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Fix errors in fortuna PRNG reseeding logic that could cause a predictable

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session key to be selected by pgp_sym_encrypt() in some cases.  This only
affects non-OpenSSL-using builds.  Marko Kreen
This commit is contained in:
Tom Lane 2006-05-21 20:22:16 +00:00
parent 515112f9d4
commit 5cf07901c5
1 changed files with 14 additions and 5 deletions
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19
contrib/pgcrypto/fortuna.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/fortuna.c,v 1.5 2005/10/15 02:49:06 momjian Exp $
* $PostgreSQL: pgsql/contrib/pgcrypto/fortuna.c,v 1.6 2006/05/21 20:22:16 tgl Exp $
*/
#include "postgres.h"
@ -219,7 +219,7 @@ encrypt_counter(FState * st, uint8 *dst)
* microseconds.
*/
static int
too_often(FState * st)
enough_time_passed(FState * st)
{
int ok;
struct timeval tv;
@ -227,13 +227,22 @@ too_often(FState * st)
gettimeofday(&tv, NULL);
/* check how much time has passed */
ok = 0;
if (tv.tv_sec != last->tv_sec)
if (tv.tv_sec > last->tv_sec + 1)
ok = 1;
else if (tv.tv_sec == last->tv_sec + 1)
{
if (1000000 + tv.tv_usec - last->tv_usec >= RESEED_INTERVAL)
ok = 1;
}
else if (tv.tv_usec - last->tv_usec >= RESEED_INTERVAL)
ok = 1;
memcpy(last, &tv, sizeof(tv));
/* reseed will happen, update last_reseed_time */
if (ok)
memcpy(last, &tv, sizeof(tv));
memset(&tv, 0, sizeof(tv));
return ok;
@ -372,7 +381,7 @@ extract_data(FState * st, unsigned count, uint8 *dst)
unsigned block_nr = 0;
/* Can we reseed? */
if (st->pool0_bytes >= POOL0_FILL && !too_often(st))
if (st->pool0_bytes >= POOL0_FILL && enough_time_passed(st))
reseed(st);
/* Is counter initialized? */