---
mingw-w64-crt/misc/__mingw_mbrtowc_cp.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
---
This issue was found by Kirill. Proper way to check for invalid input
in MultiByteToWideChar() is by calling WideCharToMultiByte() and check
if the output sequence is same.
---
diff --git a/mingw-w64-crt/misc/__mingw_mbrtowc_cp.c
b/mingw-w64-crt/misc/__mingw_mbrtowc_cp.c
index 3bd6abaa61f1..2208a01600bd 100644
--- a/mingw-w64-crt/misc/__mingw_mbrtowc_cp.c
+++ b/mingw-w64-crt/misc/__mingw_mbrtowc_cp.c
@@ -133,15 +133,31 @@ size_t __mingw_mbrtowc_cp (
int ret = MultiByteToWideChar (
cp, MB_ERR_INVALID_CHARS, conversion_state.bytes, length, &wcOut, 1
);
+#ifdef __i386__
if (ret == 0) {
/* Older Windows versons do not support MB_ERR_INVALID_CHARS.
* WinNT 3.x signals ERROR_INVALID_PARAMETER and WinNT 4.0 signals
ERROR_INVALID_FLAGS.
* Fallback case when MB_ERR_INVALID_CHARS is not supported.
*/
DWORD error = GetLastError ();
- if (error == ERROR_INVALID_PARAMETER || error == ERROR_INVALID_FLAGS)
+ if (error == ERROR_INVALID_PARAMETER || error == ERROR_INVALID_FLAGS) {
ret = MultiByteToWideChar (cp, 0, conversion_state.bytes, length,
&wcOut, 1);
+ if (ret == 1) {
+ /* Without the MB_ERR_INVALID_CHARS flag, MultiByteToWideChar will
+ * successfully convert invalid code unit sequence. When this occurs,
+ * it produces one '?' character for each input code unit. We need to
+ * do round-trip conversion back to `cp` via WideCharToMultiByte to
+ * validate that converted multibyte sequence was valid.
+ */
+ char buffer[2] = {0, 0}; /* length <= 2 */
+ int ret2 = WideCharToMultiByte (cp, 0, &wcOut, 1, buffer, length,
NULL, NULL);
+ if (ret2 != length || memcmp (buffer, conversion_state.bytes, length)
!= 0) {
+ ret = 0; /* indicate failure */
+ }
+ }
+ }
}
+#endif
if (ret != 1) {
goto eilseq;
--
2.20.1
_______________________________________________
Mingw-w64-public mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
