[wvdecrypter] Fix memory heap corruption

[CastagnaIT]

Description

After PR #1310 when you play a Widevine encrypted content on a debug build kodi crash with a memory heap corruption

the reason seem to be on changed code that looks bad and unsafe,
the code take the mem pointer from data_out and store to packet_out, this to manually copy data by using memcpy seem to avoid use the bento4 object method AppendData

the size of buffer internally of the data_out object is assumed to be big enough to contains written data, but if not so?
weird thing can happens also because at the end is called data_out.SetDataSize to update the wrong object data size,
from what i understand SetDataSize not only update the container data size but can also reallocate the object buffer,
if this happens the reallocation copy the buffer data but based on initial data size and not on what we have written with memcpy, that could exceed the size...

I do not know if I have explained myself correctly anyway dont crash anymore

maybe in the past has been done so to try limit SetDataSize uses in the
while (packet_in < packet_in_e) loop, at least with h264 i get at max 4 loops only not big things

a test confermation would be appreciated

How has this been tested?

played n€tflix on windows, debug build
played n€tflix on android, but release build

Screenshots (if appropriate):

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• None of the above (please explain below)

Checklist:

• I have read the Contributing document
• My code follows the Code Guidelines of this project
• My change requires a change to the Wiki documentation
• I have updated the documentation accordingly

[glennguy]

Hi
I don't have an opportunity tonight to test it... but I think it needs to be tested on Windows with a non-secure path sample stream e.g the bitmoving parkour one - if you get a chance before I do:

#KODIPROP:inputstreamaddon=inputstream.adaptive
#KODIPROP:inputstream=inputstream.adaptive
#KODIPROP:inputstream.adaptive.manifest_type=mpd
#KODIPROP:inputstream.adaptive.license_type=com.widevine.alpha
#KODIPROP:inputstream.adaptive.license_key=https://cwip-shaka-proxy.appspot.com/no_auth|Content-Type=|R{SSM}|
https://bitmovin-a.akamaihd.net/content/art-of-motion_drm/mpds/11331.mpd

I was testing on this in the WIP PR and had crashing..,. maybe I messed up though and it's running secure path when it doesn't need to?

[CastagnaIT]

thanks just tested, played without crashes
https://paste.kodi.tv/ofomicepan.kodi
but i would like a confermation on a system different of mine

[glennguy]

My bad here - I have secure path currently hardcoded in my branch. Playback fine here with the changes, thanks heaps for finding this so quickly!