2 * Copyright (c) 1997 - 2008 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
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7 * modification, are permitted provided that the following conditions
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11 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the Institute nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
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34 #include "krb5_locl.h"
36 #define ENTROPY_NEEDED 128
38 static HEIMDAL_MUTEX crypto_mutex
= HEIMDAL_MUTEX_INITIALIZER
;
44 char buf
[1024], seedfile
[256];
46 /* If there is a seed file, load it. But such a file cannot be trusted,
47 so use 0 for the entropy estimate */
48 if (RAND_file_name(seedfile
, sizeof(seedfile
))) {
50 fd
= open(seedfile
, O_RDONLY
| O_BINARY
| O_CLOEXEC
);
54 ret
= read(fd
, buf
, sizeof(buf
));
56 RAND_add(buf
, ret
, 0.0);
64 /* Calling RAND_status() will try to use /dev/urandom if it exists so
65 we do not have to deal with it. */
66 if (RAND_status() != 1) {
67 #ifndef NO_RAND_EGD_METHOD
72 if (!krb5_init_context(&context
)) {
73 p
= krb5_config_get_string(context
, NULL
, "libdefaults",
76 RAND_egd_bytes(p
, ENTROPY_NEEDED
);
77 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) {
87 /* Update the seed file */
89 RAND_write_file(seedfile
);
97 KRB5_LIB_FUNCTION
void KRB5_LIB_CALL
98 krb5_generate_random_block(void *buf
, size_t len
)
100 static int rng_initialized
= 0;
102 HEIMDAL_MUTEX_lock(&crypto_mutex
);
103 if (!rng_initialized
) {
104 if (seed_something())
105 krb5_abortx(NULL
, "Fatal: could not seed the "
106 "random number generator");
110 HEIMDAL_MUTEX_unlock(&crypto_mutex
);
111 if (RAND_bytes(buf
, len
) <= 0)
112 krb5_abortx(NULL
, "Failed to generate random block");