From fae8f4a9cb88a68eb14750cbb8ddf8740fd67b8b Mon Sep 17 00:00:00 2001 From: Nir Soffer <nirsof@gmail.com> Date: Fri, 7 Jul 2017 09:10:46 +0300 Subject: bpo-29854: Fix segfault in call_readline() (GH-728) If history-length is set in .inputrc, and the history file is double the history size (or more), history_get(N) returns NULL, and python segfaults. Fix that by checking for NULL return value. It seems that the root cause is incorrect handling of bigger history in readline, but Python should not segfault even if readline returns unexpected value. This issue affects only GNU readline. When using libedit emulation system history size option does not work. --- Lib/test/test_readline.py | 43 ++++++++++++++++++++-- .../2017-07-07-02-18-57.bpo-29854.J8wKb_.rst | 2 + Modules/readline.c | 10 +++-- 3 files changed, 48 insertions(+), 7 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2017-07-07-02-18-57.bpo-29854.J8wKb_.rst diff --git a/Lib/test/test_readline.py b/Lib/test/test_readline.py index 06a9149..cc3001a 100644 --- a/Lib/test/test_readline.py +++ b/Lib/test/test_readline.py @@ -9,7 +9,7 @@ import subprocess import sys import tempfile import unittest -from test.support import import_module, unlink, TESTFN +from test.support import import_module, unlink, temp_dir, TESTFN from test.support.script_helper import assert_python_ok # Skip tests if there is no readline module @@ -210,13 +210,50 @@ print("history", ascii(readline.get_history_item(1))) self.assertIn(b"result " + expected + b"\r\n", output) self.assertIn(b"history " + expected + b"\r\n", output) + @unittest.skipIf(is_editline, + "editline history size configuration is broken") + def test_history_size(self): + history_size = 10 + with temp_dir() as test_dir: + inputrc = os.path.join(test_dir, "inputrc") + with open(inputrc, "wb") as f: + f.write(b"set history-size %d\n" % history_size) + + history_file = os.path.join(test_dir, "history") + with open(history_file, "wb") as f: + # history_size * 2 items crashes readline + data = b"".join(b"item %d\n" % i + for i in range(history_size * 2)) + f.write(data) + + script = """ +import os +import readline + +history_file = os.environ["HISTORY_FILE"] +readline.read_history_file(history_file) +input() +readline.write_history_file(history_file) +""" + + env = dict(os.environ) + env["INPUTRC"] = inputrc + env["HISTORY_FILE"] = history_file + + run_pty(script, input=b"last input\r", env=env) + + with open(history_file, "rb") as f: + lines = f.readlines() + self.assertEqual(len(lines), history_size) + self.assertEqual(lines[-1].strip(), b"last input") + -def run_pty(script, input=b"dummy input\r"): +def run_pty(script, input=b"dummy input\r", env=None): pty = import_module('pty') output = bytearray() [master, slave] = pty.openpty() args = (sys.executable, '-c', script) - proc = subprocess.Popen(args, stdin=slave, stdout=slave, stderr=slave) + proc = subprocess.Popen(args, stdin=slave, stdout=slave, stderr=slave, env=env) os.close(slave) with ExitStack() as cleanup: cleanup.enter_context(proc) diff --git a/Misc/NEWS.d/next/Library/2017-07-07-02-18-57.bpo-29854.J8wKb_.rst b/Misc/NEWS.d/next/Library/2017-07-07-02-18-57.bpo-29854.J8wKb_.rst new file mode 100644 index 0000000..5c43908 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2017-07-07-02-18-57.bpo-29854.J8wKb_.rst @@ -0,0 +1,2 @@ +Fix segfault in readline when using readline's history-size option. Patch +by Nir Soffer. diff --git a/Modules/readline.c b/Modules/readline.c index dfbbb29..6ba1247 100644 --- a/Modules/readline.c +++ b/Modules/readline.c @@ -1347,15 +1347,17 @@ call_readline(FILE *sys_stdin, FILE *sys_stdout, const char *prompt) if (should_auto_add_history && n > 0) { const char *line; int length = _py_get_history_length(); - if (length > 0) + if (length > 0) { + HIST_ENTRY *hist_ent; #ifdef __APPLE__ if (using_libedit_emulation) { /* handle older 0-based or newer 1-based indexing */ - line = (const char *)history_get(length + libedit_history_start - 1)->line; + hist_ent = history_get(length + libedit_history_start - 1); } else #endif /* __APPLE__ */ - line = (const char *)history_get(length)->line; - else + hist_ent = history_get(length); + line = hist_ent ? hist_ent->line : ""; + } else line = ""; if (strcmp(p, line)) add_history(p); -- cgit v0.12