From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Sun, 12 Nov 2023 00:39:03 +0000 (+0100)
Subject: [3.12] Fix undefined behaviour in datetime.time.fromisoformat() (GH-111982) (#111992)
X-Git-Tag: v3.12.1~141
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1afc4dc3e6b95d4a23cdcbe2ebebe1d0ba09f0f4;p=thirdparty%2FPython%2Fcpython.git

[3.12] Fix undefined behaviour in datetime.time.fromisoformat() (GH-111982) (#111992)

Fix undefined behaviour in datetime.time.fromisoformat() (GH-111982)

Fix undefined behaviour in datetime.time.fromisoformat() when parsing a string without a timezone. 'tzoffset' is not assigned to by parse_isoformat_time if it returns 0, but time_fromisoformat then passes tzoffset to another function, which is undefined behaviour (even if the function in question does not use the value).
(cherry picked from commit 21615f77b5a580e83589abae618dbe7c298700e2)

Co-authored-by: T. Wouters <thomas@python.org>
---

diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index d8183c63f449..c8dbc750b0ef 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -4620,7 +4620,7 @@ time_fromisoformat(PyObject *cls, PyObject *tstr) {
     }
 
     int hour = 0, minute = 0, second = 0, microsecond = 0;
-    int tzoffset, tzimicrosecond = 0;
+    int tzoffset = 0, tzimicrosecond = 0;
     int rv = parse_isoformat_time(p, len,
                                   &hour, &minute, &second, &microsecond,
                                   &tzoffset, &tzimicrosecond);