[src/trunk]: src/sys/netinet6 Validate ip6_temp_preferred_lifetime (net.inet6...

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

details:   https://anonhg.NetBSD.org/src/rev/ba6a79b8d0a7
branches:  trunk
changeset: 455403:ba6a79b8d0a7
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Wed Oct 16 07:41:28 2019 +0000

description:
Validate ip6_temp_preferred_lifetime (net.inet6.ip6.temppltime) on a change

ip6_temp_preferred_lifetime is used to calculate an interval period to
regenerate temporary addresse by
  TEMP_PREFERRED_LIFETIME - REGEN_ADVANCE - DESYNC_FACTOR
as per RFC 3041 3.5.  So it must be greater than (REGEN_ADVANCE +
DESYNC_FACTOR), otherwise it will be negative and go wrong, for example
KASSERT(to_ticks >= 0) in callout_schedule_locked fails.

diffstat:

 sys/netinet6/ip6_input.c |  28 +++++++++++++++++++++++++---
 1 files changed, 25 insertions(+), 3 deletions(-)

diffs (56 lines):

diff -r b58011beafdd -r ba6a79b8d0a7 sys/netinet6/ip6_input.c
--- a/sys/netinet6/ip6_input.c  Wed Oct 16 07:40:40 2019 +0000
+++ b/sys/netinet6/ip6_input.c  Wed Oct 16 07:41:28 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ip6_input.c,v 1.212 2019/10/16 07:40:40 ozaki-r Exp $  */
+/*     $NetBSD: ip6_input.c,v 1.213 2019/10/16 07:41:28 ozaki-r Exp $  */
 /*     $KAME: ip6_input.c,v 1.188 2001/03/29 05:34:31 itojun Exp $     */
 
 /*
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ip6_input.c,v 1.212 2019/10/16 07:40:40 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ip6_input.c,v 1.213 2019/10/16 07:41:28 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_gateway.h"
@@ -1531,6 +1531,28 @@
        return (NETSTAT_SYSCTL(ip6stat_percpu, IP6_NSTATS));
 }
 
+static int
+sysctl_net_inet6_ip6_temppltime(SYSCTLFN_ARGS)
+{
+       int error;
+       uint32_t pltime;
+       struct sysctlnode node;
+
+       node = *rnode;
+       node.sysctl_data = &pltime;
+       pltime = ip6_temp_preferred_lifetime;
+       error = sysctl_lookup(SYSCTLFN_CALL(&node));
+       if (error || newp == NULL)
+               return error;
+
+       if (pltime <= (MAX_TEMP_DESYNC_FACTOR + TEMPADDR_REGEN_ADVANCE))
+               return EINVAL;
+
+       ip6_temp_preferred_lifetime = pltime;
+
+       return 0;
+}
+
 static void
 sysctl_net_inet6_ip6_setup(struct sysctllog **clog)
 {
@@ -1742,7 +1764,7 @@
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_INT, "temppltime",
                       SYSCTL_DESCR("preferred lifetime of a temporary address"),
-                      NULL, 0, &ip6_temp_preferred_lifetime, 0,
+                      sysctl_net_inet6_ip6_temppltime, 0, NULL, 0,
                       CTL_NET, PF_INET6, IPPROTO_IPV6,
                       CTL_CREATE, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,