From 90986ef48c0df602ab38aa831a24e99e9ed61e7e Mon Sep 17 00:00:00 2001
From: Charalampos Stratakis <cstratak@redhat.com>
Date: Mon, 4 Apr 2016 15:55:28 +0200
Subject: [PATCH] JSON decoder now accepts lone surrogates
---
Lib/json/decoder.py | 35 ++++++++++++------------
Lib/json/tests/test_scanstring.py | 56 ++++++++++++++++++++++++++++++++++++---
Modules/_json.c | 49 +++++++++-------------------------
3 files changed, 83 insertions(+), 57 deletions(-)
diff --git a/Lib/json/decoder.py b/Lib/json/decoder.py
index dfcc628..1b43238 100644
--- a/Lib/json/decoder.py
+++ b/Lib/json/decoder.py
@@ -62,6 +62,16 @@ BACKSLASH = {
DEFAULT_ENCODING = "utf-8"
+def _decode_uXXXX(s, pos):
+ esc = s[pos + 1:pos + 5]
+ if len(esc) == 4 and esc[1] not in 'xX':
+ try:
+ return int(esc, 16)
+ except ValueError:
+ pass
+ msg = "Invalid \\uXXXX escape"
+ raise ValueError(errmsg(msg, s, pos))
+
def py_scanstring(s, end, encoding=None, strict=True,
_b=BACKSLASH, _m=STRINGCHUNK.match):
"""Scan the string s for a JSON string. End is the index of the
@@ -116,25 +126,16 @@ def py_scanstring(s, end, encoding=None, strict=True,
end += 1
else:
# Unicode escape sequence
- esc = s[end + 1:end + 5]
- next_end = end + 5
- if len(esc) != 4:
- msg = "Invalid \\uXXXX escape"
- raise ValueError(errmsg(msg, s, end))
- uni = int(esc, 16)
+ uni = _decode_uXXXX(s, end)
+ end += 5
# Check for surrogate pair on UCS-4 systems
- if 0xd800 <= uni <= 0xdbff and sys.maxunicode > 65535:
- msg = "Invalid \\uXXXX\\uXXXX surrogate pair"
- if not s[end + 5:end + 7] == '\\u':
- raise ValueError(errmsg(msg, s, end))
- esc2 = s[end + 7:end + 11]
- if len(esc2) != 4:
- raise ValueError(errmsg(msg, s, end))
- uni2 = int(esc2, 16)
- uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00))
- next_end += 6
+ if sys.maxunicode > 65535 and \
+ 0xd800 <= uni <= 0xdbff and s[end:end + 2] == '\\u':
+ uni2 = _decode_uXXXX(s, end + 1)
+ if 0xdc00 <= uni2 <= 0xdfff:
+ uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00))
+ end += 6
char = unichr(uni)
- end = next_end
# Append the unescaped character
_append(char)
return u''.join(chunks), end
diff --git a/Lib/json/tests/test_scanstring.py b/Lib/json/tests/test_scanstring.py
index 4fef8cb..ed80a41 100644
--- a/Lib/json/tests/test_scanstring.py
+++ b/Lib/json/tests/test_scanstring.py
@@ -5,10 +5,6 @@ from json.tests import PyTest, CTest
class TestScanstring(object):
def test_scanstring(self):
scanstring = self.json.decoder.scanstring
- self.assertEqual(
- scanstring('"z\\ud834\\udd20x"', 1, None, True),
- (u'z\U0001d120x', 16))
-
if sys.maxunicode == 65535:
self.assertEqual(
scanstring(u'"z\U0001d120x"', 1, None, True),
@@ -94,6 +90,58 @@ class TestScanstring(object):
scanstring('["Bad value", truth]', 2, None, True),
(u'Bad value', 12))
+ def test_surrogates(self):
+ scanstring = self.json.decoder.scanstring
+ def assertScan(given, expect):
+ self.assertEqual(scanstring(given, 1, None, True),
+ (expect, len(given)))
+ if not isinstance(given, unicode):
+ given = unicode(given)
+ self.assertEqual(scanstring(given, 1, None, True),
+ (expect, len(given)))
+
+ surrogates = unichr(0xd834) + unichr(0xdd20)
+ assertScan('"z\\ud834\\u0079x"', u'z\ud834yx')
+ assertScan('"z\\ud834\\udd20x"', u'z\U0001d120x')
+ assertScan('"z\\ud834\\ud834\\udd20x"', u'z\ud834\U0001d120x')
+ assertScan('"z\\ud834x"', u'z\ud834x')
+ assertScan(u'"z\\ud834\udd20x12345"', u'z%sx12345' % surrogates)
+ assertScan('"z\\udd20x"', u'z\udd20x')
+ assertScan(u'"z\ud834\udd20x"', u'z\ud834\udd20x')
+ assertScan(u'"z\ud834\\udd20x"', u'z%sx' % surrogates)
+ assertScan(u'"z\ud834x"', u'z\ud834x')
+
+ def test_bad_escapes(self):
+ scanstring = self.json.decoder.scanstring
+ bad_escapes = [
+ '"\\"',
+ '"\\x"',
+ '"\\u"',
+ '"\\u0"',
+ '"\\u01"',
+ '"\\u012"',
+ '"\\uz012"',
+ '"\\u0z12"',
+ '"\\u01z2"',
+ '"\\u012z"',
+ '"\\u0x12"',
+ '"\\u0X12"',
+ '"\\ud834\\"',
+ '"\\ud834\\u"',
+ '"\\ud834\\ud"',
+ '"\\ud834\\udd"',
+ '"\\ud834\\udd2"',
+ '"\\ud834\\uzdd2"',
+ '"\\ud834\\udzd2"',
+ '"\\ud834\\uddz2"',
+ '"\\ud834\\udd2z"',
+ '"\\ud834\\u0x20"',
+ '"\\ud834\\u0X20"',
+ ]
+ for s in bad_escapes:
+ with self.assertRaises(ValueError):
+ scanstring(s, 1, None, True)
+
def test_issue3623(self):
self.assertRaises(ValueError, self.json.decoder.scanstring, b"xxx", 1,
"xxx")
diff --git a/Modules/_json.c b/Modules/_json.c
index 7c925fd..56d9ee4 100644
--- a/Modules/_json.c
+++ b/Modules/_json.c
@@ -524,16 +524,10 @@ scanstring_str(PyObject *pystr, Py_ssize_t end, char *encoding, int strict, Py_s
}
#ifdef Py_UNICODE_WIDE
/* Surrogate pair */
- if ((c & 0xfc00) == 0xd800) {
+ if ((c & 0xfc00) == 0xd800 && end + 6 < len &&
+ buf[next++] == '\\' &&
+ buf[next++] == 'u') {
Py_UNICODE c2 = 0;
- if (end + 6 >= len) {
- raise_errmsg("Unpaired high surrogate", pystr, end - 5);
- goto bail;
- }
- if (buf[next++] != '\\' || buf[next++] != 'u') {
- raise_errmsg("Unpaired high surrogate", pystr, end - 5);
- goto bail;
- }
end += 6;
/* Decode 4 hex digits */
for (; next < end; next++) {
@@ -554,15 +548,10 @@ scanstring_str(PyObject *pystr, Py_ssize_t end, char *encoding, int strict, Py_s
goto bail;
}
}
- if ((c2 & 0xfc00) != 0xdc00) {
- raise_errmsg("Unpaired high surrogate", pystr, end - 5);
- goto bail;
- }
- c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
- }
- else if ((c & 0xfc00) == 0xdc00) {
- raise_errmsg("Unpaired low surrogate", pystr, end - 5);
- goto bail;
+ if ((c2 & 0xfc00) == 0xdc00)
+ c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
+ else
+ end -= 6;
}
#endif
}
@@ -703,16 +692,9 @@ scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next
}
#ifdef Py_UNICODE_WIDE
/* Surrogate pair */
- if ((c & 0xfc00) == 0xd800) {
+ if ((c & 0xfc00) == 0xd800 && end + 6 < len &&
+ buf[next++] == '\\' && buf[next++] == 'u') {
Py_UNICODE c2 = 0;
- if (end + 6 >= len) {
- raise_errmsg("Unpaired high surrogate", pystr, end - 5);
- goto bail;
- }
- if (buf[next++] != '\\' || buf[next++] != 'u') {
- raise_errmsg("Unpaired high surrogate", pystr, end - 5);
- goto bail;
- }
end += 6;
/* Decode 4 hex digits */
for (; next < end; next++) {
@@ -733,15 +715,10 @@ scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next
goto bail;
}
}
- if ((c2 & 0xfc00) != 0xdc00) {
- raise_errmsg("Unpaired high surrogate", pystr, end - 5);
- goto bail;
- }
- c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
- }
- else if ((c & 0xfc00) == 0xdc00) {
- raise_errmsg("Unpaired low surrogate", pystr, end - 5);
- goto bail;
+ if ((c2 & 0xfc00) == 0xdc00)
+ c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
+ else
+ end -= 6;
}
#endif
}
--
2.5.5