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 64db7a5376c88a82607db10c24fa27b1505f8b6e..f58a9808b416b24963e461d56e5a25c960644f66 100644 (file)
--- a/src/port/erand48.c
+++ b/src/port/erand48.c
@@ -92,7 +92,7 @@ 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;