -- Anton R. Ivanov Cambridgegreys Limited. Registered in England. Company Number 10273661 https://www.cambridgegreys.com/