krb5 commit [krb5-1.18]: Fix defcred leak in krb5 gss_inquire_cred()

[Greg Hudson]

https://github.com/krb5/krb5/commit/b92be484630b38e26f5ee4bd67973fbd7627009c
commit b92be484630b38e26f5ee4bd67973fbd7627009c
Author: Greg Hudson <ghudson at mit.edu>
Date:   Wed Jul 21 13:44:30 2021 -0400

    Fix defcred leak in krb5 gss_inquire_cred()
    
    Commit 1cd2821c19b2b95e39d5fc2f451a035585a40fa5 altered the memory
    management of krb5_gss_inquire_cred(), introducing defcred to act as
    an owner pointer when the function must acquire a default credential.
    The commit neglected to update the code to release the default cred
    along the successful path.  The old code does not trigger because
    cred_handle is now reassigned, so the default credential is leaked.
    
    Reported by Pavel Březina.
    
    (a minimal alternative to commit 593e16448e1af23eef74689afe06a7bcc86e79c7)
    
    ticket: 9016
    version_fixed: 1.18.4

 src/lib/gssapi/krb5/inq_cred.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/src/lib/gssapi/krb5/inq_cred.c b/src/lib/gssapi/krb5/inq_cred.c
index a8f2541..cd8384d 100644
--- a/src/lib/gssapi/krb5/inq_cred.c
+++ b/src/lib/gssapi/krb5/inq_cred.c
@@ -197,9 +197,7 @@ krb5_gss_inquire_cred(minor_status, cred_handle, name, lifetime_ret,
         mechs = GSS_C_NO_OID_SET;
     }
 
-    if (cred_handle == GSS_C_NO_CREDENTIAL)
-        krb5_gss_release_cred(minor_status, (gss_cred_id_t *)&cred);
-
+    krb5_gss_release_cred(minor_status, &defcred);
     krb5_free_context(context);
     *minor_status = 0;
     return((lifetime == 0)?GSS_S_CREDENTIALS_EXPIRED:GSS_S_COMPLETE);