samba - Dec 2001 - smbmount appears to subvert access permissions

Hi all,

(1) I wish to mount a SMB share onto my Linux filesystem.  When I mount the
share, it modifies the permissions on the "mounting directory"
allowing other users to gain access to the share, masquerading as the mounting
user.  Lucky it doesn't give write access to anyone, but read access is bad
enough.

Can anyone explain this behaviour?  (Example transcript provided below)

(2) I had originally wished to mount a share (shall we say 'home') and
then allow individual users to access subdirectories under this share (eg
'home/user1', 'home/user2').  I had wanted individual users to
operate under their own username, much like an NFS export.  I am aware that
there may be a problem with the user's identity (since the user is going to
need UID-remapping).  Is there anyway to achieve this goal?  I would have liked
the users to keep their unix 'home directory' with their Windows home
directory.

My thanks in advance,
Paul.


INFORMATION:
smbmount version: 2.0.7
smbd version: 2.0.7
debian potato (v2.2r2)

TRANSCRIPT FOR (1) ABOVE:
paul@vanity:~$ ls -ld /tmp/paul
drwxrwxrwx    2 paul     paul         4096 Dec 17 21:44 /tmp/paul
paul@vanity:~$ chmod go-rwx /tmp/paul
paul@vanity:~$ ls -ld /tmp/paul
drwx------    2 paul     paul         4096 Dec 17 21:44 /tmp/paul
paul@vanity:~$ mount /tmp/paul
paul@vanity:~$ ls -ld /tmp/paul
drwxr-xr-x    1 paul     paul          512 Dec 18 14:20 /tmp/paul
paul@vanity:~$ chmod go-rwx /tmp/paul
paul@vanity:~$ ls -ld /tmp/paul
drwxr-xr-x    1 paul     paul          512 Dec 18 14:20 /tmp/paul
paul@vanity:~$ umount /tmp/paul
paul@vanity:~$ ls -ld /tmp/paul
drwx------    2 paul     paul         4096 Dec 17 21:44 /tmp/paul



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On 17 Dec 2001, Paul wrote:
> (1) I wish to mount a SMB share onto my Linux filesystem.  When I
> mount the share, it modifies the permissions on the "mounting
> directory" allowing other users to gain access to the share,
> masquerading as the mounting user.  Lucky it doesn't give write access
> to anyone, but read access is bad enough.
smbfs has one permission set for files and one for dirs. They are shared
by all files and dirs, including the root of the fs. You can change that
as well as who should own all files/dirs by setting appropriate flags
(uid/gid/fmask/dmask).

The reason for this simplification is that smbfs doesn't understand NT
permissions and even if it did it wouldn't know how to map that to a local
user.

Changing permissions on the root is probably just a bug.

> (2) I had originally wished to mount a share (shall we say 'home')
and
> then allow individual users to access subdirectories under this share
> (eg 'home/user1', 'home/user2').  I had wanted individual
users to
> operate under their own username, much like an NFS export.  I am aware
> that there may be a problem with the user's identity (since the user
> is going to need UID-remapping).  Is there anyway to achieve this
> goal?  I would have liked the users to keep their unix 'home
> directory' with their Windows home directory.
Mount each users home dir individually. To keep the number of active
mounts down you may want to look at autofs or pam_mount.

/Urban