diff --git a/dlls/wintrust/wintrust_priv.h b/dlls/wintrust/wintrust_priv.h
index c73f666913f..f55a1b2b9e7 100644
--- a/dlls/wintrust/wintrust_priv.h
+++ b/dlls/wintrust/wintrust_priv.h
@@ -18,8 +18,8 @@
 #ifndef __WINTRUST_PRIV_H__
 #define __WINTRUST_PRIV_H__
 
-void * WINAPI WINTRUST_Alloc(DWORD cb);
-void * WINAPI WINTRUST_ReAlloc(void *ptr, DWORD cb);
+void * WINAPI WINTRUST_Alloc(DWORD cb) __WINE_ALLOC_SIZE(1);
+void * WINAPI WINTRUST_ReAlloc(void *ptr, DWORD cb) __WINE_ALLOC_SIZE(2);
 void WINAPI WINTRUST_Free(void *p);
 BOOL WINAPI WINTRUST_AddStore(CRYPT_PROVIDER_DATA *data, HCERTSTORE store);
 BOOL WINAPI WINTRUST_AddSgnr(CRYPT_PROVIDER_DATA *data,
diff --git a/include/fci.h b/include/fci.h
index 6ced99fdc34..6ac95fa00c4 100644
--- a/include/fci.h
+++ b/include/fci.h
@@ -163,7 +163,7 @@ typedef struct {
 
 /**********************************************************************/
 
-typedef void * (__cdecl *PFNFCIALLOC)(ULONG cb);
+typedef void * (__cdecl __WINE_ALLOC_SIZE(1) *PFNFCIALLOC)(ULONG cb);
 #define FNFCIALLOC(fn) void * __cdecl fn(ULONG cb)
 
 typedef void (__cdecl *PFNFCIFREE)(void *memory);
diff --git a/include/gdiplusmem.h b/include/gdiplusmem.h
index a0496baabce..fad8ed6772d 100644
--- a/include/gdiplusmem.h
+++ b/include/gdiplusmem.h
@@ -25,7 +25,7 @@
 extern "C" {
 #endif
 
-void* WINGDIPAPI GdipAlloc(SIZE_T);
+void* WINGDIPAPI GdipAlloc(SIZE_T) __WINE_ALLOC_SIZE(1);
 void WINGDIPAPI GdipFree(void*);
 
 #ifdef __cplusplus
diff --git a/include/snmp.h b/include/snmp.h
index b41243bd1b6..cedf7b0acc0 100644
--- a/include/snmp.h
+++ b/include/snmp.h
@@ -275,8 +275,8 @@ INT WINAPI SnmpUtilVarBindListCpy(SnmpVarBindList *pVblDst,
  SnmpVarBindList *pVblSrc);
 VOID WINAPI SnmpUtilVarBindListFree(SnmpVarBindList *pVbl);
 
-LPVOID WINAPI SnmpUtilMemAlloc(UINT nBytes);
-LPVOID WINAPI SnmpUtilMemReAlloc(LPVOID pMem, UINT nBytes);
+LPVOID WINAPI SnmpUtilMemAlloc(UINT nBytes) __WINE_ALLOC_SIZE(1);
+LPVOID WINAPI SnmpUtilMemReAlloc(LPVOID pMem, UINT nBytes) __WINE_ALLOC_SIZE(2);
 VOID WINAPI SnmpUtilMemFree(LPVOID pMem);
 
 LPSTR WINAPI SnmpUtilOidToA(AsnObjectIdentifier *Oid);
diff --git a/include/wintrust.h b/include/wintrust.h
index 5408ad402c7..2e4006b2b8a 100644
--- a/include/wintrust.h
+++ b/include/wintrust.h
@@ -260,7 +260,7 @@ struct _CRYPT_PROVIDER_DATA;
 
 #define TRUSTERROR_MAX_STEPS                   38
 
-typedef void * (WINAPI *PFN_CPD_MEM_ALLOC)(DWORD cbSize);
+typedef void * (__WINE_ALLOC_SIZE(1) WINAPI *PFN_CPD_MEM_ALLOC)(DWORD cbSize);
 typedef void (WINAPI *PFN_CPD_MEM_FREE)(void *pvMem2Free);
 typedef BOOL (WINAPI *PFN_CPD_ADD_STORE)(struct _CRYPT_PROVIDER_DATA *pProvData,
  HCERTSTORE hStore2Add);