[src/trunk]: src/sys/crypto/cprng_fast Adapt cprng_fast to use entropy_epoch(...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/9d4468c21c94
branches:  trunk
changeset: 931746:9d4468c21c94
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Thu Apr 30 03:29:35 2020 +0000

description:
Adapt cprng_fast to use entropy_epoch(), not rnd_initial_entropy.

This way it has an opportunity to be reseeded after boot.

diffstat:

 sys/crypto/cprng_fast/cprng_fast.c |  15 ++++++++-------
 1 files changed, 8 insertions(+), 7 deletions(-)

diffs (74 lines):

diff -r 0d3b5546b776 -r 9d4468c21c94 sys/crypto/cprng_fast/cprng_fast.c
--- a/sys/crypto/cprng_fast/cprng_fast.c        Thu Apr 30 03:29:19 2020 +0000
+++ b/sys/crypto/cprng_fast/cprng_fast.c        Thu Apr 30 03:29:35 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cprng_fast.c,v 1.13 2015/04/13 22:43:41 riastradh Exp $        */
+/*     $NetBSD: cprng_fast.c,v 1.14 2020/04/30 03:29:35 riastradh Exp $        */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -30,16 +30,16 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cprng_fast.c,v 1.13 2015/04/13 22:43:41 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cprng_fast.c,v 1.14 2020/04/30 03:29:35 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/bitops.h>
 #include <sys/cprng.h>
 #include <sys/cpu.h>
+#include <sys/entropy.h>
 #include <sys/intr.h>
 #include <sys/percpu.h>
-#include <sys/rnd.h>           /* rnd_initial_entropy */
 
 /* ChaCha core */
 
@@ -198,7 +198,7 @@
        uint32_t        buffer[crypto_core_OUTPUTWORDS];
        uint32_t        key[crypto_core_KEYWORDS];
        uint32_t        nonce[crypto_core_INPUTWORDS];
-       bool            have_initial;
+       unsigned        epoch;
 };
 
 __CTASSERT(sizeof ((struct cprng_fast *)0)->key == CPRNG_FAST_SEED_BYTES);
@@ -233,9 +233,9 @@
        struct cprng_fast *const cprng = p;
        uint8_t seed[CPRNG_FAST_SEED_BYTES];
 
+       cprng->epoch = entropy_epoch();
        cprng_strong(kern_cprng, seed, sizeof seed, 0);
        cprng_fast_seed(cprng, seed);
-       cprng->have_initial = rnd_initial_entropy;
        (void)explicit_memset(seed, 0, sizeof seed);
 }
 
@@ -248,7 +248,7 @@
        *cprngp = cprng = percpu_getref(cprng_fast_percpu);
        s = splvm();
 
-       if (__predict_false(!cprng->have_initial))
+       if (__predict_false(cprng->epoch != entropy_epoch()))
                cprng_fast_schedule_reseed(cprng);
 
        return s;
@@ -274,6 +274,7 @@
 static void
 cprng_fast_intr(void *cookie __unused)
 {
+       unsigned epoch = entropy_epoch();
        struct cprng_fast *cprng;
        uint8_t seed[CPRNG_FAST_SEED_BYTES];
        int s;
@@ -283,7 +284,7 @@
        cprng = percpu_getref(cprng_fast_percpu);
        s = splvm();
        cprng_fast_seed(cprng, seed);
-       cprng->have_initial = rnd_initial_entropy;
+       cprng->epoch = epoch;
        splx(s);
        percpu_putref(cprng_fast_percpu);