From e5ac891c773f8893136b97a9a2c242a369ae6353 Mon Sep 17 00:00:00 2001
From: Max Bachmann <kontakt@maxbachmann.de>
Date: Sun, 26 Feb 2023 14:35:53 +0100
Subject: [PATCH 1/3] fix potential nullptr dereference + use of uninitialized
 memory

---
 Python/fileutils.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Python/fileutils.c b/Python/fileutils.c
index 897c2f9f4ea160..a236048b5cf246 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -2158,7 +2158,10 @@ _Py_join_relfile(const wchar_t *dirname, const wchar_t *relfile)
     }
     assert(wcslen(dirname) < MAXPATHLEN);
     assert(wcslen(relfile) < MAXPATHLEN - wcslen(dirname));
-    join_relfile(filename, bufsize, dirname, relfile);
+    if (join_relfile(filename, bufsize, dirname, relfile) < 0) {
+        PyMem_RawFree(filename);
+        return NULL;
+    }
     return filename;
 }
 
@@ -2196,7 +2199,7 @@ _Py_find_basename(const wchar_t *filename)
 wchar_t *
 _Py_normpath(wchar_t *path, Py_ssize_t size)
 {
-    if (!path[0] || size == 0) {
+    if (path == NULL || !path[0] || size == 0) {
         return path;
     }
     wchar_t *pEnd = size >= 0 ? &path[size] : NULL;

From 2350baf2371100adadc729154e90c82b57750f4f Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Thu, 2 Mar 2023 13:49:22 +0000
Subject: [PATCH 2/3] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../2023-03-02-13-49-21.gh-issue-102281.QCuu2N.rst               | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2023-03-02-13-49-21.gh-issue-102281.QCuu2N.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-03-02-13-49-21.gh-issue-102281.QCuu2N.rst b/Misc/NEWS.d/next/Core and Builtins/2023-03-02-13-49-21.gh-issue-102281.QCuu2N.rst
new file mode 100644
index 00000000000000..b0269dd3d92bd5
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-03-02-13-49-21.gh-issue-102281.QCuu2N.rst	
@@ -0,0 +1 @@
+Fix potential nullptr dereference and use of uninitialized memory in fileutils. Patch by Max Bachmann.

From 650b7e3a36ab9b917d2e721b957ee41083000286 Mon Sep 17 00:00:00 2001
From: Max Bachmann <kontakt@maxbachmann.de>
Date: Wed, 15 Mar 2023 00:31:38 +0100
Subject: [PATCH 3/3] apply code review

---
 Modules/getpath.c  | 5 ++++-
 Python/fileutils.c | 3 ++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/Modules/getpath.c b/Modules/getpath.c
index 13db010649fed8..d17ddbfca9ab2d 100644
--- a/Modules/getpath.c
+++ b/Modules/getpath.c
@@ -447,7 +447,10 @@ getpath_realpath(PyObject *Py_UNUSED(self) , PyObject *args)
             if (s) {
                 *s = L'\0';
             }
-            path2 = _Py_normpath(_Py_join_relfile(path, resolved), -1);
+            path2 = _Py_join_relfile(path, resolved);
+            if (path2) {
+                path2 = _Py_normpath(path2, -1);
+            }
             PyMem_RawFree((void *)path);
             path = path2;
         }
diff --git a/Python/fileutils.c b/Python/fileutils.c
index a236048b5cf246..1da6a6691f4271 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -2199,7 +2199,8 @@ _Py_find_basename(const wchar_t *filename)
 wchar_t *
 _Py_normpath(wchar_t *path, Py_ssize_t size)
 {
-    if (path == NULL || !path[0] || size == 0) {
+    assert(path != NULL);
+    if (!path[0] || size == 0) {
         return path;
     }
     wchar_t *pEnd = size >= 0 ? &path[size] : NULL;