kernel32: Mutex names are case sensitive.

dlls/kernel32/sync.c

@@ -669,8 +669,7 @@ HANDLE WINAPI CreateMutexW( SECURITY_ATTRIBUTES *sa, BOOL owner, LPCWSTR name )
     attr.Length                   = sizeof(attr);
     attr.RootDirectory            = 0;
     attr.ObjectName               = NULL;
-    attr.Attributes               = OBJ_CASE_INSENSITIVE | OBJ_OPENIF |
-                                    ((sa && sa->bInheritHandle) ? OBJ_INHERIT : 0);
+    attr.Attributes               = OBJ_OPENIF | ((sa && sa->bInheritHandle) ? OBJ_INHERIT : 0);
     attr.SecurityDescriptor       = sa ? sa->lpSecurityDescriptor : NULL;
     attr.SecurityQualityOfService = NULL;
     if (name)
@@ -722,7 +721,7 @@ HANDLE WINAPI OpenMutexW( DWORD access, BOOL inherit, LPCWSTR name )
     attr.Length                   = sizeof(attr);
     attr.RootDirectory            = 0;
     attr.ObjectName               = NULL;
-    attr.Attributes               = OBJ_CASE_INSENSITIVE | (inherit ? OBJ_INHERIT : 0);
+    attr.Attributes               = inherit ? OBJ_INHERIT : 0;
     attr.SecurityDescriptor       = NULL;
     attr.SecurityQualityOfService = NULL;
     if (name)

dlls/kernel32/tests/sync.c

@@ -148,7 +148,30 @@ static void test_mutex(void)
     todo_wine ok(!ret && (GetLastError() == ERROR_NOT_OWNER),
         "ReleaseMutex should have failed with ERROR_NOT_OWNER instead of %d\n", GetLastError());
 
+    /* test case sensitivity */
+
+    SetLastError(0xdeadbeef);
+    hOpened = OpenMutex(READ_CONTROL, FALSE, "WINETESTMUTEX");
+    ok(!hOpened, "OpenMutex succeeded\n");
+    ok(GetLastError() == ERROR_FILE_NOT_FOUND, "wrong error %u\n", GetLastError());
+
+    SetLastError(0xdeadbeef);
+    hOpened = OpenMutex(READ_CONTROL, FALSE, "winetestmutex");
+    ok(!hOpened, "OpenMutex succeeded\n");
+    ok(GetLastError() == ERROR_FILE_NOT_FOUND, "wrong error %u\n", GetLastError());
+
+    SetLastError(0xdeadbeef);
+    hOpened = CreateMutex(NULL, FALSE, "WineTestMutex");
+    ok(hOpened != NULL, "CreateMutex failed with error %d\n", GetLastError());
+    ok(GetLastError() == ERROR_ALREADY_EXISTS, "wrong error %u\n", GetLastError());
     CloseHandle(hOpened);
+
+    SetLastError(0xdeadbeef);
+    hOpened = CreateMutex(NULL, FALSE, "WINETESTMUTEX");
+    ok(hOpened != NULL, "CreateMutex failed with error %d\n", GetLastError());
+    ok(GetLastError() == 0, "wrong error %u\n", GetLastError());
+    CloseHandle(hOpened);
+
     CloseHandle(hCreated);
 }