def _pack(self, msg):
self._flags = 0
if self.st_size is not None:
self._flags |= self.FLAG_SIZE
if (self.st_uid is not None) and (self.st_gid is not None):
self._flags |= self.FLAG_UIDGID
if self.st_mode is not None:
self._flags |= self.FLAG_PERMISSIONS
if (self.st_atime is not None) and (self.st_mtime is not None):
self._flags |= self.FLAG_AMTIME
if len(self.attr) > 0:
self._flags |= self.FLAG_EXTENDED
msg.add_int(self._flags)
if self._flags & self.FLAG_SIZE:
msg.add_int64(self.st_size)
if self._flags & self.FLAG_UIDGID:
msg.add_int(self.st_uid)
msg.add_int(self.st_gid)
if self._flags & self.FLAG_PERMISSIONS:
msg.add_int(self.st_mode)
if self._flags & self.FLAG_AMTIME:
# throw away any fractional seconds
msg.add_int(long(self.st_atime))
msg.add_int(long(self.st_mtime))
if self._flags & self.FLAG_EXTENDED:
msg.add_int(len(self.attr))
for key, val in self.attr.items():
msg.add_string(key)
msg.add_string(val)
return
def _parse_kexecdh_init(self, m):
Q_C_bytes = m.get_string()
self.Q_C = ec.EllipticCurvePublicNumbers.from_encoded_point(
self.curve, Q_C_bytes)
K_S = self.transport.get_server_key().asbytes()
K = self.P.exchange(ec.ECDH(), self.Q_C.public_key(default_backend()))
K = long(hexlify(K), 16)
# compute exchange hash
hm = Message()
hm.add(self.transport.remote_version, self.transport.local_version,
self.transport.remote_kex_init, self.transport.local_kex_init)
hm.add_string(K_S)
hm.add_string(Q_C_bytes)
# SEC1: V2.0 2.3.3 Elliptic-Curve-Point-to-Octet-String Conversion
hm.add_string(self.Q_S.public_numbers().encode_point())
hm.add_mpint(long(K))
H = self.hash_algo(hm.asbytes()).digest()
self.transport._set_K_H(K, H)
sig = self.transport.get_server_key().sign_ssh_data(H)
# construct reply
m = Message()
m.add_byte(c_MSG_KEXECDH_REPLY)
m.add_string(K_S)
m.add_string(self.Q_S.public_numbers().encode_point())
m.add_string(sig)
self.transport._send_message(m)
self.transport._activate_outbound()
def check(self, hash_algorithm, offset=0, length=0, block_size=0):
"""
Ask the server for a hash of a section of this file. This can be used
to verify a successful upload or download, or for various rsync-like
operations.
The file is hashed from ``offset``, for ``length`` bytes.
If ``length`` is 0, the remainder of the file is hashed. Thus, if both
``offset`` and ``length`` are zero, the entire file is hashed.
Normally, ``block_size`` will be 0 (the default), and this method will
return a byte string representing the requested hash (for example, a
string of length 16 for MD5, or 20 for SHA-1). If a non-zero
``block_size`` is given, each chunk of the file (from ``offset`` to
``offset + length``) of ``block_size`` bytes is computed as a separate
hash. The hash results are all concatenated and returned as a single
string.
For example, ``check('sha1', 0, 1024, 512)`` will return a string of
length 40. The first 20 bytes will be the SHA-1 of the first 512 bytes
of the file, and the last 20 bytes will be the SHA-1 of the next 512
bytes.
:param str hash_algorithm:
the name of the hash algorithm to use (normally ``"sha1"`` or
``"md5"``)
:param offset:
offset into the file to begin hashing (0 means to start from the
beginning)
:param length:
number of bytes to hash (0 means continue to the end of the file)
:param int block_size:
number of bytes to hash per result (must not be less than 256; 0
means to compute only one hash of the entire segment)
:return:
`str` of bytes representing the hash of each block, concatenated
together
:raises:
``IOError`` -- if the server doesn't support the "check-file"
extension, or possibly doesn't support the hash algorithm requested
.. note:: Many (most?) servers don't support this extension yet.
.. versionadded:: 1.4
"""
t, msg = self.sftp._request(CMD_EXTENDED, 'check-file',
self.handle, hash_algorithm, long(offset),
long(length), block_size)
msg.get_text() # ext
msg.get_text() # alg
data = msg.get_remainder()
return data
def _parse_modulus(self, line):
timestamp, mod_type, tests, tries, size, generator, modulus = \
line.split()
mod_type = int(mod_type)
tests = int(tests)
tries = int(tries)
size = int(size)
generator = int(generator)
modulus = long(modulus, 16)
# weed out primes that aren't at least:
# type 2 (meets basic structural requirements)
# test 4 (more than just a small-prime sieve)
# tries < 100 if test & 4 (at least 100 tries of miller-rabin)
if (mod_type < 2 or tests < 4
or (tests & 4 and tests < 8 and tries < 100)):
self.discarded.append(
(modulus, 'does not meet basic requirements'))
return
if generator == 0:
generator = 2
# there's a bug in the ssh "moduli" file (yeah, i know: shock! dismay!
# call cnn!) where it understates the bit lengths of these primes by 1.
# this is okay.
bl = util.bit_length(modulus)
if (bl != size) and (bl != size + 1):
self.discarded.append(
(modulus, 'incorrectly reported bit length {}'.format(size)))
return
if bl not in self.pack:
self.pack[bl] = []
self.pack[bl].append((generator, modulus))
def deflate_long(n, add_sign_padding=True):
"""turns a long-int into a normalized byte string
(adapted from Crypto.Util.number)"""
# after much testing, this algorithm was deemed to be the fastest
s = bytes()
n = long(n)
while (n != 0) and (n != -1):
s = struct.pack('>I', n & xffffffff) + s
n >>= 32
# strip off leading zeros, FFs
for i in enumerate(s):
if (n == 0) and (i[1] != deflate_zero):
break
if (n == -1) and (i[1] != deflate_ff):
break
else:
# degenerate case, n was either 0 or -1
i = (0, )
if n == 0:
s = zero_byte
else:
s = max_byte
s = s[i[0]:]
if add_sign_padding:
if (n == 0) and (byte_ord(s[0]) >= 0x80):
s = zero_byte + s
if (n == -1) and (byte_ord(s[0]) < 0x80):
s = max_byte + s
return s
def _prefetch_thread(self, chunks):
# do these read requests in a temporary thread because there may be
# a lot of them, so it may block.
for offset, length in chunks:
num = self.sftp._async_request(self, CMD_READ, self.handle,
long(offset), int(length))
with self._prefetch_lock:
self._prefetch_extents[num] = (offset, length)
def inflate_long(s, always_positive=False):
"""turns a normalized byte string into a long-int
(adapted from Crypto.Util.number)"""
out = long(0)
negative = 0
if not always_positive and (len(s) > 0) and (byte_ord(s[0]) >= 0x80):
negative = 1
if len(s) % 4:
filler = zero_byte
if negative:
filler = max_byte
# never convert this to ``s +=`` because this is a string, not a number
# noinspection PyAugmentAssignment
s = filler * (4 - len(s) % 4) + s
for i in range(0, len(s), 4):
out = (out << 32) + struct.unpack('>I', s[i:i + 4])[0]
if negative:
out -= (long(1) << (8 * len(s)))
return out
def _read(self, size):
size = min(size, self.MAX_REQUEST_SIZE)
if self._prefetching:
data = self._read_prefetch(size)
if data is not None:
return data
t, msg = self.sftp._request(CMD_READ, self.handle, long(self._realpos),
int(size))
if t != CMD_DATA:
raise SFTPError('Expected data')
return msg.get_string()
def _write(self, data):
# may write less than requested if it would exceed max packet size
chunk = min(len(data), self.MAX_REQUEST_SIZE)
sftp_async_request = self.sftp._async_request(type(None), CMD_WRITE,
self.handle,
long(self._realpos),
data[:chunk])
self._reqs.append(sftp_async_request)
if (not self.pipelined
or (len(self._reqs) > 100 and self.sftp.sock.recv_ready())):
while len(self._reqs):
req = self._reqs.popleft()
t, msg = self.sftp._read_response(req)
if t != CMD_STATUS:
raise SFTPError('Expected status')
# convert_status already called
return chunk
def _parse_kexecdh_reply(self, m):
K_S = m.get_string()
Q_S_bytes = m.get_string()
self.Q_S = ec.EllipticCurvePublicNumbers.from_encoded_point(
self.curve, Q_S_bytes)
sig = m.get_binary()
K = self.P.exchange(ec.ECDH(), self.Q_S.public_key(default_backend()))
K = long(hexlify(K), 16)
# compute exchange hash and verify signature
hm = Message()
hm.add(self.transport.local_version, self.transport.remote_version,
self.transport.local_kex_init, self.transport.remote_kex_init)
hm.add_string(K_S)
# SEC1: V2.0 2.3.3 Elliptic-Curve-Point-to-Octet-String Conversion
hm.add_string(self.Q_C.public_numbers().encode_point())
hm.add_string(Q_S_bytes)
hm.add_mpint(K)
self.transport._set_K_H(K, self.hash_algo(hm.asbytes()).digest())
self.transport._verify_key(K_S, sig)
self.transport._activate_outbound()
def __init__(self, transport):
self.transport = transport
# private key, client public and server public keys
self.P = long(0)
self.Q_C = None
self.Q_S = None
def __init__(self, transport):
self.transport = transport
self.x = long(0)
self.e = long(0)
self.f = long(0)
def asbytes(s):
"""Coerce to bytes if possible or return unchanged."""
if isinstance(s, bytes_types):
return s
if isinstance(s, text_type):
# Accept text and encode as utf-8 for compatibility only.
return s.encode("utf-8")
asbytes = getattr(s, "asbytes", None)
if asbytes is not None:
return asbytes()
# May be an object that implements the buffer api, let callers handle.
return s
xffffffff = long(0xffffffff)
x80000000 = long(0x80000000)
o666 = 438
o660 = 432
o644 = 420
o600 = 384
o777 = 511
o700 = 448
o70 = 56
DEBUG = logging.DEBUG
INFO = logging.INFO
WARNING = logging.WARNING
ERROR = logging.ERROR
CRITICAL = logging.CRITICAL
class Message(object):
"""
An SSH2 message is a stream of bytes that encodes some combination of
strings, integers, bools, and infinite-precision integers (known in Python
as longs). This class builds or breaks down such a byte stream.
Normally you don't need to deal with anything this low-level, but it's
exposed for people implementing custom extensions, or features that
paramiko doesn't support yet.
"""
big_int = long(0xff000000)
def __init__(self, content=None):
"""
Create a new SSH2 message.
:param str content:
the byte stream to use as the message content (passed in only when
decomposing a message).
"""
if content is not None:
self.packet = BytesIO(content)
else:
self.packet = BytesIO()
def __str__(self):
"""
Return the byte stream content of this message, as a string/bytes obj.
"""
return self.asbytes()
def __repr__(self):
"""
Returns a string representation of this object, for debugging.
"""
return 'paramiko.Message(' + repr(self.packet.getvalue()) + ')'
def asbytes(self):
"""
Return the byte stream content of this Message, as bytes.
"""
return self.packet.getvalue()
def rewind(self):
"""
Rewind the message to the beginning as if no items had been parsed
out of it yet.
"""
self.packet.seek(0)
def get_remainder(self):
"""
Return the bytes (as a `str`) of this message that haven't already been
parsed and returned.
"""
position = self.packet.tell()
remainder = self.packet.read()
self.packet.seek(position)
return remainder
def get_so_far(self):
"""
Returns the `str` bytes of this message that have been parsed and
returned. The string passed into a message's constructor can be
regenerated by concatenating ``get_so_far`` and `get_remainder`.
"""
position = self.packet.tell()
self.rewind()
return self.packet.read(position)
def get_bytes(self, n):
"""
Return the next ``n`` bytes of the message (as a `str`), without
decomposing into an int, decoded string, etc. Just the raw bytes are
returned. Returns a string of ``n`` zero bytes if there weren't ``n``
bytes remaining in the message.
"""
b = self.packet.read(n)
max_pad_size = 1 << 20 # Limit padding to 1 MB
if len(b) < n < max_pad_size:
return b + zero_byte * (n - len(b))
return b
def get_byte(self):
"""
Return the next byte of the message, without decomposing it. This
is equivalent to `get_bytes(1) <get_bytes>`.
:return:
the next (`str`) byte of the message, or ``'\000'`` if there aren't
any bytes remaining.
"""
return self.get_bytes(1)
def get_boolean(self):
"""
Fetch a boolean from the stream.
"""
b = self.get_bytes(1)
return b != zero_byte
def get_adaptive_int(self):
"""
Fetch an int from the stream.
:return: a 32-bit unsigned `int`.
"""
byte = self.get_bytes(1)
if byte == max_byte:
return util.inflate_long(self.get_binary())
byte += self.get_bytes(3)
return struct.unpack('>I', byte)[0]
def get_int(self):
"""
Fetch an int from the stream.
"""
return struct.unpack('>I', self.get_bytes(4))[0]
def get_int64(self):
"""
Fetch a 64-bit int from the stream.
:return: a 64-bit unsigned integer (`long`).
"""
return struct.unpack('>Q', self.get_bytes(8))[0]
def get_mpint(self):
"""
Fetch a long int (mpint) from the stream.
:return: an arbitrary-length integer (`long`).
"""
return util.inflate_long(self.get_binary())
def get_string(self):
"""
Fetch a `str` from the stream. This could be a byte string and may
contain unprintable characters. (It's not unheard of for a string to
contain another byte-stream message.)
"""
return self.get_bytes(self.get_int())
def get_text(self):
"""
Fetch a Unicode string from the stream.
"""
return u(self.get_string())
def get_binary(self):
"""
Fetch a string from the stream. This could be a byte string and may
contain unprintable characters. (It's not unheard of for a string to
contain another byte-stream Message.)
"""
return self.get_bytes(self.get_int())
def get_list(self):
"""
Fetch a list of `strings <str>` from the stream.
These are trivially encoded as comma-separated values in a string.
"""
return self.get_text().split(',')
def add_bytes(self, b):
"""
Write bytes to the stream, without any formatting.
:param str b: bytes to add
"""
self.packet.write(b)
return self
def add_byte(self, b):
"""
Write a single byte to the stream, without any formatting.
:param str b: byte to add
"""
self.packet.write(b)
return self
def add_boolean(self, b):
"""
Add a boolean value to the stream.
:param bool b: boolean value to add
"""
if b:
self.packet.write(one_byte)
else:
self.packet.write(zero_byte)
return self
def add_int(self, n):
"""
Add an integer to the stream.
:param int n: integer to add
"""
self.packet.write(struct.pack('>I', n))
return self
def add_adaptive_int(self, n):
"""
Add an integer to the stream.
:param int n: integer to add
"""
if n >= Message.big_int:
self.packet.write(max_byte)
self.add_string(util.deflate_long(n))
else:
self.packet.write(struct.pack('>I', n))
return self
def add_int64(self, n):
"""
Add a 64-bit int to the stream.
:param long n: long int to add
"""
self.packet.write(struct.pack('>Q', n))
return self
def add_mpint(self, z):
"""
Add a long int to the stream, encoded as an infinite-precision
integer. This method only works on positive numbers.
:param long z: long int to add
"""
self.add_string(util.deflate_long(z))
return self
def add_string(self, s):
"""
Add a string to the stream.
:param str s: string to add
"""
s = asbytes(s)
self.add_int(len(s))
self.packet.write(s)
return self
def add_list(self, l):
"""
Add a list of strings to the stream. They are encoded identically to
a single string of values separated by commas. (Yes, really, that's
how SSH2 does it.)
:param l: list of strings to add
"""
self.add_string(','.join(l))
return self
def _add(self, i):
if type(i) is bool:
return self.add_boolean(i)
elif isinstance(i, integer_types):
return self.add_adaptive_int(i)
elif type(i) is list:
return self.add_list(i)
else:
return self.add_string(i)
def add(self, *seq):
"""
Add a sequence of items to the stream. The values are encoded based
on their type: str, int, bool, list, or long.
.. warning::
Longs are encoded non-deterministically. Don't use this method.
:param seq: the sequence of items
"""
for item in seq:
self._add(item)
