From patchwork Fri Jul 24 13:35:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 11683307 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A8A1D1392 for ; Fri, 24 Jul 2020 13:35:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F133206D7 for ; Fri, 24 Jul 2020 13:35:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hEF46etQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727790AbgGXNfv (ORCPT ); Fri, 24 Jul 2020 09:35:51 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:52207 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727048AbgGXNfu (ORCPT ); Fri, 24 Jul 2020 09:35:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595597749; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5B7NRLNMJVGbU812ZltjTFTKIzdAhqkdhwjD/nwzlmY=; b=hEF46etQaz8uhYE+bMXtoyHkkgQls+wvgvxnecHf+CijFRBvY9Pm/0qx6gHla8bhoRMfEL h28R49uwCCIXDTqZAYlqTt6NKplceflWe9ayHw577WidtRrWkfPiipkWyx2aOkQ8DvvG9R ederNwZg5krUXGN0y6MneOBsf790BIk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-143-6sAAWNFoMaqUKE2W65pvdA-1; Fri, 24 Jul 2020 09:35:45 -0400 X-MC-Unique: 6sAAWNFoMaqUKE2W65pvdA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B79241009446; Fri, 24 Jul 2020 13:35:43 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-112-32.rdu2.redhat.com [10.10.112.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id 451382DE72; Fri, 24 Jul 2020 13:35:41 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 06/17] fsinfo: Add a uniquifier ID to struct mount [ver #20] From: David Howells To: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk Cc: dhowells@redhat.com, raven@themaw.net, mszeredi@redhat.com, christian@brauner.io, jannh@google.com, darrick.wong@oracle.com, kzak@redhat.com, jlayton@redhat.com, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Date: Fri, 24 Jul 2020 14:35:40 +0100 Message-ID: <159559774044.2144584.14085699755046222864.stgit@warthog.procyon.org.uk> In-Reply-To: <159559768062.2144584.13583793543173131929.stgit@warthog.procyon.org.uk> References: <159559768062.2144584.13583793543173131929.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Add a uniquifier ID to struct mount that is effectively unique over the kernel lifetime to deal around mnt_id values being reused. This can then be exported through fsinfo() to allow detection of replacement mounts that happen to end up with the same mount ID. The normal mount handle is still used for referring to a particular mount. Signed-off-by: David Howells --- fs/mount.h | 3 +++ fs/namespace.c | 3 +++ 2 files changed, 6 insertions(+) diff --git a/fs/mount.h b/fs/mount.h index 1c777f651446..c3e0bb6e5782 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -79,6 +79,9 @@ struct mount { int mnt_expiry_mark; /* true if marked for expiry */ struct hlist_head mnt_pins; struct hlist_head mnt_stuck_children; +#ifdef CONFIG_FSINFO + u64 mnt_unique_id; /* ID unique over lifetime of kernel */ +#endif #ifdef CONFIG_MOUNT_NOTIFICATIONS atomic_t mnt_topology_changes; /* Number of topology changes applied */ atomic_t mnt_attr_changes; /* Number of attribute changes applied */ diff --git a/fs/namespace.c b/fs/namespace.c index b2b9920ffd3c..1db8a64cd76f 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -115,6 +115,9 @@ static int mnt_alloc_id(struct mount *mnt) if (res < 0) return res; mnt->mnt_id = res; +#ifdef CONFIG_FSINFO + mnt->mnt_unique_id = atomic64_inc_return(&vfs_unique_counter); +#endif return 0; }