1 files changed, 267 insertions, 0 deletions
diff --git a/source4/lib/genrand.c b/source4/lib/genrand.c
new file mode 100644
index 0000000000..e2e66f7e58
--- /dev/null
+++ b/source4/lib/genrand.c
@@ -0,0 +1,267 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   Functions to create reasonable random numbers for crypto use.
+
+   Copyright (C) Jeremy Allison 2001
+   
+   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"
+
+static unsigned char hash[258];
+static uint32 counter;
+static unsigned char *reseed_data;
+static size_t reseed_data_size;
+
+/**************************************************************** 
+ Copy any user given reseed data.
+*****************************************************************/
+
+void set_rand_reseed_data(unsigned char *data, size_t len)
+{
+	SAFE_FREE(reseed_data);
+	reseed_data_size = 0;
+
+	reseed_data = (unsigned char *)memdup(data, len);
+	if (reseed_data)
+		reseed_data_size = len;
+}
+
+/**************************************************************** 
+ Setup the seed.
+*****************************************************************/
+
+static void seed_random_stream(unsigned char *seedval, size_t seedlen)
+{
+	unsigned char j = 0;
+	size_t ind;
+
+	for (ind = 0; ind < 256; ind++)
+		hash[ind] = (unsigned char)ind;
+
+	for( ind = 0; ind < 256; ind++) {
+		unsigned char tc;
+
+		j += (hash[ind] + seedval[ind%seedlen]);
+
+		tc = hash[ind];
+		hash[ind] = hash[j];
+		hash[j] = tc;
+	}
+
+	hash[256] = 0;
+	hash[257] = 0;
+}
+
+/**************************************************************** 
+ Get datasize bytes worth of random data.
+*****************************************************************/
+
+static void get_random_stream(unsigned char *data, size_t datasize)
+{
+	unsigned char index_i = hash[256];
+	unsigned char index_j = hash[257];
+	size_t ind;
+
+	for( ind = 0; ind < datasize; ind++) {
+		unsigned char tc;
+		unsigned char t;
+
+		index_i++;
+		index_j += hash[index_i];
+
+		tc = hash[index_i];
+		hash[index_i] = hash[index_j];
+		hash[index_j] = tc;
+
+		t = hash[index_i] + hash[index_j];
+		data[ind] = hash[t];
+	}
+
+	hash[256] = index_i;
+	hash[257] = index_j;
+}
+
+/****************************************************************
+ Get a 16 byte hash from the contents of a file.
+ Note that the hash is not initialised.
+*****************************************************************/
+
+static void do_filehash(const char *fname, unsigned char *the_hash)
+{
+	unsigned char buf[1011]; /* deliberate weird size */
+	unsigned char tmp_md4[16];
+	int fd, n;
+
+	fd = sys_open(fname,O_RDONLY,0);
+	if (fd == -1)
+		return;
+
+	while ((n = read(fd, (char *)buf, sizeof(buf))) > 0) {
+		mdfour(tmp_md4, buf, n);
+		for (n=0;n<16;n++)
+			the_hash[n] ^= tmp_md4[n];
+	}
+	close(fd);
+}
+
+/**************************************************************
+ Try and get a good random number seed. Try a number of
+ different factors. Firstly, try /dev/urandom - use if exists.
+
+ We use /dev/urandom as a read of /dev/random can block if
+ the entropy pool dries up. This leads clients to timeout
+ or be very slow on connect.
+
+ If we can't use /dev/urandom then seed the stream random generator
+ above...
+**************************************************************/
+
+static int do_reseed(BOOL use_fd, int fd)
+{
+	unsigned char seed_inbuf[40];
+	uint32 v1, v2; struct timeval tval; pid_t mypid;
+	struct passwd *pw;
+
+	if (use_fd) {
+		if (fd != -1)
+			return fd;
+
+		fd = sys_open( "/dev/urandom", O_RDONLY,0);
+		if(fd >= 0)
+			return fd;
+	}
+
+	/* Add in some secret file contents */
+
+	do_filehash("/etc/shadow", &seed_inbuf[0]);
+	do_filehash(lp_smb_passwd_file(), &seed_inbuf[16]);
+
+	/*
+	 * Add in the root encrypted password.
+	 * On any system where security is taken
+	 * seriously this will be secret.
+	 */
+
+	pw = getpwnam_alloc("root");
+	if (pw && pw->pw_passwd) {
+		size_t i;
+		unsigned char md4_tmp[16];
+		mdfour(md4_tmp, (unsigned char *)pw->pw_passwd, strlen(pw->pw_passwd));
+		for (i=0;i<16;i++)
+			seed_inbuf[8+i] ^= md4_tmp[i];
+		passwd_free(&pw);
+	}
+
+	/*
+	 * Add the counter, time of day, and pid.
+	 */
+
+	GetTimeOfDay(&tval);
+	mypid = getpid();
+	v1 = (counter++) + mypid + tval.tv_sec;
+	v2 = (counter++) * mypid + tval.tv_usec;
+
+	SIVAL(seed_inbuf, 32, v1 ^ IVAL(seed_inbuf, 32));
+	SIVAL(seed_inbuf, 36, v2 ^ IVAL(seed_inbuf, 36));
+
+	/*
+	 * Add any user-given reseed data.
+	 */
+
+	if (reseed_data) {
+		size_t i;
+		for (i = 0; i < sizeof(seed_inbuf); i++)
+			seed_inbuf[i] ^= reseed_data[i % reseed_data_size];
+	}
+
+	seed_random_stream(seed_inbuf, sizeof(seed_inbuf));
+
+	return -1;
+}
+
+/*******************************************************************
+ Interface to the (hopefully) good crypto random number generator.
+********************************************************************/
+
+void generate_random_buffer( unsigned char *out, int len, BOOL do_reseed_now)
+{
+	static BOOL done_reseed = False;
+	static int urand_fd = -1;
+	unsigned char md4_buf[64];
+	unsigned char tmp_buf[16];
+	unsigned char *p;
+
+	if(!done_reseed || do_reseed_now) {
+		urand_fd = do_reseed(True, urand_fd);
+		done_reseed = True;
+	}
+
+	if (urand_fd != -1 && len > 0) {
+
+		if (read(urand_fd, out, len) == len)
+			return; /* len bytes of random data read from urandom. */
+
+		/* Read of urand error, drop back to non urand method. */
+		close(urand_fd);
+		urand_fd = -1;
+		do_reseed(False, -1);
+		done_reseed = True;
+	}
+
+	/*
+	 * Generate random numbers in chunks of 64 bytes,
+	 * then md4 them & copy to the output buffer.
+	 * This way the raw state of the stream is never externally
+	 * seen.
+	 */
+
+	p = out;
+	while(len > 0) {
+		int copy_len = len > 16 ? 16 : len;
+
+		get_random_stream(md4_buf, sizeof(md4_buf));
+		mdfour(tmp_buf, md4_buf, sizeof(md4_buf));
+		memcpy(p, tmp_buf, copy_len);
+		p += copy_len;
+		len -= copy_len;
+	}
+}
+
+/*******************************************************************
+ Use the random number generator to generate a random string.
+********************************************************************/
+
+static char c_list[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+_-#.,";
+
+char *generate_random_str(size_t len)
+{
+	static unsigned char retstr[256];
+	size_t i;
+
+	memset(retstr, '\0', sizeof(retstr));
+
+	if (len > sizeof(retstr)-1)
+		len = sizeof(retstr) -1;
+	generate_random_buffer( retstr, len, False);
+	for (i = 0; i < len; i++)
+		retstr[i] = c_list[ retstr[i] % (sizeof(c_list)-1) ];
+
+	retstr[i] = '\0';
+
+	return (char *)retstr;
+}