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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45EE4C4332F for ; Mon, 23 May 2022 09:59:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233662AbiEWJ7x (ORCPT ); Mon, 23 May 2022 05:59:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233896AbiEWJ7n (ORCPT ); Mon, 23 May 2022 05:59:43 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9A34302; Mon, 23 May 2022 02:59:42 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4B213B80EB4; Mon, 23 May 2022 09:59:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3167EC385A9; Mon, 23 May 2022 09:59:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653299980; bh=xllwVvxa/zTtheTg1NgvcRi8ov009dxPWjGecps7DxQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZMsleth+k/LOoxGbiXcaxOHO+9D6U34bsUs9u5/aMf2p6dnxKzdct9/HgpUY0T4O3 ExSE2uCr5FiVOsPTd35IsQ4JX61K+3o7pHUr/BH3EEyGGz8xCMVjalqATVv4R+MXTl U2MWwKxAJlhPkA+wDA9SUgMIHeGFLDePTrLJA/EjIr+85KaQtbqDKOqNcXqlrZ93Xf xEbay21Gvn7rGNVRXOLysSpQkGc2kbZ/CKDXHQPzenFPTLwXIM2gZCDjiuBprxCOib gsKoXAOQJH64+0BxUss5Mcd/Y0uCr60xi2frtgkZATuzvTB0ix/ltJHrC5wNuc4ZSx Yf3YD/VNhcOow== Date: Mon, 23 May 2022 11:59:32 +0200 From: Christian Brauner To: "Serge E. Hallyn" Cc: Stefan Berger , linux-integrity@vger.kernel.org, zohar@linux.ibm.com, christian.brauner@ubuntu.com, containers@lists.linux.dev, dmitry.kasatkin@gmail.com, ebiederm@xmission.com, krzysztof.struczynski@huawei.com, roberto.sassu@huawei.com, mpeters@redhat.com, lhinds@redhat.com, lsturman@redhat.com, puiterwi@redhat.com, jejb@linux.ibm.com, jamjoom@us.ibm.com, linux-kernel@vger.kernel.org, paul@paul-moore.com, rgb@redhat.com, linux-security-module@vger.kernel.org, jmorris@namei.org, jpenumak@redhat.com Subject: Re: [PATCH v12 13/26] userns: Add pointer to ima_namespace to user_namespace Message-ID: <20220523095932.adr2r26o2obch4r5@wittgenstein> References: <20220420140633.753772-1-stefanb@linux.ibm.com> <20220420140633.753772-14-stefanb@linux.ibm.com> <20220522182426.GA24765@mail.hallyn.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220522182426.GA24765@mail.hallyn.com> Precedence: bulk List-ID: On Sun, May 22, 2022 at 01:24:26PM -0500, Serge Hallyn wrote: > On Wed, Apr 20, 2022 at 10:06:20AM -0400, Stefan Berger wrote: > > Add a pointer to ima_namespace to the user_namespace and initialize > > the init_user_ns with a pointer to init_ima_ns. We need a pointer from > > the user namespace to its associated IMA namespace since IMA namespaces > > are piggybacking on user namespaces. > > > > Signed-off-by: Stefan Berger > > Acked-by: Christian Brauner > > Reviewed-by: Mimi Zohar > > > > --- > > v11: > > - Added lost A-b from Christian back > > - Added sentence to patch description explaining why we need the pointer > > > > v9: > > - Deferred implementation of ima_ns_from_user_ns() to later patch > > --- > > include/linux/ima.h | 2 ++ > > include/linux/user_namespace.h | 4 ++++ > > kernel/user.c | 4 ++++ > > 3 files changed, 10 insertions(+) > > > > diff --git a/include/linux/ima.h b/include/linux/ima.h > > index 426b1744215e..fcb60a44e05f 100644 > > --- a/include/linux/ima.h > > +++ b/include/linux/ima.h > > @@ -14,6 +14,8 @@ > > #include > > struct linux_binprm; > > > > +extern struct ima_namespace init_ima_ns; > > + > > #ifdef CONFIG_IMA > > extern enum hash_algo ima_get_current_hash_algo(void); > > extern int ima_bprm_check(struct linux_binprm *bprm); > > diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h > > index 33a4240e6a6f..019e8cf7b633 100644 > > --- a/include/linux/user_namespace.h > > +++ b/include/linux/user_namespace.h > > @@ -36,6 +36,7 @@ struct uid_gid_map { /* 64 bytes -- 1 cache line */ > > #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED > > > > struct ucounts; > > +struct ima_namespace; > > > > enum ucount_type { > > UCOUNT_USER_NAMESPACES, > > @@ -99,6 +100,9 @@ struct user_namespace { > > #endif > > struct ucounts *ucounts; > > long ucount_max[UCOUNT_COUNTS]; > > +#ifdef CONFIG_IMA_NS > > It's probably worth putting a comment here saying that user_ns does not > pin ima_ns. > > That the only time the ima_ns will be freed is when user_ns is freed, > and only time it will be changed is when user_ns is freed, or during > ima_fs_ns_init() (under smp_load_acquire) during a new mount. > > > + struct ima_namespace *ima_ns; > > So, if I create a new user_ns with a new ima_ns, and in there I > create a new user_ns again, it looks like ima_ns will be NULL in > the new user_ns? Should it not be set to the parent->ima_ns? > (which would cause trouble for the way it's currently being > freed...) Would also work and wouldn't be difficult to do imho.