BUG: Pass Invalid LOGINREC * to dbopen() May GP Fault Server

• Microsoft SQL Server Programmer's Toolkit, version 4.2

       NT:  193 (4.2)

SYMPTOMS

When calling the dbopen() function from a DB-Library client application, SQL Server generates a general protection fault (GP fault).

CAUSE

Passing an invalid pointer as the first parameter to dbopen() may cause the SQL Server to general protection fault (GP fault). If the LOGINREC * points to a random location in memory, or if the LOGINREC * has been freed prior to the call to dbopen() by dbfreelogin(), garbage will be sent to the SQL Server when the client attempts to connect. Although SQL Server may simply reject the login attempt, certain combinations of bad data can cause the server to GP fault.

WORKAROUND

Ensure that all DB-Library code passes a valid LOGINREC * as the first parameter to dbopen().

STATUS

Microsoft has confirmed this to be a problem in version 4.2 of SQL Server. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.