By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
464,456 Members | 982 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 464,456 IT Pros & Developers. It's quick & easy.

Mixed mode app fails to run from UNC path on Windows 2000 Server only

P: n/a
emu
Hi All,

I have an unmanaged C++ application that references a mixed mode image
DLL (mixed managed and unmanaged). Under .NET 1.1 we could trust the
dll (the mixed mode dll) by running the following command line:

caspol.exe -polchgprompt off -machine -addgroup 1 -url "file://<UNC
path to dll>\mixedMode.dll" FullTrust ame "GroupName" -polchgprompt on
Then running the application from a UNC path would succeed.

We recompiled the DLL under VS2005 and .NET 2.0 and now just trusting
the DLL as above (running the .NET 2.0 version of CASPOL) is not
sufficient. When we run the application we receive a security error.
Only turning security off "caspol -s off" or trusting the entire path
using the command line below allows the application to run.

caspol.exe -m -ag 1 -url file://<UNC path to dll>/* FullTrust
However, when running the .NET 2.0 version of the application on a
Windows XP Pro machine, the first caspol command line is sufficient
(i.e. trusting the actual DLL).

So the situation is:
- Windows 2000 Server box runs .NET 1.1 version of app when DLL is
trusted
- Windows 2000 Server box does NOT run .NET 2.0 version of app when DLL
is trusted
- Windows 2000 Server box runs .NET 2.0 version of app when entire UNC
path is trusted
- Windows 2000 Server box runs .NET 2.0 version of app when CAS is
disabled (caspol -s off)
- Windows XP Pro box runs .NET 1.1 version of app when DLL is trusted
- Windows XP Pro box runs .NET 2.0 version of app when DLL is trusted

The error dialog looks something like:

Unhandled Exception! ExpCode: E0434F4D ExpFlags: 1 ExpAddress: 7C59BC3F
I believe, although I'm not certain, that E0434F4D simply indicates a
try block failed and an exception occurred.

I've included two stack traces, the first is when the DLL is granted
fulltrust using CASPOL and the second is when the DLL is not trusted
and neither is the path (and thus should fail to load). I didn't
included the entire stack but if it's helpful, I can provide it (it's
all stuff on the unmanaged and non-microsoft side).

DLL FullTrust
-------------------------
<EXCEPTION code="E0434F4D" addr="7C59BC3F" date="08/09/06"
time="00:18:25" code_desc="<unkown exception>" more_desc="">
<STACKENTRY decl="RaiseException" decl_offset="+86" srcfile=""
module="KERNEL32" base="7c570000" />
<STACKENTRY decl="DllCanUnloadNowInternal" decl_offset="+14249"
srcfile="" module="mscorwks" base="79e70000" />
<STACKENTRY decl="GetAddrOfContractShutoffFlag" decl_offset="+42967"
srcfile="" module="mscorwks" base="79e70000" />
<STACKENTRY decl="GetAddrOfContractShutoffFlag" decl_offset="+43136"
srcfile="" module="mscorwks" base="79e70000" />
<STACKENTRY decl="GetAddrOfContractShutoffFlag" decl_offset="+43147"
srcfile="" module="mscorwks" base="79e70000" />
</EXCEPTION>
DLL No Trust
------------------------
<EXCEPTION code="E0434F4D" addr="7C59BC3F" date="08/08/06"
time="23:53:12" code_desc="<unkown exception>" more_desc="">
<STACKENTRY decl="RaiseException" decl_offset="+86" srcfile=""
module="KERNEL32" base="7c570000" />
<STACKENTRY decl="DllCanUnloadNowInternal" decl_offset="+14249"
srcfile="" module="mscorwks" base="79e70000" />
<STACKENTRY decl="DllCanUnloadNowInternal" decl_offset="+14868"
srcfile="" module="mscorwks" base="79e70000" />
<STACKENTRY decl="CorDllMainForThunk" decl_offset="+195" srcfile=""
module="mscorwks" base="79e70000" />
<STACKENTRY decl="CorDllMainWorker" decl_offset="+188" srcfile=""
module="mscoree" base="79000000" />
<STACKENTRY decl="GetTargetForVTableEntry" decl_offset="+34" srcfile=""
module="mscoree" base="79000000" />
...... Some of the stack omitted for brevity.
Very different stack traces, so obviously code is following a different
path when the DLL is granted fulltrust. Perhaps something else has to
be done on a Windows 2000 Server machine to enable CAS to allow the DLL
to be loaded???

The fusion log shows pretty much the same thing whether I trust just
the DLL and the app fails to run or I turn off security and the app
runs correctly. The fusion log says it binds to the the mixed mode DLL
successfully etc. even when security settings cause the app to fail.
The only difference I've noticed is that in the successful case it
shows that System.Xml.dll is being loaded (our mixed mode DLL
references System.Xml.dll) where as in the failure case it never loads
System.Xml.dll.

Any ideas on how to find out more about what is happening during the
loading of the assemblies and .NET security checks?

Does anyone know why CAS on a Windows 2000 Server box would behave
differently to a Windows XP box when using .NET 2.0 apps? The mixed
mode DLL is not signed.

Thanks,
D.

Aug 11 '06 #1
Share this question for a faster answer!
Share on Google+

This discussion thread is closed

Replies have been disabled for this discussion.