py/builtinevex: Handle invalid filenames for execfile.

If a non-string buffer was passed to execfile, then it would be passed
as a non-null-terminated char* to mp_lexer_new_from_file.

This changes mp_lexer_new_from_file to take a qstr instead (as in almost
all cases a qstr will be created from this input anyway to set the
`__file__` attribute on the module).

This now makes execfile require a string (not generic buffer) argument,
which is probably a good fix to make anyway.

Fixes issue #12522.

This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/extmod/vfs_reader.c b/extmod/vfs_reader.c
index d3904c5c5..3c6ff52a9 100644
--- a/extmod/vfs_reader.c
+++ b/extmod/vfs_reader.c
@@ -69,10 +69,10 @@ STATIC void mp_reader_vfs_close(void *data) {
     m_del_obj(mp_reader_vfs_t, reader);
 }
 
-void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
+void mp_reader_new_file(mp_reader_t *reader, qstr filename) {
     mp_reader_vfs_t *rf = m_new_obj(mp_reader_vfs_t);
     mp_obj_t args[2] = {
-        mp_obj_new_str(filename, strlen(filename)),
+        MP_OBJ_NEW_QSTR(filename),
         MP_OBJ_NEW_QSTR(MP_QSTR_rb),
     };
     rf->file = mp_vfs_open(MP_ARRAY_SIZE(args), &args[0], (mp_map_t *)&mp_const_empty_map);