krb5 commit: Check mech cred in gss_inquire_cred_by_mech()

https://github.com/krb5/krb5/commit/8ea7e36661cfa6d8acb2b1af615870092a408cce
commit 8ea7e36661cfa6d8acb2b1af615870092a408cce
Author: Greg Hudson <[email protected]>
Date:   Thu Sep 13 17:03:36 2018 -0400

    Check mech cred in gss_inquire_cred_by_mech()
    
    If gss_inquire_cred_by_mech() is called with a mechanism and there is
    no corresponding mechanism credential in the union cred, return
    GSS_S_NO_CRED (as Heimdal does) instead of interrogating the mechanism
    about the default credential.
    
    ticket: 8736 (new)
    tags: pullup
    target_version: 1.16-next
    target_version: 1.15-next

 src/lib/gssapi/mechglue/g_inq_cred.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/src/lib/gssapi/mechglue/g_inq_cred.c b/src/lib/gssapi/mechglue/g_inq_cred.c
index cbe045a..4ed7774 100644
--- a/src/lib/gssapi/mechglue/g_inq_cred.c
+++ b/src/lib/gssapi/mechglue/g_inq_cred.c
@@ -197,6 +197,8 @@ gss_inquire_cred_by_mech(minor_status, cred_handle, mech_type, name,
 
     union_cred = (gss_union_cred_t) cred_handle;
     mech_cred = gssint_get_mechanism_cred(union_cred, selected_mech);
+    if (cred_handle != GSS_C_NO_CREDENTIAL && mech_cred == GSS_C_NO_CREDENTIAL)
+	return (GSS_S_NO_CRED);
 
     public_mech = gssint_get_public_oid(selected_mech);
     status = mech->gss_inquire_cred_by_mech(minor_status,