[PATCH 0/1] MR6920: msvcp60: Fix NULL dst argument handling in wcsrtombs.

[Piotr Caban (＠piotr)]

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https://gitlab.winehq.org/wine/wine/-/merge_requests/6920

[PATCH 1/1] msvcp60: Fix NULL dst argument handling in wcsrtombs.

[Piotr Caban]

From: Piotr Caban <piotr(a)codeweavers.com>

---
 dlls/msvcp90/locale.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/dlls/msvcp90/locale.c b/dlls/msvcp90/locale.c
index 6cbc91d5f5a..2aa3377281c 100644
--- a/dlls/msvcp90/locale.c
+++ b/dlls/msvcp90/locale.c
@@ -12809,8 +12809,11 @@ size_t __cdecl wcsrtombs(char *dst, const wchar_t **pstr, size_t n, mbstate_t *s
     {
         int len = _Wcrtomb( buffer, *src, state, NULL );
         if (len <= 0) return -1;
-        if (n < ret + len) break;
-        memcpy( dst + ret, buffer, len );
+        if (dst)
+        {
+            if (n < ret + len) break;
+            memcpy( dst + ret, buffer, len );
+        }
         ret += len;
         if (!buffer[0]) break;
         src++;
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/6920

[Fabian Maurer (＠DarkShadow44)]

Looks correct to me, but IMHO a test would be useful. We also still seem to have an off-my-one error in that function, I noticed while testing your changes. If you want, I'd offer to create a bunch of tests, in hopes of saving you the work?

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/6920#note_89155