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/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* _ _
* _ __ ___ ___ __| | ___ ___| | mod_ssl
* | '_ ` _ \ / _ \ / _` | / __/ __| | Apache Interface to OpenSSL
* | | | | | | (_) | (_| | \__ \__ \ |
* |_| |_| |_|\___/ \__,_|___|___/___/_|
* |_____|
* ssl_engine_rand.c
* Random Number Generator Seeding
*/
/* ``The generation of random
numbers is too important
to be left to chance.'' */
#include "ssl_private.h"
/* _________________________________________________________________
**
** Support for better seeding of SSL library's RNG
** _________________________________________________________________
*/
static int ssl_rand_choosenum(int, int);
static int ssl_rand_feedfp(apr_pool_t *, apr_file_t *, int);
int ssl_rand_seed(server_rec *s, apr_pool_t *p, ssl_rsctx_t nCtx, char *prefix)
{
SSLModConfigRec *mc;
apr_array_header_t *apRandSeed;
ssl_randseed_t *pRandSeeds;
ssl_randseed_t *pRandSeed;
unsigned char stackdata[256];
int nDone;
apr_file_t *fp;
int i, n, l;
mc = myModConfig(s);
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) {
if (pRandSeed->nSrc == SSL_RSSRC_FILE) {
/*
* seed in contents of an external file
*/
if (apr_file_open(&fp, pRandSeed->cpPath,
APR_READ, APR_OS_DEFAULT, p) != APR_SUCCESS)
continue;
nDone += ssl_rand_feedfp(p, fp, pRandSeed->nBytes);
apr_file_close(fp);
}
else if (pRandSeed->nSrc == SSL_RSSRC_EXEC) {
const char *cmd = pRandSeed->cpPath;
const char **argv = apr_palloc(p, sizeof(char *) * 3);
/*
* seed in contents generated by an external program
*/
argv[0] = cmd;
argv[1] = apr_itoa(p, pRandSeed->nBytes);
argv[2] = NULL;
if ((fp = ssl_util_ppopen(s, p, cmd, argv)) == NULL)
continue;
nDone += ssl_rand_feedfp(p, fp, pRandSeed->nBytes);
ssl_util_ppclose(s, p, fp);
}
#ifdef HAVE_RAND_EGD
else if (pRandSeed->nSrc == SSL_RSSRC_EGD) {
/*
* seed in contents provided by the external
* Entropy Gathering Daemon (EGD)
*/
if ((n = RAND_egd(pRandSeed->cpPath)) == -1)
continue;
nDone += n;
}
#endif
else if (pRandSeed->nSrc == SSL_RSSRC_BUILTIN) {
struct {
time_t t;
pid_t pid;
} my_seed;
/*
* seed in the current time (usually just 4 bytes)
*/
my_seed.t = time(NULL);
/*
* seed in the current process id (usually just 4 bytes)
*/
my_seed.pid = mc->pid;
l = sizeof(my_seed);
RAND_seed((unsigned char *)&my_seed, l);
nDone += l;
/*
* seed in some current state of the run-time stack (128 bytes)
*/
n = ssl_rand_choosenum(0, sizeof(stackdata)-128-1);
RAND_seed(stackdata+n, 128);
nDone += 128;
}
}
}
ap_log_error(APLOG_MARK, APLOG_TRACE2, 0, s,
"%sSeeding PRNG with %d bytes of entropy", prefix, nDone);
if (RAND_status() == 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(01990)
"%sPRNG still contains insufficient entropy!", prefix);
return nDone;
}
#define BUFSIZE 8192
static int ssl_rand_feedfp(apr_pool_t *p, apr_file_t *fp, int nReq)
{
apr_size_t nDone;
unsigned char caBuf[BUFSIZE];
apr_size_t nBuf;
apr_size_t nRead;
apr_size_t nTodo;
nDone = 0;
nRead = BUFSIZE;
nTodo = nReq;
while (1) {
if (nReq > 0)
nRead = (nTodo < BUFSIZE ? nTodo : BUFSIZE);
nBuf = nRead;
if (apr_file_read(fp, caBuf, &nBuf) != APR_SUCCESS)
break;
RAND_seed(caBuf, nBuf);
nDone += nBuf;
if (nReq > 0) {
nTodo -= nBuf;
if (nTodo <= 0)
break;
}
}
return nDone;
}
static int ssl_rand_choosenum(int l, int h)
{
int i;
char buf[50];
apr_snprintf(buf, sizeof(buf), "%.0f",
(((double)(rand()%RAND_MAX)/RAND_MAX)*(h-l)));
i = atoi(buf)+1;
if (i < l) i = l;
if (i > h) i = h;
return i;
}
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