krb5 commit: Fix kdcpreauth counting bug

[Greg Hudson]

https://github.com/krb5/krb5/commit/2c3c44ce0555110a919aff0902d143b7f00e26ef
commit 2c3c44ce0555110a919aff0902d143b7f00e26ef
Author: Greg Hudson <ghudson at mit.edu>
Date:   Thu Jul 9 01:00:40 2015 -0400

    Fix kdcpreauth counting bug
    
    In kdc_preauth.c, commit be20a5f5cee8d6c4072d1b81712520dbf9f6eefd made
    load_preauth_plugins() handle negative preauth type numbers.
    get_plugin_vtables() also needs to handle negative preauth type
    numbers, or it can return the wrong count and load_preauth_plugins()
    can overflow the table.
    
    ticket: 8200

 src/kdc/kdc_preauth.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/kdc/kdc_preauth.c b/src/kdc/kdc_preauth.c
index 34775f3..e121c5d 100644
--- a/src/kdc/kdc_preauth.c
+++ b/src/kdc/kdc_preauth.c
@@ -235,7 +235,7 @@ get_plugin_vtables(krb5_context context,
             n_tables++;
     }
     for (i = 0, n_systems = 0; i < n_tables; i++) {
-        for (count = 0; vtables[i].pa_type_list[count] > 0; count++);
+        for (count = 0; vtables[i].pa_type_list[count] != 0; count++);
         n_systems += count;
     }
     *vtables_out = vtables;