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INN temporary directory configuration
From: Russ Allbery <rra () ISC ORG>
Date: Tue, 16 Jan 2001 12:57:20 -0800

It's recently come to our attention that some repackagers of INN have
mistakenly shipped INN packages configured to use the system temporary
directory (either /tmp or /var/tmp) for create temporary files.  INN
expects its configured temporary directory to only be writeable by the
news user and does not take sufficient precautions when creating temporary
files to be able to use world-writeable temporary directories.  This
configuration could be exploited to gain access to the news account.

This was partly a configuration error and partly a documentation problem.
This issue should have been much more clearly pointed out in the
installation documentation (fixed in the current version of INN).

If you are using a pre-compiled version of INN, please check the
configuration in inn.conf and make sure that pathtmp points to a directory
that is not world-writeable.  If it does point to a world-writeable
directory, create a new directory owned by the news user and only
writeable by that user, change pathtmp in inn.conf to point to that
directory, and restart INN (with rc.news stop; rc.news start).

If you package INN as part of a distribution, please make sure that INN is
configured to use a private temporary directory.  If you configure INN
with --prefix=/usr, you will need to use --with-tmp-path to ensure that
the temporary directory is not set to /usr/tmp.

As of INN 2.3.1, which was released on 2001-01-11, INN will warn loudly at
configure time if the configured temporary directory is world-writeable.
There is also additional documentation of this issue in INSTALL.

There is work underway both to make FHS-compliance a standard configure
option so that these sorts of problems can be caught and solved in one
place and to make INN more robust against use of a world-writeable
temporary directory.  We will always strongly recommend, however, that INN
be configured to use a private temporary directory, since getting all of
the details of safe temporary file handling right in a portable manner is
difficult and there's no reason not to use a private directory.

Thanks to Greg KH and Steve Beattie at WireX for bringing this to our

                                        Russ Allbery
                                        Katsuhiro Kondou
                                        inn () isc org

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