From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 3 Sep 2011 20:17:52 +0000 (-0400)
Subject: Fix typo in pg_srand48 (srand48 in older branches).
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=a0634241bcaf71886eeaf1cb49d43a5426bfa4de;p=users%2Fc2main%2Fpostgres.git

Fix typo in pg_srand48 (srand48 in older branches).

">" should be ">>".  This typo results in failure to use all of the bits
of the provided seed.

This might rise to the level of a security bug if we were relying on
srand48 for any security-critical purposes, but we are not --- in fact,
it's not used at all unless the platform lacks srandom(), which is
improbable.  Even on such a platform the exposure seems minimal.

Reported privately by Andres Freund.
---

diff --git a/src/port/rand.c b/src/port/rand.c
index 8559ef8c17..5982ef9cb7 100644
--- a/src/port/rand.c
+++ b/src/port/rand.c
@@ -74,7 +74,7 @@ srand48(long seed)
 {
 	_rand48_seed[0] = RAND48_SEED_0;
 	_rand48_seed[1] = (unsigned short) seed;
-	_rand48_seed[2] = (unsigned short) (seed > 16);
+	_rand48_seed[2] = (unsigned short) (seed >> 16);
 	_rand48_mult[0] = RAND48_MULT_0;
 	_rand48_mult[1] = RAND48_MULT_1;
 	_rand48_mult[2] = RAND48_MULT_2;