[PATCH] ntdll: Always add a tail to heap allocations.

[Brendan Shanks]

Fixes the Rockstar Games Launcher installer (and possibly other
NSIS-based installers) from crashing due to passing a too-small buffer
to GetWindowInfo().

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47783
Signed-off-by: Brendan Shanks <bshanks at codeweavers.com>
---
 dlls/ntdll/heap.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/dlls/ntdll/heap.c b/dlls/ntdll/heap.c
index e8ac1ffa7a..e7da86e09a 100644
--- a/dlls/ntdll/heap.c
+++ b/dlls/ntdll/heap.c
@@ -110,9 +110,8 @@ C_ASSERT( sizeof(ARENA_LARGE) % LARGE_ALIGNMENT == 0 );
 #define HEAP_MIN_SHRINK_SIZE  (HEAP_MIN_DATA_SIZE+sizeof(ARENA_FREE))
 /* minimum size to start allocating large blocks */
 #define HEAP_MIN_LARGE_BLOCK_SIZE  0x7f000
-/* extra size to add at the end of block for tail checking */
-#define HEAP_TAIL_EXTRA_SIZE(flags) \
-    ((flags & HEAP_TAIL_CHECKING_ENABLED) || RUNNING_ON_VALGRIND ? ALIGNMENT : 0)
+/* extra size to add at the end of block to mitigate overruns and allow tail checking */
+#define HEAP_TAIL_EXTRA_SIZE ALIGNMENT
 
 /* There will be a free list bucket for every arena size up to and including this value */
 #define HEAP_MAX_SMALL_FREE_LIST 0x100
@@ -722,7 +721,7 @@ static void HEAP_ShrinkBlock(SUBHEAP *subheap, ARENA_INUSE *pArena, SIZE_T size)
 static void *allocate_large_block( HEAP *heap, DWORD flags, SIZE_T size )
 {
     ARENA_LARGE *arena;
-    SIZE_T block_size = sizeof(*arena) + ROUND_SIZE(size) + HEAP_TAIL_EXTRA_SIZE(flags);
+    SIZE_T block_size = sizeof(*arena) + ROUND_SIZE(size) + HEAP_TAIL_EXTRA_SIZE;
     LPVOID address = NULL;
 
     if (block_size < size) return NULL;  /* overflow */
@@ -1674,7 +1673,7 @@ void * WINAPI DECLSPEC_HOTPATCH RtlAllocateHeap( HANDLE heap, ULONG flags, SIZE_
     if (!heapPtr) return NULL;
     flags &= HEAP_GENERATE_EXCEPTIONS | HEAP_NO_SERIALIZE | HEAP_ZERO_MEMORY;
     flags |= heapPtr->flags;
-    rounded_size = ROUND_SIZE(size) + HEAP_TAIL_EXTRA_SIZE( flags );
+    rounded_size = ROUND_SIZE(size) + HEAP_TAIL_EXTRA_SIZE;
     if (rounded_size < size)  /* overflow */
     {
         if (flags & HEAP_GENERATE_EXCEPTIONS) RtlRaiseStatus( STATUS_NO_MEMORY );
@@ -1828,7 +1827,7 @@ PVOID WINAPI RtlReAllocateHeap( HANDLE heap, ULONG flags, PVOID ptr, SIZE_T size
     flags |= heapPtr->flags;
     if (!(flags & HEAP_NO_SERIALIZE)) RtlEnterCriticalSection( &heapPtr->critSection );
 
-    rounded_size = ROUND_SIZE(size) + HEAP_TAIL_EXTRA_SIZE(flags);
+    rounded_size = ROUND_SIZE(size) + HEAP_TAIL_EXTRA_SIZE;
     if (rounded_size < size) goto oom;  /* overflow */
     if (rounded_size < HEAP_MIN_DATA_SIZE) rounded_size = HEAP_MIN_DATA_SIZE;
 
-- 
2.17.1