Raise the maximum authentication token (Kerberos ticket) size in GSSAPI

and SSPI athentication methods. While the old 2000 byte limit was more than
enough for Unix Kerberos implementations, tickets issued by Windows Domain
Controllers can be much larger.

Ian Turner

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 0c9fc850db0716aca7a39b0ac2a00a80f24d0ec9..9ec424fc5d019e6f00dfea0ebef86afe76a713f0 100644 (file)
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/libpq/auth.c,v 1.164.2.2 2009/06/25 11:30:12 mha Exp $
+ *       $PostgreSQL: pgsql/src/backend/libpq/auth.c,v 1.164.2.3 2009/10/14 07:27:44 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -90,6 +90,20 @@ ULONG(*__ldap_start_tls_sA) (
 static int     CheckLDAPAuth(Port *port);
 #endif
 
+/*
+ * Maximum size of GSS and SSPI authentication tokens.
+ *
+ * Kerberos tickets are usually quite small, but the TGTs issued by Windows
+ * domain controllers include an authorization field known as the Privilege
+ * Attribute Certificate (PAC), which contains the user's Windows permissions
+ * (group memberships etc.). The PAC is copied into all tickets obtained on
+ * the basis of this TGT (even those issued by Unix realms which the Windows
+ * realm trusts), and can be several kB in size. The maximum token size
+ * accepted by Windows systems is determined by the MaxAuthToken Windows
+ * registry setting. Microsoft recommends that it is not set higher than
+ * 65535 bytes, so that seems like a reasonable limit for us as well.
+ */
+#define MAX_AUTH_TOKEN_LENGTH  65535
 
 #ifdef KRB5
 /*----------------------------------------------------------------
@@ -463,7 +477,7 @@ pg_GSS_recvauth(Port *port)
 
                /* Get the actual GSS token */
                initStringInfo(&buf);
-               if (pq_getmessage(&buf, 2000))
+               if (pq_getmessage(&buf, MAX_AUTH_TOKEN_LENGTH))
                {
                        /* EOF - pq_getmessage already logged error */
                        pfree(buf.data);
@@ -725,7 +739,7 @@ pg_SSPI_recvauth(Port *port)
 
                /* Get the actual SSPI token */
                initStringInfo(&buf);
-               if (pq_getmessage(&buf, 2000))
+               if (pq_getmessage(&buf, MAX_AUTH_TOKEN_LENGTH))
                {
                        /* EOF - pq_getmessage already logged error */
                        pfree(buf.data);