--- /dev/null
+/*
+ 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 smb_arc4_state[258];
+static uint32 counter;
+
+static BOOL done_reseed = False;
+static void (*reseed_callback)(int *newseed);
+
+/****************************************************************
+ Copy any user given reseed data.
+*****************************************************************/
+
+void set_rand_reseed_callback(void (*fn)(int *))
+{
+ reseed_callback = fn;
+ set_need_random_reseed();
+}
+
+void set_need_random_reseed(void)
+{
+ done_reseed = False;
+}
+
+static void get_rand_reseed_data(int *reseed_data)
+{
+ if (reseed_callback) {
+ reseed_callback(reseed_data);
+ } else {
+ *reseed_data = 0;
+ }
+}
+
+/****************************************************************
+ 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;
+ int reseed_data = 0;
+
+ 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 = sys_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.
+ */
+
+ get_rand_reseed_data(&reseed_data);
+ if (reseed_data) {
+ size_t i;
+ for (i = 0; i < sizeof(seed_inbuf); i++)
+ seed_inbuf[i] ^= ((char *)(&reseed_data))[i % sizeof(reseed_data)];
+ }
+
+ smb_arc4_init(smb_arc4_state, 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)
+{
+ static int urand_fd = -1;
+ unsigned char md4_buf[64];
+ unsigned char tmp_buf[16];
+ unsigned char *p;
+
+ if(!done_reseed) {
+ 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;
+
+ smb_arc4_crypt(smb_arc4_state, 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);
+ for (i = 0; i < len; i++)
+ retstr[i] = c_list[ retstr[i] % (sizeof(c_list)-1) ];
+
+ retstr[i] = '\0';
+
+ return (char *)retstr;
+}
projects / samba / blobdiff