afs string to key requires crypt #1247
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commit a9bd3c6 ("Fix racy file ccache corruption in cred_delete()") implemented krb5_cc_remove_cred() for "FILE" ccaches by overwriting the removed credential endtime value with zero (Unix Epoch). However, it did not modify fcc_get_next() to filter out these deleted entries. As a result, invalid credentials can be returned from the FILE ccache where endtime < starttime. RFC4120 requires endtime >= starttime for all tickets. MIT Kerberos since d3b39a8bac6206b5ea78b0bf6a2958c1df0b0dd5 ("Implement krb5_cc_remove_cred for remaining types") modifies a removed cred by setting endtime = 0 authtime = -1 and then filters out removed creds from the fcc_next_cred() results. In 2013 Heimdal broke interop with MIT processes that share the FILE ccache by implementing remove by setting "endtime = 0" and now MIT has broken interop with the Heimdal implementation of fcc_remove_cred() by checking for both "endtime = 0" and "authtime = -1". This change filters results from fcc_get_next() when the "endtime == 0" which is acceptable because a KDC is not permitted to return a ticket with an endtime == 0.
MIT commit d3b39a8bac6206b5ea78b0bf6a2958c1df0b0dd5 implemented krb5_cc_remove_cred() for FILE ccaches by setting endtime to zero and authtime to minus one and then filtering out those credentials from get_next(). This change sets "authtime = -1" for the removed cred to permit MIT krb5 to ignore removed credentials from a shared FILE ccache.
If crypt() is unavailable then DES_AFS3_string_to_key() cannot be implemented for passwords up to 8 characters in length. Do not advertise support for "afs3-salt" when crypt() is missing.
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If crypt() is unavailable, do not register support for afs-string-to-key