Piotr Caban : msvcrt: Fix buffer overflow in _get_tzname.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 79188582f067b16e3aaebfad4a853d84f3a310cc
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=79188582f067b16e3aaebfad4a853d84f3a310cc

Author: Piotr Caban <piotr at codeweavers.com>
Date:   Wed Feb 27 18:37:10 2019 +0100

msvcrt: Fix buffer overflow in _get_tzname.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=46481
Signed-off-by: Piotr Caban <piotr at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/msvcrt/time.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/dlls/msvcrt/time.c b/dlls/msvcrt/time.c
index 14f4ba0..e6493b0 100644
--- a/dlls/msvcrt/time.c
+++ b/dlls/msvcrt/time.c
@@ -939,6 +939,11 @@ int CDECL MSVCRT__get_tzname(MSVCRT_size_t *ret, char *buf, MSVCRT_size_t bufsiz
     *ret = strlen(timezone)+1;
     if(!buf && !bufsize)
         return 0;
+    if(*ret > bufsize)
+    {
+        buf[0] = 0;
+        return MSVCRT_ERANGE;
+    }
 
     strcpy(buf, timezone);
     return 0;