mirror of https://github.com/python/cpython
388 lines
13 KiB
Python
388 lines
13 KiB
Python
# This module implements the RFCs 3490 (IDNA) and 3491 (Nameprep)
|
|
|
|
import stringprep, re, codecs
|
|
from unicodedata import ucd_3_2_0 as unicodedata
|
|
|
|
# IDNA section 3.1
|
|
dots = re.compile("[\u002E\u3002\uFF0E\uFF61]")
|
|
|
|
# IDNA section 5
|
|
ace_prefix = b"xn--"
|
|
sace_prefix = "xn--"
|
|
|
|
# This assumes query strings, so AllowUnassigned is true
|
|
def nameprep(label): # type: (str) -> str
|
|
# Map
|
|
newlabel = []
|
|
for c in label:
|
|
if stringprep.in_table_b1(c):
|
|
# Map to nothing
|
|
continue
|
|
newlabel.append(stringprep.map_table_b2(c))
|
|
label = "".join(newlabel)
|
|
|
|
# Normalize
|
|
label = unicodedata.normalize("NFKC", label)
|
|
|
|
# Prohibit
|
|
for i, c in enumerate(label):
|
|
if stringprep.in_table_c12(c) or \
|
|
stringprep.in_table_c22(c) or \
|
|
stringprep.in_table_c3(c) or \
|
|
stringprep.in_table_c4(c) or \
|
|
stringprep.in_table_c5(c) or \
|
|
stringprep.in_table_c6(c) or \
|
|
stringprep.in_table_c7(c) or \
|
|
stringprep.in_table_c8(c) or \
|
|
stringprep.in_table_c9(c):
|
|
raise UnicodeEncodeError("idna", label, i, i+1, f"Invalid character {c!r}")
|
|
|
|
# Check bidi
|
|
RandAL = [stringprep.in_table_d1(x) for x in label]
|
|
if any(RandAL):
|
|
# There is a RandAL char in the string. Must perform further
|
|
# tests:
|
|
# 1) The characters in section 5.8 MUST be prohibited.
|
|
# This is table C.8, which was already checked
|
|
# 2) If a string contains any RandALCat character, the string
|
|
# MUST NOT contain any LCat character.
|
|
for i, x in enumerate(label):
|
|
if stringprep.in_table_d2(x):
|
|
raise UnicodeEncodeError("idna", label, i, i+1,
|
|
"Violation of BIDI requirement 2")
|
|
# 3) If a string contains any RandALCat character, a
|
|
# RandALCat character MUST be the first character of the
|
|
# string, and a RandALCat character MUST be the last
|
|
# character of the string.
|
|
if not RandAL[0]:
|
|
raise UnicodeEncodeError("idna", label, 0, 1,
|
|
"Violation of BIDI requirement 3")
|
|
if not RandAL[-1]:
|
|
raise UnicodeEncodeError("idna", label, len(label)-1, len(label),
|
|
"Violation of BIDI requirement 3")
|
|
|
|
return label
|
|
|
|
def ToASCII(label): # type: (str) -> bytes
|
|
try:
|
|
# Step 1: try ASCII
|
|
label_ascii = label.encode("ascii")
|
|
except UnicodeEncodeError:
|
|
pass
|
|
else:
|
|
# Skip to step 3: UseSTD3ASCIIRules is false, so
|
|
# Skip to step 8.
|
|
if 0 < len(label_ascii) < 64:
|
|
return label_ascii
|
|
if len(label) == 0:
|
|
raise UnicodeEncodeError("idna", label, 0, 1, "label empty")
|
|
else:
|
|
raise UnicodeEncodeError("idna", label, 0, len(label), "label too long")
|
|
|
|
# Step 2: nameprep
|
|
label = nameprep(label)
|
|
|
|
# Step 3: UseSTD3ASCIIRules is false
|
|
# Step 4: try ASCII
|
|
try:
|
|
label_ascii = label.encode("ascii")
|
|
except UnicodeEncodeError:
|
|
pass
|
|
else:
|
|
# Skip to step 8.
|
|
if 0 < len(label) < 64:
|
|
return label_ascii
|
|
if len(label) == 0:
|
|
raise UnicodeEncodeError("idna", label, 0, 1, "label empty")
|
|
else:
|
|
raise UnicodeEncodeError("idna", label, 0, len(label), "label too long")
|
|
|
|
# Step 5: Check ACE prefix
|
|
if label.lower().startswith(sace_prefix):
|
|
raise UnicodeEncodeError(
|
|
"idna", label, 0, len(sace_prefix), "Label starts with ACE prefix")
|
|
|
|
# Step 6: Encode with PUNYCODE
|
|
label_ascii = label.encode("punycode")
|
|
|
|
# Step 7: Prepend ACE prefix
|
|
label_ascii = ace_prefix + label_ascii
|
|
|
|
# Step 8: Check size
|
|
# do not check for empty as we prepend ace_prefix.
|
|
if len(label_ascii) < 64:
|
|
return label_ascii
|
|
raise UnicodeEncodeError("idna", label, 0, len(label), "label too long")
|
|
|
|
def ToUnicode(label):
|
|
if len(label) > 1024:
|
|
# Protection from https://github.com/python/cpython/issues/98433.
|
|
# https://datatracker.ietf.org/doc/html/rfc5894#section-6
|
|
# doesn't specify a label size limit prior to NAMEPREP. But having
|
|
# one makes practical sense.
|
|
# This leaves ample room for nameprep() to remove Nothing characters
|
|
# per https://www.rfc-editor.org/rfc/rfc3454#section-3.1 while still
|
|
# preventing us from wasting time decoding a big thing that'll just
|
|
# hit the actual <= 63 length limit in Step 6.
|
|
if isinstance(label, str):
|
|
label = label.encode("utf-8", errors="backslashreplace")
|
|
raise UnicodeDecodeError("idna", label, 0, len(label), "label way too long")
|
|
# Step 1: Check for ASCII
|
|
if isinstance(label, bytes):
|
|
pure_ascii = True
|
|
else:
|
|
try:
|
|
label = label.encode("ascii")
|
|
pure_ascii = True
|
|
except UnicodeEncodeError:
|
|
pure_ascii = False
|
|
if not pure_ascii:
|
|
assert isinstance(label, str)
|
|
# Step 2: Perform nameprep
|
|
label = nameprep(label)
|
|
# It doesn't say this, but apparently, it should be ASCII now
|
|
try:
|
|
label = label.encode("ascii")
|
|
except UnicodeEncodeError as exc:
|
|
raise UnicodeEncodeError("idna", label, exc.start, exc.end,
|
|
"Invalid character in IDN label")
|
|
# Step 3: Check for ACE prefix
|
|
assert isinstance(label, bytes)
|
|
if not label.lower().startswith(ace_prefix):
|
|
return str(label, "ascii")
|
|
|
|
# Step 4: Remove ACE prefix
|
|
label1 = label[len(ace_prefix):]
|
|
|
|
# Step 5: Decode using PUNYCODE
|
|
try:
|
|
result = label1.decode("punycode")
|
|
except UnicodeDecodeError as exc:
|
|
offset = len(ace_prefix)
|
|
raise UnicodeDecodeError("idna", label, offset+exc.start, offset+exc.end, exc.reason)
|
|
|
|
# Step 6: Apply ToASCII
|
|
label2 = ToASCII(result)
|
|
|
|
# Step 7: Compare the result of step 6 with the one of step 3
|
|
# label2 will already be in lower case.
|
|
if str(label, "ascii").lower() != str(label2, "ascii"):
|
|
raise UnicodeDecodeError("idna", label, 0, len(label),
|
|
f"IDNA does not round-trip, '{label!r}' != '{label2!r}'")
|
|
|
|
# Step 8: return the result of step 5
|
|
return result
|
|
|
|
### Codec APIs
|
|
|
|
class Codec(codecs.Codec):
|
|
def encode(self, input, errors='strict'):
|
|
|
|
if errors != 'strict':
|
|
# IDNA is quite clear that implementations must be strict
|
|
raise UnicodeError(f"Unsupported error handling: {errors}")
|
|
|
|
if not input:
|
|
return b'', 0
|
|
|
|
try:
|
|
result = input.encode('ascii')
|
|
except UnicodeEncodeError:
|
|
pass
|
|
else:
|
|
# ASCII name: fast path
|
|
labels = result.split(b'.')
|
|
for i, label in enumerate(labels[:-1]):
|
|
if len(label) == 0:
|
|
offset = sum(len(l) for l in labels[:i]) + i
|
|
raise UnicodeEncodeError("idna", input, offset, offset+1,
|
|
"label empty")
|
|
for i, label in enumerate(labels):
|
|
if len(label) >= 64:
|
|
offset = sum(len(l) for l in labels[:i]) + i
|
|
raise UnicodeEncodeError("idna", input, offset, offset+len(label),
|
|
"label too long")
|
|
return result, len(input)
|
|
|
|
result = bytearray()
|
|
labels = dots.split(input)
|
|
if labels and not labels[-1]:
|
|
trailing_dot = b'.'
|
|
del labels[-1]
|
|
else:
|
|
trailing_dot = b''
|
|
for i, label in enumerate(labels):
|
|
if result:
|
|
# Join with U+002E
|
|
result.extend(b'.')
|
|
try:
|
|
result.extend(ToASCII(label))
|
|
except (UnicodeEncodeError, UnicodeDecodeError) as exc:
|
|
offset = sum(len(l) for l in labels[:i]) + i
|
|
raise UnicodeEncodeError(
|
|
"idna",
|
|
input,
|
|
offset + exc.start,
|
|
offset + exc.end,
|
|
exc.reason,
|
|
)
|
|
return bytes(result+trailing_dot), len(input)
|
|
|
|
def decode(self, input, errors='strict'):
|
|
|
|
if errors != 'strict':
|
|
raise UnicodeError(f"Unsupported error handling: {errors}")
|
|
|
|
if not input:
|
|
return "", 0
|
|
|
|
# IDNA allows decoding to operate on Unicode strings, too.
|
|
if not isinstance(input, bytes):
|
|
# XXX obviously wrong, see #3232
|
|
input = bytes(input)
|
|
|
|
if ace_prefix not in input.lower():
|
|
# Fast path
|
|
try:
|
|
return input.decode('ascii'), len(input)
|
|
except UnicodeDecodeError:
|
|
pass
|
|
|
|
labels = input.split(b".")
|
|
|
|
if labels and len(labels[-1]) == 0:
|
|
trailing_dot = '.'
|
|
del labels[-1]
|
|
else:
|
|
trailing_dot = ''
|
|
|
|
result = []
|
|
for i, label in enumerate(labels):
|
|
try:
|
|
u_label = ToUnicode(label)
|
|
except (UnicodeEncodeError, UnicodeDecodeError) as exc:
|
|
offset = sum(len(x) for x in labels[:i]) + len(labels[:i])
|
|
raise UnicodeDecodeError(
|
|
"idna", input, offset+exc.start, offset+exc.end, exc.reason)
|
|
else:
|
|
result.append(u_label)
|
|
|
|
return ".".join(result)+trailing_dot, len(input)
|
|
|
|
class IncrementalEncoder(codecs.BufferedIncrementalEncoder):
|
|
def _buffer_encode(self, input, errors, final):
|
|
if errors != 'strict':
|
|
# IDNA is quite clear that implementations must be strict
|
|
raise UnicodeError(f"Unsupported error handling: {errors}")
|
|
|
|
if not input:
|
|
return (b'', 0)
|
|
|
|
labels = dots.split(input)
|
|
trailing_dot = b''
|
|
if labels:
|
|
if not labels[-1]:
|
|
trailing_dot = b'.'
|
|
del labels[-1]
|
|
elif not final:
|
|
# Keep potentially unfinished label until the next call
|
|
del labels[-1]
|
|
if labels:
|
|
trailing_dot = b'.'
|
|
|
|
result = bytearray()
|
|
size = 0
|
|
for label in labels:
|
|
if size:
|
|
# Join with U+002E
|
|
result.extend(b'.')
|
|
size += 1
|
|
try:
|
|
result.extend(ToASCII(label))
|
|
except (UnicodeEncodeError, UnicodeDecodeError) as exc:
|
|
raise UnicodeEncodeError(
|
|
"idna",
|
|
input,
|
|
size + exc.start,
|
|
size + exc.end,
|
|
exc.reason,
|
|
)
|
|
size += len(label)
|
|
|
|
result += trailing_dot
|
|
size += len(trailing_dot)
|
|
return (bytes(result), size)
|
|
|
|
class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
|
|
def _buffer_decode(self, input, errors, final):
|
|
if errors != 'strict':
|
|
raise UnicodeError("Unsupported error handling: {errors}")
|
|
|
|
if not input:
|
|
return ("", 0)
|
|
|
|
# IDNA allows decoding to operate on Unicode strings, too.
|
|
if isinstance(input, str):
|
|
labels = dots.split(input)
|
|
else:
|
|
# Must be ASCII string
|
|
try:
|
|
input = str(input, "ascii")
|
|
except (UnicodeEncodeError, UnicodeDecodeError) as exc:
|
|
raise UnicodeDecodeError("idna", input,
|
|
exc.start, exc.end, exc.reason)
|
|
labels = input.split(".")
|
|
|
|
trailing_dot = ''
|
|
if labels:
|
|
if not labels[-1]:
|
|
trailing_dot = '.'
|
|
del labels[-1]
|
|
elif not final:
|
|
# Keep potentially unfinished label until the next call
|
|
del labels[-1]
|
|
if labels:
|
|
trailing_dot = '.'
|
|
|
|
result = []
|
|
size = 0
|
|
for label in labels:
|
|
try:
|
|
u_label = ToUnicode(label)
|
|
except (UnicodeEncodeError, UnicodeDecodeError) as exc:
|
|
raise UnicodeDecodeError(
|
|
"idna",
|
|
input.encode("ascii", errors="backslashreplace"),
|
|
size + exc.start,
|
|
size + exc.end,
|
|
exc.reason,
|
|
)
|
|
else:
|
|
result.append(u_label)
|
|
if size:
|
|
size += 1
|
|
size += len(label)
|
|
|
|
result = ".".join(result) + trailing_dot
|
|
size += len(trailing_dot)
|
|
return (result, size)
|
|
|
|
class StreamWriter(Codec,codecs.StreamWriter):
|
|
pass
|
|
|
|
class StreamReader(Codec,codecs.StreamReader):
|
|
pass
|
|
|
|
### encodings module API
|
|
|
|
def getregentry():
|
|
return codecs.CodecInfo(
|
|
name='idna',
|
|
encode=Codec().encode,
|
|
decode=Codec().decode,
|
|
incrementalencoder=IncrementalEncoder,
|
|
incrementaldecoder=IncrementalDecoder,
|
|
streamwriter=StreamWriter,
|
|
streamreader=StreamReader,
|
|
)
|