Date: Fri, 17 Jan 2003 09:08:09 +0900
From: Jun Kuriyama <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Cc: Current <[EMAIL PROTECTED]>
Subject: dump -L and privilege
X-ASK-Info: Confirmed by User
I'm trying to use dump -L option to dump with snapshot on
-current/RELENG_5_0 family.
I found dump -L needs writable permission to the device (that's
reasonable because it *writes* snapshot file). But when I try to dump
by operator group, it's impossible to dump with -L option (target
device has root:operator and crw-r-----).
This behavior is understandable. But in actual backup operations,
what should we do? I'd like to hear what you thought in design.
(1) Do dump as root with -L option.
(2) Do chmod g+w for device.
(3) Other ideas?
--
Jun Kuriyama <[EMAIL PROTECTED]> // IMG SRC, Inc.
<[EMAIL PROTECTED]> // FreeBSD Project
Sorry for the slow reply. I am just back from several weeks of
travel and am trying to get caught up on my email.
You have raised an important point here. By default (that is when
vfs.usermount == 0) only root is allowed to do mounts. Since dump -L
needs to do a snapshot, that can only be done by a root process.
I see two possible solutions to the problem. The first would be
to change the default for vfs.usermount == 1 and then have dump -L
create the snapshot in a directory owned by "operator" (or by
whatever user runs the dumps). Then the snapshot could be created,
used, and deleted by that user. The other alternative would be to
create a setuid-to-root program that would take a snapshot and
chown it to the user that does dumps. This setuid program could
then be invoked by dump -L to create a snapshot for it. I favor
the first approach, but there may be good security issues of which
I am unaware that make that a bad choice. Perhaps we could get
someone like Robert Watson to comment on these choices.
Kirk McKusick
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