diff options
Diffstat (limited to 'modules/ssl/ssl_engine_rand.c')
| -rw-r--r-- | modules/ssl/ssl_engine_rand.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/modules/ssl/ssl_engine_rand.c b/modules/ssl/ssl_engine_rand.c new file mode 100644 index 0000000..4e1a9c1 --- /dev/null +++ b/modules/ssl/ssl_engine_rand.c @@ -0,0 +1,177 @@ +/* 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; +} + |