[PATCH 0/1] MR2696: ntdll: Avoid integer overflow in block_get_subheap().

[Paul Gofman (＠gofman)]

'block->base_offset * REGION_ALIGN' overflows once WORD base_offset value reaches 0x8000, so block_get_subheap() returns wrong address.

[PATCH 1/1] ntdll: Avoid integer overflow in block_get_subheap().

[Paul Gofman]

From: Paul Gofman

---
 dlls/ntdll/heap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/ntdll/heap.c b/dlls/ntdll/heap.c
index 7547ac50f61..5c882def50e 100644
--- a/dlls/ntdll/heap.c
+++ b/dlls/ntdll/heap.c
@@ -357,7 +357,7 @@ static inline void block_set_type( struct block *block, UINT type )
 static inline SUBHEAP *block_get_subheap( const struct heap *heap, const struct block *block )
 {
     char *offset = ROUND_ADDR( block, REGION_ALIGN - 1 );
-    void *base = offset - block->base_offset * REGION_ALIGN;
+    void *base = offset - (SIZE_T)block->base_offset * REGION_ALIGN;
     if (base != (void *)heap) return base;
     else return (SUBHEAP *)&heap->subheap;
 }

[PATCH 0/1] MR2696: ntdll: Avoid integer overflow in block_get_subheap(). - approved

[Rémi Bernon (＠rbernon)]

This merge request was approved by Rémi Bernon.