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>

2 files changed, 4 insertions, 4 deletions

diff --git a/shared/memzip/lexermemzip.c b/shared/memzip/lexermemzip.c
index 6b26961bd..1915a04c0 100644
--- a/shared/memzip/lexermemzip.c
+++ b/shared/memzip/lexermemzip.c
@@ -5,15 +5,15 @@
 #include "py/mperrno.h"
 #include "memzip.h"
 
-mp_lexer_t *mp_lexer_new_from_file(const char *filename)
+mp_lexer_t *mp_lexer_new_from_file(qstr filename)
 {
     void *data;
     size_t len;
 
-    if (memzip_locate(filename, &data, &len) != MZ_OK) {
+    if (memzip_locate(qstr_str(filename), &data, &len) != MZ_OK) {
         mp_raise_OSError(MP_ENOENT);
     }
 
-    return mp_lexer_new_from_str_len(qstr_from_str(filename), (const char *)data, (mp_uint_t)len, 0);
+    return mp_lexer_new_from_str_len(filename, (const char *)data, (mp_uint_t)len, 0);
 }
 
diff --git a/shared/runtime/pyexec.c b/shared/runtime/pyexec.c
index e32150e5e..9f6d9a100 100644
--- a/shared/runtime/pyexec.c
+++ b/shared/runtime/pyexec.c
@@ -100,7 +100,7 @@ STATIC int parse_compile_execute(const void *source, mp_parse_input_kind_t input
             } else if (exec_flags & EXEC_FLAG_SOURCE_IS_READER) {
                 lex = mp_lexer_new(MP_QSTR__lt_stdin_gt_, *(mp_reader_t *)source);
             } else if (exec_flags & EXEC_FLAG_SOURCE_IS_FILENAME) {
-                lex = mp_lexer_new_from_file(source);
+                lex = mp_lexer_new_from_file(qstr_from_str(source));
             } else {
                 lex = (mp_lexer_t *)source;
             }