/*
- Unix SMB/Netbios implementation.
- Version 1.9.
+ Unix SMB/CIFS implementation.
Functions to create reasonable random numbers for crypto use.
- Copyright (C) Jeremy Allison 1998
+ 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
#include "includes.h"
-extern int DEBUGLEVEL;
-static uint32 counter = 0;
+static unsigned char hash[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;
+ }
+}
+
+/****************************************************************
+ 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.
+ Get a 16 byte hash from the contents of a file.
+ Note that the hash is not initialised.
*****************************************************************/
-static void do_filehash(char *fname, unsigned char *hash)
+
+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;
+ if (fd == -1)
+ return;
while ((n = read(fd, (char *)buf, sizeof(buf))) > 0) {
mdfour(tmp_md4, buf, n);
for (n=0;n<16;n++)
- hash[n] ^= tmp_md4[n];
+ the_hash[n] ^= tmp_md4[n];
}
close(fd);
}
-
-
-/****************************************************************
- Try and get a seed by looking at the atimes of files in a given
- directory. XOR them into the buf array.
-*****************************************************************/
-
-static void do_dirrand(char *name, unsigned char *buf, int buf_len)
-{
- DIR *dp = opendir(name);
- pstring fullname;
- size_t len_left;
- size_t fullname_len;
- char *pos;
-
- pstrcpy(fullname, name);
- fullname_len = strlen(fullname);
-
- if(fullname_len + 2 > sizeof(pstring))
- return;
-
- if(fullname[fullname_len] != '/') {
- fullname[fullname_len] = '/';
- fullname[fullname_len+1] = '\0';
- fullname_len = strlen(fullname);
- }
-
- len_left = sizeof(pstring) - fullname_len - 1;
- pos = &fullname[fullname_len];
-
- if(dp != NULL) {
- char *p;
-
- while ((p = readdirname(dp))) {
- SMB_STRUCT_STAT st;
-
- if(strlen(p) <= len_left)
- pstrcpy(pos, p);
-
- if(sys_stat(fullname,&st) == 0) {
- SIVAL(buf, ((counter * 4)%(buf_len-4)),
- IVAL(buf,((counter * 4)%(buf_len-4))) ^ st.st_atime);
- counter++;
- DEBUG(10,("do_dirrand: value from file %s.\n", fullname));
- }
- }
- closedir(dp);
- }
-}
-
/**************************************************************
Try and get a good random number seed. Try a number of
- different factors. Firstly, try /dev/urandom and try and
- read from this. If this fails iterate through /tmp and
- /dev and XOR all the file timestamps. Next add in
- a hash of the contents of /etc/shadow and the smb passwd
- file and a combination of pid and time of day (yes I know this
- sucks :-). Finally md4 the result.
+ 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.
- The result goes in a 16 byte buffer passed from the caller
+ If we can't use /dev/urandom then seed the stream random generator
+ above...
**************************************************************/
-static uint32 do_reseed(unsigned char *md4_outbuf)
+static int do_reseed(BOOL use_fd, int fd)
{
- unsigned char md4_inbuf[40];
- BOOL got_random = False;
- uint32 v1, v2, ret;
- int fd;
- struct timeval tval;
- pid_t mypid;
- struct passwd *pw;
-
- memset(md4_inbuf, '\0', sizeof(md4_inbuf));
-
- fd = sys_open( "/dev/urandom", O_RDONLY,0);
- if(fd >= 0) {
- /*
- * We can use /dev/urandom !
- */
- if(read(fd, md4_inbuf, 40) == 40) {
- got_random = True;
- DEBUG(10,("do_reseed: got 40 bytes from /dev/urandom.\n"));
- }
- close(fd);
- }
-
- if(!got_random) {
- /*
- * /dev/urandom failed - try /dev for timestamps.
- */
- do_dirrand("/dev", md4_inbuf, sizeof(md4_inbuf));
- }
-
- /* possibly add in some secret file contents */
- do_filehash("/etc/shadow", &md4_inbuf[0]);
- do_filehash(lp_smb_passwd_file(), &md4_inbuf[16]);
-
- /* add in the root encrypted password. On any system where security is taken
- seriously this will be secret */
- pw = getpwnam("root");
- if (pw && pw->pw_passwd) {
- int i;
- unsigned char md4_tmp[16];
- mdfour(md4_tmp, (unsigned char *)pw->pw_passwd, strlen(pw->pw_passwd));
- for (i=0;i<16;i++)
- md4_inbuf[8+i] ^= md4_tmp[i];
- }
-
- /*
- * Finally 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(md4_inbuf, 32, v1 ^ IVAL(md4_inbuf, 32));
- SIVAL(md4_inbuf, 36, v2 ^ IVAL(md4_inbuf, 36));
-
- mdfour(md4_outbuf, md4_inbuf, sizeof(md4_inbuf));
-
- /*
- * Return a 32 bit int created from XORing the
- * 16 bit return buffer.
- */
-
- ret = IVAL(md4_outbuf, 0);
- ret ^= IVAL(md4_outbuf, 4);
- ret ^= IVAL(md4_outbuf, 8);
- return (ret ^ IVAL(md4_outbuf, 12));
+ 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)];
+ }
+
+ 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 re_seed)
+void generate_random_buffer( unsigned char *out, int len)
{
- static BOOL done_reseed = False;
- static unsigned char md4_buf[16];
- unsigned char tmp_buf[16];
- unsigned char *p;
-
- if(!done_reseed || re_seed) {
- sys_srandom(do_reseed(md4_buf));
- done_reseed = True;
- }
-
- /*
- * Generate random numbers in chunks of 64 bytes,
- * then md4 them & copy to the output buffer.
- * Added XOR with output from random, seeded
- * by the original md4_buf. This is to stop the
- * output from this function being the previous
- * md4_buf md4'ed. The output from this function
- * is often output onto the wire, and so it should
- * not be possible to guess the next output from
- * this function based on the previous output.
- * XORing in the output from random(), seeded by
- * the original md4 hash should stop this. JRA.
- */
-
- p = out;
- while(len > 0) {
- int i;
- int copy_len = len > 16 ? 16 : len;
- mdfour(tmp_buf, md4_buf, sizeof(md4_buf));
- memcpy(md4_buf, tmp_buf, sizeof(md4_buf));
- /* XOR in output from random(). */
- for(i = 0; i < 4; i++)
- SIVAL(tmp_buf, i*4, (IVAL(tmp_buf, i*4) ^ (uint32)sys_random()));
- memcpy(p, tmp_buf, copy_len);
- p += copy_len;
- len -= copy_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;
+
+ 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);
+ for (i = 0; i < len; i++)
+ retstr[i] = c_list[ retstr[i] % (sizeof(c_list)-1) ];
+
+ retstr[i] = '\0';
+
+ return (char *)retstr;
}
git.samba.org / tprouty / samba.git / blobdiff