| /* |
| * magic.c - PPP Magic Number routines. |
| * |
| * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The name "Carnegie Mellon University" must not be used to |
| * endorse or promote products derived from this software without |
| * prior written permission. For permission or any legal |
| * details, please contact |
| * Office of Technology Transfer |
| * Carnegie Mellon University |
| * 5000 Forbes Avenue |
| * Pittsburgh, PA 15213-3890 |
| * (412) 268-4387, fax: (412) 268-7395 |
| * tech-transfer@andrew.cmu.edu |
| * |
| * 4. Redistributions of any form whatsoever must retain the following |
| * acknowledgment: |
| * "This product includes software developed by Computing Services |
| * at Carnegie Mellon University (http://www.cmu.edu/computing/)." |
| * |
| * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO |
| * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY |
| * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE |
| * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN |
| * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING |
| * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| /***************************************************************************** |
| * randm.c - Random number generator program file. |
| * |
| * Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc. |
| * Copyright (c) 1998 by Global Election Systems Inc. |
| * |
| * The authors hereby grant permission to use, copy, modify, distribute, |
| * and license this software and its documentation for any purpose, provided |
| * that existing copyright notices are retained in all copies and that this |
| * notice and the following disclaimer are included verbatim in any |
| * distributions. No written agreement, license, or royalty fee is required |
| * for any of the authorized uses. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| ****************************************************************************** |
| * REVISION HISTORY |
| * |
| * 03-01-01 Marc Boucher <marc@mbsi.ca> |
| * Ported to lwIP. |
| * 98-06-03 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc. |
| * Extracted from avos. |
| *****************************************************************************/ |
| |
| #include "netif/ppp/ppp_opts.h" |
| #if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */ |
| |
| #include "netif/ppp/ppp_impl.h" |
| #include "netif/ppp/magic.h" |
| |
| #if PPP_MD5_RANDM /* Using MD5 for better randomness if enabled */ |
| |
| #include "netif/ppp/pppcrypt.h" |
| |
| #define MD5_HASH_SIZE 16 |
| static char magic_randpool[MD5_HASH_SIZE]; /* Pool of randomness. */ |
| static long magic_randcount; /* Pseudo-random incrementer */ |
| static u32_t magic_randomseed; /* Seed used for random number generation. */ |
| |
| /* |
| * Churn the randomness pool on a random event. Call this early and often |
| * on random and semi-random system events to build randomness in time for |
| * usage. For randomly timed events, pass a null pointer and a zero length |
| * and this will use the system timer and other sources to add randomness. |
| * If new random data is available, pass a pointer to that and it will be |
| * included. |
| * |
| * Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427 |
| */ |
| static void magic_churnrand(char *rand_data, u32_t rand_len) { |
| lwip_md5_context md5_ctx; |
| |
| /* LWIP_DEBUGF(LOG_INFO, ("magic_churnrand: %u@%P\n", rand_len, rand_data)); */ |
| lwip_md5_init(&md5_ctx); |
| lwip_md5_starts(&md5_ctx); |
| lwip_md5_update(&md5_ctx, (u_char *)magic_randpool, sizeof(magic_randpool)); |
| if (rand_data) { |
| lwip_md5_update(&md5_ctx, (u_char *)rand_data, rand_len); |
| } else { |
| struct { |
| /* INCLUDE fields for any system sources of randomness */ |
| u32_t jiffies; |
| #ifdef LWIP_RAND |
| u32_t rand; |
| #endif /* LWIP_RAND */ |
| } sys_data; |
| magic_randomseed += sys_jiffies(); |
| sys_data.jiffies = magic_randomseed; |
| #ifdef LWIP_RAND |
| sys_data.rand = LWIP_RAND(); |
| #endif /* LWIP_RAND */ |
| /* Load sys_data fields here. */ |
| lwip_md5_update(&md5_ctx, (u_char *)&sys_data, sizeof(sys_data)); |
| } |
| lwip_md5_finish(&md5_ctx, (u_char *)magic_randpool); |
| lwip_md5_free(&md5_ctx); |
| /* LWIP_DEBUGF(LOG_INFO, ("magic_churnrand: -> 0\n")); */ |
| } |
| |
| /* |
| * Initialize the random number generator. |
| */ |
| void magic_init(void) { |
| magic_churnrand(NULL, 0); |
| } |
| |
| /* |
| * Randomize our random seed value. |
| */ |
| void magic_randomize(void) { |
| magic_churnrand(NULL, 0); |
| } |
| |
| /* |
| * magic_random_bytes - Fill a buffer with random bytes. |
| * |
| * Use the random pool to generate random data. This degrades to pseudo |
| * random when used faster than randomness is supplied using magic_churnrand(). |
| * Note: It's important that there be sufficient randomness in magic_randpool |
| * before this is called for otherwise the range of the result may be |
| * narrow enough to make a search feasible. |
| * |
| * Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427 |
| * |
| * XXX Why does he not just call magic_churnrand() for each block? Probably |
| * so that you don't ever publish the seed which could possibly help |
| * predict future values. |
| * XXX Why don't we preserve md5 between blocks and just update it with |
| * magic_randcount each time? Probably there is a weakness but I wish that |
| * it was documented. |
| */ |
| void magic_random_bytes(unsigned char *buf, u32_t buf_len) { |
| lwip_md5_context md5_ctx; |
| u_char tmp[MD5_HASH_SIZE]; |
| u32_t n; |
| |
| while (buf_len > 0) { |
| lwip_md5_init(&md5_ctx); |
| lwip_md5_starts(&md5_ctx); |
| lwip_md5_update(&md5_ctx, (u_char *)magic_randpool, sizeof(magic_randpool)); |
| lwip_md5_update(&md5_ctx, (u_char *)&magic_randcount, sizeof(magic_randcount)); |
| lwip_md5_finish(&md5_ctx, tmp); |
| lwip_md5_free(&md5_ctx); |
| magic_randcount++; |
| n = LWIP_MIN(buf_len, MD5_HASH_SIZE); |
| MEMCPY(buf, tmp, n); |
| buf += n; |
| buf_len -= n; |
| } |
| } |
| |
| /* |
| * Return a new random number. |
| */ |
| u32_t magic(void) { |
| u32_t new_rand; |
| |
| magic_random_bytes((unsigned char *)&new_rand, sizeof(new_rand)); |
| |
| return new_rand; |
| } |
| |
| #else /* PPP_MD5_RANDM */ |
| |
| /*****************************/ |
| /*** LOCAL DATA STRUCTURES ***/ |
| /*****************************/ |
| #ifndef LWIP_RAND |
| static int magic_randomized; /* Set when truely randomized. */ |
| #endif /* LWIP_RAND */ |
| static u32_t magic_randomseed; /* Seed used for random number generation. */ |
| |
| |
| /***********************************/ |
| /*** PUBLIC FUNCTION DEFINITIONS ***/ |
| /***********************************/ |
| |
| /* |
| * Initialize the random number generator. |
| * |
| * Here we attempt to compute a random number seed but even if |
| * it isn't random, we'll randomize it later. |
| * |
| * The current method uses the fields from the real time clock, |
| * the idle process counter, the millisecond counter, and the |
| * hardware timer tick counter. When this is invoked |
| * in startup(), then the idle counter and timer values may |
| * repeat after each boot and the real time clock may not be |
| * operational. Thus we call it again on the first random |
| * event. |
| */ |
| void magic_init(void) { |
| magic_randomseed += sys_jiffies(); |
| #ifndef LWIP_RAND |
| /* Initialize the Borland random number generator. */ |
| srand((unsigned)magic_randomseed); |
| #endif /* LWIP_RAND */ |
| } |
| |
| /* |
| * magic_init - Initialize the magic number generator. |
| * |
| * Randomize our random seed value. Here we use the fact that |
| * this function is called at *truely random* times by the polling |
| * and network functions. Here we only get 16 bits of new random |
| * value but we use the previous value to randomize the other 16 |
| * bits. |
| */ |
| void magic_randomize(void) { |
| #ifndef LWIP_RAND |
| if (!magic_randomized) { |
| magic_randomized = !0; |
| magic_init(); |
| /* The initialization function also updates the seed. */ |
| } else { |
| #endif /* LWIP_RAND */ |
| magic_randomseed += sys_jiffies(); |
| #ifndef LWIP_RAND |
| } |
| #endif /* LWIP_RAND */ |
| } |
| |
| /* |
| * Return a new random number. |
| * |
| * Here we use the Borland rand() function to supply a pseudo random |
| * number which we make truely random by combining it with our own |
| * seed which is randomized by truely random events. |
| * Thus the numbers will be truely random unless there have been no |
| * operator or network events in which case it will be pseudo random |
| * seeded by the real time clock. |
| */ |
| u32_t magic(void) { |
| #ifdef LWIP_RAND |
| return LWIP_RAND() + magic_randomseed; |
| #else /* LWIP_RAND */ |
| return ((u32_t)rand() << 16) + (u32_t)rand() + magic_randomseed; |
| #endif /* LWIP_RAND */ |
| } |
| |
| /* |
| * magic_random_bytes - Fill a buffer with random bytes. |
| */ |
| void magic_random_bytes(unsigned char *buf, u32_t buf_len) { |
| u32_t new_rand, n; |
| |
| while (buf_len > 0) { |
| new_rand = magic(); |
| n = LWIP_MIN(buf_len, sizeof(new_rand)); |
| MEMCPY(buf, &new_rand, n); |
| buf += n; |
| buf_len -= n; |
| } |
| } |
| #endif /* PPP_MD5_RANDM */ |
| |
| /* |
| * Return a new random number between 0 and (2^pow)-1 included. |
| */ |
| u32_t magic_pow(u8_t pow) { |
| return magic() & ~(~0UL<<pow); |
| } |
| |
| #endif /* PPP_SUPPORT */ |