[src/trunk]: src/sys/rump/net/lib/libshmif shmif: use cprng_strong64 instead ...

[ozaki-r <ozaki-r%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b0ee68d76b68
branches:  trunk
changeset: 969623:b0ee68d76b68
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Tue Feb 25 03:24:48 2020 +0000

description:
shmif: use cprng_strong64 instead of cprng_fast64 to generate a unique ID

shmif uses random bytes generated by cprng(9) as a unique device ID
between rump kernels to identify packets fed by itself and not receive
them.  So if generated bytes are identical between shmif interfaces on
different rump kernels, shmif may drop incoming packets unintentionally.
This is one cause of recent ATF test failures of IPsec.

Fix it by using cprng_strong64 instead of cprng_fast64.  This is a
workaround and we should also investigate why cprng_fast64 starts
failing on rump kernels, although using cprng_strong64 in initialization
itself is feasible.

Fix PR kern/54897

diffstat:

 sys/rump/net/lib/libshmif/if_shmem.c |  6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diffs (27 lines):

diff -r 659f1c0a806b -r b0ee68d76b68 sys/rump/net/lib/libshmif/if_shmem.c
--- a/sys/rump/net/lib/libshmif/if_shmem.c      Tue Feb 25 00:42:12 2020 +0000
+++ b/sys/rump/net/lib/libshmif/if_shmem.c      Tue Feb 25 03:24:48 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_shmem.c,v 1.78 2020/02/20 08:06:15 ozaki-r Exp $    */
+/*     $NetBSD: if_shmem.c,v 1.79 2020/02/25 03:24:48 ozaki-r Exp $    */
 
 /*
  * Copyright (c) 2009, 2010 Antti Kantee.  All Rights Reserved.
@@ -28,7 +28,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.78 2020/02/20 08:06:15 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.79 2020/02/25 03:24:48 ozaki-r Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -172,7 +172,7 @@
        sc = kmem_zalloc(sizeof(*sc), KM_SLEEP);
        sc->sc_memfd = -1;
        sc->sc_unit = unit;
-       sc->sc_uuid = cprng_fast64();
+       sc->sc_uuid = cprng_strong64();
 
        ifp = &sc->sc_ec.ec_if;