1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 * _ __ ___ ___ __| | ___ ___| | mod_ssl
19 * | '_ ` _ \ / _ \ / _` | / __/ __| | Apache Interface to OpenSSL
20 * | | | | | | (_) | (_| | \__ \__ \ |
21 * |_| |_| |_|\___/ \__,_|___|___/___/_|
24 * Random Number Generator Seeding
26 /* ``The generation of random
27 numbers is too important
28 to be left to chance.'' */
32 /* _________________________________________________________________
34 ** Support for better seeding of SSL library's RNG
35 ** _________________________________________________________________
38 static int ssl_rand_choosenum(int, int);
39 static int ssl_rand_feedfp(apr_pool_t *, apr_file_t *, int);
41 int ssl_rand_seed(server_rec *s, apr_pool_t *p, ssl_rsctx_t nCtx, char *prefix)
44 apr_array_header_t *apRandSeed;
45 ssl_randseed_t *pRandSeeds;
46 ssl_randseed_t *pRandSeed;
47 unsigned char stackdata[256];
55 apRandSeed = mc->aRandSeed;
56 pRandSeeds = (ssl_randseed_t *)apRandSeed->elts;
57 for (i = 0; i < apRandSeed->nelts; i++) {
58 pRandSeed = &pRandSeeds[i];
59 if (pRandSeed->nCtx == nCtx) {
60 nReq += pRandSeed->nBytes;
61 if (pRandSeed->nSrc == SSL_RSSRC_FILE) {
63 * seed in contents of an external file
65 if (apr_file_open(&fp, pRandSeed->cpPath,
66 APR_READ, APR_OS_DEFAULT, p) != APR_SUCCESS)
68 nDone += ssl_rand_feedfp(p, fp, pRandSeed->nBytes);
71 else if (pRandSeed->nSrc == SSL_RSSRC_EXEC) {
72 const char *cmd = pRandSeed->cpPath;
73 const char **argv = apr_palloc(p, sizeof(char *) * 3);
75 * seed in contents generated by an external program
78 argv[1] = apr_itoa(p, pRandSeed->nBytes);
81 if ((fp = ssl_util_ppopen(s, p, cmd, argv)) == NULL)
83 nDone += ssl_rand_feedfp(p, fp, pRandSeed->nBytes);
84 ssl_util_ppclose(s, p, fp);
86 #ifdef HAVE_SSL_RAND_EGD
87 else if (pRandSeed->nSrc == SSL_RSSRC_EGD) {
89 * seed in contents provided by the external
90 * Entropy Gathering Daemon (EGD)
92 if ((n = RAND_egd(pRandSeed->cpPath)) == -1)
97 else if (pRandSeed->nSrc == SSL_RSSRC_BUILTIN) {
104 * seed in the current time (usually just 4 bytes)
106 my_seed.t = time(NULL);
109 * seed in the current process id (usually just 4 bytes)
111 my_seed.pid = mc->pid;
114 RAND_seed((unsigned char *)&my_seed, l);
118 * seed in some current state of the run-time stack (128 bytes)
120 n = ssl_rand_choosenum(0, sizeof(stackdata)-128-1);
121 RAND_seed(stackdata+n, 128);
127 ap_log_error(APLOG_MARK, APLOG_INFO, 0, s,
128 "%sSeeding PRNG with %d bytes of entropy", prefix, nDone);
130 if (RAND_status() == 0)
131 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
132 "%sPRNG still contains insufficient entropy!", prefix);
139 static int ssl_rand_feedfp(apr_pool_t *p, apr_file_t *fp, int nReq)
142 unsigned char caBuf[BUFSIZE];
152 nRead = (nTodo < BUFSIZE ? nTodo : BUFSIZE);
154 if (apr_file_read(fp, caBuf, &nBuf) != APR_SUCCESS)
156 RAND_seed(caBuf, nBuf);
167 static int ssl_rand_choosenum(int l, int h)
172 apr_snprintf(buf, sizeof(buf), "%.0f",
173 (((double)(rand()%RAND_MAX)/RAND_MAX)*(h-l)));