mirror of
https://github.com/python/cpython.git
synced 2026-04-14 07:41:00 +00:00
70ecd56113
gh-144759: Fix undefined behavior from NULL pointer arithmetic in lexer (GH-144788)
Guard against NULL pointer arithmetic in `_PyLexer_remember_fstring_buffers`
and `_PyLexer_restore_fstring_buffers`. When `start` or `multi_line_start`
are NULL (uninitialized in tok_mode_stack[0]), performing `NULL - tok->buf`
is undefined behavior. Add explicit NULL checks to store -1 as sentinel
and restore NULL accordingly.
Add test_lexer_buffer_realloc_with_null_start to test_repl.py that
exercises the code path where the lexer buffer is reallocated while
tok_mode_stack[0] has NULL start/multi_line_start pointers. This
triggers _PyLexer_remember_fstring_buffers and verifies the NULL
checks prevent undefined behavior.
(cherry picked from commit
|
||
|---|---|---|
| .. | ||
| lexer | ||
| tokenizer | ||
| action_helpers.c | ||
| asdl.py | ||
| asdl_c.py | ||
| myreadline.c | ||
| parser.c | ||
| peg_api.c | ||
| pegen.c | ||
| pegen.h | ||
| pegen_errors.c | ||
| Python.asdl | ||
| string_parser.c | ||
| string_parser.h | ||
| token.c | ||