Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 24 Jul 1997 18:53:10 +0200 | From | Pavel Machek <> | Subject | Re: fmount system call |
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> Date: Wed, 23 Jul 1997 18:18:18 +0200 > From: "Volker.Lendecke" <lendecke@math.uni-goettingen.de> > > during the smbfs-rewrite I remembered the security problem in smbmount > and ncpmount. Both programs are designed to let the user mount remote > file systems of his own. This is necessary because the remote file > systems are per-user password protected. To do this, they check > whether the user has write permissions on the mount point and then > mount the file. Playing with links between the check and the real > mount creates quite well-known races. > > As far as I can see this problem can be removed by a system call that > accepts a file descriptor as a mount point. > > An alternate solution would be to allow users to run the mount system > call as unprivileged users, but have the kernel enforce some basic > security policy (users must own the mount point, nosuid, nodev, > etc. would be turned on, etc.) I think BSD does this, and it's not > necessarily a bad idea....
I do not agree. You can easily crash kernel by mounting damaged image. Secure sites will not want this - so it should not be done in kernel.
-- -- This is my little buggy signature... Pavel GCM d? s-: !g p?:+ au- a--@ w+ v- C++@ UL+++ L++ N++ E++ W--- M- Y- R+
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