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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
This commit is contained in:
Lennart Poettering 2016-01-28 17:00:38 +01:00
parent b430f85f22
commit ad6b1fa287

View File

@ -95,17 +95,18 @@ 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();