Re: Fix for ssh-1.2.27 symlink/bind problem

[casper () HOLLAND SUN COM (Casper Dik)]

>  It has always been my understanding of UNIX sockets that they need
> not appear in the filesystem at all; whether inodes and directory
> entries are allocated for them is an implementation detail.  The only
> guarantee is that if one process is listen()ing on a socket, and
> another process connect()s to a socket with the same path, they will
> be talking to each other.

Yes, that's in the 4.2 BSD manuals.

>  If this is not the desired behavior, at least a mechanism needs to
> be provided which can instruct the kernel not to follow symlinks (like
> the O_EXCL or O_NOFOLLOW flags passed to open(2) on BSD or Linux) when
> binding to a UNIX domain socket.

It would be interesting to make a comparison between the various flavours
of Unix and the various system calls that create non files to see whether
they follow symlinks or not.

On Solaris, only open(O_CREAT) (w/o O_EXCL) and creat() do so;
the following do not follow symbolic links as the last component of
the pathname:

        mknod (making pipes or devices)
        mkdir
        bind

        (others?)
        
        (doors are created as files followed by fattach, so the
        user has control)

Casper