Module Name: src
Committed By: riastradh
Date: Mon May 11 17:27:48 UTC 2020
Modified Files:
src/sys/kern: subr_cprng.c
Log Message:
Work around early calls to cprng_strong.
The bottleneck here is getting percpu_create to work early enough.
We should really fix that, but for now, this workaround will serve.
Should fix PR port-arm32/55252.
To generate a diff of this commit:
cvs rdiff -u -r1.37 -r1.38 src/sys/kern/subr_cprng.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/subr_cprng.c
diff -u src/sys/kern/subr_cprng.c:1.37 src/sys/kern/subr_cprng.c:1.38
--- src/sys/kern/subr_cprng.c:1.37 Thu Apr 30 17:36:06 2020
+++ src/sys/kern/subr_cprng.c Mon May 11 17:27:48 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_cprng.c,v 1.37 2020/04/30 17:36:06 nia Exp $ */
+/* $NetBSD: subr_cprng.c,v 1.38 2020/05/11 17:27:48 riastradh Exp $ */
/*-
* Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -52,7 +52,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.37 2020/04/30 17:36:06 nia Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.38 2020/05/11 17:27:48 riastradh Exp $");
#include <sys/types.h>
#include <sys/cprng.h>
@@ -102,6 +102,7 @@ struct cprng_strong *kern_cprng __read_m
struct cprng_strong *user_cprng __read_mostly; /* IPL_NONE */
static struct sysctllog *cprng_sysctllog __read_mostly;
+static bool cprng_initialized __read_mostly = false;
void
cprng_init(void)
@@ -128,6 +129,9 @@ cprng_init(void)
CTLFLAG_PERMANENT|CTLFLAG_READONLY, CTLTYPE_INT /*lie*/, "arandom",
SYSCTL_DESCR("Independent uniform random bytes, up to 256 bytes"),
sysctl_kern_arandom, 0, NULL, 0, CTL_KERN, KERN_ARND, CTL_EOL);
+
+ /* Ready to go. */
+ cprng_initialized = true;
}
/*
@@ -274,6 +278,25 @@ cprng_strong(struct cprng_strong *cprng,
int s;
/*
+ * Some device drivers try to use cprng_strong in attach during
+ * autoconf, e.g. to randomly generate MAC addresses, before we
+ * percpu is available -- percpu is not available until after
+ * CPUs have been detected during autoconf. We should make
+ * percpu available sooner, but for now this works around it.
+ */
+ if (__predict_false(!cprng_initialized)) {
+ struct nist_hash_drbg drbg;
+ entropy_extract(seed, sizeof seed, 0);
+ if (__predict_false(nist_hash_drbg_instantiate(&drbg,
+ seed, sizeof seed, NULL, 0, NULL, 0)))
+ panic("nist_hash_drbg_instantiate");
+ if (__predict_false(nist_hash_drbg_generate(&drbg, buf, len,
+ NULL, 0)))
+ panic("nist_hash_drbg_generate");
+ return len;
+ }
+
+ /*
* Verify maximum request length. Caller should really limit
* their requests to 32 bytes to avoid spending much time with
* preemption disabled -- use the 32 bytes to seed a private
