[src/trunk]: src/sys/kern Lock cprng->cs_lock around rndsink_request to avoid...

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

details:   https://anonhg.NetBSD.org/src/rev/b12bc6056473
branches:  trunk
changeset: 801712:b12bc6056473
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Thu Aug 14 16:28:30 2014 +0000

description:
Lock cprng->cs_lock around rndsink_request to avoid race with callback.

diffstat:

 sys/kern/subr_cprng.c |  6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diffs (34 lines):

diff -r 7a3b64b0c00e -r b12bc6056473 sys/kern/subr_cprng.c
--- a/sys/kern/subr_cprng.c     Thu Aug 14 16:27:55 2014 +0000
+++ b/sys/kern/subr_cprng.c     Thu Aug 14 16:28:30 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_cprng.c,v 1.24 2014/08/10 16:44:36 tls Exp $ */
+/*     $NetBSD: subr_cprng.c,v 1.25 2014/08/14 16:28:30 riastradh Exp $ */
 
 /*-
  * Copyright (c) 2011-2013 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.24 2014/08/10 16:44:36 tls Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.25 2014/08/14 16:28:30 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -151,6 +151,7 @@
 
        /* Get some initial entropy.  Record whether it is full entropy.  */
        uint8_t seed[NIST_BLOCK_KEYLEN_BYTES];
+       mutex_enter(&cprng->cs_lock);
        cprng->cs_ready = rndsink_request(cprng->cs_rndsink, seed,
            sizeof(seed));
        if (nist_ctr_drbg_instantiate(&cprng->cs_drbg, seed, sizeof(seed),
@@ -168,6 +169,7 @@
        if (!cprng->cs_ready && !ISSET(flags, CPRNG_INIT_ANY))
                printf("cprng %s: creating with partial entropy\n",
                    cprng->cs_name);
+       mutex_exit(&cprng->cs_lock);
 
        return cprng;
 }