"Annual" pgcrypto update from Marko Kreen:

Few cleanups and couple of new things:

 - add SHA2 algorithm to older OpenSSL
 - add BIGNUM math to have public-key cryptography work on non-OpenSSL
   build.
 - gen_random_bytes() function

The status of SHA2 algoritms and public-key encryption can now be
changed to 'always available.'

That makes pgcrypto functionally complete and unless there will be new
editions of AES, SHA2 or OpenPGP standards, there is no major changes
planned.

1 files changed, 29 insertions, 15 deletions

diff --git a/contrib/pgcrypto/fortuna.c b/contrib/pgcrypto/fortuna.c
index cf69cee28bc..cd08fd2bc68 100644
--- a/contrib/pgcrypto/fortuna.c
+++ b/contrib/pgcrypto/fortuna.c
@@ -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 1.6 2006/05/21 20:22:16 tgl Exp $
+ * $PostgreSQL: pgsql/contrib/pgcrypto/fortuna.c,v 1.7 2006/07/13 04:15:24 neilc Exp $
  */
 
 #include "postgres.h"
@@ -125,7 +125,7 @@ struct fortuna_state
 	struct timeval last_reseed_time;
 	unsigned	pool0_bytes;
 	unsigned	rnd_pos;
-	int			counter_init;
+	int			tricks_done;
 };
 typedef struct fortuna_state FState;
 
@@ -332,7 +332,7 @@ add_entropy(FState * st, const uint8 *data, unsigned len)
 	/*
 	 * Make sure the pool 0 is initialized, then update randomly.
 	 */
-	if (st->reseed_count == 0 && st->pool0_bytes < POOL0_FILL)
+	if (st->reseed_count == 0)
 		pos = 0;
 	else
 		pos = get_rand_pool(st);
@@ -357,21 +357,34 @@ rekey(FState * st)
 }
 
 /*
- * Fortuna relies on AES standing known-plaintext attack.
- * In case it does not, slow down the attacker by initialising
- * the couter to random value.
+ * Hide public constants. (counter, pools > 0)
+ *
+ * This can also be viewed as spreading the startup
+ * entropy over all of the components.
  */
 static void
-init_counter(FState * st)
+startup_tricks(FState * st)
 {
+	int i;
+	uint8 buf[BLOCK];
+
 	/* Use next block as counter. */
 	encrypt_counter(st, st->counter);
 
+	/* Now shuffle pools, excluding #0 */
+	for (i = 1; i < NUM_POOLS; i++)
+	{
+		encrypt_counter(st, buf);
+		encrypt_counter(st, buf + CIPH_BLOCK);
+		md_update(&st->pool[i], buf, BLOCK);
+	}
+	memset(buf, 0, BLOCK);
+
 	/* Hide the key. */
 	rekey(st);
 
-	/* The counter can be shuffled only once. */
-	st->counter_init = 1;
+	/* This can be done only once. */
+	st->tricks_done = 1;
 }
 
 static void
@@ -380,13 +393,14 @@ extract_data(FState * st, unsigned count, uint8 *dst)
 	unsigned	n;
 	unsigned	block_nr = 0;
 
-	/* Can we reseed? */
-	if (st->pool0_bytes >= POOL0_FILL && enough_time_passed(st))
-		reseed(st);
+	/* Should we reseed? */
+	if (st->pool0_bytes >= POOL0_FILL || st->reseed_count == 0)
+		if (enough_time_passed(st))
+			reseed(st);
 
-	/* Is counter initialized? */
-	if (!st->counter_init)
-		init_counter(st);
+	/* Do some randomization on first call */
+	if (!st->tricks_done)
+		startup_tricks(st);
 
 	while (count > 0)
 	{