auth-kerberos: avoid crash with MIT krb5 1.10.0 in gss_get_name_attribute()

gss_get_name_attribute() can return unintialized pac_display_buffer
and later gss_release_buffer() will crash on attempting to release it.

The fix on MIT krb5 side is in 1.10.1, reported in both Debian and MIT upstream:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=658514
http://krbdev.mit.edu/rt/Ticket/Display.html?user=guest&pass=guest&id=7087

We need to initialize variables before using gss_get_name_attribute()

Autobuild-User: Alexander Bokovoy <ab@samba.org>
Autobuild-Date: Wed Jun  6 18:22:51 CEST 2012 on sn-devel-104

diff --git a/auth/kerberos/gssapi_pac.c b/auth/kerberos/gssapi_pac.c
index dadae1afa2680452cac16a3e6293be609f4adfde..a17405211d06f7d56d9c8565334bf3ef2557ac8e 100644 (file)
--- a/auth/kerberos/gssapi_pac.c
+++ b/auth/kerberos/gssapi_pac.c
@@ -80,8 +80,24 @@ NTSTATUS gssapi_obtain_pac_blob(TALLOC_CTX *mem_ctx,
        NTSTATUS status;
        OM_uint32 gss_maj, gss_min;
 #ifdef HAVE_GSS_GET_NAME_ATTRIBUTE
-       gss_buffer_desc pac_buffer;
-       gss_buffer_desc pac_display_buffer;
+/*
+ * gss_get_name_attribute() in MIT krb5 1.10.0 can return unintialized pac_display_buffer
+ * and later gss_release_buffer() will crash on attempting to release it.
+ *
+ * So always initialize the buffer descriptors.
+ *
+ * See following links for more details:
+ * http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=658514
+ * http://krbdev.mit.edu/rt/Ticket/Display.html?user=guest&pass=guest&id=7087
+ */
+       gss_buffer_desc pac_buffer = {
+               .value = NULL,
+               .length = 0
+       };
+       gss_buffer_desc pac_display_buffer = {
+               .value = NULL,
+               .length = 0
+       };
        gss_buffer_desc pac_name = {
                .value = discard_const("urn:mspac:"),
                .length = sizeof("urn:mspac:")-1