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Validate portions of mpy load to detect corruption #1971

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Validate portions of mpy load to detect corruption #1971

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11 changes: 9 additions & 2 deletions py/persistentcode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -128,6 +128,12 @@ STATIC qstr load_qstr(mp_reader_t *reader) {
size_t len = read_uint(reader);
char str[len];
read_bytes(reader, (byte*)str, len);
// Validate the QSTRs by ensuring they do not contain any null terminations. They are length encoded instead.
for (size_t i = 0; i < len; i++) {
if (str[i] == '\0') {
mp_raise_RuntimeError(translate("Corrupt .mpy file"));
}
}
qstr qst = qstr_from_strn(str, len);
return qst;
}
Expand All @@ -145,11 +151,12 @@ STATIC mp_obj_t load_obj(mp_reader_t *reader) {
return mp_obj_new_str_from_vstr(obj_type == 's' ? &mp_type_str : &mp_type_bytes, &vstr);
} else if (obj_type == 'i') {
return mp_parse_num_integer(vstr.buf, vstr.len, 10, NULL);
} else {
assert(obj_type == 'f' || obj_type == 'c');
} else if (obj_type == 'f' || obj_type == 'c') {
return mp_parse_num_decimal(vstr.buf, vstr.len, obj_type == 'c', false, NULL);
}
}
mp_raise_RuntimeError(translate("Corrupt .mpy file"));
return MP_OBJ_FROM_PTR(&mp_const_none_obj);
}

STATIC void load_bytecode_qstrs(mp_reader_t *reader, byte *ip, byte *ip_top) {
Expand Down