bpo-33770: improve base64 exception message for encoded inputs of invalid length (GH-7416) (GH-7602)
(cherry picked from commit 1b85c71a2136d3fa6a1da05b27b1fe4e4b8ee45e)
Co-authored-by: Tal Einat <taleinat+github@gmail.com>
diff --git a/Lib/test/test_binascii.py b/Lib/test/test_binascii.py
index 8fa57cd..7418a9ce9 100644
--- a/Lib/test/test_binascii.py
+++ b/Lib/test/test_binascii.py
@@ -110,6 +110,34 @@
# empty strings. TBD: shouldn't it raise an exception instead ?
self.assertEqual(binascii.a2b_base64(self.type2test(fillers)), b'')
+ def test_base64errors(self):
+ # Test base64 with invalid padding
+ def assertIncorrectPadding(data):
+ with self.assertRaisesRegex(binascii.Error, r'(?i)Incorrect padding'):
+ binascii.a2b_base64(self.type2test(data))
+
+ assertIncorrectPadding(b'ab')
+ assertIncorrectPadding(b'ab=')
+ assertIncorrectPadding(b'abc')
+ assertIncorrectPadding(b'abcdef')
+ assertIncorrectPadding(b'abcdef=')
+ assertIncorrectPadding(b'abcdefg')
+ assertIncorrectPadding(b'a=b=')
+ assertIncorrectPadding(b'a\nb=')
+
+ # Test base64 with invalid number of valid characters (1 mod 4)
+ def assertInvalidLength(data):
+ with self.assertRaisesRegex(binascii.Error, r'(?i)invalid.+length'):
+ binascii.a2b_base64(self.type2test(data))
+
+ assertInvalidLength(b'a')
+ assertInvalidLength(b'a=')
+ assertInvalidLength(b'a==')
+ assertInvalidLength(b'a===')
+ assertInvalidLength(b'a' * 5)
+ assertInvalidLength(b'a' * (4 * 87 + 1))
+ assertInvalidLength(b'A\tB\nC ??DE') # only 5 valid characters
+
def test_uu(self):
MAX_UU = 45
for backtick in (True, False):