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Add half our entropy from RAND_poll in OpenSSL. These know how to use egd (if present) openbsd weirdness (if present), vms/os2 weirdness (if we ever port there), and more in the future.

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svn:r5215
This commit is contained in:
Nick Mathewson 2005-10-07 19:03:09 +00:00
parent 46af2d26d0
commit a53ecc94f9
1 changed files with 42 additions and 21 deletions
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63
src/common/crypto.c
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@ -1575,42 +1575,63 @@ crypto_dh_free(crypto_dh_env_t *dh)
/* random numbers */
/* This is how much entropy OpenSSL likes to add right now, so maybe it will
* work for us too. */
#define ADD_ENTROPY 32
/* Use RAND_poll if openssl is 0.9.6 release or later. (The "f" means
"release".) */
#define USE_RAND_POLL (OPENSSL_VERSION_NUMBER >= 0x0090600fl)
/** Seed OpenSSL's random number generator with bytes from the
* operating system. Return 0 on success, -1 on failure.
*/
int
crypto_seed_rng(void)
{
char buf[64];
char buf[ADD_ENTROPY];
int rand_poll_status;
/* local variables */
#ifdef MS_WINDOWS
static int provider_set = 0;
static HCRYPTPROV provider;
if (!provider_set) {
if (!CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) {
if (GetLastError() != NTE_BAD_KEYSET) {
log_fn(LOG_ERR,"Can't get CryptoAPI provider [1]");
return -1;
}
}
provider_set = 1;
}
if (!CryptGenRandom(provider, sizeof(buf), buf)) {
log_fn(LOG_ERR,"Can't get entropy from CryptoAPI.");
return -1;
}
RAND_seed(buf, sizeof(buf));
/* And add the current screen state to the entropy pool for
* good measure. */
RAND_screen();
return 0;
#else
static const char *filenames[] = {
"/dev/srandom", "/dev/urandom", "/dev/random", NULL
};
int fd;
int i, n;
#endif
#if USE_RAND_POLL
/* OpenSSL 0.9.6 adds a RAND_poll function that knows about more kinds of
* entropy than we do. We'll try calling that, *and* calling our own entropy
* functions. If one succeeds, we'll accept the RNG as seeded. */
rand_poll_status = RAND_poll();
if (rand_poll_status == 0)
log_fn(LOG_WARN, "RAND_poll() failed.");
#else
rand_poll_status = 0;
#endif
#ifdef MS_WINDOWS
if (!provider_set) {
if (!CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) {
if (GetLastError() != NTE_BAD_KEYSET) {
log_fn(LOG_ERR,"Can't get CryptoAPI provider [1]");
return rand_poll_status ? 0 : -1;
}
}
provider_set = 1;
}
if (!CryptGenRandom(provider, sizeof(buf), buf)) {
log_fn(LOG_ERR,"Can't get entropy from CryptoAPI.");
return rand_poll_status ? 0 : -1;
}
RAND_seed(buf, sizeof(buf));
return 0;
#else
for (i = 0; filenames[i]; ++i) {
fd = open(filenames[i], O_RDONLY, 0);
if (fd<0) continue;
@ -1626,7 +1647,7 @@ crypto_seed_rng(void)
}
log_fn(LOG_WARN, "Cannot seed RNG -- no entropy source found.");
return -1;
return rand_poll_status ? 0 : -1;
#endif
}