From: Matthias Klose <doko@ubuntu.com>
Date: Sat, 4 Apr 2009 14:18:13 +0000 (+0000)
Subject: - Issue #3845: In PyRun_SimpleFileExFlags avoid invalid memory access with
X-Git-Tag: v2.7a1~1579
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=edb5e1e09ecf92a4911c154217c9c979d827caeb;p=python

- Issue #3845: In PyRun_SimpleFileExFlags avoid invalid memory access with
  short file names.
---

diff --git a/Misc/NEWS b/Misc/NEWS
index 1a7aaa68e5..db86b517b2 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -204,6 +204,9 @@ Core and Builtins
 
 - The re.sub(), re.subn() and re.split() functions now accept a flags parameter.
 
+- Issue #3845: In PyRun_SimpleFileExFlags avoid invalid memory access with
+  short file names.
+
 Library
 -------
 
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index b3866cebb8..8fc0ca199f 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -898,7 +898,7 @@ PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit,
 {
 	PyObject *m, *d, *v;
 	const char *ext;
-	int set_file_name = 0, ret;
+	int set_file_name = 0, ret, len;
 
 	m = PyImport_AddModule("__main__");
 	if (m == NULL)
@@ -915,7 +915,8 @@ PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit,
 		set_file_name = 1;
 		Py_DECREF(f);
 	}
-	ext = filename + strlen(filename) - 4;
+	len = strlen(filename);
+	ext = filename + len - (len > 4 ? 4 : 0);
 	if (maybe_pyc_file(fp, filename, ext, closeit)) {
 		/* Try to run a pyc file. First, re-open in binary */
 		if (closeit)