GeoVision GeoWebPlayer Websocket Server out-of-bounds read vulnerability

GeoWebPlayer (also called "Web Plugin" in the GV-VMS documentation and "WS Player" for VMS-Cloud) is an addon that can be installed with various GeoVision software (GV-VMS, GV-Cloud, ...). It creates a websocket server that expands the capabilities of the various web-interfaces provided by the GeoVision software and may be necessary for them to function properly.

The Websocket server can accept various commands coming from localhost. Many of the commands will take an `index` value that is then used to access various arrays to enter critical sections, perform various actions via function calls, etc. However the `index` value is usually not checked for valid range, and as such it can be used to access multiple arrays out-of-bound.

### saveVideo command index-out-of-bound

When sending the `saveVideo` command, the `index` field is extracted from the websocket message [1]. Then without checking the range of the index, it is used to trigger a CriticalSection ([2]) and releases it [3]. The release function call ([3]) is executed using a function pointer which will be read out of bounds potentially leading to code execution:

v6 = get_entry(a2, "index");

result = json_is_value_int(v6);

if ( (_BYTE)result )

{

v8 = get_entry(a2, "index");

index = json_value_to_int(&v8->value); // [1]

result = CCriticalSection::EnterCritSection(&this->crit_sections[index]); //[2]

if ( result )

{

if ( this->array_of_IPCams[index] )

{

if ( this->array_of_IPCams[index]->field_20 )

do_PostMessageA((CViewer *)this->array_of_IPCams[index], 0x111u, 0x139Fu, v11);

}

return (*(int (__thiscall **)(CCriticalSection *))(this->crit_sections[index].vtbl + 20))(&this->crit_sections[index]); //[3]

}

}