Dmitry Timoshkov : msvcrt: Fix handling of dst == src in wcscpy_s.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 9ade30d0ce7f107e775c72e628ff6e4444b9bdf4
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=9ade30d0ce7f107e775c72e628ff6e4444b9bdf4

Author: Dmitry Timoshkov <dmitry at baikal.ru>
Date:   Mon Jun 24 11:49:34 2019 +0800

msvcrt: Fix handling of dst == src in wcscpy_s.

Signed-off-by: Dmitry Timoshkov <dmitry at baikal.ru>
Signed-off-by: Piotr Caban <piotr at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/msvcrt/tests/string.c |  5 +++++
 dlls/msvcrt/wcs.c          | 13 +++++++++----
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/dlls/msvcrt/tests/string.c b/dlls/msvcrt/tests/string.c
index 0f1ee47..59f9e1d 100644
--- a/dlls/msvcrt/tests/string.c
+++ b/dlls/msvcrt/tests/string.c
@@ -1020,6 +1020,11 @@ static void test_wcscpy_s(void)
     ok(ret == 0, "expected 0 got %d\n", ret);
     ok(lstrcmpW(szDest, szLongText) == 0, "szDest != szLongText\n");
 
+    /* dest == source */
+    ret = p_wcscpy_s(szDest, 18, szDest);
+    ok(ret == 0, "expected 0 got %d\n", ret);
+    ok(lstrcmpW(szDest, szLongText) == 0, "szDest != szLongText\n");
+
     /* Copy smaller buffer size */
     errno = EBADF;
     szDest[0] = 'A';
diff --git a/dlls/msvcrt/wcs.c b/dlls/msvcrt/wcs.c
index e62ac25..6b8c7bb 100644
--- a/dlls/msvcrt/wcs.c
+++ b/dlls/msvcrt/wcs.c
@@ -2041,16 +2041,21 @@ INT CDECL MSVCRT_wcscpy_s( MSVCRT_wchar_t* wcDest, MSVCRT_size_t numElement, con
     if(!MSVCRT_CHECK_PMT(wcDest)) return MSVCRT_EINVAL;
     if(!MSVCRT_CHECK_PMT(numElement)) return MSVCRT_EINVAL;
 
-    wcDest[0] = 0;
-
-    if(!MSVCRT_CHECK_PMT(wcSrc)) return MSVCRT_EINVAL;
+    if(!MSVCRT_CHECK_PMT(wcSrc))
+    {
+        wcDest[0] = 0;
+        return MSVCRT_EINVAL;
+    }
 
     size = strlenW(wcSrc) + 1;
 
     if(!MSVCRT_CHECK_PMT_ERR(size <= numElement, MSVCRT_ERANGE))
+    {
+        wcDest[0] = 0;
         return MSVCRT_ERANGE;
+    }
 
-    memcpy( wcDest, wcSrc, size*sizeof(WCHAR) );
+    memmove( wcDest, wcSrc, size*sizeof(WCHAR) );
 
     return 0;
 }