[PATCH 1/1] mingw: fix possible buffer overrun when calling `GetUserNameW()`

["Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

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>
---
 compat/mingw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index b8a62bf914..a0eb695653 100644
--- 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;
-- 
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