bpo-28806: Improve the netrc library

Doc/library/netrc.rst

@@ -18,7 +18,7 @@ the Unix :program:`ftp` program and other FTP clients.
 
 .. class:: netrc([file])
 
- A :class:`~netrc.netrc` instance or subclass instance encapsulates data from  a netrc
+ A :class:`~netrc.netrc` instance or subclass instance encapsulates data from a netrc
  file. The initialization argument, if present, specifies the file to parse. If
  no argument is given, the file :file:`.netrc` in the user's home directory will
  be read. Parse errors will raise :exc:`NetrcParseError` with diagnostic
@@ -32,6 +32,12 @@ the Unix :program:`ftp` program and other FTP clients.
 
  .. versionchanged:: 3.4 Added the POSIX permission check.
 
+ .. versionchanged:: 3.7
+ The entry in the netrc file no longer needs to contain all tokens. The missing
+ tokens' value default to an empty string. All the tokens and their values now
+ can contain arbitrary characters, like whitespace and non-ASCII characters.
+ If the login name is anonymous, it won't trigger the security check.
+
 
 .. exception:: NetrcParseError
 
@@ -75,11 +81,3 @@ Instances of :class:`~netrc.netrc` have public instance variables:
 .. attribute:: netrc.macros
 
  Dictionary mapping macro names to string lists.
-
-.. note::
-
- Passwords are limited to a subset of the ASCII character set. All ASCII
- punctuation is allowed in passwords, however, note that whitespace and
- non-printable characters are not allowed in passwords. This is a limitation
- of the way the .netrc file is parsed and may be removed in the future.
-

Lib/netrc.py

@@ -19,6 +19,51 @@ def __str__(self):
  return "%s (%s, line %s)" % (self.msg, self.filename, self.lineno)
 
 
+class _netrclex:
+ def __init__(self, fp):
+ self.lineno = 1
+ self.instream = fp
+ self.whitespace = "\n\t\r "
+ self._stack = []
+
+ def _read_char(self):
+ ch = self.instream.read(1)
+ if ch == "\n":
+ self.lineno += 1
+ return ch
+
+ def get_token(self):
+ if self._stack:
+ return self._stack.pop(0)
+ token = ""
+ fiter = iter(self._read_char, "")
+ for ch in fiter:
+ if ch in self.whitespace:
+ continue
+ if ch == "\"":
+ for ch in fiter:
+ if ch != "\"":
+ if ch == "\\":
+ ch = self._read_char()
+ token += ch
+ continue
+ return token
+ else:
+ if ch == "\\":
+ ch = self._read_char()
+ token += ch
+ for ch in fiter:
+ if ch not in self.whitespace:
+ if ch == "\\":
+ ch = self._read_char()
+ token += ch
+ continue
+ return token
+ return token
+
+ def push_token(self, token):
+ self._stack.append(token)
+
 class netrc:
  def __init__(self, file=None):
  default_netrc = file is None
@@ -33,61 +78,61 @@ def __init__(self, file=None):
  self._parse(file, fp, default_netrc)
 
  def _parse(self, file, fp, default_netrc):
- lexer = shlex.shlex(fp)
- lexer.wordchars += r"""!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""
- lexer.commenters = lexer.commenters.replace('#', '')
+ lexer = _netrclex(fp)
  while 1:
  # Look for a machine, default, or macdef top-level keyword
- saved_lineno = lexer.lineno
- toplevel = tt = lexer.get_token()
+ prev_lineno = lexer.lineno
+ tt = lexer.get_token()
  if not tt:
  break
  elif tt[0] == '#':
- if lexer.lineno == saved_lineno and len(tt) == 1:
+ if prev_lineno == lexer.lineno:
  lexer.instream.readline()
  continue
  elif tt == 'machine':
  entryname = lexer.get_token()
  elif tt == 'default':
  entryname = 'default'
- elif tt == 'macdef': # Just skip to end of macdefs
+ elif tt == 'macdef':
  entryname = lexer.get_token()
  self.macros[entryname] = []
- lexer.whitespace = ' \t'
  while 1:
  line = lexer.instream.readline()
- if not line or line == '\012':
- lexer.whitespace = ' \t\r\n'
+ if not line:
+ raise NetrcParseError(
+ "Macro definition missing null line terminator.",
+ file, lexer.lineno)
+ if line == '\n':
  break
  self.macros[entryname].append(line)
  continue
  else:
  raise NetrcParseError(
  "bad toplevel token %r" % tt, file, lexer.lineno)
 
+ if not entryname:
+ raise NetrcParseError("missing %r name" % tt, file, lexer.lineno)
+
  # We're looking at start of an entry for a named machine or default.
- login = ''
- account = password = None
+ login = account = password = ''
  self.hosts[entryname] = {}
  while 1:
+ prev_lineno = lexer.lineno
  tt = lexer.get_token()
- if (tt.startswith('#') or
- tt in {'', 'machine', 'default', 'macdef'}):
- if password:
- self.hosts[entryname] = (login, account, password)
- lexer.push_token(tt)
- break
- else:
- raise NetrcParseError(
- "malformed %s entry %s terminated by %s"
- % (toplevel, entryname, repr(tt)),
- file, lexer.lineno)
+ if tt.startswith('#'):
+ if lexer.lineno == prev_lineno:
+ lexer.instream.readline()
+ continue
+ if tt in {'', 'machine', 'default', 'macdef'}:
+ self.hosts[entryname] = (login, account, password)
+ lexer.push_token(tt)
+ break
  elif tt == 'login' or tt == 'user':
  login = lexer.get_token()
  elif tt == 'account':
  account = lexer.get_token()
  elif tt == 'password':
- if os.name == 'posix' and default_netrc:
+ if os.name == 'posix' and default_netrc and login != "anonymous":
  prop = os.fstat(fp.fileno())
  if prop.st_uid != os.getuid():
  import pwd
@@ -127,10 +172,10 @@ def __repr__(self):
  rep = ""
  for host in self.hosts.keys():
  attrs = self.hosts[host]
- rep = rep + "machine "+ host + "\n\tlogin " + repr(attrs[0]) + "\n"
+ rep = rep + "machine "+ host + "\n\tlogin " + attrs[0] + "\n"
  if attrs[1]:
- rep = rep + "account " + repr(attrs[1])
- rep = rep + "\tpassword " + repr(attrs[2]) + "\n"
+ rep = rep + "account " + attrs[1]
+ rep = rep + "\tpassword " + attrs[2] + "\n"
  for macro in self.macros.keys():
  rep = rep + "macdef " + macro + "\n"
  for line in self.macros[macro]: