Discussion of krb5_get_init_creds_password() behavior was Re:problem with the kinit_prompter in kfw 2.5

Jeffrey Altman jaltman at columbia.edu
Thu Feb 19 12:13:12 EST 2004

The kerberos at mit.edu mailing list is an inappropriate place for this 
Please hold this discussion on krbdev at mit.edu OR open a bug report in the
Request Tracker by sending e-mail to krb5-bugs at mit.edu.

Thank you.

John Hascall wrote:

>>Beata A. Pruski wrote:
>>>I must say I don't understand why within krb5_get_init_creds_password,
>>>after the first call to krb5_get_init_creds (with use_master being 0)
>>>returns KRB5KDC_ERR_KEY_EXP, there is still another call made to the
>>>same function with use_master set to 1. Shouldn't there be some sort
>>>of "goto" statement:
>>>	if (ret == KRB5KDC_ERR_KEY_EXP) ...
>>Consider the situation in which the user has just changed their password
>>but there are multiple secondary KDCs and the password change has not 
>>yet been propagated from the primary KDC.  The secondary KDCs will think 
>>the password is still expired when in fact it has been changed. 
>>Therefore, if the password fails we must attempt to contact the Primary 
>>KDC in order to ensure that current password is indeed contacted.
>I still think the logic in krb5_get_init_creds_password()
>where it double calls krb5_get_init_creds() is seriously wrong.
>One problem I previously mentioned was (after the core-dump issue
>I raised is resolved) it will double prompt for password, if the user
>enters an empty password.
>% ./some-program-that-calls-krb5_get_init_creds_password
>Password ...:                 <Oh, I didn't mean to do that, I'll just return>
>Password ...:                 <huh?>
>Another problem is that almost for sure you get 2 strikes against
>the "5 strikes and you are out" code for every wrong attempt
>(since the attempt with use_master = 0 contacted the master).
>Ugly as it is, I think the only way to make this really work
>properly is for krb5_get_init_creds() to return an indication
>as to whether or not the reply it is returning came from the
>master kdc and if so, skip the 2nd call (with use_master = 1).

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