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Fortuna fixes. Marko Kreen

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This commit is contained in:
Tom Lane
2005-07-18 17:12:54 +00:00
parent 2787db9b1d
commit 35c675a7fd
5 changed files with 194 additions and 89 deletions
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45
contrib/pgcrypto/internal.c
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@ -26,7 +26,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $PostgreSQL: pgsql/contrib/pgcrypto/internal.c,v 1.21 2005/07/18 17:09:01 tgl Exp $
* $PostgreSQL: pgsql/contrib/pgcrypto/internal.c,v 1.22 2005/07/18 17:12:54 tgl Exp $
*/
#include "postgres.h"
@ -42,9 +42,22 @@
#include "fortuna.h"
/*
* How often to try to acquire system entropy. (In seconds)
* System reseeds should be separated at least this much.
*/
#define SYSTEM_RESEED_FREQ (3*60*60)
#define SYSTEM_RESEED_MIN (20*60) /* 20 min */
/*
* How often to roll dice.
*/
#define SYSTEM_RESEED_CHECK_TIME (10*60) /* 10 min */
/*
* The chance is x/256 that the reseed happens.
*/
#define SYSTEM_RESEED_CHANCE (4) /* 256/4 * 10min ~ 10h */
/*
* If this much time has passed, force reseed.
*/
#define SYSTEM_RESEED_MAX (12*60*60) /* 12h */
#ifndef MD5_DIGEST_LENGTH
@ -823,20 +836,40 @@ px_get_pseudo_random_bytes(uint8 *dst, unsigned count)
}
static time_t seed_time = 0;
static time_t check_time = 0;
static void system_reseed(void)
{
uint8 buf[1024];
int n;
time_t t;
int skip = 1;
t = time(NULL);
if (seed_time && (t - seed_time) < SYSTEM_RESEED_FREQ)
if (seed_time == 0)
skip = 0;
else if ((t - seed_time) < SYSTEM_RESEED_MIN)
skip = 1;
else if ((t - seed_time) > SYSTEM_RESEED_MAX)
skip = 0;
else if (!check_time || (t - check_time) > SYSTEM_RESEED_CHECK_TIME)
{
check_time = t;
/* roll dice */
px_get_random_bytes(buf, 1);
skip = buf[0] >= SYSTEM_RESEED_CHANCE;
}
/* clear 1 byte */
memset(buf, 0, sizeof(buf));
if (skip)
return;
n = px_acquire_system_randomness(buf);
if (n > 0)
fortuna_add_entropy(SYSTEM_ENTROPY, buf, n);
fortuna_add_entropy(buf, n);
seed_time = t;
memset(buf, 0, sizeof(buf));
@ -854,7 +887,7 @@ int
px_add_entropy(const uint8 *data, unsigned count)
{
system_reseed();
fortuna_add_entropy(USER_ENTROPY, data, count);
fortuna_add_entropy(data, count);
return 0;
}