[PATCH v2 1/3] kernelbase: Implement compatibility mode for GetVersionEx.

[Gabriel Ivăncescu]

On 17/03/2020 18:28, Nikolay Sivov wrote:
> On 3/17/20 7:07 PM, Gabriel Ivăncescu wrote:
>> +/***********************************************************************
>> + * Win8 info, reported if app doesn't provide compat GUID in manifest.
>> + */
>> +static const RTL_OSVERSIONINFOEXW windows8_version_data =
>> +{
>> +    sizeof(RTL_OSVERSIONINFOEXW), 6, 2, 0x23f0, VER_PLATFORM_WIN32_NT,
>> +    {0}, 0, 0, VER_SUITE_SINGLEUSERTS, VER_NT_WORKSTATION, 0
>> +};
>> +
>> +
>> +/***********************************************************************
>> + * Windows versions that need compatibility GUID specified in manifest
>> + * in order to be reported by the APIs.
>> + */
>> +static const struct
>> +{
>> +    RTL_OSVERSIONINFOEXW info;
>> +    GUID guid;
>> +} version_data[] =
>> +{
>> +    /* Windows 8.1 */
>> +    {
>> +        {
>> +            sizeof(RTL_OSVERSIONINFOEXW), 6, 3, 0x2580, 
>> VER_PLATFORM_WIN32_NT,
>> +            {0}, 0, 0, VER_SUITE_SINGLEUSERTS, VER_NT_WORKSTATION, 0
>> +        },
>> +        
>> {0x1f676c76,0x80e1,0x4239,{0x95,0xbb,0x83,0xd0,0xf6,0xd0,0xda,0x78}}
>> +    },
>> +    /* Windows 10 */
>> +    {
>> +        {
>> +            sizeof(RTL_OSVERSIONINFOEXW), 10, 0, 0x42ee, 
>> VER_PLATFORM_WIN32_NT,
>> +            {0}, 0, 0, VER_SUITE_SINGLEUSERTS, VER_NT_WORKSTATION, 0
>> +        },
>> +        
>> {0x8e0f7a12,0xbfb3,0x4fe8,{0xb9,0xa5,0x48,0xfd,0x50,0xa1,0x5a,0x9a}}
>> +    }
>> +};
> For that you only need to store 3 values - major/minor/build.

Ah alright, I just copy-pasted the entires from ntdll.

>> +/***********************************************************************
>> + * Holds the current version (including compatibility mode).
>> + * Call init_current_version before using it.
>> + */
>> +static RTL_OSVERSIONINFOEXW current_version;
>> +
>> +
>> +/****************************************************************************** 
>>
>> + *  init_current_version
>> + *
>> + * Initialize the current_version variable.
>> + *
>> + * For compatibility, Windows 8.1 and later report Win8 version 
>> unless the app
>> + * has a manifest that confirms its compatibility with newer versions 
>> of Windows.
>> + *
>> + */
>> +static BOOL CALLBACK init_current_version_callback(PINIT_ONCE 
>> init_once, PVOID parameter, PVOID *context)
>> +{
> Should it actually be static and initialized once? What happens if you 
> activate another context dynamically?
> 

I actually have no idea, didn't know you can do that. I'm somewhat 
unfamiliar with activation context APIs. What API should I be using to 
test this?

>> +    /*ACTIVATION_CONTEXT_COMPATIBILITY_INFORMATION*/DWORD *acci;
> Why not use proper type pointer?

I don't know, ntdll does the same thing when filling it, for some reason 
we don't even have that structure so I couldn't use it, although I did 
find it in headers. So I was a bit confused and just copied what ntdll 
does, assuming it had a good reason to.

> 
>> +                if (elements[i].Type == 
>> ACTCX_COMPATIBILITY_ELEMENT_TYPE_OS &&
>> +                    IsEqualGUID(&elements[i].Id, 
>> &version_data[idx].guid))
> Type value name has a typo.
> 

Right, but that's in our headers, I thought it was intentional. Should I 
send a fix for this?