From 13b77a54bad4d9b390d2e31f70d8f130eab48635 Mon Sep 17 00:00:00 2001
From: Dmitry Timoshkov <dmitry@baikal.ru>
Date: Thu, 28 Apr 2016 17:01:16 +0200
Subject: [PATCH] libs/wine: Allow to modify reserved LDT entries.

Some implementation notes:

1. Some copy protections call NtSetLdtEntries(0x000f) and then with 'retf'
instruction jump to that selector expecting that it works (the tests show that
NtSetLdtEntries(0x000f,0x001f) should succeed). In order to make this work a
limitation to set only selectors > LDT_FIRST_ENTRY (512) in wine_ldt_set_entry()
was removed.

2. wine_ldt_set_entry() was made to always mark modified selector entries as
WINE_LDT_FLAGS_ALLOCATED, otherwise get_selector_entry() server call returns
entries without that flag set and NtQueryInformationThread(ThreadDescriptorTableEntry)
fails.
---
 dlls/kernel32/tests/thread.c  | 4 ----
 dlls/ntdll/unix/signal_i386.c | 2 --
 libs/wine/ldt.c               | 4 +---
 3 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/dlls/kernel32/tests/thread.c b/dlls/kernel32/tests/thread.c
index a76d74cb698..881db6d6513 100644
--- a/dlls/kernel32/tests/thread.c
+++ b/dlls/kernel32/tests/thread.c
@@ -1341,16 +1341,12 @@ static void test_NtSetLdtEntries(void)
     {
         memset(&sel.entry, 0x9a, sizeof(sel.entry));
         ret = GetThreadSelectorEntry(GetCurrentThread(), 0x000f, &sel.entry);
-        todo_wine
         ok(ret, "GetThreadSelectorEntry failed\n");
-        todo_wine
         ok(!memcmp(&ds_entry, &sel.entry, sizeof(ds_entry)), "entries do not match\n");
 
         memset(&sel.entry, 0x9a, sizeof(sel.entry));
         ret = GetThreadSelectorEntry(GetCurrentThread(), 0x001f, &sel.entry);
-        todo_wine
         ok(ret, "GetThreadSelectorEntry failed\n");
-        todo_wine
         ok(!memcmp(&ds_entry, &sel.entry, sizeof(ds_entry)), "entries do not match\n");
     }
 }
diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index 30f1aee4d62..0ab09c1b4df 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -2098,8 +2098,6 @@ NTSTATUS WINAPI NtSetLdtEntries( ULONG sel1, LDT_ENTRY entry1, ULONG sel2, LDT_E
     sigset_t sigset;
 
     if (sel1 >> 16 || sel2 >> 16) return STATUS_INVALID_LDT_DESCRIPTOR;
-    if (sel1 && (sel1 >> 3) < first_ldt_entry) return STATUS_INVALID_LDT_DESCRIPTOR;
-    if (sel2 && (sel2 >> 3) < first_ldt_entry) return STATUS_INVALID_LDT_DESCRIPTOR;
 
     server_enter_uninterrupted_section( &ldt_mutex, &sigset );
     if (sel1) ldt_set_entry( sel1, entry1 );
diff --git a/libs/wine/ldt.c b/libs/wine/ldt.c
index 18b0b9be9bf..30d9b945f73 100644
--- a/libs/wine/ldt.c
+++ b/libs/wine/ldt.c
@@ -200,8 +200,6 @@ static int internal_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 {
     int ret = 0, index = sel >> 3;
 
-    if (index < LDT_FIRST_ENTRY) return 0;  /* cannot modify reserved entries */
-
 #ifdef linux
     {
         struct modify_ldt_s ldt_info;
@@ -253,7 +251,7 @@ static int internal_set_entry( unsigned short sel, const LDT_ENTRY *entry )
         wine_ldt_copy_obsolete.limit[index] = wine_ldt_get_limit(entry);
         wine_ldt_copy_obsolete.flags[index] = (entry->HighWord.Bits.Type |
                                  (entry->HighWord.Bits.Default_Big ? WINE_LDT_FLAGS_32BIT : 0) |
-                                 (wine_ldt_copy_obsolete.flags[index] & WINE_LDT_FLAGS_ALLOCATED));
+                                 WINE_LDT_FLAGS_ALLOCATED);
     }
     return ret;
 }
-- 
2.27.0

