obs-vst: Fix crash by checking hash before applying "chunk_data"

[walker-WSH]

Description

Before applying chunk-data, we should check if data is for this VST plugin.
Some VST plugin will crash at effSetChunk if chunk-data is not for it.
Besides, it is meaningless to apply chunk-data to a mismatched VST plugin.

For example:

It can also be reproduced with:
readelay-standalone.dll
BL-Denoiser.dll
spire-1.5.dll

Motivation and Context

Fix crash

How Has This Been Tested?

switch selected VST and reboot OBS

Types of changes

Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[WizardCM]

How would a user fall into this error case?

[walker-WSH]

How would a user fall into this error case?

How to reproduce this crash ?

1. add VST filter for audio source, select any available VST plugin (eg: named "VST-1");
2. exit OBS, then chunk-data of "VST-1" will be saved;
3. run OBS, switch VST plugin from VST-1 to "BC Triple EQ 4 VST";
   chunk-data of "VST-1" will be applied to "BC Triple EQ", then crash!

[WizardCM]

Could you list a couple of free VST plugins that this issue can be reproduced with?

[walker-WSH]

Could you list a couple of free VST plugins that this issue can be reproduced with?

I have attached a image for free VST plugin, you can use it to reproduce.

[walker-WSH]

@WizardCM

this VST plugin can also be used to reproduce:
readelay-standalone.dll
BL-Denoiser.dll
spire-1.5.dll

[WizardCM]

Unfortunately I am unable to reproduce this crash on current master.

[walker-WSH]

Unfortunately I am unable to reproduce this crash on current master.

That is strange. I can reproduce it every time with the given Plugins.
I tried apply chunk-data of different Plugin to the given Plugins, crash still happen.

Even you can't reproduce it, we should not apply chunk-data of plugin A to plugin B.
So I think this commit is necessary.

[WizardCM]

I agree.