cpython/Lib/email/_parseaddr.py

561 lines
18 KiB
Python
Raw Normal View History

# Copyright (C) 2002-2007 Python Software Foundation
# Contact: email-sig@python.org
"""Email address parsing code.
Lifted directly from rfc822.py. This should eventually be rewritten.
"""
__all__ = [
'mktime_tz',
'parsedate',
'parsedate_tz',
'quote',
]
import time
SPACE = ' '
EMPTYSTRING = ''
COMMASPACE = ', '
# Parse a date field
_monthnames = ['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul',
'aug', 'sep', 'oct', 'nov', 'dec',
'january', 'february', 'march', 'april', 'may', 'june', 'july',
'august', 'september', 'october', 'november', 'december']
_daynames = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun']
# The timezone table does not include the military time zones defined
# in RFC822, other than Z. According to RFC1123, the description in
# RFC822 gets the signs wrong, so we can't rely on any such time
# zones. RFC1123 recommends that numeric timezone indicators be used
# instead of timezone names.
_timezones = {'UT':0, 'UTC':0, 'GMT':0, 'Z':0,
'AST': -400, 'ADT': -300, # Atlantic (used in Canada)
'EST': -500, 'EDT': -400, # Eastern
'CST': -600, 'CDT': -500, # Central
'MST': -700, 'MDT': -600, # Mountain
'PST': -800, 'PDT': -700 # Pacific
}
def parsedate_tz(data):
"""Convert a date string to a time tuple.
Accounts for military timezones.
"""
res = _parsedate_tz(data)
if not res:
return
if res[9] is None:
res[9] = 0
return tuple(res)
def _parsedate_tz(data):
"""Convert date to extended time tuple.
The last (additional) element is the time zone offset in seconds, except if
the timezone was specified as -0000. In that case the last element is
None. This indicates a UTC timestamp that explicitly declaims knowledge of
the source timezone, as opposed to a +0000 timestamp that indicates the
source timezone really was UTC.
"""
if not data:
return None
data = data.split()
bpo-45001: Make email date parsing more robust against malformed input (GH-27946) Various date parsing utilities in the email module, such as email.utils.parsedate(), are supposed to gracefully handle invalid input, typically by raising an appropriate exception or by returning None. The internal email._parseaddr._parsedate_tz() helper used by some of these date parsing routines tries to be robust against malformed input, but unfortunately it can still crash ungracefully when a non-empty but whitespace-only input is passed. This manifests as an unexpected IndexError. In practice, this can happen when parsing an email with only a newline inside a ‘Date:’ header, which unfortunately happens occasionally in the real world. Here's a minimal example: $ python Python 3.9.6 (default, Jun 30 2021, 10:22:16) [GCC 11.1.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import email.utils >>> email.utils.parsedate('foo') >>> email.utils.parsedate(' ') Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/lib/python3.9/email/_parseaddr.py", line 176, in parsedate t = parsedate_tz(data) File "/usr/lib/python3.9/email/_parseaddr.py", line 50, in parsedate_tz res = _parsedate_tz(data) File "/usr/lib/python3.9/email/_parseaddr.py", line 72, in _parsedate_tz if data[0].endswith(',') or data[0].lower() in _daynames: IndexError: list index out of range The fix is rather straight-forward: guard against empty lists, after splitting on whitespace, but before accessing the first element.
2021-08-26 11:49:03 -03:00
if not data: # This happens for whitespace-only input.
return None
# The FWS after the comma after the day-of-week is optional, so search and
# adjust for this.
if data[0].endswith(',') or data[0].lower() in _daynames:
# There's a dayname here. Skip it
del data[0]
else:
i = data[0].rfind(',')
if i >= 0:
data[0] = data[0][i+1:]
if len(data) == 3: # RFC 850 date, deprecated
stuff = data[0].split('-')
if len(stuff) == 3:
data = stuff + data[1:]
if len(data) == 4:
s = data[3]
i = s.find('+')
if i == -1:
i = s.find('-')
if i > 0:
data[3:] = [s[:i], s[i:]]
else:
data.append('') # Dummy tz
if len(data) < 5:
return None
data = data[:5]
[dd, mm, yy, tm, tz] = data
if not (dd and mm and yy):
return None
mm = mm.lower()
if mm not in _monthnames:
dd, mm = mm, dd.lower()
if mm not in _monthnames:
return None
mm = _monthnames.index(mm) + 1
if mm > 12:
mm -= 12
if dd[-1] == ',':
dd = dd[:-1]
i = yy.find(':')
if i > 0:
yy, tm = tm, yy
if yy[-1] == ',':
yy = yy[:-1]
if not yy:
return None
if not yy[0].isdigit():
yy, tz = tz, yy
if tm[-1] == ',':
tm = tm[:-1]
tm = tm.split(':')
if len(tm) == 2:
[thh, tmm] = tm
tss = '0'
elif len(tm) == 3:
[thh, tmm, tss] = tm
elif len(tm) == 1 and '.' in tm[0]:
# Some non-compliant MUAs use '.' to separate time elements.
tm = tm[0].split('.')
if len(tm) == 2:
[thh, tmm] = tm
tss = 0
elif len(tm) == 3:
[thh, tmm, tss] = tm
else:
return None
else:
return None
try:
yy = int(yy)
dd = int(dd)
thh = int(thh)
tmm = int(tmm)
tss = int(tss)
except ValueError:
return None
# Check for a yy specified in two-digit format, then convert it to the
# appropriate four-digit format, according to the POSIX standard. RFC 822
# calls for a two-digit yy, but RFC 2822 (which obsoletes RFC 822)
# mandates a 4-digit yy. For more information, see the documentation for
# the time module.
if yy < 100:
# The year is between 1969 and 1999 (inclusive).
if yy > 68:
yy += 1900
# The year is between 2000 and 2068 (inclusive).
else:
yy += 2000
tzoffset = None
tz = tz.upper()
if tz in _timezones:
tzoffset = _timezones[tz]
else:
try:
tzoffset = int(tz)
except ValueError:
pass
if tzoffset==0 and tz.startswith('-'):
tzoffset = None
# Convert a timezone offset into seconds ; -0500 -> -18000
if tzoffset:
if tzoffset < 0:
tzsign = -1
tzoffset = -tzoffset
else:
tzsign = 1
tzoffset = tzsign * ( (tzoffset//100)*3600 + (tzoffset % 100)*60)
# Daylight Saving Time flag is set to -1, since DST is unknown.
return [yy, mm, dd, thh, tmm, tss, 0, 1, -1, tzoffset]
def parsedate(data):
"""Convert a time string to a time tuple."""
t = parsedate_tz(data)
if isinstance(t, tuple):
return t[:9]
else:
return t
def mktime_tz(data):
"""Turn a 10-tuple as returned by parsedate_tz() into a POSIX timestamp."""
if data[9] is None:
# No zone info, so localtime is better assumption than GMT
return time.mktime(data[:8] + (-1,))
else:
# Delay the import, since mktime_tz is rarely used
import calendar
t = calendar.timegm(data)
return t - data[9]
def quote(str):
"""Prepare string to be used in a quoted string.
Turns backslash and double quote characters into quoted pairs. These
are the only characters that need to be quoted inside a quoted string.
Does not add the surrounding double quotes.
"""
return str.replace('\\', '\\\\').replace('"', '\\"')
class AddrlistClass:
"""Address parser class by Ben Escoto.
To understand what this class does, it helps to have a copy of RFC 2822 in
front of you.
Note: this class interface is deprecated and may be removed in the future.
2011-11-11 14:35:42 -04:00
Use email.utils.AddressList instead.
"""
def __init__(self, field):
"""Initialize a new instance.
`field' is an unparsed address header field, containing
one or more addresses.
"""
self.specials = '()<>@,:;.\"[]'
self.pos = 0
self.LWS = ' \t'
self.CR = '\r\n'
self.FWS = self.LWS + self.CR
self.atomends = self.specials + self.LWS + self.CR
# Note that RFC 2822 now specifies `.' as obs-phrase, meaning that it
# is obsolete syntax. RFC 2822 requires that we recognize obsolete
# syntax, so allow dots in phrases.
self.phraseends = self.atomends.replace('.', '')
self.field = field
self.commentlist = []
def gotonext(self):
"""Skip white space and extract comments."""
wslist = []
while self.pos < len(self.field):
if self.field[self.pos] in self.LWS + '\n\r':
if self.field[self.pos] not in '\n\r':
wslist.append(self.field[self.pos])
self.pos += 1
elif self.field[self.pos] == '(':
self.commentlist.append(self.getcomment())
else:
break
return EMPTYSTRING.join(wslist)
def getaddrlist(self):
"""Parse all addresses.
Returns a list containing all of the addresses.
"""
result = []
while self.pos < len(self.field):
ad = self.getaddress()
if ad:
result += ad
else:
result.append(('', ''))
return result
def getaddress(self):
"""Parse the next address."""
self.commentlist = []
self.gotonext()
oldpos = self.pos
oldcl = self.commentlist
plist = self.getphraselist()
self.gotonext()
returnlist = []
if self.pos >= len(self.field):
# Bad email address technically, no domain.
if plist:
returnlist = [(SPACE.join(self.commentlist), plist[0])]
elif self.field[self.pos] in '.@':
# email address is just an addrspec
# this isn't very efficient since we start over
self.pos = oldpos
self.commentlist = oldcl
addrspec = self.getaddrspec()
returnlist = [(SPACE.join(self.commentlist), addrspec)]
elif self.field[self.pos] == ':':
# address is a group
returnlist = []
fieldlen = len(self.field)
self.pos += 1
while self.pos < len(self.field):
self.gotonext()
if self.pos < fieldlen and self.field[self.pos] == ';':
self.pos += 1
break
returnlist = returnlist + self.getaddress()
elif self.field[self.pos] == '<':
# Address is a phrase then a route addr
routeaddr = self.getrouteaddr()
if self.commentlist:
returnlist = [(SPACE.join(plist) + ' (' +
' '.join(self.commentlist) + ')', routeaddr)]
else:
returnlist = [(SPACE.join(plist), routeaddr)]
else:
if plist:
returnlist = [(SPACE.join(self.commentlist), plist[0])]
elif self.field[self.pos] in self.specials:
self.pos += 1
self.gotonext()
if self.pos < len(self.field) and self.field[self.pos] == ',':
self.pos += 1
return returnlist
def getrouteaddr(self):
"""Parse a route address (Return-path value).
This method just skips all the route stuff and returns the addrspec.
"""
if self.field[self.pos] != '<':
return
expectroute = False
self.pos += 1
self.gotonext()
adlist = ''
while self.pos < len(self.field):
if expectroute:
self.getdomain()
expectroute = False
elif self.field[self.pos] == '>':
self.pos += 1
break
elif self.field[self.pos] == '@':
self.pos += 1
expectroute = True
elif self.field[self.pos] == ':':
self.pos += 1
else:
adlist = self.getaddrspec()
self.pos += 1
break
self.gotonext()
return adlist
def getaddrspec(self):
"""Parse an RFC 2822 addr-spec."""
aslist = []
self.gotonext()
while self.pos < len(self.field):
preserve_ws = True
if self.field[self.pos] == '.':
if aslist and not aslist[-1].strip():
aslist.pop()
aslist.append('.')
self.pos += 1
preserve_ws = False
elif self.field[self.pos] == '"':
aslist.append('"%s"' % quote(self.getquote()))
elif self.field[self.pos] in self.atomends:
if aslist and not aslist[-1].strip():
aslist.pop()
break
else:
aslist.append(self.getatom())
ws = self.gotonext()
if preserve_ws and ws:
aslist.append(ws)
if self.pos >= len(self.field) or self.field[self.pos] != '@':
return EMPTYSTRING.join(aslist)
aslist.append('@')
self.pos += 1
self.gotonext()
domain = self.getdomain()
if not domain:
# Invalid domain, return an empty address instead of returning a
# local part to denote failed parsing.
return EMPTYSTRING
return EMPTYSTRING.join(aslist) + domain
def getdomain(self):
"""Get the complete domain name from an address."""
sdlist = []
while self.pos < len(self.field):
if self.field[self.pos] in self.LWS:
self.pos += 1
elif self.field[self.pos] == '(':
self.commentlist.append(self.getcomment())
elif self.field[self.pos] == '[':
sdlist.append(self.getdomainliteral())
elif self.field[self.pos] == '.':
self.pos += 1
sdlist.append('.')
elif self.field[self.pos] == '@':
# bpo-34155: Don't parse domains with two `@` like
# `a@malicious.org@important.com`.
return EMPTYSTRING
elif self.field[self.pos] in self.atomends:
break
else:
sdlist.append(self.getatom())
return EMPTYSTRING.join(sdlist)
def getdelimited(self, beginchar, endchars, allowcomments=True):
"""Parse a header fragment delimited by special characters.
`beginchar' is the start character for the fragment.
If self is not looking at an instance of `beginchar' then
getdelimited returns the empty string.
`endchars' is a sequence of allowable end-delimiting characters.
Parsing stops when one of these is encountered.
If `allowcomments' is non-zero, embedded RFC 2822 comments are allowed
within the parsed fragment.
"""
if self.field[self.pos] != beginchar:
return ''
slist = ['']
quote = False
self.pos += 1
while self.pos < len(self.field):
if quote:
slist.append(self.field[self.pos])
quote = False
elif self.field[self.pos] in endchars:
self.pos += 1
break
elif allowcomments and self.field[self.pos] == '(':
slist.append(self.getcomment())
continue # have already advanced pos from getcomment
elif self.field[self.pos] == '\\':
quote = True
else:
slist.append(self.field[self.pos])
self.pos += 1
return EMPTYSTRING.join(slist)
def getquote(self):
"""Get a quote-delimited fragment from self's field."""
return self.getdelimited('"', '"\r', False)
def getcomment(self):
"""Get a parenthesis-delimited fragment from self's field."""
return self.getdelimited('(', ')\r', True)
def getdomainliteral(self):
"""Parse an RFC 2822 domain-literal."""
return '[%s]' % self.getdelimited('[', ']\r', False)
def getatom(self, atomends=None):
"""Parse an RFC 2822 atom.
Optional atomends specifies a different set of end token delimiters
(the default is to use self.atomends). This is used e.g. in
getphraselist() since phrase endings must not include the `.' (which
is legal in phrases)."""
atomlist = ['']
if atomends is None:
atomends = self.atomends
while self.pos < len(self.field):
if self.field[self.pos] in atomends:
break
else:
atomlist.append(self.field[self.pos])
self.pos += 1
return EMPTYSTRING.join(atomlist)
def getphraselist(self):
"""Parse a sequence of RFC 2822 phrases.
A phrase is a sequence of words, which are in turn either RFC 2822
atoms or quoted-strings. Phrases are canonicalized by squeezing all
runs of continuous whitespace into one space.
"""
plist = []
while self.pos < len(self.field):
if self.field[self.pos] in self.FWS:
self.pos += 1
elif self.field[self.pos] == '"':
plist.append(self.getquote())
elif self.field[self.pos] == '(':
self.commentlist.append(self.getcomment())
elif self.field[self.pos] in self.phraseends:
break
else:
plist.append(self.getatom(self.phraseends))
return plist
class AddressList(AddrlistClass):
"""An AddressList encapsulates a list of parsed RFC 2822 addresses."""
def __init__(self, field):
AddrlistClass.__init__(self, field)
if field:
self.addresslist = self.getaddrlist()
else:
self.addresslist = []
def __len__(self):
return len(self.addresslist)
def __add__(self, other):
# Set union
newaddr = AddressList(None)
newaddr.addresslist = self.addresslist[:]
for x in other.addresslist:
if not x in self.addresslist:
newaddr.addresslist.append(x)
return newaddr
def __iadd__(self, other):
# Set union, in-place
for x in other.addresslist:
if not x in self.addresslist:
self.addresslist.append(x)
return self
def __sub__(self, other):
# Set difference
newaddr = AddressList(None)
for x in self.addresslist:
if not x in other.addresslist:
newaddr.addresslist.append(x)
return newaddr
def __isub__(self, other):
# Set difference, in-place
for x in other.addresslist:
if x in self.addresslist:
self.addresslist.remove(x)
return self
def __getitem__(self, index):
# Make indexing, slices, and 'in' work
return self.addresslist[index]