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From: blymn@awadi.com.au (Brett Lymn)
Newsgroups: comp.os.386bsd.bugs
Subject: Re: Filesystem bug (permission handling)
Date: 07 Mar 1995 03:08:42 GMT
Organization: AWA Defence Industries
Lines: 31
Message-ID: <BLYMN.95Mar7133842@mallee.awadi.com.au>
References: <3iidig$lrk@tyrell.s.bawue.de>
NNTP-Posting-Host: mallee.awadi.com.au
In-reply-to: rodney@tyrell.s.bawue.de's message of 23 Feb 1995 17:36:32 +0100
>>>>> "Rodney" == Rodney Volz <rodney@tyrell.s.bawue.de> writes:
In article <3iidig$lrk@tyrell.s.bawue.de> rodney@tyrell.s.bawue.de (Rodney Volz) writes:
Rodney> Hello, I don't know if this has been discussed long ago;
Rodney> if that should be the case, just ignore my posting.
Rodney> I came across the following bug (I am just giving the
Rodney> symptoms here, since unfortunately I do not have the time
Rodney> to track it down. Alas, it should be easy to find):
Rodney> - Set the permissions of a mount point to 0700, owner root
Rodney> (before mounting the fs, of course)
Rodney> - Mount your filesystem.
This is not a bug it is correct behaviour. If you think _carefully_
about what is going on it makes sense. It works something like this:
The information about the parent directory is found by following the
.. entry in the directory. In the case of a mounted filesystem ..
needs to point at the mount point so you can get information about the
parent's parent and so forth - if a normal user cannot read the mount
point then they cannot find out this information, hence the error
message. Doing anything else would break the "one tree" concept of
the filesystem, in some places you would do an ls .. and get . (like
you do in /) just because the directory happens to be a mount point
which would be most disconcerting.
--
Brett Lymn