Merge flask framework and other stuff from master

1 files changed, 241 insertions, 0 deletions

diff --git a/python/werkzeug/security.py b/python/werkzeug/security.py
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+# -*- coding: utf-8 -*-
+"""
+    werkzeug.security
+    ~~~~~~~~~~~~~~~~~
+
+    Security related helpers such as secure password hashing tools.
+
+    :copyright: 2007 Pallets
+    :license: BSD-3-Clause
+"""
+import codecs
+import hashlib
+import hmac
+import os
+import posixpath
+from random import SystemRandom
+from struct import Struct
+
+from ._compat import izip
+from ._compat import PY2
+from ._compat import range_type
+from ._compat import text_type
+from ._compat import to_bytes
+from ._compat import to_native
+
+SALT_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+DEFAULT_PBKDF2_ITERATIONS = 150000
+
+_pack_int = Struct(">I").pack
+_builtin_safe_str_cmp = getattr(hmac, "compare_digest", None)
+_sys_rng = SystemRandom()
+_os_alt_seps = list(
+    sep for sep in [os.path.sep, os.path.altsep] if sep not in (None, "/")
+)
+
+
+def pbkdf2_hex(
+    data, salt, iterations=DEFAULT_PBKDF2_ITERATIONS, keylen=None, hashfunc=None
+):
+    """Like :func:`pbkdf2_bin`, but returns a hex-encoded string.
+
+    .. versionadded:: 0.9
+
+    :param data: the data to derive.
+    :param salt: the salt for the derivation.
+    :param iterations: the number of iterations.
+    :param keylen: the length of the resulting key.  If not provided,
+                   the digest size will be used.
+    :param hashfunc: the hash function to use.  This can either be the
+                     string name of a known hash function, or a function
+                     from the hashlib module.  Defaults to sha256.
+    """
+    rv = pbkdf2_bin(data, salt, iterations, keylen, hashfunc)
+    return to_native(codecs.encode(rv, "hex_codec"))
+
+
+def pbkdf2_bin(
+    data, salt, iterations=DEFAULT_PBKDF2_ITERATIONS, keylen=None, hashfunc=None
+):
+    """Returns a binary digest for the PBKDF2 hash algorithm of `data`
+    with the given `salt`. It iterates `iterations` times and produces a
+    key of `keylen` bytes. By default, SHA-256 is used as hash function;
+    a different hashlib `hashfunc` can be provided.
+
+    .. versionadded:: 0.9
+
+    :param data: the data to derive.
+    :param salt: the salt for the derivation.
+    :param iterations: the number of iterations.
+    :param keylen: the length of the resulting key.  If not provided
+                   the digest size will be used.
+    :param hashfunc: the hash function to use.  This can either be the
+                     string name of a known hash function or a function
+                     from the hashlib module.  Defaults to sha256.
+    """
+    if not hashfunc:
+        hashfunc = "sha256"
+
+    data = to_bytes(data)
+    salt = to_bytes(salt)
+
+    if callable(hashfunc):
+        _test_hash = hashfunc()
+        hash_name = getattr(_test_hash, "name", None)
+    else:
+        hash_name = hashfunc
+    return hashlib.pbkdf2_hmac(hash_name, data, salt, iterations, keylen)
+
+
+def safe_str_cmp(a, b):
+    """This function compares strings in somewhat constant time.  This
+    requires that the length of at least one string is known in advance.
+
+    Returns `True` if the two strings are equal, or `False` if they are not.
+
+    .. versionadded:: 0.7
+    """
+    if isinstance(a, text_type):
+        a = a.encode("utf-8")
+    if isinstance(b, text_type):
+        b = b.encode("utf-8")
+
+    if _builtin_safe_str_cmp is not None:
+        return _builtin_safe_str_cmp(a, b)
+
+    if len(a) != len(b):
+        return False
+
+    rv = 0
+    if PY2:
+        for x, y in izip(a, b):
+            rv |= ord(x) ^ ord(y)
+    else:
+        for x, y in izip(a, b):
+            rv |= x ^ y
+
+    return rv == 0
+
+
+def gen_salt(length):
+    """Generate a random string of SALT_CHARS with specified ``length``."""
+    if length <= 0:
+        raise ValueError("Salt length must be positive")
+    return "".join(_sys_rng.choice(SALT_CHARS) for _ in range_type(length))
+
+
+def _hash_internal(method, salt, password):
+    """Internal password hash helper.  Supports plaintext without salt,
+    unsalted and salted passwords.  In case salted passwords are used
+    hmac is used.
+    """
+    if method == "plain":
+        return password, method
+
+    if isinstance(password, text_type):
+        password = password.encode("utf-8")
+
+    if method.startswith("pbkdf2:"):
+        args = method[7:].split(":")
+        if len(args) not in (1, 2):
+            raise ValueError("Invalid number of arguments for PBKDF2")
+        method = args.pop(0)
+        iterations = args and int(args[0] or 0) or DEFAULT_PBKDF2_ITERATIONS
+        is_pbkdf2 = True
+        actual_method = "pbkdf2:%s:%d" % (method, iterations)
+    else:
+        is_pbkdf2 = False
+        actual_method = method
+
+    if is_pbkdf2:
+        if not salt:
+            raise ValueError("Salt is required for PBKDF2")
+        rv = pbkdf2_hex(password, salt, iterations, hashfunc=method)
+    elif salt:
+        if isinstance(salt, text_type):
+            salt = salt.encode("utf-8")
+        mac = _create_mac(salt, password, method)
+        rv = mac.hexdigest()
+    else:
+        rv = hashlib.new(method, password).hexdigest()
+    return rv, actual_method
+
+
+def _create_mac(key, msg, method):
+    if callable(method):
+        return hmac.HMAC(key, msg, method)
+
+    def hashfunc(d=b""):
+        return hashlib.new(method, d)
+
+    # Python 2.7 used ``hasattr(digestmod, '__call__')``
+    # to detect if hashfunc is callable
+    hashfunc.__call__ = hashfunc
+    return hmac.HMAC(key, msg, hashfunc)
+
+
+def generate_password_hash(password, method="pbkdf2:sha256", salt_length=8):
+    """Hash a password with the given method and salt with a string of
+    the given length. The format of the string returned includes the method
+    that was used so that :func:`check_password_hash` can check the hash.
+
+    The format for the hashed string looks like this::
+
+        method$salt$hash
+
+    This method can **not** generate unsalted passwords but it is possible
+    to set param method='plain' in order to enforce plaintext passwords.
+    If a salt is used, hmac is used internally to salt the password.
+
+    If PBKDF2 is wanted it can be enabled by setting the method to
+    ``pbkdf2:method:iterations`` where iterations is optional::
+
+        pbkdf2:sha256:80000$salt$hash
+        pbkdf2:sha256$salt$hash
+
+    :param password: the password to hash.
+    :param method: the hash method to use (one that hashlib supports). Can
+                   optionally be in the format ``pbkdf2:<method>[:iterations]``
+                   to enable PBKDF2.
+    :param salt_length: the length of the salt in letters.
+    """
+    salt = gen_salt(salt_length) if method != "plain" else ""
+    h, actual_method = _hash_internal(method, salt, password)
+    return "%s$%s$%s" % (actual_method, salt, h)
+
+
+def check_password_hash(pwhash, password):
+    """check a password against a given salted and hashed password value.
+    In order to support unsalted legacy passwords this method supports
+    plain text passwords, md5 and sha1 hashes (both salted and unsalted).
+
+    Returns `True` if the password matched, `False` otherwise.
+
+    :param pwhash: a hashed string like returned by
+                   :func:`generate_password_hash`.
+    :param password: the plaintext password to compare against the hash.
+    """
+    if pwhash.count("$") < 2:
+        return False
+    method, salt, hashval = pwhash.split("$", 2)
+    return safe_str_cmp(_hash_internal(method, salt, password)[0], hashval)
+
+
+def safe_join(directory, *pathnames):
+    """Safely join `directory` and one or more untrusted `pathnames`.  If this
+    cannot be done, this function returns ``None``.
+
+    :param directory: the base directory.
+    :param pathnames: the untrusted pathnames relative to that directory.
+    """
+    parts = [directory]
+    for filename in pathnames:
+        if filename != "":
+            filename = posixpath.normpath(filename)
+        for sep in _os_alt_seps:
+            if sep in filename:
+                return None
+        if os.path.isabs(filename) or filename == ".." or filename.startswith("../"):
+            return None
+        parts.append(filename)
+    return posixpath.join(*parts)