diff options
Diffstat (limited to 'paramiko/primes.py')
| -rw-r--r-- | paramiko/primes.py | 63 |
1 files changed, 22 insertions, 41 deletions
diff --git a/paramiko/primes.py b/paramiko/primes.py index 9419cd6..8e02e80 100644 --- a/paramiko/primes.py +++ b/paramiko/primes.py @@ -20,33 +20,17 @@ Utility functions for dealing with primes. """ -from Crypto.Util import number +import os from paramiko import util +from paramiko.py3compat import byte_mask, long from paramiko.ssh_exception import SSHException -def _generate_prime(bits, rng): - "primtive attempt at prime generation" - hbyte_mask = pow(2, bits % 8) - 1 - while True: - # loop catches the case where we increment n into a higher bit-range - x = rng.read((bits+7) // 8) - if hbyte_mask > 0: - x = chr(ord(x[0]) & hbyte_mask) + x[1:] - n = util.inflate_long(x, 1) - n |= 1 - n |= (1 << (bits - 1)) - while not number.isPrime(n): - n += 2 - if util.bit_length(n) == bits: - break - return n - -def _roll_random(rng, n): - "returns a random # from 0 to N-1" - bits = util.bit_length(n-1) - bytes = (bits + 7) // 8 +def _roll_random(n): + """returns a random # from 0 to N-1""" + bits = util.bit_length(n - 1) + byte_count = (bits + 7) // 8 hbyte_mask = pow(2, bits % 8) - 1 # so here's the plan: @@ -56,9 +40,9 @@ def _roll_random(rng, n): # fits, so i can't guarantee that this loop will ever finish, but the odds # of it looping forever should be infinitesimal. while True: - x = rng.read(bytes) + x = os.urandom(byte_count) if hbyte_mask > 0: - x = chr(ord(x[0]) & hbyte_mask) + x[1:] + x = byte_mask(x[0], hbyte_mask) + x[1:] num = util.inflate_long(x, 1) if num < n: break @@ -71,11 +55,10 @@ class ModulusPack (object): on systems that have such a file. """ - def __init__(self, rpool): + def __init__(self): # pack is a hash of: bits -> [ (generator, modulus) ... ] self.pack = {} self.discarded = [] - self.rng = rpool def _parse_modulus(self, line): timestamp, mod_type, tests, tries, size, generator, modulus = line.split() @@ -109,29 +92,27 @@ class ModulusPack (object): def read_file(self, filename): """ - @raise IOError: passed from any file operations that fail. + :raises IOError: passed from any file operations that fail. """ self.pack = {} - f = open(filename, 'r') - for line in f: - line = line.strip() - if (len(line) == 0) or (line[0] == '#'): - continue - try: - self._parse_modulus(line) - except: - continue - f.close() + with open(filename, 'r') as f: + for line in f: + line = line.strip() + if (len(line) == 0) or (line[0] == '#'): + continue + try: + self._parse_modulus(line) + except: + continue def get_modulus(self, min, prefer, max): - bitsizes = self.pack.keys() - bitsizes.sort() + bitsizes = sorted(self.pack.keys()) if len(bitsizes) == 0: raise SSHException('no moduli available') good = -1 # find nearest bitsize >= preferred for b in bitsizes: - if (b >= prefer) and (b < max) and ((b < good) or (good == -1)): + if (b >= prefer) and (b < max) and (b < good or good == -1): good = b # if that failed, find greatest bitsize >= min if good == -1: @@ -147,5 +128,5 @@ class ModulusPack (object): if min > good: good = bitsizes[-1] # now pick a random modulus of this bitsize - n = _roll_random(self.rng, len(self.pack[good])) + n = _roll_random(len(self.pack[good])) return self.pack[good][n] |