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=-19.7 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,URIBL_BLOCKED,USER_AGENT_GIT 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 3BCAEC636CA for ; Fri, 16 Jul 2021 10:46:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26EE361400 for ; Fri, 16 Jul 2021 10:46:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239560AbhGPKtl (ORCPT ); Fri, 16 Jul 2021 06:49:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:52078 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239511AbhGPKtk (ORCPT ); Fri, 16 Jul 2021 06:49:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 67396613E9; Fri, 16 Jul 2021 10:46:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626432405; bh=1aR2USH0CSQL4T/c6HKpO22PJzNSucyRjc4FadtDIlg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qK7goXNrq0nmffRXGExed9j+F8pXvlZzQ4zzJRV90PzwR24m/XAWtAsitB/k0kJdG O28XZ1xur/QgXXlc+HExsOy06lnHtOpH5/CCMUqXoxk+te5E3PN49REzHs4PJ1NlZz 0X3Xa1WvQypQtAm+8407zB4LkrWK3b1w9HcY9VFumya0Y/jDyoLJ5ryP4DTLA6Eqgd zM1m+fh2ELqg+IpprKbQrVkZxDksbflQ7k5wfLEK2nfI5XieqmDoC9i5THMdGlys6H dGbC4jrO8n2rZbcv2xw9JNPMLl4NBNmpTYeyzimzrxLIqVJ22GDMGDS2bRRdSHP7cI nDpK4Y+7iqwdg== From: Alexey Gladkov To: LKML , "Eric W . Biederman" Cc: Alexander Viro , Kees Cook , Linux Containers , Linux FS Devel Subject: [RESEND PATCH v6 1/5] docs: proc: add documentation about mount restrictions Date: Fri, 16 Jul 2021 12:45:59 +0200 Message-Id: X-Mailer: git-send-email 2.29.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Signed-off-by: Alexey Gladkov --- Documentation/filesystems/proc.rst | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 2fa69f710e2a..5a1bb0e081fd 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -50,6 +50,7 @@ fixes/update part 1.1 Stefani Seibold June 9 2009 4 Configuring procfs 4.1 Mount options + 4.2 Mount restrictions 5 Filesystem behavior @@ -2175,6 +2176,19 @@ information about processes information, just add identd to this group. subset=pid hides all top level files and directories in the procfs that are not related to tasks. +4.2 Mount restrictions +-------------------------- + +If user namespaces are in use, the kernel additionally checks the instances of +procfs available to the mounter and will not allow procfs to be mounted if: + + 1. This mount is not fully visible. + + a. It's root directory is not the root directory of the filesystem. + b. If any file or non-empty procfs directory is hidden by another mount. + + 2. A new mount overrides the readonly option or any option from atime familty. + Chapter 5: Filesystem behavior ============================== -- 2.29.3