The DxgkDdiEscape handler for 0x70000d5 lacks bounds checks:
...
if ( g_saved_size )
{
escape->size = g_saved_size;
if ( (unsigned int)g_saved_size > 0 )
{
do
{
v5 = v2++;
escape->data[v5] = global_array[v5 + 77];
}
while ( v2 < g_saved_size );
}
return;
}
data = 0i64;
...
if ( escape->size > 0 )
{
do
{
ii = i++;
global_array[ii + 77] = escape->data[ii];
}
while ( i < escape->size );
...
g_saved_size = escape->size;
This handler copies data to/from a global array, but lacks any form of bounds checking, as
|escape->size| is controlled by the user. This leads to overflow of the global buffer, and pool overflows
when it's copied back into the escape data.
A PoC is attached that should cause a crash (Win 10 x64, 372.54):
KERNEL_SECURITY_CHECK_FAILURE (139)
A kernel component has corrupted a critical data structure. The corruption
could potentially allow a malicious user to gain control of this machine.
Arguments:
Arg1: 0000000000000002, Stack cookie instrumentation code detected a stack-based
buffer overrun.
Arg2: ffffd00022de52c0, Address of the trap frame for the exception that caused the bugcheck
Arg3: ffffd00022de5218, Address of the exception record for the exception that caused the bugcheck
Arg4: 0000000000000000, Reserved
This bug is subject to a 90 day disclosure deadline. If 90 days elapse
without a broadly available patch, then the bug report will automatically
become visible to the public.
