#1475 Server crashes after too many updates

[Bobby Ricardo]

I am sharing a portion of my screen which contains an electron BrowserWindow. When the user scrolls I want to update the position of the window and also the sharing rectangle.

Initially I was sending the coordinates everytime the scroll event was triggered. That was consistently causing the tvnserver to crash.
I then changed it so that the coordinates were only sent when scrolling stops (i.e. less updates). Even so, the server still seems to crash, although now it takes slightly longer.

Using WinVNC.exe (from tightVNC 1.3) this issue does not occur.

Any ideas? Below is the crash dump

Dump Summary

Dump File: crash.dmp : C:\Users\Bobby Ricardo\AppData\Roaming\TightVNC\crash.dmp
Last Write Time: 25/07/2019 09:08:10
Process Name: tvnserver.exe : C:\Git\electron\angular-electron\electron\vnc2\tvnserver.exe
Process Architecture: x64
Exception Code: 0xC0000005
Exception Information: The thread tried to read from or write to a virtual address for which it does not have the appropriate access.
Heap Information: Not Present

System Information

OS Version: 10.0.17763
CLR Version(s):

Modules

Module Name Module Path Module Version

---

tvnserver.exe C:\Git\electron\angular-electron\electron\vnc2\tvnserver.exe 2.8.23.0
ntdll.dll C:\Windows\System32\ntdll.dll 6.2.17763.592
kernel32.dll C:\Windows\System32\kernel32.dll 6.2.17763.475
KERNELBASE.dll C:\Windows\System32\KERNELBASE.dll 6.2.17763.615
psapi.dll C:\Windows\System32\psapi.dll 6.2.17763.1
user32.dll C:\Windows\System32\user32.dll 6.2.17763.168
winmm.dll C:\Windows\System32\winmm.dll 6.2.17763.1
win32u.dll C:\Windows\System32\win32u.dll 6.2.17763.1
gdi32.dll C:\Windows\System32\gdi32.dll 6.2.17763.592
msvcrt.dll C:\Windows\System32\msvcrt.dll 7.0.17763.475
gdi32full.dll C:\Windows\System32\gdi32full.dll 6.2.17763.615
WINMMBASE.dll C:\Windows\System32\WINMMBASE.dll 6.2.17763.1
cfgmgr32.dll C:\Windows\System32\cfgmgr32.dll 6.2.17763.1
msvcp_win.dll C:\Windows\System32\msvcp_win.dll 6.2.17763.348
ucrtbase.dll C:\Windows\System32\ucrtbase.dll 6.2.17763.404
advapi32.dll C:\Windows\System32\advapi32.dll 6.2.17763.1
sechost.dll C:\Windows\System32\sechost.dll 6.2.17763.1
rpcrt4.dll C:\Windows\System32\rpcrt4.dll 6.2.17763.379
shell32.dll C:\Windows\System32\shell32.dll 6.2.17763.615
SHCore.dll C:\Windows\System32\SHCore.dll 6.2.17763.1
combase.dll C:\Windows\System32\combase.dll 6.2.17763.615
bcryptPrimitives.dll C:\Windows\System32\bcryptPrimitives.dll 6.2.17763.615
windows.storage.dll C:\Windows\System32\windows.storage.dll 6.2.17763.615
profapi.dll C:\Windows\System32\profapi.dll 6.2.17763.1
powrprof.dll C:\Windows\System32\powrprof.dll 6.2.17763.1
shlwapi.dll C:\Windows\System32\shlwapi.dll 6.2.17763.1
kernel.appcore.dll C:\Windows\System32\kernel.appcore.dll 6.2.17763.1
cryptsp.dll C:\Windows\System32\cryptsp.dll 6.2.17763.1
ws2_32.dll C:\Windows\System32\ws2_32.dll 6.2.17763.1
comctl32.dll C:\Windows\WinSxS\amd64_microsoft.windows.common-controls_6595b64144ccf1df_6.0.17763.615_none_05b4414a072024d4\comctl32.dll 6.10.17763.592
version.dll C:\Windows\System32\version.dll 6.2.17763.1
imm32.dll C:\Windows\System32\imm32.dll 6.2.17763.1
ntmarta.dll C:\Windows\System32\ntmarta.dll 6.2.17763.1
mswsock.dll C:\Windows\System32\mswsock.dll 6.2.17763.292
NapiNSP.dll C:\Windows\System32\NapiNSP.dll 6.2.17763.1
pnrpnsp.dll C:\Windows\System32\pnrpnsp.dll 6.2.17763.1
dnsapi.dll C:\Windows\System32\dnsapi.dll 6.2.17763.615
nsi.dll C:\Windows\System32\nsi.dll 6.2.17763.1
IPHLPAPI.DLL C:\Windows\System32\IPHLPAPI.DLL 6.2.17763.615
winrnr.dll C:\Windows\System32\winrnr.dll 6.2.17763.1
nlaapi.dll C:\Windows\System32\nlaapi.dll 6.2.17763.134
wshbth.dll C:\Windows\System32\wshbth.dll 6.2.17763.1
FWPUCLNT.DLL C:\Windows\System32\FWPUCLNT.DLL 6.2.17763.1
bcrypt.dll C:\Windows\System32\bcrypt.dll 6.2.17763.1
rasadhlp.dll C:\Windows\System32\rasadhlp.dll 6.2.17763.1
wtsapi32.dll C:\Windows\System32\wtsapi32.dll 6.2.17763.1
uxtheme.dll C:\Windows\System32\uxtheme.dll 6.2.17763.1
dwmapi.dll C:\Windows\System32\dwmapi.dll 6.2.17763.1
crypt32.dll C:\Windows\System32\crypt32.dll 6.2.17763.1
msasn1.dll C:\Windows\System32\msasn1.dll 6.2.17763.1
d3d11.dll C:\Windows\System32\d3d11.dll 6.2.17763.1
dxgi.dll C:\Windows\System32\dxgi.dll 6.2.17763.1
vm3dum64_loader.dll C:\Windows\System32\vm3dum64_loader.dll 8.16.1.24
ole32.dll C:\Windows\System32\ole32.dll 6.2.17763.503
CRYPTBASE.DLL C:\Windows\System32\CRYPTBASE.DLL 6.2.17763.1
vm3dum64_10.dll C:\Windows\System32\vm3dum64_10.dll 8.16.1.24
dbghelp.dll C:\Windows\System32\dbghelp.dll 6.2.17763.1
dbgcore.dll C:\Windows\System32\dbgcore.dll 6.2.17763.1
msctf.dll C:\Windows\System32\msctf.dll 6.2.17763.529
oleaut32.dll C:\Windows\System32\oleaut32.dll 6.2.17763.437
TextInputFramework.dll C:\Windows\System32\TextInputFramework.dll 6.2.17763.1
CoreMessaging.dll C:\Windows\System32\CoreMessaging.dll 6.2.17763.194
CoreUIComponents.dll C:\Windows\System32\CoreUIComponents.dll 6.2.17763.1
WinTypes.dll C:\Windows\System32\WinTypes.dll 6.2.17763.134

[Bobby Ricardo]

UPDATE: Noticed that it only seems to happen when resizing the Rectangle that is being shared. So does not appear to be related to scrolling (I am resizing the window if the coordinates become out of bounds against the parent, as soon as that happens it crashes). It also happens by just maximizing and restoring as the browser size (and rectangle that is shared) is responsive

Using the tvnviewer.exe I can see the following error:

Error in TightVNC Viewer: Error in protocol: incorrect size of rectangle

[Anton]

Hello.
Please send crash.dmp to anton@glavsoft.com

[Anton]

Hello.

Can you test this version?

[Bobby Ricardo]

This looks to have fixed it. Thanks for your help Anton.