s4-auth: avoid double free of krb5 kt_entries when compiling with MIT kerberos library.

Guenther

Pair-Programmed-With: Andreas Schneider <asn@samba.org>

Signed-off-by: Guenther Deschner <gd@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>

diff --git a/source4/auth/kerberos/srv_keytab.c b/source4/auth/kerberos/srv_keytab.c
index 3baba1427e8ccc186a87546c41af7c4f9fa15597..1ffd1e3f33de070a7fc37e1cee278a6430f83e9e 100644 (file)
--- a/source4/auth/kerberos/srv_keytab.c
+++ b/source4/auth/kerberos/srv_keytab.c
@@ -380,6 +380,7 @@ static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
                unsigned int i;
                bool matched = false;
                krb5_keytab_entry entry;
+
                ret = krb5_kt_next_entry(context, keytab, &entry, &cursor);
                if (ret) {
                        break;
@@ -397,6 +398,8 @@ static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
                        /* Free the entry,
                         * it wasn't the one we were looking for anyway */
                        krb5_kt_free_entry(context, &entry);
+                       /* Make sure we do not double free */
+                       ZERO_STRUCT(entry);
                        continue;
                }
 
@@ -414,11 +417,15 @@ static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
 
                        ret = krb5_kt_remove_entry(context, keytab, &entry);
                        krb5_kt_free_entry(context, &entry);
+                       /* Make sure we do not double free */
+                       ZERO_STRUCT(entry);
 
                        /* Deleted: Restart from the top */
                        ret2 = krb5_kt_start_seq_get(context, keytab, &cursor);
                        if (ret2) {
                                krb5_kt_free_entry(context, &entry);
+                               /* Make sure we do not double free */
+                               ZERO_STRUCT(entry);
                                DEBUG(1, ("failed to restart enumeration of keytab: %s\n",
                                          smb_get_krb5_error_message(context,
                                                                ret, mem_ctx)));
@@ -437,6 +444,8 @@ static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
 
                /* Free the entry, we don't need it any more */
                krb5_kt_free_entry(context, &entry);
+               /* Make sure we do not double free */
+               ZERO_STRUCT(entry);
        }
        krb5_kt_end_seq_get(context, keytab, &cursor);