Author: glebius
Date: Fri May 25 07:46:24 2012
New Revision: 235979
URL: http://svn.freebsd.org/changeset/base/235979
Log:
Revert my local not yet properly tested changes, that leaked in
with r235923.
Modified:
head/sys/netgraph/ng_mppc.c
Modified: head/sys/netgraph/ng_mppc.c
==============================================================================
--- head/sys/netgraph/ng_mppc.c Fri May 25 07:32:26 2012 (r235978)
+++ head/sys/netgraph/ng_mppc.c Fri May 25 07:46:24 2012 (r235979)
@@ -98,6 +98,15 @@ static MALLOC_DEFINE(M_NETGRAPH_MPPC, "n
/* Key length */
#define KEYLEN(b) (((b) & MPPE_128) ? 16 : 8)
+/*
+ * When packets are lost with MPPE, we may have to re-key arbitrarily
+ * many times to 'catch up' to the new jumped-ahead sequence number.
+ * Since this can be expensive, we pose a limit on how many re-keyings
+ * we will do at one time to avoid a possible D.O.S. vulnerability.
+ * This should instead be a configurable parameter.
+ */
+#define MPPE_MAX_REKEY 1000
+
/* MPPC packet header bits */
#define MPPC_FLAG_FLUSHED 0x8000 /* xmitter reset state */
#define MPPC_FLAG_RESTART 0x4000 /* compress history restart */
@@ -632,22 +641,20 @@ ng_mppc_decompress(node_p node, struct m
#endif
#ifdef NETGRAPH_MPPC_ENCRYPTION
if ((d->cfg.bits & MPPE_BITS) != 0) {
- u_int rekey;
-
- /* How many times are we going to have to re-key? */
- rekey = ((d->cfg.bits & MPPE_STATELESS) != 0) ?
- numLost : (numLost / (MPPE_UPDATE_MASK + 1));
- if (rekey > 1000)
- log(LOG_ERR, "%s: %d packets dropped, "
- "node [%x]\n", __func__, numLost,
- node->nd_ID);
-
- /*
- * When packets are lost or re-ordered with MPPE,
- * we may have to re-key up to 0xfff times to 'catch
- * up' to the new jumped-ahead sequence number. Yep,
- * this is heavy, but what else can we do?
- */
+ u_int rekey;
+
+ /* How many times are we going to have to re-key? */
+ rekey = ((d->cfg.bits & MPPE_STATELESS) != 0) ?
+ numLost : (numLost / (MPPE_UPDATE_MASK + 1));
+ if (rekey > MPPE_MAX_REKEY) {
+ log(LOG_ERR, "%s: too many (%d) packets"
+ " dropped, disabling node %p!",
+ __func__, numLost, node);
+ priv->recv.cfg.enable = 0;
+ goto failed;
+ }
+
+ /* Re-key as necessary to catch up to peer */
while (d->cc != cc) {
if ((d->cfg.bits & MPPE_STATELESS) != 0
|| (d->cc & MPPE_UPDATE_MASK)
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
