mingw: fix possible buffer overrun when calling `GetUserNameW()`

In 39a98e9b68b8 (mingw: get pw_name in UTF-8 format, 2019-06-27), this
developer missed the fact that the `GetUserNameW()` function takes the
number of characters as `len` parameter, not the number of bytes.

Reported-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/compat/mingw.c b/compat/mingw.c
index b8a62bf9147092e6c689fecf3170d03316b4dc06..a0eb695653ef3564c52360aa6a32032758d020e0 100644 (file)
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1952,7 +1952,7 @@ struct passwd *getpwuid(int uid)
        if (initialized)
                return p;
 
-       len = sizeof(buf);
+       len = ARRAY_SIZE(buf);
        if (!GetUserNameW(buf, &len)) {
                initialized = 1;
                return NULL;