[project @ Arch-1:robey@lag.net--2003-public%secsh--dev--1.0--base-0]

initial import

(automatically generated log message)

1 files changed, 121 insertions, 0 deletions

diff --git a/dsskey.py b/dsskey.py
new file mode 100644
index 00000000..c2031291
--- /dev/null
+++ b/dsskey.py
@@ -0,0 +1,121 @@
+#!/usr/bin/python
+
+import base64
+from message import Message
+from transport import MSG_USERAUTH_REQUEST
+from util import inflate_long, deflate_long
+from Crypto.PublicKey import DSA
+from Crypto.Hash import SHA
+from ber import BER
+
+from util import format_binary
+
+
+class DSSKey(object):
+
+    def __init__(self, msg=None):
+        self.valid = 0
+        if (msg == None) or (msg.get_string() != 'ssh-dss'):
+            return
+        self.p = msg.get_mpint()
+        self.q = msg.get_mpint()
+        self.g = msg.get_mpint()
+        self.y = msg.get_mpint()
+        self.size = len(deflate_long(self.p, 0))
+        self.valid = 1
+
+    def __str__(self):
+        if not self.valid:
+            return ''
+        m = Message()
+        m.add_string('ssh-dss')
+        m.add_mpint(self.p)
+        m.add_mpint(self.q)
+        m.add_mpint(self.g)
+        m.add_mpint(self.y)
+        return str(m)
+
+    def get_name(self):
+        return 'ssh-dss'
+
+    def verify_ssh_sig(self, data, msg):
+        if not self.valid:
+            return 0
+        if len(str(msg)) == 40:
+            # spies.com bug: signature has no header
+            sig = str(msg)
+        else:
+            kind = msg.get_string()
+            if kind != 'ssh-dss':
+                return 0
+            sig = msg.get_string()
+
+        # pull out (r, s) which are NOT encoded as mpints
+        sigR = inflate_long(sig[:20], 1)
+        sigS = inflate_long(sig[20:], 1)
+        sigM = inflate_long(SHA.new(data).digest(), 1)
+
+        dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q)))
+        return dss.verify(sigM, (sigR, sigS))
+
+    def sign_ssh_data(self, data):
+        hash = SHA.new(data).digest()
+        dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q), long(self.x)))
+        # generate a suitable k
+        qsize = len(deflate_long(self.q, 0))
+        while 1:
+            k = inflate_long(randpool.get_bytes(qsize), 1)
+            if (k > 2) and (k < self.q):
+                break
+        r, s = dss.sign(inflate_long(hash, 1), k)
+        m = Message()
+        m.add_string('ssh-dss')
+        m.add_string(deflate_long(r, 0) + deflate_long(s, 0))
+        return str(m)
+
+
+        rsa = RSA.construct((long(self.n), long(self.e), long(self.d)))
+        sig = deflate_long(rsa.sign(self.pkcs1imify(hash), '')[0], 0)
+        m = Message()
+        m.add_string('ssh-rsa')
+        m.add_string(sig)
+        return str(m)
+
+    def read_private_key_file(self, filename):
+        # private key file contains:
+        # DSAPrivateKey = { version = 0, p, q, g, y, x }
+        self.valid = 0
+        try:
+            f = open(filename, 'r')
+            lines = f.readlines()
+            f.close()
+        except:
+            return
+        if lines[0].strip() != '-----BEGIN DSA PRIVATE KEY-----':
+            return
+        try:
+            data = base64.decodestring(''.join(lines[1:-1]))
+        except:
+            return
+        keylist = BER(data).decode()
+        if (type(keylist) != type([])) or (len(keylist) < 6) or (keylist[0] != 0):
+            return
+        self.p = keylist[1]
+        self.q = keylist[2]
+        self.g = keylist[3]
+        self.y = keylist[4]
+        self.x = keylist[5]
+        self.size = len(deflate_long(self.p, 0))
+        self.valid = 1
+
+    def sign_ssh_session(self, randpool, sid, username):
+        m = Message()
+        m.add_string(sid)
+        m.add_byte(chr(MSG_USERAUTH_REQUEST))
+        m.add_string(username)
+        m.add_string('ssh-connection')
+        m.add_string('publickey')
+        m.add_boolean(1)
+        m.add_string('ssh-dss')
+        m.add_string(str(self))
+        return self.sign_ssh_data(str(m))