[PATCH v2 03/25] winansi: avoid buffer overrun

[Johannes Schindelin]

When we could not convert the UTF-8 sequence into Unicode for writing to
the Console, we should not try to write an insanely-long sequence of
invalid wide characters (mistaking the negative return value for an
unsigned length).

Reported by Coverity.

Signed-off-by: Johannes Schindelin <johannes.schinde...@gmx.de>
---
 compat/winansi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/compat/winansi.c b/compat/winansi.c
index fd6910746c8..861b79d8c31 100644
--- a/compat/winansi.c
+++ b/compat/winansi.c
@@ -135,6 +135,11 @@ static void write_console(unsigned char *str, size_t len)
 
        /* convert utf-8 to utf-16 */
        int wlen = xutftowcsn(wbuf, (char*) str, ARRAY_SIZE(wbuf), len);
+       if (wlen < 0) {
+               wchar_t *err = L"[invalid]";
+               WriteConsoleW(console, err, wcslen(err), &dummy, NULL);
+               return;
+       }
 
        /* write directly to console */
        WriteConsoleW(console, wbuf, wlen, &dummy, NULL);
-- 
2.12.2.windows.2.800.gede8f145e06