lkml.org 
[lkml]   [2005]   [Apr]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] FUSE permission modell (Was: fuse review bits)
On 4/11/05, Miklos Szeredi <miklos@szeredi.hu> wrote:
>
> 1) Only allow mount over a directory for which the user has write
> access (and is not sticky)
>
> 2) Use nosuid,nodev mount options
>
> [ parts deleted ]

Do these solve all the security concerns with unprivileged mounts, or
are there other barriers/concerns? Should there be ulimit (or rlimit)
style restrictions on how many mounts/binds a user is allowed to have
to prevent users from abusing mount privs?

I was thinking about this a while back and thought having a user-mount
permissions file might be the right way to address lots of these
issues. Essentially it would contain information about what
users/groups were allowed to mount what sources to what destinations
and with what mandatory options.

You can get the start of this with the user/users/etc. stuff in
/etc/fstab, but I was envisioning something a bit more dynamic with
regular expression based rules for sources and destinations. So,
something like:

# /etc/usermounts: user mount permissions

# <fs> <mount point> <type> <opts>

# allow users to mount any file system under their home directory
* $HOME *
nosuid, nosgid
# allow users to bind over /usr/bin as long as its only in their
private namespace
* /usr/bin
bind newns
# allow users to loopback mount distributed file systems to /mnt
127.0.0.1 /mnt *
nosuid, nosgid
# allow users to mount files over any directory they have right access to
* (perm=0222) *
nosuid, nosgid

Is this unnecessary? Is this not enough?

-eric
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-04-17 20:05    [W:2.300 / U:0.392 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site