From 2c197517f2a82970ab6866e197f06a3099418324 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Thu, 9 Jun 2016 08:39:25 +0100 Subject: [PATCH] [libc] Always use a non-zero seed for the (non-crypto) RNG The non-cryptographic RNG implemented by random() has the property that a seed value of zero will result in a generated sequence of all-zero values. This situation can arise if currticks() returns zero at start of day. Work around this problem by falling back to a fixed non-zero seed if necessary. This has no effect on the separate DRBG used by cryptographic code. Signed-off-by: Michael Brown --- src/core/random.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/core/random.c b/src/core/random.c index a74175a79..975a03cf5 100644 --- a/src/core/random.c +++ b/src/core/random.c @@ -18,6 +18,8 @@ static int32_t rnd_seed = 0; */ void srandom ( unsigned int seed ) { rnd_seed = seed; + if ( ! rnd_seed ) + rnd_seed = 4; /* Chosen by fair dice roll */ } /**