About LogOff/LogOn issue during driver is loaded.

c++ / delphi package - dll injection and api hooking
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Joined: Sat May 23, 2009 8:55 am

About LogOff/LogOn issue during driver is loaded.

Post by power888 »


I have some question.

I used one driver file (namely, MyDriver.Sys/MyDriver64.Sys) and 2 hooking dlls.
But Always, I have problem for LogOff/LogOn.. if problem happen, then Black screen is displayed.
(I tested with 3.1.8 and 3.1.10, and OS is Win7-64)

1. on PC, created 2 user account (user-A, and user-B)
2. Reboot PC, and logon by user-A
3. load driver. (driver name is MyDriver.Sys/MyDriver64.Sys)
4. laod 1st-hooking library. (for example, TerminationHook(64).Dll)
5. laod 2nd-hooking library. (for example, PrintHook(64).Dll)
6. Now click LogOff
7. Now, OS display logon screen, in this screen select user-B
8. ** sometimes, at this point, Black screen is displayed.. (namlely, dont display user-B desktop)
9. if user-B logon is successfully,
10. then in this time, 1st, 2nd hook-dlls are alived.
11. now logoff user-B
12. on logon screen, select user-A
13. ** Then, always display Black screen....
(if you click shift+Alt+Del, and execute Explorer.exe, then Desktop is displayed)
14. *** If I exclude explorer.exe in Load-Library(), then everything is worked well.

**** If I loaded one Hooking DLL, then, worked well...

Is it known issues?
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Re: About LogOff/LogOn issue during driver is loaded.

Post by madshi »

No, it's not a known issue.

My suggestion would be to comment out all the HookAPI() calls in both hook dlls. Then check if the problem is still there. If not, put the HookAPI calls back in step by step. Maybe this way you can figure out which HookAPI calls makes problems?
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