# [PATCH] mingw: consider that UNICODE_STRING::Length counts bytes

1 messages from 2016-12-17 to 2016-12-17. Participants: Max Kirillov.
Thread: https://gitlist.dev/t/44725

## Max Kirillov, 2016-12-17 13:20

Subject: [PATCH] mingw: consider that UNICODE_STRING::Length counts bytes
Message-ID: <1481980831-18511-1-git-send-email-max@max630.net>
URL: https://gitlist.dev/e/1481980831-18511-1-git-send-email-max%40max630.net

```
UNICODE_STRING::Length field means size of buffer in bytes[1], despite of buffer
itself being array of wchar_t. Because of that terminating zero is placed twice
as far. Fix it.

[1] https://msdn.microsoft.com/en-us/library/windows/desktop/aa380518.aspx

Signed-off-by: Max Kirillov <max@max630.net>
---
Access outside of buffer was very unlikely (for that user needed to redirect
standard fd to a file with path longer than ~250 symbols), it still did not
seem to do any harm, and otherwise it did not break because only substring is
checked, but it was still incorrect.
 compat/winansi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compat/winansi.c b/compat/winansi.c
index 3be60ce..6b4f736 100644
--- a/compat/winansi.c
+++ b/compat/winansi.c
@@ -553,7 +553,7 @@ static void detect_msys_tty(int fd)
 			buffer, sizeof(buffer) - 2, &result)))
 		return;
 	name = nameinfo->Name.Buffer;
-	name[nameinfo->Name.Length] = 0;
+	name[nameinfo->Name.Length / sizeof(*name)] = 0;
 
 	/* check if this could be a MSYS2 pty pipe ('msys-XXXX-ptyN-XX') */
 	if (!wcsstr(name, L"msys-") || !wcsstr(name, L"-pty"))
-- 
2.3.4.2801.g3d0809b


```