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Diffstat (limited to 'source4/lib/util/genrand.c')
-rw-r--r-- | source4/lib/util/genrand.c | 361 |
1 files changed, 0 insertions, 361 deletions
diff --git a/source4/lib/util/genrand.c b/source4/lib/util/genrand.c deleted file mode 100644 index 7df4ec4e20..0000000000 --- a/source4/lib/util/genrand.c +++ /dev/null @@ -1,361 +0,0 @@ -/* - 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 "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; - -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) -{ - 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) - 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)]; - } - - seed_random_stream(seed_inbuf, sizeof(seed_inbuf)); - - return -1; -} - -/** - 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; - } - - /* - * 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; - } -} - -/** - Interface to the (hopefully) good crypto random number generator. - Will always use /dev/urandom if available. -**/ -_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; - 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(s)/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; -} |