Akihiro Sagawa : user32: Fix a memory allocation strategy.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: cb0e4f5f4f7dc10a0933349ad780a11405cd736e
URL:    https://gitlab.winehq.org/wine/wine/-/commit/cb0e4f5f4f7dc10a0933349ad780a11...

Author: Akihiro Sagawa <sagawa.aki(a)gmail.com>
Date:   Mon Sep 19 22:10:24 2022 +0900

user32: Fix a memory allocation strategy.

Otherwise, the function allocates a heap memory when prev_size is enough.
What is worse is that it returns the buffer untouched if the prev_size
is insufficient.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=53703

---

 dlls/user32/winproc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/dlls/user32/winproc.c b/dlls/user32/winproc.c
index 2ca802e647a..6cd41b51435 100644
--- a/dlls/user32/winproc.c
+++ b/dlls/user32/winproc.c
@@ -747,7 +747,8 @@ void dispatch_win_proc_params( struct win_proc_params *params )
 /* make sure that there is space for 'size' bytes in buffer, growing it if needed */
 static inline void *get_buffer_space( void **buffer, size_t size, size_t prev_size )
 {
-    if (prev_size > size && !(*buffer = HeapAlloc( GetProcessHeap(), 0, size ))) return NULL;
+    if (prev_size < size)
+        *buffer = HeapAlloc( GetProcessHeap(), 0, size );
     return *buffer;
 }