-/*
+/*
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 3 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, see <http://www.gnu.org/licenses/>.
*/
-#include "includes.h"
+#include "replace.h"
#include "system/filesys.h"
-#include "../lib/crypto/crypto.h"
-#include "system/locale.h"
-
-/**
- * @file
- * @brief Random number generation
- */
-
-static unsigned char hash[258];
-static uint32_t counter;
-
-static bool done_reseed = false;
-static unsigned int bytes_since_reseed = 0;
+#include "lib/util/genrand.h"
+#include "sys_rw_data.h"
+#include "lib/util/blocking.h"
static int urand_fd = -1;
-static void (*reseed_callback)(void *userdata, int *newseed);
-static void *reseed_callback_userdata = NULL;
-
-/**
- Copy any user given reseed data.
-**/
-
-_PUBLIC_ void set_rand_reseed_callback(void (*fn)(void *, int *), void *userdata)
-{
- reseed_callback = fn;
- reseed_callback_userdata = userdata;
- set_need_random_reseed();
-}
-
-/**
- * Tell the random number generator it needs to reseed.
- */
-_PUBLIC_ void set_need_random_reseed(void)
-{
- done_reseed = false;
- bytes_since_reseed = 0;
-}
-
-static void get_rand_reseed_data(int *reseed_data)
-{
- if (reseed_callback) {
- reseed_callback(reseed_callback_userdata, 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)
+static void open_urandom(void)
{
- 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 initialised, because the extra entropy is not
- worth the valgrind pain.
-*****************************************************************/
-
-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;
-
- ZERO_STRUCT(tmp_md4);
-
- fd = open(fname,O_RDONLY,0);
- if (fd == -1)
+ if (urand_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_t v1, v2; struct timeval tval; pid_t mypid;
- int reseed_data = 0;
-
- if (use_fd) {
- if (fd == -1) {
- fd = open( "/dev/urandom", O_RDONLY,0);
- }
- if (fd != -1
- && (read(fd, seed_inbuf, sizeof(seed_inbuf)) == sizeof(seed_inbuf))) {
- seed_random_stream(seed_inbuf, sizeof(seed_inbuf));
- return fd;
- }
- }
-
- /* Add in some secret file contents */
-
- do_filehash("/etc/shadow", &seed_inbuf[0]);
-
- /*
- * 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.
- */
-
- 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)];
+ urand_fd = open( "/dev/urandom", O_RDONLY,0);
+ if (urand_fd == -1) {
+ abort();
}
-
- seed_random_stream(seed_inbuf, sizeof(seed_inbuf));
-
- return -1;
+ smb_set_close_on_exec(urand_fd);
}
-/**
- Interface to the (hopefully) good crypto random number generator.
- Will use our internal PRNG if more than 40 bytes of random generation
- has been requested, otherwise tries to read from /dev/random
-**/
_PUBLIC_ void generate_random_buffer(uint8_t *out, int len)
{
- unsigned char md4_buf[64];
- unsigned char tmp_buf[16];
- unsigned char *p;
-
- if(!done_reseed) {
- bytes_since_reseed += len;
-
- /* Magic constant to try and avoid reading 40 bytes
- * and setting up the PRNG if the app only ever wants
- * a few bytes */
- if (bytes_since_reseed < 40) {
- if (urand_fd == -1) {
- urand_fd = open( "/dev/urandom", O_RDONLY,0);
- }
- if(urand_fd != -1 && (read(urand_fd, out, len) == len)) {
- return;
- }
- }
-
- urand_fd = do_reseed(true, urand_fd);
- done_reseed = true;
- }
+ ssize_t rw_ret;
- /*
- * 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.
- */
+ open_urandom();
- 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;
+ rw_ret = read_data(urand_fd, out, len);
+ if (rw_ret != len) {
+ abort();
}
}
-/**
- Interface to the (hopefully) good crypto random number generator.
- Will always use /dev/urandom if available.
-**/
+/*
+ * Keep generate_secret_buffer in case we ever want to do something
+ * different
+ */
_PUBLIC_ void generate_secret_buffer(uint8_t *out, int len)
{
- if (urand_fd == -1) {
- urand_fd = open( "/dev/urandom", O_RDONLY,0);
- }
- if(urand_fd != -1 && (read(urand_fd, out, len) == len)) {
- return;
- }
-
generate_random_buffer(out, len);
}
-
-/**
- generate a single random uint32_t
-**/
-_PUBLIC_ uint32_t generate_random(void)
-{
- uint8_t v[4];
- generate_random_buffer(v, 4);
- return IVAL(v, 0);
-}
-
-
-/**
- very basic password quality checker
-**/
-_PUBLIC_ bool check_password_quality(const char *s)
-{
- int has_digit=0, has_capital=0, has_lower=0, has_special=0, has_high=0;
- const char* reals = s;
- while (*s) {
- if (isdigit((unsigned char)*s)) {
- has_digit |= 1;
- } else if (isupper((unsigned char)*s)) {
- has_capital |= 1;
- } else if (islower((unsigned char)*s)) {
- has_lower |= 1;
- } else if (isascii((unsigned char)*s)) {
- has_special |= 1;
- } else {
- has_high++;
- }
- s++;
- }
-
- return ((has_digit + has_lower + has_capital + has_special) >= 3
- || (has_high > strlen(reals)/2));
-}
-
-/**
- Use the random number generator to generate a random string.
-**/
-
-_PUBLIC_ char *generate_random_str_list(TALLOC_CTX *mem_ctx, size_t len, const char *list)
-{
- size_t i;
- size_t list_len = strlen(list);
-
- char *retstr = talloc_array(mem_ctx, char, len + 1);
- if (!retstr) return NULL;
-
- generate_random_buffer((uint8_t *)retstr, len);
- for (i = 0; i < len; i++) {
- retstr[i] = list[retstr[i] % list_len];
- }
- retstr[i] = '\0';
-
- return retstr;
-}
-
-/**
- * Generate a random text string consisting of the specified length.
- * The returned string will be allocated.
- *
- * Characters used are: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+_-#.,
- */
-
-_PUBLIC_ char *generate_random_str(TALLOC_CTX *mem_ctx, size_t len)
-{
- char *retstr;
- const char *c_list = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+_-#.,";
-
-again:
- retstr = generate_random_str_list(mem_ctx, len, c_list);
- if (!retstr) return NULL;
-
- /* we need to make sure the random string passes basic quality tests
- or it might be rejected by windows as a password */
- if (len >= 7 && !check_password_quality(retstr)) {
- talloc_free(retstr);
- goto again;
- }
-
- return retstr;
-}
-
-/**
- * Generate a random text password.
- */
-
-_PUBLIC_ char *generate_random_password(TALLOC_CTX *mem_ctx, size_t min, size_t max)
-{
- char *retstr;
- /* This list does not include { or } because they cause
- * problems for our provision (it can create a substring
- * ${...}, and for Fedora DS (which treats {...} at the start
- * of a stored password as special
- * -- Andrew Bartlett 2010-03-11
- */
- const char *c_list = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+_-#.,@$%&!?:;<=>()[]~";
- size_t len = max;
- size_t diff;
-
- if (min > max) {
- errno = EINVAL;
- return NULL;
- }
-
- diff = max - min;
-
- if (diff > 0 ) {
- size_t tmp;
-
- generate_random_buffer((uint8_t *)&tmp, sizeof(tmp));
-
- tmp %= diff;
-
- len = min + tmp;
- }
-
-again:
- retstr = generate_random_str_list(mem_ctx, len, c_list);
- if (!retstr) return NULL;
-
- /* we need to make sure the random string passes basic quality tests
- or it might be rejected by windows as a password */
- if (len >= 7 && !check_password_quality(retstr)) {
- talloc_free(retstr);
- goto again;
- }
-
- return retstr;
-}
-
-/**
- * Generate an array of unique text strings all of the same length.
- * The returned string will be allocated.
- * Returns NULL if the number of unique combinations cannot be created.
- *
- * Characters used are: abcdefghijklmnopqrstuvwxyz0123456789+_-#.,
- */
-_PUBLIC_ char** generate_unique_strs(TALLOC_CTX *mem_ctx, size_t len,
- uint32_t num)
-{
- const char *c_list = "abcdefghijklmnopqrstuvwxyz0123456789+_-#.,";
- const unsigned c_size = 42;
- int i, j;
- unsigned rem;
- char ** strs = NULL;
-
- if (num == 0 || len == 0)
- return NULL;
-
- strs = talloc_array(mem_ctx, char *, num);
- if (strs == NULL) return NULL;
-
- for (i = 0; i < num; i++) {
- char *retstr = (char *)talloc_size(strs, len + 1);
- if (retstr == NULL) {
- talloc_free(strs);
- return NULL;
- }
- rem = i;
- for (j = 0; j < len; j++) {
- retstr[j] = c_list[rem % c_size];
- rem = rem / c_size;
- }
- retstr[j] = 0;
- strs[i] = retstr;
- if (rem != 0) {
- /* we were not able to fit the number of
- * combinations asked for in the length
- * specified */
- DEBUG(0,(__location__ ": Too many combinations %u for length %u\n",
- num, (unsigned)len));
-
- talloc_free(strs);
- return NULL;
- }
- }
-
- return strs;
-}
git.samba.org / samba.git / blobdiff