Re: [libvirt] [PATCH 08/10] virrandom: Make virRandomBits better

Now that we have strong PRNG generator implemented in virRandomBytes() let's use that instead of gnulib's random_r. Problem with the latter is in way we seed it: current UNIX time and libvirtd's PID are not that random as one might think. Imagine two hosts booting at the same time. There's a fair chance that those hosts spawn libvirtds at the same time and with the same PID. This will result in both daemons generating the same sequence of say MAC addresses [1]. 1: https://www.redhat.com/archives/libvirt-users/2018-May/msg00097.html Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/util/virrandom.c | 63 ++-------------------------------------------------- 1 file changed, 2 insertions(+), 61 deletions(-)

-static int -virRandomOnceInit(void) -{ - unsigned int seed = time(NULL) ^ getpid(); - -#if 0 - /* Normally we want a decent seed. But if reproducible debugging - * of a fixed pseudo-random sequence is ever required, uncomment - * this block to let an environment variable force the seed. */ - const char *debug = virGetEnvBlockSUID("VIR_DEBUG_RANDOM_SEED"); - - if (debug && virStrToLong_ui(debug, NULL, 0, &seed) < 0) - return -1;