Module Name: src
Committed By: ozaki-r
Date: Tue Jul 10 01:23:13 UTC 2018
Modified Files:
src/sys/net: if_llatbl.c
Log Message:
Don't overwrite an existing llentry on RTM_ADD to avoid race conditions
Reported and tested by christos@
To generate a diff of this commit:
cvs rdiff -u -r1.27 -r1.28 src/sys/net/if_llatbl.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/net/if_llatbl.c
diff -u src/sys/net/if_llatbl.c:1.27 src/sys/net/if_llatbl.c:1.28
--- src/sys/net/if_llatbl.c:1.27 Tue Jun 5 01:25:59 2018
+++ src/sys/net/if_llatbl.c Tue Jul 10 01:23:13 2018
@@ -1,4 +1,4 @@
-/* $NetBSD: if_llatbl.c,v 1.27 2018/06/05 01:25:59 nonaka Exp $ */
+/* $NetBSD: if_llatbl.c,v 1.28 2018/07/10 01:23:13 ozaki-r Exp $ */
/*
* Copyright (c) 2004 Luigi Rizzo, Alessandro Cerri. All rights reserved.
* Copyright (c) 2004-2008 Qing Li. All rights reserved.
@@ -672,7 +672,7 @@ lla_rt_output(const u_char rtm_type, con
/* Add static LLE */
IF_AFDATA_WLOCK(ifp);
- lle = lla_lookup(llt, 0, dst);
+ lle = lla_lookup(llt, LLE_EXCLUSIVE, dst);
/* Cannot overwrite an existing static entry */
if (lle != NULL &&
@@ -684,8 +684,18 @@ lla_rt_output(const u_char rtm_type, con
error = EEXIST;
goto out;
}
- if (lle != NULL)
- LLE_RUNLOCK(lle);
+
+ /*
+ * We can't overwrite an existing entry to avoid race
+ * conditions so remove it first.
+ */
+ if (lle != NULL) {
+ size_t pkts_dropped = llentry_free(lle);
+ if (dst->sa_family == AF_INET) {
+ arp_stat_add(ARP_STAT_DFRDROPPED,
+ (uint64_t)pkts_dropped);
+ }
+ }
lle = lla_create(llt, 0, dst, rt);
if (lle == NULL) {
