Andrew Wesie : ntdll: Read entry point in LdrInitializeThunk.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 06c5a9ab55751b1c66ea0847aea4d4a45d8d343c
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=06c5a9ab55751b1c66ea0847ae...

Author: Andrew Wesie 
Date:   Thu Feb  9 20:11:52 2017 +0100

ntdll: Read entry point in LdrInitializeThunk.

Overwatch overwrites the PE header contents in a TLS callback. This results in
a crash on wine, because the entry point will be incorrect in start_process.

Signed-off-by: Andrew Wesie 
Signed-off-by: Sebastian Lackner 
Signed-off-by: Alexandre Julliard

---

dlls/kernel32/process.c | 11 +++--------
 dlls/ntdll/loader.c     | 18 +++++++++++++++---
 2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/dlls/kernel32/process.c b/dlls/kernel32/process.c
index 5a9fea2..0cb3d9b 100644
--- a/dlls/kernel32/process.c
+++ b/dlls/kernel32/process.c
@@ -1083,16 +1083,11 @@ static inline DWORD call_process_entry( PEB *peb, LPTHREAD_START_ROUTINE entry )
  *
  * Startup routine of a new process. Runs on the new process stack.
  */
-static DWORD WINAPI start_process( PEB *peb )
+static DWORD WINAPI start_process( LPTHREAD_START_ROUTINE entry )
 {
-    IMAGE_NT_HEADERS *nt;
-    LPTHREAD_START_ROUTINE entry;
-
-    nt = RtlImageNtHeader( peb->ImageBaseAddress );
-    entry = (LPTHREAD_START_ROUTINE)((char *)peb->ImageBaseAddress +
-                                     nt->OptionalHeader.AddressOfEntryPoint);
+    PEB *peb = NtCurrentTeb()->Peb;

-    if (!nt->OptionalHeader.AddressOfEntryPoint)
+    if (!entry)
     {
         ERR( "%s doesn't have an entry point, it cannot be executed\n",
              debugstr_w(peb->ProcessParameters->ImagePathName.Buffer) );
diff --git a/dlls/ntdll/loader.c b/dlls/ntdll/loader.c
index f1ef7ab..cf75850 100644
--- a/dlls/ntdll/loader.c
+++ b/dlls/ntdll/loader.c
@@ -99,6 +99,12 @@ struct builtin_load_info
 static struct builtin_load_info default_load_info;
 static struct builtin_load_info *builtin_load_info = &default_load_info;

+struct start_params
+{
+    void                   *kernel_start;
+    LPTHREAD_START_ROUTINE  entry;
+};
+
 static HANDLE main_exe_file;
 static UINT tls_module_count;      /* number of modules with TLS directory */
 static IMAGE_TLS_DIRECTORY *tls_dirs;  /* array of TLS directories */
@@ -3042,9 +3048,10 @@ static void load_global_options(void)
 /***********************************************************************
  *           start_process
  */
-static void start_process( void *kernel_start )
+static void start_process( void *arg )
 {
-    call_thread_entry_point( kernel_start, NtCurrentTeb()->Peb );
+    struct start_params *start_params = (struct start_params *)arg;
+    call_thread_entry_point( start_params->kernel_start, start_params->entry );
 }

/******************************************************************
@@ -3059,6 +3066,7 @@ void WINAPI LdrInitializeThunk( void *kernel_start, ULONG_PTR unknown2,
     WINE_MODREF *wm;
     LPCWSTR load_path;
     PEB *peb = NtCurrentTeb()->Peb;
+    struct start_params start_params;

if (main_exe_file) NtClose( main_exe_file );  /* at this point the main module is created */

@@ -3095,12 +3103,16 @@ void WINAPI LdrInitializeThunk( void *kernel_start, ULONG_PTR unknown2,
     if ((status = fixup_imports( wm, load_path )) != STATUS_SUCCESS) goto error;
     heap_set_debug_flags( GetProcessHeap() );

+    /* Store original entrypoint (in case it gets corrupted) */
+    start_params.kernel_start = kernel_start;
+    start_params.entry = wm->ldr.EntryPoint;
+
     status = wine_call_on_stack( attach_process_dlls, wm, NtCurrentTeb()->Tib.StackBase );
     if (status != STATUS_SUCCESS) goto error;

virtual_release_address_space();
     virtual_clear_thread_stack();
-    wine_switch_to_stack( start_process, kernel_start, NtCurrentTeb()->Tib.StackBase );
+    wine_switch_to_stack( start_process, &start_params, NtCurrentTeb()->Tib.StackBase );

error:
     ERR( "Main exe initialization for %s failed, status %x\n",