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/* _ _
** _ __ ___ ___ __| | ___ ___| | mod_ssl
** | '_ ` _ \ / _ \ / _` | / __/ __| | Apache Interface to OpenSSL
** | | | | | | (_) | (_| | \__ \__ \ | www.modssl.org
** |_| |_| |_|\___/ \__,_|___|___/___/_| ftp.modssl.org
** |_____|
** ssl_engine_rand.c
** Random Number Generator Seeding
*/
/* ====================================================================
* Copyright (c) 1998-2003 Ralf S. Engelschall. 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. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by
* Ralf S. Engelschall <rse@engelschall.com> for use in the
* mod_ssl project (http://www.modssl.org/)."
*
* 4. The names "mod_ssl" must not be used to endorse or promote
* products derived from this software without prior written
* permission. For written permission, please contact
* rse@engelschall.com.
*
* 5. Products derived from this software may not be called "mod_ssl"
* nor may "mod_ssl" appear in their names without prior
* written permission of Ralf S. Engelschall.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by
* Ralf S. Engelschall <rse@engelschall.com> for use in the
* mod_ssl project (http://www.modssl.org/)."
*
* THIS SOFTWARE IS PROVIDED BY RALF S. ENGELSCHALL ``AS IS'' AND ANY
* EXPRESSED 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 RALF S. ENGELSCHALL OR
* HIS 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.
* ====================================================================
*/
/* ``The generation of random
numbers is too important
to be left to chance.'' */
#include "mod_ssl.h"
/* _________________________________________________________________
**
** Support for better seeding of SSL library's RNG
** _________________________________________________________________
*/
static int ssl_rand_choosenum(int);
static int ssl_rand_feedfp(pool *, FILE *, int);
int ssl_rand_seed(server_rec *s, pool *p, ssl_rsctx_t nCtx, char *prefix)
{
SSLModConfigRec *mc;
array_header *apRandSeed;
ssl_randseed_t *pRandSeeds;
ssl_randseed_t *pRandSeed;
unsigned char stackdata[256];
int nReq, nDone;
FILE *fp;
int i, n, l;
time_t t;
pid_t pid;
int m;
mc = myModConfig();
nReq = 0;
nDone = 0;
apRandSeed = mc->aRandSeed;
pRandSeeds = (ssl_randseed_t *)apRandSeed->elts;
for (i = 0; i < apRandSeed->nelts; i++) {
pRandSeed = &pRandSeeds[i];
if (pRandSeed->nCtx == nCtx) {
nReq += pRandSeed->nBytes;
if (pRandSeed->nSrc == SSL_RSSRC_FILE) {
/*
* seed in contents of an external file
*/
if ((fp = ap_pfopen(p, pRandSeed->cpPath, "r")) == NULL)
continue;
nDone += ssl_rand_feedfp(p, fp, pRandSeed->nBytes);
ap_pfclose(p, fp);
}
else if (pRandSeed->nSrc == SSL_RSSRC_EXEC) {
/*
* seed in contents generated by an external program
*/
if ((fp = ssl_util_ppopen(s, p, ap_psprintf(p, "%s %d",
pRandSeed->cpPath, pRandSeed->nBytes))) == NULL)
continue;
nDone += ssl_rand_feedfp(p, fp, pRandSeed->nBytes);
ssl_util_ppclose(s, p, fp);
}
else if (pRandSeed->nSrc == SSL_RSSRC_EGD) {
/*
* seed in contents provided by the external
* Entropy Gathering Daemon (EGD)
*/
if ((n = RAND_egd_bytes(pRandSeed->cpPath, pRandSeed->nBytes)) == -1)
continue;
nDone += n;
}
else if (pRandSeed->nSrc == SSL_RSSRC_BUILTIN) {
/*
* seed in the current time (usually just 4 bytes)
*/
t = time(NULL);
l = sizeof(time_t);
RAND_seed((unsigned char *)&t, l);
nDone += l;
/*
* seed in the current process id (usually just 4 bytes)
*/
pid = getpid();
l = sizeof(pid_t);
RAND_seed((unsigned char *)&pid, l);
nDone += l;
/*
* seed in some current state of the run-time stack (128 bytes)
*/
n = ssl_rand_choosenum(sizeof(stackdata)-128-1);
RAND_seed(stackdata+n, 128);
nDone += 128;
/*
* seed in extract data from the current scoreboard
*/
if (ap_scoreboard_image != NULL && SCOREBOARD_SIZE > 16) {
if ((m = ((SCOREBOARD_SIZE / 2) - 1)) > 1024)
m = 1024;
n = ssl_rand_choosenum(m);
RAND_seed(((unsigned char *)ap_scoreboard_image)+n, m);
nDone += m;
}
}
}
}
ssl_log(s, SSL_LOG_INFO, "%sSeeding PRNG with %d bytes of entropy", prefix, nDone);
if (RAND_status() == 0)
ssl_log(s, SSL_LOG_WARN, "%sPRNG still contains insufficient entropy!", prefix);
return nDone;
}
#define BUFSIZE 8192
static int ssl_rand_feedfp(pool *p, FILE *fp, int nReq)
{
int nDone;
unsigned char caBuf[BUFSIZE];
int nBuf;
int nRead;
int nTodo;
nDone = 0;
nRead = BUFSIZE;
nTodo = nReq;
while (1) {
if (nReq > 0)
nRead = (nTodo < BUFSIZE ? nTodo : BUFSIZE);
if ((nBuf = (int)fread(caBuf, 1, nRead, fp)) <= 0)
break;
RAND_seed(caBuf, nBuf);
nDone += nBuf;
if (nReq > 0) {
nTodo -= nBuf;
if (nTodo <= 0)
break;
}
}
return nDone;
}
/* Generate a random number in the range 1-h */
static int ssl_rand_choosenum(int h)
{
return (int)(arc4random() / ((double)0xffffffffU + 1) * h + 1);
}
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