[project @ Arch-1:robey@lag.net--2003-public%secsh--dev--1.0--patch-87]
clean up pkey interface change the pkey interface so that it's no longer possible to have a pkey that doesn't represent a valid key. (ie: no more "blank" key objects.) also add "get_bits" and "can_sign" methods to determine the key bit length and whether it can sign things (contains the "private parts") respectively.
This commit is contained in:
Robey Pointer
parent
0737ea2ca4
commit
12287b3e0e
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@ -38,22 +38,24 @@ class DSSKey (PKey):
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data.
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"""
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def __init__(self, msg=None, data=None):
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self.valid = False
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def __init__(self, msg=None, data=None, filename=None, password=None, vals=None):
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if filename is not None:
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self._from_private_key_file(filename, password)
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return
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if (msg is None) and (data is not None):
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msg = Message(data)
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if vals is not None:
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self.p, self.q, self.g, self.y = vals
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else:
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if (msg is None) or (msg.get_string() != 'ssh-dss'):
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return
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raise SSHException('Invalid key')
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self.p = msg.get_mpint()
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self.q = msg.get_mpint()
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self.g = msg.get_mpint()
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self.y = msg.get_mpint()
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self.size = len(util.deflate_long(self.p, 0))
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self.valid = True
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self.size = util.bit_length(self.p)
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def __str__(self):
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if not self.valid:
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return ''
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m = Message()
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m.add_string('ssh-dss')
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m.add_mpint(self.p)
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@ -74,6 +76,12 @@ class DSSKey (PKey):
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def get_name(self):
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return 'ssh-dss'
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def get_bits(self):
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return self.size
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def can_sign(self):
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return hasattr(self, 'x')
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def sign_ssh_data(self, randpool, data):
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hash = SHA.new(data).digest()
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dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q), long(self.x)))
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@ -90,8 +98,6 @@ class DSSKey (PKey):
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return m
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def verify_ssh_sig(self, data, msg):
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if not self.valid:
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return 0
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if len(str(msg)) == 40:
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# spies.com bug: signature has no header
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sig = str(msg)
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@ -109,28 +115,7 @@ class DSSKey (PKey):
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dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q)))
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return dss.verify(sigM, (sigR, sigS))
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def read_private_key_file(self, filename, password=None):
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# private key file contains:
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# DSAPrivateKey = { version = 0, p, q, g, y, x }
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self.valid = False
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data = self._read_private_key_file('DSA', filename, password)
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try:
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keylist = BER(data).decode()
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except BERException, x:
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raise SSHException('Unable to parse key file: ' + str(x))
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if (type(keylist) is not list) or (len(keylist) < 6) or (keylist[0] != 0):
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raise SSHException('not a valid DSA private key file (bad ber encoding)')
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self.p = keylist[1]
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self.q = keylist[2]
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self.g = keylist[3]
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self.y = keylist[4]
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self.x = keylist[5]
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self.size = len(util.deflate_long(self.p, 0))
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self.valid = True
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def write_private_key_file(self, filename, password=None):
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if not self.valid:
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raise SSHException('Invalid key')
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keylist = [ 0, self.p, self.q, self.g, self.y, self.x ]
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try:
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b = BER()
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@ -155,12 +140,29 @@ class DSSKey (PKey):
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@since: fearow
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"""
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dsa = DSA.generate(bits, randpool.get_bytes, progress_func)
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key = DSSKey()
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key.p = dsa.p
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key.q = dsa.q
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key.g = dsa.g
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key.y = dsa.y
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key = DSSKey(vals=(dsa.p, dsa.q, dsa.g, dsa.y))
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key.x = dsa.x
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key.valid = True
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return key
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generate = staticmethod(generate)
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### internals...
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def _from_private_key_file(self, filename, password):
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# private key file contains:
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# DSAPrivateKey = { version = 0, p, q, g, y, x }
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data = self._read_private_key_file('DSA', filename, password)
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try:
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keylist = BER(data).decode()
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except BERException, x:
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raise SSHException('Unable to parse key file: ' + str(x))
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if (type(keylist) is not list) or (len(keylist) < 6) or (keylist[0] != 0):
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raise SSHException('not a valid DSA private key file (bad ber encoding)')
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self.p = keylist[1]
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self.q = keylist[2]
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self.g = keylist[3]
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self.y = keylist[4]
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self.x = keylist[5]
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self.size = util.bit_length(self.p)
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@ -55,7 +55,10 @@ class PKey (object):
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type.
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@type msg: L{Message}
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@param data: an optional string containing a public key of this type
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@type data: string
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@type data: str
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@raise SSHException: if a key cannot be created from the C{data} or
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C{msg} given, or no key was passed in.
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"""
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pass
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@ -66,7 +69,7 @@ class PKey (object):
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re-create the key object later.
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@return: string representation of an SSH key message.
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@rtype: string
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@rtype: str
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"""
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return ''
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@ -94,10 +97,30 @@ class PKey (object):
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@return: name of this private key type, in SSH terminology (for
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example, C{"ssh-rsa"}).
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@rtype: string
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@rtype: str
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"""
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return ''
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def get_bits(self):
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"""
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Return the number of significant bits in this key. This is useful
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for judging the relative security of a key.
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@return: bits in the key.
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@rtype: int
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"""
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return 0
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def can_sign(self):
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"""
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Return C{True} if this key has the private part necessary for signing
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data.
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@return: C{True} if this is a private key.
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@rtype: bool
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"""
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return False
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def get_fingerprint(self):
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"""
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Return an MD5 fingerprint of the public part of this key. Nothing
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@ -105,7 +128,7 @@ class PKey (object):
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@return: a 16-byte string (binary) of the MD5 fingerprint, in SSH
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format.
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@rtype: string
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@rtype: str
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"""
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return MD5.new(str(self)).digest()
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@ -116,7 +139,7 @@ class PKey (object):
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public key files or recognized host keys.
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@return: a base64 string containing the public part of the key.
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@rtype: string
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@rtype: str
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@since: fearow
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"""
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@ -130,7 +153,7 @@ class PKey (object):
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@param randpool: a secure random number generator.
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@type randpool: L{Crypto.Util.randpool.RandomPool}
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@param data: the data to sign.
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@type data: string
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@type data: str
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@return: an SSH signature message.
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@rtype: L{Message}
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"""
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@ -142,7 +165,7 @@ class PKey (object):
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that data, verify that it was signed with this key.
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@param data: the data that was signed.
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@type data: string
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@type data: str
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@param msg: an SSH signature message
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@type msg: L{Message}
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@return: C{True} if the signature verifies correctly; C{False}
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@ -151,39 +174,20 @@ class PKey (object):
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"""
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return False
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def read_private_key_file(self, filename, password=None):
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"""
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Read private key contents from a file into this object. If the private
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key is encrypted and C{password} is not C{None}, the given password
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will be used to decrypt the key (otherwise L{PasswordRequiredException}
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is thrown).
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@param filename: name of the file to read.
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@type filename: string
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@param password: an optional password to use to decrypt the key file,
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if it's encrypted.
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@type password: string
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@raise IOError: if there was an error reading the file.
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@raise PasswordRequiredException: if the private key file is
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encrypted, and C{password} is C{None}.
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@raise SSHException: if the key file is invalid.
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"""
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raise exception('Not implemented in PKey')
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def from_private_key_file(cl, filename, password=None):
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"""
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Create a key object by reading a private key file. This is roughly
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equivalent to creating a new key object and then calling
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L{read_private_key_file} on it. Through the magic of python, this
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factory method will exist in all subclasses of PKey (such as L{RSAKey}
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or L{DSSKey}), but is useless on the abstract PKey class.
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Create a key object by reading a private key file. If the private
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key is encrypted and C{password} is not C{None}, the given password
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will be used to decrypt the key (otherwise L{PasswordRequiredException}
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is thrown). Through the magic of python, this factory method will
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exist in all subclasses of PKey (such as L{RSAKey} or L{DSSKey}), but
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is useless on the abstract PKey class.
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@param filename: name of the file to read.
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@type filename: string
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@type filename: str
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@param password: an optional password to use to decrypt the key file,
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if it's encrypted
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@type password: string
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@type password: str
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@return: a new key object based on the given private key.
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@rtype: L{PKey}
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@ -194,8 +198,7 @@ class PKey (object):
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@since: fearow
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"""
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key = cl()
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key.read_private_key_file(filename, password)
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key = cl(filename=filename, password=password)
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return key
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from_private_key_file = classmethod(from_private_key_file)
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@ -205,9 +208,9 @@ class PKey (object):
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C{None}, the key is encrypted before writing.
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@param filename: name of the file to write.
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@type filename: string
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@type filename: str
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@param password: an optional password to use to encrypt the key file.
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@type password: string
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@type password: str
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@raise IOError: if there was an error writing the file.
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@raise SSHException: if the key is invalid.
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@ -225,14 +228,14 @@ class PKey (object):
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the key (otherwise L{PasswordRequiredException} is thrown).
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@param tag: C{"RSA"} or C{"DSA"}, the tag used to mark the data block.
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@type tag: string
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@type tag: str
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@param filename: name of the file to read.
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@type filename: string
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@type filename: str
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@param password: an optional password to use to decrypt the key file,
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if it's encrypted.
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@type password: string
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@type password: str
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@return: data blob that makes up the private key.
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@rtype: string
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@rtype: str
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@raise IOError: if there was an error reading the file.
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@raise PasswordRequiredException: if the private key file is
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@ -296,13 +299,13 @@ class PKey (object):
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a password is given, DES-EDE3-CBC is used.
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@param tag: C{"RSA"} or C{"DSA"}, the tag used to mark the data block.
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@type tag: string
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@type tag: str
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@param filename: name of the file to write.
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@type filename: string
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@type filename: str
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@param data: data blob that makes up the private key.
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@type data: string
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@type data: str
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@param password: an optional password to use to encrypt the file.
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@type password: string
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@type password: str
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@raise IOError: if there was an error writing the file.
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"""
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@ -39,20 +39,22 @@ class RSAKey (PKey):
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data.
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"""
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def __init__(self, msg=None, data=''):
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self.valid = False
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def __init__(self, msg=None, data='', filename=None, password=None, vals=None):
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if filename is not None:
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self._from_private_key_file(filename, password)
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return
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if (msg is None) and (data is not None):
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msg = Message(data)
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if vals is not None:
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self.e, self.n = vals
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else:
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if (msg is None) or (msg.get_string() != 'ssh-rsa'):
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return
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raise SSHException('Invalid key')
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self.e = msg.get_mpint()
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self.n = msg.get_mpint()
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self.size = len(util.deflate_long(self.n, 0))
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self.valid = True
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self.size = util.bit_length(self.n)
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def __str__(self):
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if not self.valid:
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return ''
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m = Message()
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m.add_string('ssh-rsa')
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m.add_mpint(self.e)
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@ -68,14 +70,11 @@ class RSAKey (PKey):
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def get_name(self):
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return 'ssh-rsa'
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def _pkcs1imify(self, data):
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"""
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turn a 20-byte SHA1 hash into a blob of data as large as the key's N,
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using PKCS1's \"emsa-pkcs1-v1_5\" encoding. totally bizarre.
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"""
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SHA1_DIGESTINFO = '\x30\x21\x30\x09\x06\x05\x2b\x0e\x03\x02\x1a\x05\x00\x04\x14'
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filler = '\xff' * (self.size - len(SHA1_DIGESTINFO) - len(data) - 3)
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return '\x00\x01' + filler + '\x00' + SHA1_DIGESTINFO + data
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def get_bits(self):
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return self.size
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def can_sign(self):
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return hasattr(self, 'd')
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def sign_ssh_data(self, randpool, data):
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hash = SHA.new(data).digest()
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@ -87,7 +86,7 @@ class RSAKey (PKey):
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return m
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def verify_ssh_sig(self, data, msg):
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if (not self.valid) or (msg.get_string() != 'ssh-rsa'):
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if msg.get_string() != 'ssh-rsa':
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return False
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sig = util.inflate_long(msg.get_string(), 1)
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# verify the signature by SHA'ing the data and encrypting it using the
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@ -97,29 +96,7 @@ class RSAKey (PKey):
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rsa = RSA.construct((long(self.n), long(self.e)))
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return rsa.verify(hash, (sig,))
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def read_private_key_file(self, filename, password=None):
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# private key file contains:
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# RSAPrivateKey = { version = 0, n, e, d, p, q, d mod p-1, d mod q-1, q**-1 mod p }
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self.valid = False
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data = self._read_private_key_file('RSA', filename, password)
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try:
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keylist = BER(data).decode()
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except BERException:
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raise SSHException('Unable to parse key file')
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if (type(keylist) is not list) or (len(keylist) < 4) or (keylist[0] != 0):
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raise SSHException('Not a valid RSA private key file (bad ber encoding)')
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self.n = keylist[1]
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self.e = keylist[2]
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self.d = keylist[3]
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# not really needed
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self.p = keylist[4]
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self.q = keylist[5]
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self.size = len(util.deflate_long(self.n, 0))
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self.valid = True
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def write_private_key_file(self, filename, password=None):
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if not self.valid:
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raise SSHException('Invalid key')
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keylist = [ 0, self.n, self.e, self.d, self.p, self.q,
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self.d % (self.p - 1), self.d % (self.q - 1),
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util.mod_inverse(self.q, self.p) ]
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@ -146,12 +123,42 @@ class RSAKey (PKey):
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@since: fearow
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"""
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rsa = RSA.generate(bits, randpool.get_bytes, progress_func)
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key = RSAKey()
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key.n = rsa.n
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key.e = rsa.e
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key = RSAKey(vals=(rsa.e, rsa.n))
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key.d = rsa.d
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key.p = rsa.p
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key.q = rsa.q
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key.valid = True
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return key
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generate = staticmethod(generate)
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### internals...
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def _pkcs1imify(self, data):
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"""
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turn a 20-byte SHA1 hash into a blob of data as large as the key's N,
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using PKCS1's \"emsa-pkcs1-v1_5\" encoding. totally bizarre.
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"""
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SHA1_DIGESTINFO = '\x30\x21\x30\x09\x06\x05\x2b\x0e\x03\x02\x1a\x05\x00\x04\x14'
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size = len(util.deflate_long(self.n, 0))
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filler = '\xff' * (size - len(SHA1_DIGESTINFO) - len(data) - 3)
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return '\x00\x01' + filler + '\x00' + SHA1_DIGESTINFO + data
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def _from_private_key_file(self, filename, password):
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# private key file contains:
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# RSAPrivateKey = { version = 0, n, e, d, p, q, d mod p-1, d mod q-1, q**-1 mod p }
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||||
data = self._read_private_key_file('RSA', filename, password)
|
||||
try:
|
||||
keylist = BER(data).decode()
|
||||
except BERException:
|
||||
raise SSHException('Unable to parse key file')
|
||||
if (type(keylist) is not list) or (len(keylist) < 4) or (keylist[0] != 0):
|
||||
raise SSHException('Not a valid RSA private key file (bad ber encoding)')
|
||||
self.n = keylist[1]
|
||||
self.e = keylist[2]
|
||||
self.d = keylist[3]
|
||||
# not really needed
|
||||
self.p = keylist[4]
|
||||
self.q = keylist[5]
|
||||
self.size = util.bit_length(self.n)
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue