[PATCH] kernel32: return copy of environment blockinGetEnvironmentStringsW

[Alexandre Julliard]

"Dmitry Timoshkov" <dmitry at codeweavers.com> writes:

> "Peter Beutner" <p.beutner at gmx.net> wrote:
>> @@ -148,6 +148,10 @@ LPWSTR WINAPI GetEnvironmentStringsW(void)
>>  */
>> BOOL WINAPI FreeEnvironmentStringsA( LPSTR ptr )
>> {
>> +    /* broken app passes ptr it got from GetEnvironmentStringsW */
>> +    if(ptr == NtCurrentTeb()->Peb->ProcessParameters->Environment)
>> +        return TRUE;
>> +
>>     return HeapFree( GetProcessHeap(), 0, ptr );
>> }
>
> Personally I think that adding an exception handler or probably just a more
> strict consistency check inside of RtlFreeHeap should be better.

An exception handler is probably too slow, but yes RtlFreeHeap should
have noticed that this block isn't part of the heap. Try something
like this:

diff --git a/dlls/ntdll/heap.c b/dlls/ntdll/heap.c
index 80ddaf2..61b25db 100644
--- a/dlls/ntdll/heap.c
+++ b/dlls/ntdll/heap.c
@@ -395,7 +395,8 @@ static SUBHEAP *HEAP_FindSubHeap(
     while (sub)
     {
         if (((const char *)ptr >= (const char *)sub) &&
-            ((const char *)ptr < (const char *)sub + sub->size)) return (SUBHEAP*)sub;
+            ((const char *)ptr < (const char *)sub + sub->size - sizeof(ARENA_INUSE)))
+            return (SUBHEAP *)sub;
         sub = sub->next;
     }
     return NULL;
@@ -783,7 +784,7 @@ static ARENA_FREE *HEAP_FindFreeBlock( HEAP *heap, SIZE_T size,
  *
  * Check that the pointer is inside the range possible for arenas.
  */
-static BOOL HEAP_IsValidArenaPtr( const HEAP *heap, const void *ptr )
+static BOOL HEAP_IsValidArenaPtr( const HEAP *heap, const ARENA_FREE *ptr )
 {
     int i;
     const SUBHEAP *subheap = HEAP_FindSubHeap( heap, ptr );
@@ -1003,13 +1004,12 @@ static BOOL HEAP_IsRealArena( HEAP *heapPtr,   /* [in] ptr to the heap */
     if (!(flags & HEAP_NO_SERIALIZE))
         RtlEnterCriticalSection( &heapPtr->critSection );
 
-    if (block)
+    if (block)  /* only check this single memory block */
     {
-        /* Only check this single memory block */
+        const ARENA_INUSE *arena = (const ARENA_INUSE *)block - 1;
 
-        if (!(subheap = HEAP_FindSubHeap( heapPtr, block )) ||
-            ((const char *)block < (char *)subheap + subheap->headerSize
-                                   + sizeof(ARENA_INUSE)))
+        if (!(subheap = HEAP_FindSubHeap( heapPtr, arena )) ||
+            ((const char *)arena < (char *)subheap + subheap->headerSize))
         {
             if (quiet == NOISY)
                 ERR("Heap %p: block %p is not inside heap\n", heapPtr, block );
@@ -1017,7 +1017,7 @@ static BOOL HEAP_IsRealArena( HEAP *heapPtr,   /* [in] ptr to the heap */
                 WARN("Heap %p: block %p is not inside heap\n", heapPtr, block );
             ret = FALSE;
         } else
-            ret = HEAP_ValidateInUseArena( subheap, (const ARENA_INUSE *)block - 1, quiet );
+            ret = HEAP_ValidateInUseArena( subheap, arena, quiet );
 
         if (!(flags & HEAP_NO_SERIALIZE))
             RtlLeaveCriticalSection( &heapPtr->critSection );

-- 
Alexandre Julliard
julliard at winehq.org