Arch Linux

FrugArch

Member

From: Chile

Registered: 2007-10-26

Posts: 6

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Access to partition from two distributions with rw permission for user

Hi:
I have two distributions on my laptop: ArchLinux (/dev/sda5) and Debian (/dev/sda7), both with a user called dreamer. Also, I have created a partition / dev/sda3 in "/ mnt / compartida" for the user to "dreamer" can write and save some documents. The question is how can this be done, considering that the user "dreamer" was created in two different distributions.

Will be sufficient to run in each distribution: "chown dreamer /mnt/compartida"?.

Someone has done this before? Any idea?:rolleyes:

My fstab:

# 
# /etc/fstab: static file system information
#
# <file system>        <dir>         <type>    <options>          <dump> <pass>
none                   /dev/pts      devpts    defaults            0      0
none                   /dev/shm      tmpfs     defaults            0      0
/dev/cdrom /media/cdrom   auto    ro,user,noauto,unhide            0      0
/dev/dvd   /media/dvd     auto    ro,user,noauto,unhide            0      0
UUID=394106b5-7acd-4cd4-b1d6-1fc42f68a0ee    / ext3 defaults       0      1
UUID=b39dd0cd-932c-4206-8dbe-028857bd49a6 swap swap defaults       0      0
/dev/sda1 /mnt/win ntfs  auto,ro,umask=0,utf8                      0      0
/dev/sda3 /mnt/frugal reiserfs auto,noexec,                          0      0  
/dev/sda7 /mnt/kanotix ext3 noauto,user                            0      0
/dev/sda6 /mnt/compartida reiserfs noauto,user                     0      0

ChoK

Member

From: France

Registered: 2008-10-01

Posts: 346

Re: Access to partition from two distributions with rw permission for user

mount with the option suid

http://www.unix.com.ua/orelly/networkin … h05_05.htm[url]]
5.5 SUID

Sometimes, unprivileged users must be able to accomplish tasks that require privileges. An example is the passwd program, which allows you to change your password. Changing a user's password requires modifying the password field in the /etc/passwd file. However, you should not give a user access to change this file directly - the user could change everybody else's password as well! Likewise, the mail program requires that you be able to insert a message into the mailbox of another user, yet you should not to give one user unrestricted access to another's mailbox.

To get around these problems, UNIX allows programs to be endowed with privilege. Processes executing these programs can assume another UID or GID when they're running. A program that changes its UID is called a SUID program (set-UID); a program that changes its GID is called a SGID program (set-GID). A program can be both SUID and SGID at the same time.

When a SUID program is run, its effective UID[22] becomes that of the owner of the file, rather than of the user who is running it. This concept is so clever that AT&T patented it.[23]

mmmm rereading it I don't think it works that way but well

chmodding works that's for sure but you can't have 2 owner of a file, it's saved by the filesystem, instead you can define a group owning the file and put them in it

Last edited by ChoK (2008-10-25 22:46:12)

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foutrelis

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From: Athens, Greece

Registered: 2008-07-28

Posts: 705

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Re: Access to partition from two distributions with rw permission for user

mount with the option suid

That applies to files on the partition allowing their suid/sgid bits to be effective and I don't think it's what the OP wants.

@FrugArch: If your user is assigned the same uid/gid on both distros, I believe you should be able to access your files right away in either Arch or Debian.

Last edited by foutrelis (2008-10-25 22:43:01)