Line data    Source code

       1             : /*
       2             :    Unix SMB/CIFS implementation.
       3             : 
       4             :    Functions to create reasonable random numbers for crypto use.
       5             : 
       6             :    Copyright (C) Jeremy Allison 2001
       7             : 
       8             :    This program is free software; you can redistribute it and/or modify
       9             :    it under the terms of the GNU General Public License as published by
      10             :    the Free Software Foundation; either version 3 of the License, or
      11             :    (at your option) any later version.
      12             : 
      13             :    This program is distributed in the hope that it will be useful,
      14             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      16             :    GNU General Public License for more details.
      17             : 
      18             :    You should have received a copy of the GNU General Public License
      19             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.
      20             : */
      21             : 
      22             : #include "replace.h"
      23             : #include "lib/util/genrand.h"
      24             : 
      25             : #include <gnutls/gnutls.h>
      26             : #include <gnutls/crypto.h>
      27             : 
      28             : /*
      29             :  * Details about the GnuTLS CSPRNG:
      30             :  *
      31             :  * https://nikmav.blogspot.com/2017/03/improving-by-simplifying-gnutls-prng.html
      32             :  */
      33             : 
      34     2656896 : _PUBLIC_ void generate_random_buffer(uint8_t *out, int len)
      35             : {
      36             :         /* Random number generator for temporary keys. */
      37     2656896 :         gnutls_rnd(GNUTLS_RND_RANDOM, out, len);
      38     2656896 : }
      39             : 
      40       39938 : _PUBLIC_ void generate_secret_buffer(uint8_t *out, int len)
      41             : {
      42             :         /*
      43             :          * Random number generator for long term keys.
      44             :          *
      45             :          * The key generator, will re-seed after a fixed amount of bytes is
      46             :          * generated (typically less than the nonce), and will also re-seed
      47             :          * based on time, i.e., after few hours of operation without reaching
      48             :          * the limit for a re-seed. For its re-seed it mixes mixes data obtained
      49             :          * from the OS random device with the previous key.
      50             :          */
      51       39938 :         gnutls_rnd(GNUTLS_RND_KEY, out, len);
      52       39938 : }
      53             : 
      54       54377 : _PUBLIC_ void generate_nonce_buffer(uint8_t *out, int len)
      55             : {
      56             :         /*
      57             :          * Random number generator for nonce and initialization vectors.
      58             :          *
      59             :          * The nonce generator will reseed after outputting a fixed amount of
      60             :          * bytes (typically few megabytes), or after few hours of operation
      61             :          * without reaching the limit has passed.
      62             :          */
      63       54377 :         gnutls_rnd(GNUTLS_RND_NONCE, out, len);
      64       54377 : }