Messages in this thread | | | From | (Matthias Urlichs) | Subject | Re: Security Anti Symlink Attack Patch for 2.1.71 | Date | 9 Jan 1998 18:03:02 +0100 |
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Christoph Lameter <chris@waterf.org> writes: > > without any complaints by the kernel. Then if root tries to write to a > file in /tmp that has been redirected with a user symlink, a permission > denied results and the script to be run by root fails. Not good. > But that is easy to fix; instead of returning EPERM, delete the symlink (if the file is opened with O_CREAT) and proceed normally.
> 1. They cannot be absolute (i.e. they cannot begin with /) > 2. They are not allowed to point to a higher directory IMHO that is too complicated. The rule "only follow your own symlinks in "sticky" directories" is easy, and I cannot think of any program which would require different behavior.
> And maybe the functionality should be switchable on and off by writing to > a file in /proc/sys/kernel/xxxx ? > Yep. But IMHO it is overkill to specify that on a per-directory basis. Per filesystem, maybe, as a mount option (NFS does not support any special EXT2 options we might want to invent).
-- Matthias Urlichs noris network GmbH
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