Log Message:
Update to 2.5.4. From the announcement message:

This release fixes one signature correctness bug in the library and a few
bugs which could result in crashes in the filter itself.  An upgrade is
recommended if you're using the filter.

The formal release notes entry:

2.5.4           2008/04/17
        Skip signatures with errors in dkimf_authorsigok().
        Avoid a NULL dereference in dkimf_config_reload() when starting
                without a configuration file.
        Fix an alignment problem in dkimf_checkip().  Problem reported
                by Jeff A. Earickson.
        LIBDKIM: Fix bug #SF1942387: Per RFC4871, disallow "l=" values
                that exceed the size of the canonicalized message body.