dbghelp: Correctly determine the wine loader base address.

dlls/dbghelp/dbghelp_private.h

@@ -542,6 +542,27 @@ struct cpu
 
 extern struct cpu*      dbghelp_current_cpu DECLSPEC_HIDDEN;
 
+/* Abbreviated 32-bit PEB */
+typedef struct _PEB32
+{
+    BOOLEAN InheritedAddressSpace;
+    BOOLEAN ReadImageFileExecOptions;
+    BOOLEAN BeingDebugged;
+    BOOLEAN SpareBool;
+    DWORD   Mutant;
+    DWORD   ImageBaseAddress;
+    DWORD   LdrData;
+    DWORD   ProcessParameters;
+    DWORD   SubSystemData;
+    DWORD   ProcessHeap;
+    DWORD   FastPebLock;
+    DWORD   FastPebLockRoutine;
+    DWORD   FastPebUnlockRoutine;
+    ULONG   EnvironmentUpdateCount;
+    DWORD   KernelCallbackTable;
+    ULONG   Reserved[2];
+} PEB32;
+
 /* dbghelp.c */
 extern struct process* process_find_by_handle(HANDLE hProcess) DECLSPEC_HIDDEN;
 extern BOOL         validate_addr64(DWORD64 addr) DECLSPEC_HIDDEN;

dlls/dbghelp/elf_module.c

@@ -1574,8 +1574,27 @@ static BOOL elf_search_loader(struct process* pcs, struct elf_info* elf_info)
     ULONG_PTR base = 0;
     BOOL ret;
 
-    if (!NtQueryInformationProcess( pcs->handle, ProcessBasicInformation, &pbi, sizeof(pbi), NULL ))
-        ReadProcessMemory( pcs->handle, &pbi.PebBaseAddress->Reserved[0], &base, sizeof(base), NULL );
+    if (NtQueryInformationProcess( pcs->handle, ProcessBasicInformation,
+                                   &pbi, sizeof(pbi), NULL ))
+        return FALSE;
+
+    if (!pcs->is_64bit)
+    {
+        PEB32 *peb32 = (PEB32 *)pbi.PebBaseAddress;
+        DWORD base32;
+
+        if (!ReadProcessMemory( pcs->handle, &peb32->Reserved[0], &base32,
+                                sizeof(base32), NULL ))
+            return FALSE;
+
+        base = base32;
+    }
+    else
+    {
+        if (!ReadProcessMemory( pcs->handle, &pbi.PebBaseAddress->Reserved[0],
+                                &base, sizeof(base), NULL ))
+            return FALSE;
+    }
 
     ret = elf_search_and_load_file(pcs, loader, base, 0, elf_info);
     heap_free(loader);