From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 3 Sep 2011 20:17:34 +0000 (-0400)
Subject: Fix typo in pg_srand48 (srand48 in older branches).
X-Git-Tag: REL9_2_BETA1~1155
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=48e4b8dc08ea7ec0cc7cd8e5001f8a29e1c0b987;p=postgresql

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/erand48.c b/src/port/erand48.c
index 1c0eb467f6..9d471197c3 100644
--- a/src/port/erand48.c
+++ b/src/port/erand48.c
@@ -96,7 +96,7 @@ pg_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;