[15901] in Kerberos-V5-bugs
Re: [krbdev.mit.edu #8651] kinit -kt KDB: Cannot find/read stored
daemon@ATHENA.MIT.EDU (Richard Basch via RT)
Sun Mar 18 12:52:58 2018
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From: "Richard Basch via RT" <rt-comment@KRBDEV-PROD-APP-1.mit.edu>
In-Reply-To: <rt-8651@krbdev.mit.edu>
Message-ID: <rt-8651-48302.9.8521026785928@krbdev.mit.edu>
To: "'AdminCc of krbdev.mit.edu Ticket #8651'":;
Date: Sun, 18 Mar 2018 12:52:18 -0400 (EDT)
Reply-To: rt-comment@KRBDEV-PROD-APP-1.mit.edu
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I ran a tight loop and simulated the issue.
In my test, the following conditions existed:
- The stash file is a non-standard location (and defined in the KRB5_KDC_PROFILE config (key_stash_file).
- Standard location stash file did not exist (not even as a symlink)
All my test essentially did was:
while true ; do
rm -f /tmp/ktrace.out /tmp/strace.out
KRB5_KDC_PROFILE=… KRB5_CONFIG=… KRB5_TRACE=/tmp/ktrace.out strace -f -o /tmp/strace.out kinit -kt KDB: kadmin/admin || break
done
The final run (after thousands of success) showed it looking for the STANDARD location stash file.
> On Mar 17, 2018, at 9:51 PM, Greg Hudson via RT <rt-comment@KRBDEV-PROD-APP-1.mit.edu> wrote:
>
> [I moderated through the first copy to krb5-bugs, but not the second
> copy, and I didn't moderate through to krbdev. I prefer if messages
> go to just one project list, so that the follow-up conversation
> doesn't get fragmented.]
>
> The cause of this bug is obscured by an error handling flaw in kinit
> -t KDB:. When kinit calls kinit_kbd_init(), it destroys and
> recreates the krb5_context, but doesn't reset the global variable
> errctx which is used by extended_com_err_fn(). That can be fixed
> with the following patch:
>
> diff --git a/src/clients/kinit/kinit.c b/src/clients/kinit/kinit.c
> index a518284..3fdae28 100644
> --- a/src/clients/kinit/kinit.c
> +++ b/src/clients/kinit/kinit.c
> @@ -718,6 +718,7 @@ k5_kinit(struct k_opts *opts, struct k5_data *k5)
> #ifndef _WIN32
> if (strncmp(opts->keytab_name, "KDB:", 4) == 0) {
> ret = kinit_kdb_init(&k5->ctx, k5->me->realm.data);
> + errctx = k5->ctx;
> if (ret) {
> com_err(progname, ret,
> _("while setting up KDB keytab for realm
> %s"),
>
> Without that fix, we just have the error string for
> KRB5_KDB_CANTREAD_STORED, not the extended error message set in
> krb5_db_def_fetch_mkey(). So all we know for now is that
> krb5_db_def_fetch_mkey_keytab() didn't succeed. It's hard to
> theorize beyond that. kt_file.c does contain locking calls, but they
> are straightforward blocking POSIX file locks which shouldn't fail.
> _______________________________________________
> krb5-bugs mailing list
> krb5-bugs@mit.edu
> https://mailman.mit.edu/mailman/listinfo/krb5-bugs
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