From efb71742ca8ff9ec3211c5b3cf5d311fdceecd1c Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra@samba.org>
Date: Mon, 20 Apr 1998 22:43:54 +0000
Subject: Makefile: Added genrand.o clientgen.c: Changed to fill change
 password buffer with random stuff. password.c: Changed to get challenge from
 genrand.c server.c: Added #ifdef around O_SYNC. version.h: Changed to
 1.9.19prealpha. genrand.c:

   New code to generate (hopefully) good random numbers for
use in crypto challenges/session keys etc.

PLEASE REVIEW THIS CODE AND SUGGEST IMPROVEMENTS !!!!!!

Jeremy.
(This used to be commit 608e98546392fd0aac9b33f4feac43615dbb4405)
---
 source3/lib/genrand.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 source3/lib/genrand.c

(limited to 'source3/lib/genrand.c')

diff --git a/source3/lib/genrand.c b/source3/lib/genrand.c
new file mode 100644
index 0000000000..b26269f091
--- /dev/null
+++ b/source3/lib/genrand.c
@@ -0,0 +1,137 @@
+/* 
+   Unix SMB/Netbios implementation.
+   Version 1.9.
+
+   Functions to create reasonable random numbers for crypto use.
+
+   Copyright (C) Jeremy Allison 1998
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+extern int DEBUGLEVEL;
+
+/**************************************************************
+ Try and get a good random number seed. Try a number of
+ different factors. Firstly, try /dev/random and try and
+ read from this. If this fails iterate through /tmp and
+ XOR all the file timestamps. If this fails then just use
+ a combination of pid and time of day (yes I know this
+ sucks :-). Finally md4 the result.
+**************************************************************/
+
+static uint32 do_reseed(void)
+{
+  static int counter = 0;
+  unsigned char md4_outbuf[16];
+  unsigned char md4_inbuf[40];
+  BOOL got_random = False;
+  uint32 v1, v2, ret;
+  int fd;
+  struct timeval tval;
+
+  memset(md4_inbuf, '\0', sizeof(md4_inbuf));
+
+  fd = open( "/dev/random", O_RDONLY);
+  if(fd >= 0) {
+    /* 
+     * We can use /dev/random !
+     */
+    if(read(fd, md4_inbuf, 40) == 40) {
+      got_random = True;
+      DEBUG(10,("do_reseed: got 40 bytes from /dev/random.\n"));
+    }
+    close(fd);
+  }
+
+  if(!got_random) {
+    /*
+     * /dev/random failed - try /tmp/ for timestamps.
+     */
+    void *dp = sys_opendir("/tmp");
+
+    if(dp != NULL) {
+      char *p;
+
+      while ((p = readdirname(dp))) {           
+        struct stat st;
+        if(sys_stat(p,&st) != 0)
+          SIVAL(md4_inbuf, ((counter%sizeof(md4_inbuf))/4), 
+                IVAL(md4_inbuf,((counter%sizeof(md4_inbuf))/4)) ^ st.st_atime);
+          counter++;
+          DEBUG(10,("do_reseed: value from file %s.\n", p));
+        }
+      }
+    closedir(dp); 
+  }
+
+  /*
+   * Finally add the counter, time of day, and pid.
+   */
+  GetTimeOfDay(&tval);
+  v1 = (counter++) + getpid() + tval.tv_sec;
+  v2 = (counter++) * getpid() + tval.tv_usec;
+
+  SIVAL(md4_inbuf, 32, v1 ^ IVAL(md4_inbuf, 32));
+  SIVAL(md4_inbuf, 36, v1 ^ IVAL(md4_inbuf, 36));
+
+  mdfour(md4_outbuf, md4_inbuf, sizeof(md4_inbuf));
+
+  /* XOR everything togther in blocks of 4 bytes. */
+  ret = IVAL(md4_outbuf,0);
+  ret ^= IVAL(md4_outbuf,4);
+  ret ^= IVAL(md4_outbuf,8);
+  ret ^= IVAL(md4_outbuf,12);
+
+  DEBUG(10,("do_reseed: returning seed %lu\n", ret));
+
+  return ret;
+}
+
+/*******************************************************************
+ Interface to the (hopefully) good crypto random number generator.
+********************************************************************/
+
+void generate_random_buffer( unsigned char *out, int len, BOOL re_seed)
+{
+  static BOOL done_reseed = False;
+  unsigned char tmp_buf[64];
+  unsigned char md4_buf[16];
+  unsigned char *p;
+
+  if(!done_reseed || re_seed) {
+    srandom(do_reseed());
+    done_reseed = True;
+  }
+
+  /*
+   * Generate random numbers in chunks of 64 bytes,
+   * then md4 them & copy to the output buffer.
+   */
+
+  p = out;
+  while(len > 0) {
+    int i;
+    int copy_len = len > 16 ? 16 : len;
+    for( i = 0; i < 16; i++)
+      SIVAL(tmp_buf, i*4, random());
+    mdfour(md4_buf, tmp_buf, sizeof(tmp_buf));
+    memcpy(p, md4_buf, copy_len);
+    p += copy_len;
+    len -= copy_len;
+  }
+}
-- 
cgit