NetAccessGetInfo() on Redirected Drives

ID: Q93443

The information in this article applies to:

Microsoft LAN Manager, versions 2.0, 2.1

SUMMARY

PROBLEM ID: PRLAN9212004

SYMPTOMS

The servername obtained from resolving a redirected drive overrides the one provided with the NetAccessGetInfo() API.

NetAccessGetInfo() is used to get permission information for a resource. It is used as follows:


      unsigned far pascal
      NetAccessGetInfo(
         char far * servername,  /* where to execute */ 
         char far * resource,    /* resource pathname */ 
         short level,            /* level of detail */ 
         char far * buf,         /* return data buffer */ 
         USHORT buflen,          /* size of buf */ 
         USHORT far * btotal     /* total bytes available */ 
         )

The API should do the following


      if(servername == NULL)
         if(IsRedirectedDrive(resource))
            return ERROR;

because redirected drives should be resolved only if you say "change ACLs on my E drive, which just happens to be redirected". If you actually pass NetAccessGetInfo() a servername, it should not resolve any drive letters because they are not local.

CAUSE

Suppose \\server1 provides a share


      net share share1 =  f:\usrs\usrshare

and a workstation connects to this share as follows:


      net use e: \\server1\share1

The following NetAccessGetInfo() call from the workstation will not be resolved as expected:


      NetAccessGetInfo("\\server2","e:",parm,...);

What occurs is:


      NetAccessGetInfo("\\server1","f:\usrs\usrshare",parm,...);

As a result, the API gets information from the wrong server. This is undesirable because it is common for servers to have D and E drives and it is also common for workstations that do not have D or E drives to use D and E on the server as redirected drives. The validity of ACLs cannot be guaranteed in this situation.

RESOLUTION

Do not use NetAccessGetInfo() on a drive that is redirected to a server other than the one mentioned as the first parameter to the call.

STATUS

Microsoft has confirmed this to be a problem in LAN Manager versions 2.0 and 2.1. We are researching this problem and will post new information here as it becomes available.

Additional query words:

Keywords :
Version : :2.0,2.1
Platform :
Issue type :