Re: tty locks up

[<sudheer@xxxxxxxxxxxxx>]

On Thu, 1 Jul 1999, Sharad Joshi wrote:

On Wed, 30 Jun 1999, Lokesh Setia wrote:
> + crw--w----   1 User_A       tty        4,   4 Aug 28 21:12 /dev/tty4
> + 
> + See that the group tty has write access to the tty, but not read access.
> + This write access has only been given because of the various commands like
> + "write" and "wall" (which are setgid to "tty"). 
> 
> Uh... this does not seems to be the case here. 've read permissions too
> for others. Anyway, i'll notify my server admin abt changing permissions.
> 
> + 
> + What may be happening in your case is that user B may be root, in which
> + case it has read permission for any file, or that user B is the same as
> + user A, in which case it can access the file.
> +
> 
> Heh.. no. Checked it with different non-root users. That's the reason of
> posting it here.


    No. I agree with Lokesh . When A & B are two different users and B
tries to read A , the permission for B is denied. BUT, this can happen
if and only if
 
The user A has logged in using 'su' command from a terminal which is 
owned by B. When you do an 'su' , either the "tty" or the ownership
won't change. That could be the reason why you were able to read
the terminal for different users.

If i am wrong, don't mind in taking a liberty to correct me.

sudheer
 


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