Comments on the checksum vulnerabilities

[Greg Hudson]

On Fri, 2010-12-03 at 13:37 -0500, Sam Hartman wrote:h
> We might be able to get away with changing behavior for the
> krb5_k_interface and adding a way to set on a krb5 key object whether
> unkeyed checksums are permitted.  That's probably more ugly than a new
> API.

Or in the krb5_context, but yeah, ugly either way.

> We could potentially have a flag to or-in with keyusages.  Or have a set
> of key usages for which unkeyed checksums are permitted.

I like this idea.  libk5crypto already knows a little bit about key
usages (RC4 key usage translations, as well as the workaround for the AD
TGS subkey RC4 key usage bug).