From: Casey Schaufler <casey@schaufler-ca.com>
To: Jan Koester <jan.koester@tuxist.de>,
Christian Brauner <brauner@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
"Serge E. Hallyn" <serge@hallyn.com>
Cc: Jan Kara <jack@suse.cz>, "Theodore Y. Ts'o" <tytso@mit.edu>,
Paul Moore <paul@paul-moore.com>, Arnd Bergmann <arnd@arndb.de>,
linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-arch@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org,
netdev@vger.kernel.org, audit@vger.kernel.org,
keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
Casey Schaufler <casey@schaufler-ca.com>
Subject: Re: [RFC PATCH v2 00/41] UUID and GUID user and group ids (*_r system calls)
Date: Thu, 22 Oct 2026 10:00:16 -0700 [thread overview]
Message-ID: <018ca365-ce9b-424c-b600-bd9c8aefc9a1@schaufler-ca.com> (raw)
In-Reply-To: <cover.1792552161.git.jan.koester@tuxist.de>
On 10/20/2026 8:15 PM, Jan Koester wrote:
> Hi,
>
> this RFC series lets a user or group id be a UUID (RFC 9562, version 4)
> or a Microsoft GUID as well as a classic 32-bit number. Processes can run
> as such a user, files can be owned by one, and credentials, ACLs, keys,
> System V IPC, sockets, signals, audit and procfs carry the whole id.
I can't see this being acceptable for a variety of reasons, including
but not limited to performance and configuration complexity. It's a
general solution for a special case or two, and the impact is significant.
If you're willing to use a UUID and/or GUID in addition to a UID/GID
instead of in place of it you could consider implementing this as an
LSM. There are a number of issues you'd still run into there (e.g. UDS
attributes) and I can't say if the resulting behavior would be what
you're looking for. I also can't say that the security community would
necessarily be any happier with it than the general population, but if
you really want this it might be worth a shot.
next prev parent reply other threads:[~2026-10-22 17:00 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-21 3:15 Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 01/41] uuid: move uuid_t and guid_t into <linux/uuid_types.h> Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 02/41] uapi: add <linux/uidgid_r.h> for 128 bit capable user and group ids Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 03/41] uidgid: add uid_is_legacy() and gid_is_legacy() Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 04/41] net: sock: read sk_uid through a seqcount Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 05/41] af_unix: keep sender ids in skb->cb only when they are classic ids Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 06/41] netlink: keep classic sender ids in skb->cb Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 07/41] Bluetooth: " Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 08/41] smb: client: use __kuid_val() for the unix SIDs of the caller Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 09/41] uidgid: let kuid_t and kgid_t hold a UUID or a GUID Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 10/41] uidgid: convert between kernel ids and the ids of the *_r system calls Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 11/41] fscrypt: show the whole uid in the description of user key claims Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 12/41] keys: name per-user keyrings of UUID and GUID users by the whole uid Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 13/41] ublk: refuse unprivileged devices to UUID and GUID users Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 14/41] nfsd: don't hand out uid 0 for read layouts of UUID-owned files Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 15/41] SUNRPC: name UUID and GUID users to gssd as uid_r= Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 16/41] ecryptfs: hash daemons by kuid_hash() Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 17/41] quota: don't account UUID and GUID owners Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 18/41] fs: keep UUID and GUID owners off filesystems that can't store them Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 19/41] cred: add the *_r variants of the get/set*id() system calls Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 20/41] groups: add getgroups_r() and setgroups_r() Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 21/41] fs: add chown_r(), lchown_r(), fchown_r() and fchownat_r() Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 22/41] arch: wire up the *_r uid and gid system calls Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 23/41] statx: report UUID and GUID owners Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 24/41] shmem, ramfs: allow " Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 25/41] uidgid: parse and print ids in their text form Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 26/41] proc: show UUID and GUID ids in status, accept them for loginuid Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 27/41] audit: log UUID and GUID ids in full Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 28/41] net: add SO_PEERCRED_R, SO_PEERGROUPS_R and SCM_CREDENTIALS_R Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 29/41] signal: report the sender's UUID or GUID uid in si_uid_r Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 30/41] ipc: add IPC_STAT_R and IPC_SET_R Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 31/41] ext4: add the uid_r feature for UUID and GUID owners Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 32/41] ext4: let uid_r be turned on while the filesystem is mounted Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 33/41] posix_acl: support UUID and GUID entries Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 34/41] ext4: store ACLs with UUID and GUID entries on uid_r filesystems Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 35/41] Documentation: describe UUID and GUID user and group ids Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 36/41] selftests: add tests for UUID and GUID ids Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 37/41] ovl: allow UUID and GUID owners when the upper layer does Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 38/41] devpts: allow UUID and GUID owners Jan Koester
2026-10-21 3:15 ` [RFC PATCH v2 39/41] ksmbd: log in UUID and GUID users and map them to SIDs Jan Koester
2026-10-21 3:16 ` [RFC PATCH v2 40/41] nfsd, nfs: carry UUID and GUID owners as their text form Jan Koester
2026-10-21 17:35 ` Chuck Lever
2026-10-22 2:52 ` Takeshi Nishimura
2026-10-21 3:16 ` [RFC PATCH v2 41/41] Documentation: uid_r: describe SMB and NFSv4 Jan Koester
2026-10-21 3:20 ` [RFC PATCH v2 00/41] UUID and GUID user and group ids (*_r system calls) jan Koester
2026-10-21 14:26 ` Adding dreaded Windows SID-style, or. Repeating history, the bad chapters. UUID/GUIDRe: " Lionel Cons
2026-10-22 17:00 ` Casey Schaufler [this message]
2026-10-22 18:26 ` Theodore Tso
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