From 9e830df83c27d0d757df16904ec23b3844da2733 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 28 Jan 2016 17:00:38 +0100 Subject: [PATCH] basic: getauxval(AT_RANDOM) is apparently not necessarily aligned Let's make sure we read it in a way compatible with non-aligned memory. Fixes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=812928 --- src/basic/random-util.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/src/basic/random-util.c b/src/basic/random-util.c index 2f5c16e2a..34cc7cbce 100644 --- a/src/basic/random-util.c +++ b/src/basic/random-util.c @@ -94,17 +94,18 @@ void initialize_srand(void) { if (srand_called) return; - x = 0; - #ifdef HAVE_SYS_AUXV_H - /* The kernel provides us with a bit of entropy in auxv, so - * let's try to make use of that to seed the pseudo-random - * generator. It's better than nothing... */ + /* The kernel provides us with 16 bytes of entropy in auxv, so let's try to make use of that to seed the + * pseudo-random generator. It's better than nothing... */ auxv = (void*) getauxval(AT_RANDOM); - if (auxv) - x ^= *(unsigned*) auxv; + if (auxv) { + assert_cc(sizeof(x) < 16); + memcpy(&x, auxv, sizeof(x)); + } else #endif + x = 0; + x ^= (unsigned) now(CLOCK_REALTIME); x ^= (unsigned) gettid(); -- 2.30.2