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34 #include "krb5_locl.h"
36 #define ENTROPY_NEEDED 128
38 static HEIMDAL_MUTEX crypto_mutex = HEIMDAL_MUTEX_INITIALIZER;
43 char buf[1024], seedfile[256];
45 /* If there is a seed file, load it. But such a file cannot be trusted,
46 so use 0 for the entropy estimate */
47 if (RAND_file_name(seedfile, sizeof(seedfile))) {
49 fd = open(seedfile, O_RDONLY | O_BINARY | O_CLOEXEC);
53 ret = read(fd, buf, sizeof(buf));
55 RAND_add(buf, ret, 0.0);
62 /* Calling RAND_status() will try to use /dev/urandom if it exists so
63 we do not have to deal with it. */
64 if (RAND_status() != 1) {
66 #ifndef OPENSSL_NO_EGD
71 if (!krb5_init_context(&context)) {
72 p = krb5_config_get_string(context, NULL, "libdefaults",
75 RAND_egd_bytes(p, ENTROPY_NEEDED);
76 krb5_free_context(context);
80 /* TODO: Once a Windows CryptoAPI RAND method is defined, we
81 can use that and failover to another method. */
85 if (RAND_status() == 1) {
86 /* Update the seed file */
88 RAND_write_file(seedfile);
95 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
96 krb5_generate_random_block(void *buf, size_t len)
98 static int rng_initialized = 0;
100 HEIMDAL_MUTEX_lock(&crypto_mutex);
101 if (!rng_initialized) {
102 if (seed_something())
103 krb5_abortx(NULL, "Fatal: could not seed the "
104 "random number generator");
108 HEIMDAL_MUTEX_unlock(&crypto_mutex);
109 if (RAND_bytes(buf, len) <= 0)
110 krb5_abortx(NULL, "Failed to generate random block");