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, 3 insertions, 3 deletions

diff --git a/py/reader.c b/py/reader.c
index 57b12b3b6..d2af62cfb 100644
--- a/py/reader.c
+++ b/py/reader.c
@@ -134,12 +134,12 @@ void mp_reader_new_file_from_fd(mp_reader_t *reader, int fd, bool close_fd) {
 
 #if !MICROPY_VFS_POSIX
 // If MICROPY_VFS_POSIX is defined then this function is provided by the VFS layer
-void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
+void mp_reader_new_file(mp_reader_t *reader, qstr filename) {
     MP_THREAD_GIL_EXIT();
-    int fd = open(filename, O_RDONLY, 0644);
+    int fd = open(qstr_str(filename), O_RDONLY, 0644);
     MP_THREAD_GIL_ENTER();
     if (fd < 0) {
-        mp_raise_OSError_with_filename(errno, filename);
+        mp_raise_OSError_with_filename(errno, qstr_str(filename));
     }
     mp_reader_new_file_from_fd(reader, fd, true);
 }