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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 E9983C48BC2 for ; Wed, 23 Jun 2021 13:41:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE43E610A0 for ; Wed, 23 Jun 2021 13:41:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230286AbhFWNoK (ORCPT ); Wed, 23 Jun 2021 09:44:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:45876 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230061AbhFWNoJ (ORCPT ); Wed, 23 Jun 2021 09:44:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C12CF61076; Wed, 23 Jun 2021 13:41:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624455712; bh=ahAIQzGeIV5bSA+izmWMgZyiMYHJ37sy5dm5nG35WsY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Q2fs3xfj1k5ez23+zg+C8YgfDHiuth2aI+p7UqiOQwWK2sSAqUXxaqnpFRxiPL+Vu yrIX6Ii4gw63FUm9vIRgoLmKYmuxHFoLda7MqkRAbTnqhzc8v3FehQkcyzXhtl1rlC Vbk1eDjCtC15gwnY0osT+KmneZmHey/NlU4Kb5RG3t5fnUlFwxQ9Ybknkx4qBd74jn BLx467xAqWjRurwe/dOHVwf+46JGH25SbcJFgG0mKWWOQWaCgqezEYEFGPFPTNi4X1 zIvAmd7tAe+ovpIG9dYW6RilEpCxGJiBD3U9PxvlYX2rh7w/At/AArTHZ1JuWpbVh6 867z2BiQTgPkQ== Date: Wed, 23 Jun 2021 16:41:50 +0300 From: Jarkko Sakkinen To: Dave Hansen Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, tim.gardner@canonical.com, reinette.chatre@intel.com, shuah@kernel.org, linux-sgx@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH] selftests/sgx: remove checks for file execute permissions Message-ID: <20210623134150.j4qjhcepmtohsxdo@kernel.org> References: <20210621190556.4B5DCBB1@viggo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210621190556.4B5DCBB1@viggo.jf.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Mon, Jun 21, 2021 at 12:05:56PM -0700, Dave Hansen wrote: > > The SGX selftests can fail for a bunch of non-obvious reasons > like 'noexec' permissions on /dev (which is the default *EVERYWHERE* > it seems). > > A new test mistakenly also looked for +x permission on the > /dev/sgx_enclave. File execute permissions really only apply to > the ability of execve() to work on a file, *NOT* on the ability > for an application to map the file with PROT_EXEC. SGX needs to > mmap(PROT_EXEC), but doesn't need to execve() the device file. > > Remove the check. > > Fixes: 4284f7acb78b ("selftests/sgx: Improve error detection and messages") > Reported-by: Tim Gardner > Cc: Jarkko Sakkinen > Cc: Reinette Chatre > Cc: Dave Hansen > Cc: Shuah Khan > Cc: linux-sgx@vger.kernel.org > Cc: linux-kselftest@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > > --- > > b/tools/testing/selftests/sgx/load.c | 16 +++------------- > 1 file changed, 3 insertions(+), 13 deletions(-) > > diff -puN tools/testing/selftests/sgx/load.c~sgx-no-file-exec tools/testing/selftests/sgx/load.c > --- a/tools/testing/selftests/sgx/load.c~sgx-no-file-exec 2021-06-21 11:48:25.226294281 -0700 > +++ b/tools/testing/selftests/sgx/load.c 2021-06-21 12:03:28.023292029 -0700 > @@ -150,16 +150,6 @@ bool encl_load(const char *path, struct > goto err; > } > > - /* > - * This just checks if the /dev file has these permission > - * bits set. It does not check that the current user is > - * the owner or in the owning group. > - */ > - if (!(sb.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))) { > - fprintf(stderr, "no execute permissions on device file %s\n", device_path); > - goto err; > - } > - > ptr = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0); > if (ptr == (void *)-1) { > perror("mmap for read"); > @@ -169,13 +159,13 @@ bool encl_load(const char *path, struct > > #define ERR_MSG \ > "mmap() succeeded for PROT_READ, but failed for PROT_EXEC.\n" \ > -" Check that current user has execute permissions on %s and \n" \ > -" that /dev does not have noexec set: mount | grep \"/dev .*noexec\"\n" \ > +" Check that /dev does not have noexec set:\n" \ > +" \tmount | grep \"/dev .*noexec\"\n" \ > " If so, remount it executable: mount -o remount,exec /dev\n\n" > > ptr = mmap(NULL, PAGE_SIZE, PROT_EXEC, MAP_SHARED, fd, 0); > if (ptr == (void *)-1) { > - fprintf(stderr, ERR_MSG, device_path); > + fprintf(stderr, ERR_MSG); > goto err; > } > munmap(ptr, PAGE_SIZE); > _ > Reviewed-by: Jarkko Sakkinen /Jarkko