From 5a910c0715dc4de3e73d2b4c87663e18ff5a73b7 Mon Sep 17 00:00:00 2001
From: Felix Fontein <felix@fontein.de>
Date: Thu, 2 May 2024 15:58:28 +0200
Subject: [PATCH] ACME timestamp parser: do not choke on nanoseconds.

---
 plugins/module_utils/acme/backends.py         | 23 +++++++++++++++++++
 .../plugins/module_utils/acme/backend_data.py |  4 ++++
 2 files changed, 27 insertions(+)

diff --git a/plugins/module_utils/acme/backends.py b/plugins/module_utils/acme/backends.py
index 2db282667..2f7f5d01a 100644
--- a/plugins/module_utils/acme/backends.py
+++ b/plugins/module_utils/acme/backends.py
@@ -40,8 +40,31 @@
 )
 
 
+_FRACTIONAL_MATCHER = re.compile(r'^(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2})(|\.\d+)(Z|[+-]\d{2}:?\d{2}.*)$')
+
+
+def _reduce_fractional_digits(timestamp_str):
+    """
+    Given a RFC 3339 timestamp that includes too many digits for the fractional seconds part, reduces these to at most 6.
+    """
+    # RFC 3339 (https://www.rfc-editor.org/info/rfc3339)
+    m = _FRACTIONAL_MATCHER.match(timestamp_str)
+    if not m:
+        raise BackendException('Cannot parse ISO 8601 timestamp {0!r}'.format(timestamp_str))
+    timestamp, fractional, timezone = m.groups()
+    if len(fractional) > 7:
+        # Python does not support anything smaller than microseconds
+        # (Golang supports nanoseconds, Boulder often emits more fractional digits, which Python chokes on)
+        fractional = fractional[:7]
+    return '%s%s%s' % (timestamp, fractional, timezone)
+
+
 def _parse_acme_timestamp(timestamp_str, with_timezone):
+    """
+    Parses a RFC 3339 timestamp.
+    """
     # RFC 3339 (https://www.rfc-editor.org/info/rfc3339)
+    timestamp_str = _reduce_fractional_digits(timestamp_str)
     for format in ('%Y-%m-%dT%H:%M:%SZ', '%Y-%m-%dT%H:%M:%S.%fZ', '%Y-%m-%dT%H:%M:%S%z', '%Y-%m-%dT%H:%M:%S.%f%z'):
         # Note that %z won't work with Python 2... https://stackoverflow.com/a/27829491
         try:
diff --git a/tests/unit/plugins/module_utils/acme/backend_data.py b/tests/unit/plugins/module_utils/acme/backend_data.py
index eed1fb3fa..31d083a7c 100644
--- a/tests/unit/plugins/module_utils/acme/backend_data.py
+++ b/tests/unit/plugins/module_utils/acme/backend_data.py
@@ -117,6 +117,10 @@ def load_fixture(name):
         '2024-01-01T00:11:22.123Z',
         dict(year=2024, month=1, day=1, hour=0, minute=11, second=22, microsecond=123000),
     ),
+    (
+        '2024-04-17T06:54:13.333333334Z',
+        dict(year=2024, month=4, day=17, hour=6, minute=54, second=13, microsecond=333333.334),
+    ),
 ]
 
 if sys.version_info >= (3, 5):