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Generate a warning if the kernel's arc4random() is seeded with bogus entropy.

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This commit is contained in:
David Schultz 2012-01-16 20:18:10 +00:00
parent cb659153f9
commit a7eaecefba
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=230230
1 changed files with 8 additions and 0 deletions
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8
sys/dev/random/harvest.c
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@ -37,6 +37,7 @@ __FBSDID("$FreeBSD$");
#include <sys/queue.h>
#include <sys/random.h>
#include <sys/selinfo.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
@ -48,6 +49,7 @@ static int read_random_phony(void *, int);
/* Structure holding the desired entropy sources */
struct harvest_select harvest = { 1, 1, 1, 0 };
static int warned = 0;
/* hold the address of the routine which is actually called if
* the randomdev is loaded
@ -71,6 +73,7 @@ random_yarrow_deinit_harvester(void)
{
reap_func = NULL;
read_func = read_random_phony;
warned = 0;
}
/* Entropy harvesting routine. This is supposed to be fast; do
@ -108,6 +111,11 @@ read_random_phony(void *buf, int count)
u_long randval;
int size, i;
if (!warned) {
log(LOG_WARNING, "random device not loaded; using insecure entropy\n");
warned = 1;
}
/* srandom() is called in kern/init_main.c:proc0_post() */
/* Fill buf[] with random(9) output */