ntdll: Avoid shrinking large heap block to small block.

Even though this is a waste of memory it seems to trip on some UAF with some games. Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=54475

ntdll: Avoid shrinking large heap block to small block.
63fb1633 · Rémi Bernon · Alexandre Julliard · 26c1edf4 · 63fb1633
Commit 63fb1633 authored Feb 20, 2023 by Rémi Bernon Committed by Alexandre Julliard Feb 23, 2023
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heap.c dlls/ntdll/heap.c +0 -1

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--- a/dlls/ntdll/heap.c
+++ b/dlls/ntdll/heap.c
@@ -2092,7 +2092,6 @@ static NTSTATUS heap_resize_large( struct heap *heap, ULONG flags, struct block 
    SIZE_T old_block_size = large->block_size;
    *old_size = large->data_size;

-    if (block_size < HEAP_MIN_LARGE_BLOCK_SIZE / 4) return STATUS_NO_MEMORY;  /* shrinking large block to small block */
    if (old_block_size < block_size) return STATUS_NO_MEMORY;

    /* FIXME: we could remap zero-pages instead */